AST Matcher Reference

Matches attributes.
Attributes may be attached with a variety of different syntaxes (including
keywords, C++11 attributes, GNU ``__attribute``` and MSVC `__declspec``,
and ``#pragma``s). They may also be implicit.

Given
  struct [[nodiscard]] Foo{};
  void bar(int * __attribute__((nonnull)) );
  __declspec(noinline) void baz();

  #pragma omp declare simd
  int min();
attr()
  matches "nodiscard", "nonnull", "noinline", and the whole "#pragma" line.

Matches class bases.

Examples matches public virtual B.
  class B {};
  class C : public virtual B {};

Matches constructor initializers.

Examples matches i(42).
  class C {
    C() : i(42) {}
    int i;
  };

Matches C++ access specifier declarations.

Given
  class C {
  public:
    int a;
  };
accessSpecDecl()
  matches 'public:'

Matches binding declarations
Example matches foo and bar
(matcher = bindingDecl()

  auto [foo, bar] = std::make_pair{42, 42};

Matches block declarations.

Example matches the declaration of the nameless block printing an input
integer.

  myFunc(^(int p) {
    printf("%d", p);
  })

Matches C++ class template declarations.

Example matches Z
  template<class T> class Z {};

Matches C++ class template partial specializations.

Given
  template<class T1, class T2, int I>
  class A {};

  template<class T, int I>
  class A<T, T*, I> {};

  template<>
  class A<int, int, 1> {};
classTemplatePartialSpecializationDecl()
  matches the specialization A<T,T*,I> but not A<int,int,1>

Matches C++ class template specializations.

Given
  template<typename T> class A {};
  template<> class A<double> {};
  A<int> a;
classTemplateSpecializationDecl()
  matches the specializations A<int> and A<double>

Matches C++ constructor declarations.

Example matches Foo::Foo() and Foo::Foo(int)
  class Foo {
   public:
    Foo();
    Foo(int);
    int DoSomething();
  };

Matches conversion operator declarations.

Example matches the operator.
  class X { operator int() const; };

Matches user-defined and implicitly generated deduction guide.

Example matches the deduction guide.
  template<typename T>
  class X { X(int) };
  X(int) -> X<int>;

Matches explicit C++ destructor declarations.

Example matches Foo::~Foo()
  class Foo {
   public:
    virtual ~Foo();
  };

Matches method declarations.

Example matches y
  class X { void y(); };

Matches C++ class declarations.

Example matches X, Z
  class X;
  template<class T> class Z {};

Matches declarations.

Examples matches X, C, and the friend declaration inside C;
  void X();
  class C {
    friend X;
  };

Matches declarator declarations (field, variable, function
and non-type template parameter declarations).

Given
  class X { int y; };
declaratorDecl()
  matches int y.

Matches decomposition-declarations.

Examples matches the declaration node with foo and bar, but not
number.
(matcher = declStmt(has(decompositionDecl())))

  int number = 42;
  auto [foo, bar] = std::make_pair{42, 42};

Matches enum constants.

Example matches A, B, C
  enum X {
    A, B, C
  };

Matches enum declarations.

Example matches X
  enum X {
    A, B, C
  };

Matches field declarations.

Given
  class X { int m; };
fieldDecl()
  matches 'm'.

Matches friend declarations.

Given
  class X { friend void foo(); };
friendDecl()
  matches 'friend void foo()'.

Matches function declarations.

Example matches f
  void f();

Matches C++ function template declarations.

Example matches f
  template<class T> void f(T t) {}

Matches indirect field declarations.

Given
  struct X { struct { int a; }; };
indirectFieldDecl()
  matches 'a'.

Matches a declaration of label.

Given
  goto FOO;
  FOO: bar();
labelDecl()
  matches 'FOO:'

Matches a declaration of a linkage specification.

Given
  extern "C" {}
linkageSpecDecl()
  matches "extern "C" {}"

Matches a declaration of anything that could have a name.

Example matches X, S, the anonymous union type, i, and U;
  typedef int X;
  struct S {
    union {
      int i;
    } U;
  };

Matches a declaration of a namespace alias.

Given
  namespace test {}
  namespace alias = ::test;
namespaceAliasDecl()
  matches "namespace alias" but not "namespace test"

Matches a declaration of a namespace.

Given
  namespace {}
  namespace test {}
namespaceDecl()
  matches "namespace {}" and "namespace test {}"

Matches non-type template parameter declarations.

Given
  template <typename T, int N> struct C {};
nonTypeTemplateParmDecl()
  matches 'N', but not 'T'.

Matches Objective-C category declarations.

Example matches Foo (Additions)
  @interface Foo (Additions)
  @end

Matches Objective-C category definitions.

Example matches Foo (Additions)
  @implementation Foo (Additions)
  @end

Matches Objective-C implementation declarations.

Example matches Foo
  @implementation Foo
  @end

Matches Objective-C interface declarations.

Example matches Foo
  @interface Foo
  @end

Matches Objective-C instance variable declarations.

Example matches _enabled
  @implementation Foo {
    BOOL _enabled;
  }
  @end

Matches Objective-C method declarations.

Example matches both declaration and definition of -[Foo method]
  @interface Foo
  - (void)method;
  @end

  @implementation Foo
  - (void)method {}
  @end

Matches Objective-C property declarations.

Example matches enabled
  @interface Foo
  @property BOOL enabled;
  @end

Matches Objective-C protocol declarations.

Example matches FooDelegate
  @protocol FooDelegate
  @end

Matches parameter variable declarations.

Given
  void f(int x);
parmVarDecl()
  matches int x.

Matches class, struct, and union declarations.

Example matches X, Z, U, and S
  class X;
  template<class T> class Z {};
  struct S {};
  union U {};

Matches a C++ static_assert declaration.

Example:
  staticAssertExpr()
matches
  static_assert(sizeof(S) == sizeof(int))
in
  struct S {
    int x;
  };
  static_assert(sizeof(S) == sizeof(int));

Matches tag declarations.

Example matches X, Z, U, S, E
  class X;
  template<class T> class Z {};
  struct S {};
  union U {};
  enum E {
    A, B, C
  };

Matches template template parameter declarations.

Given
  template <template <typename> class Z, int N> struct C {};
templateTypeParmDecl()
  matches 'Z', but not 'N'.

Matches template type parameter declarations.

Given
  template <typename T, int N> struct C {};
templateTypeParmDecl()
  matches 'T', but not 'N'.

Matches the top declaration context.

Given
  int X;
  namespace NS {
  int Y;
  }  // namespace NS
decl(hasDeclContext(translationUnitDecl()))
  matches "int X", but not "int Y".

Matches type alias declarations.

Given
  typedef int X;
  using Y = int;
typeAliasDecl()
  matches "using Y = int", but not "typedef int X"

Matches type alias template declarations.

typeAliasTemplateDecl() matches
  template <typename T>
  using Y = X<T>;

Matches typedef declarations.

Given
  typedef int X;
  using Y = int;
typedefDecl()
  matches "typedef int X", but not "using Y = int"

Matches typedef name declarations.

Given
  typedef int X;
  using Y = int;
typedefNameDecl()
  matches "typedef int X" and "using Y = int"

Matches unresolved using value declarations that involve the
typename.

Given
  template <typename T>
  struct Base { typedef T Foo; };

  template<typename T>
  struct S : private Base<T> {
    using typename Base<T>::Foo;
  };
unresolvedUsingTypenameDecl()
  matches using Base<T>::Foo 

Matches unresolved using value declarations.

Given
  template<typename X>
  class C : private X {
    using X::x;
  };
unresolvedUsingValueDecl()
  matches using X::x 

Matches using declarations.

Given
  namespace X { int x; }
  using X::x;
usingDecl()
  matches using X::x 

Matches using namespace declarations.

Given
  namespace X { int x; }
  using namespace X;
usingDirectiveDecl()
  matches using namespace X 

Matches using-enum declarations.

Given
  namespace X { enum x {...}; }
  using enum X::x;
usingEnumDecl()
  matches using enum X::x 

Matches any value declaration.

Example matches A, B, C and F
  enum X { A, B, C };
  void F();

Matches variable declarations.

Note: this does not match declarations of member variables, which are
"field" declarations in Clang parlance.

Example matches a
  int a;

Matches lambda captures.

Given
  int main() {
    int x;
    auto f = [x](){};
    auto g = [x = 1](){};
  }
In the matcher `lambdaExpr(hasAnyCapture(lambdaCapture()))`,
`lambdaCapture()` matches `x` and `x=1`.

Same as nestedNameSpecifier but matches NestedNameSpecifierLoc.

Matches nested name specifiers.

Given
  namespace ns {
    struct A { static void f(); };
    void A::f() {}
    void g() { A::f(); }
  }
  ns::A a;
nestedNameSpecifier()
  matches "ns::" and both "A::"

Matches OpenMP ``default`` clause.

Given

  #pragma omp parallel default(none)
  #pragma omp parallel default(shared)
  #pragma omp parallel default(firstprivate)
  #pragma omp parallel

``ompDefaultClause()`` matches ``default(none)``, ``default(shared)``, and
``default(firstprivate)``

Matches QualTypes in the clang AST.

Matches address of label statements (GNU extension).

Given
  FOO: bar();
  void *ptr = &&FOO;
  goto *bar;
addrLabelExpr()
  matches '&&FOO'

Matches array subscript expressions.

Given
  int i = a[1];
arraySubscriptExpr()
  matches "a[1]"

Matches asm statements.

 int i = 100;
  __asm("mov al, 2");
asmStmt()
  matches '__asm("mov al, 2")'

Matches atomic builtins.
Example matches __atomic_load_n(ptr, 1)
  void foo() { int *ptr; __atomic_load_n(ptr, 1); }

Matches an Objective-C autorelease pool statement.

Given
  @autoreleasepool {
    int x = 0;
  }
autoreleasePoolStmt(stmt()) matches the declaration of "x"
inside the autorelease pool.

Matches binary conditional operator expressions (GNU extension).

Example matches a ?: b
  (a ?: b) + 42;

Matches binary operator expressions.

Example matches a || b
  !(a || b)
See also the binaryOperation() matcher for more-general matching.

Matches a reference to a block.

Example: matches "^{}":
  void f() { ^{}(); }

Matches break statements.

Given
  while (true) { break; }
breakStmt()
  matches 'break'

Matches a C-style cast expression.

Example: Matches (int) 2.2f in
  int i = (int) 2.2f;

Matches call expressions.

Example matches x.y() and y()
  X x;
  x.y();
  y();

Matches case statements inside switch statements.

Given
  switch(a) { case 42: break; default: break; }
caseStmt()
  matches 'case 42:'.

Matches any cast nodes of Clang's AST.

Example: castExpr() matches each of the following:
  (int) 3;
  const_cast<Expr *>(SubExpr);
  char c = 0;
but does not match
  int i = (0);
  int k = 0;

Matches character literals (also matches wchar_t).

Not matching Hex-encoded chars (e.g. 0x1234, which is a IntegerLiteral),
though.

Example matches 'a', L'a'
  char ch = 'a';
  wchar_t chw = L'a';

Matches GNU __builtin_choose_expr.

Matches co_await expressions.

Given
  co_await 1;
coawaitExpr()
  matches 'co_await 1'

Matches compound (i.e. non-scalar) literals

Example match: {1}, (1, 2)
  int array[4] = {1};
  vector int myvec = (vector int)(1, 2);

Matches compound statements.

Example matches '{}' and '{{}}' in 'for (;;) {{}}'
  for (;;) {{}}

Matches conditional operator expressions.

Example matches a ? b : c
  (a ? b : c) + 42

Matches a constant expression wrapper.

Example matches the constant in the case statement:
    (matcher = constantExpr())
  switch (a) {
  case 37: break;
  }

Matches continue statements.

Given
  while (true) { continue; }
continueStmt()
  matches 'continue'

Matches co_return statements.

Given
  while (true) { co_return; }
coreturnStmt()
  matches 'co_return'

Matches co_yield expressions.

Given
  co_yield 1;
coyieldExpr()
  matches 'co_yield 1'

Matches CUDA kernel call expression.

Example matches,
  kernel<<<i,j>>>();

Matches nodes where temporaries are created.

Example matches FunctionTakesString(GetStringByValue())
    (matcher = cxxBindTemporaryExpr())
  FunctionTakesString(GetStringByValue());
  FunctionTakesStringByPointer(GetStringPointer());

Matches bool literals.

Example matches true
  true

Matches catch statements.

  try {} catch(int i) {}
cxxCatchStmt()
  matches 'catch(int i)'

Matches a const_cast expression.

Example: Matches const_cast<int*>(&r) in
  int n = 42;
  const int &r(n);
  int* p = const_cast<int*>(&r);

Matches constructor call expressions (including implicit ones).

Example matches string(ptr, n) and ptr within arguments of f
    (matcher = cxxConstructExpr())
  void f(const string &a, const string &b);
  char *ptr;
  int n;
  f(string(ptr, n), ptr);

Matches the value of a default argument at the call site.

Example matches the CXXDefaultArgExpr placeholder inserted for the
    default value of the second parameter in the call expression f(42)
    (matcher = cxxDefaultArgExpr())
  void f(int x, int y = 0);
  f(42);

Matches delete expressions.

Given
  delete X;
cxxDeleteExpr()
  matches 'delete X'.

Matches member expressions where the actual member referenced could not be
resolved because the base expression or the member name was dependent.

Given
  template <class T> void f() { T t; t.g(); }
cxxDependentScopeMemberExpr()
  matches t.g

Matches a dynamic_cast expression.

Example:
  cxxDynamicCastExpr()
matches
  dynamic_cast<D*>(&b);
in
  struct B { virtual ~B() {} }; struct D : B {};
  B b;
  D* p = dynamic_cast<D*>(&b);

Matches range-based for statements.

cxxForRangeStmt() matches 'for (auto a : i)'
  int i[] =  {1, 2, 3}; for (auto a : i);
  for(int j = 0; j < 5; ++j);

Matches functional cast expressions

Example: Matches Foo(bar);
  Foo f = bar;
  Foo g = (Foo) bar;
  Foo h = Foo(bar);

Matches member call expressions.

Example matches x.y()
  X x;
  x.y();

Matches new expressions.

Given
  new X;
cxxNewExpr()
  matches 'new X'.

Matches noexcept expressions.

Given
  bool a() noexcept;
  bool b() noexcept(true);
  bool c() noexcept(false);
  bool d() noexcept(noexcept(a()));
  bool e = noexcept(b()) || noexcept(c());
cxxNoexceptExpr()
  matches `noexcept(a())`, `noexcept(b())` and `noexcept(c())`.
  doesn't match the noexcept specifier in the declarations a, b, c or d.

Matches nullptr literal.

Matches overloaded operator calls.

Note that if an operator isn't overloaded, it won't match. Instead, use
binaryOperator matcher.
Currently it does not match operators such as new delete.
FIXME: figure out why these do not match?

Example matches both operator<<((o << b), c) and operator<<(o, b)
    (matcher = cxxOperatorCallExpr())
  ostream &operator<< (ostream &out, int i) { };
  ostream &o; int b = 1, c = 1;
  o << b << c;
See also the binaryOperation() matcher for more-general matching of binary
uses of this AST node.

Matches a reinterpret_cast expression.

Either the source expression or the destination type can be matched
using has(), but hasDestinationType() is more specific and can be
more readable.

Example matches reinterpret_cast<char*>(&p) in
  void* p = reinterpret_cast<char*>(&p);

Matches rewritten binary operators

Example matches use of "<":
  #include <compare>
  struct HasSpaceshipMem {
    int a;
    constexpr auto operator<=>(const HasSpaceshipMem&) const = default;
  };
  void compare() {
    HasSpaceshipMem hs1, hs2;
    if (hs1 < hs2)
        return;
  }
See also the binaryOperation() matcher for more-general matching
of this AST node.

Matches a C++ static_cast expression.

See also: hasDestinationType
See also: reinterpretCast

Example:
  cxxStaticCastExpr()
matches
  static_cast<long>(8)
in
  long eight(static_cast<long>(8));

Matches C++ initializer list expressions.

Given
  std::vector<int> a({ 1, 2, 3 });
  std::vector<int> b = { 4, 5 };
  int c[] = { 6, 7 };
  std::pair<int, int> d = { 8, 9 };
cxxStdInitializerListExpr()
  matches "{ 1, 2, 3 }" and "{ 4, 5 }"

Matches functional cast expressions having N != 1 arguments

Example: Matches Foo(bar, bar)
  Foo h = Foo(bar, bar);

Matches implicit and explicit this expressions.

Example matches the implicit this expression in "return i".
    (matcher = cxxThisExpr())
struct foo {
  int i;
  int f() { return i; }
};

Matches throw expressions.

  try { throw 5; } catch(int i) {}
cxxThrowExpr()
  matches 'throw 5'

Matches try statements.

  try {} catch(int i) {}
cxxTryStmt()
  matches 'try {}'

Matches unresolved constructor call expressions.

Example matches T(t) in return statement of f
    (matcher = cxxUnresolvedConstructExpr())
  template <typename T>
  void f(const T& t) { return T(t); }

Matches expressions that refer to declarations.

Example matches x in if (x)
  bool x;
  if (x) {}

Matches declaration statements.

Given
  int a;
declStmt()
  matches 'int a'.

Matches default statements inside switch statements.

Given
  switch(a) { case 42: break; default: break; }
defaultStmt()
  matches 'default:'.

Matches co_await expressions where the type of the promise is dependent

Matches C99 designated initializer expressions [C99 6.7.8].

Example: Matches { [2].y = 1.0, [0].x = 1.0 }
  point ptarray[10] = { [2].y = 1.0, [0].x = 1.0 };

Matches do statements.

Given
  do {} while (true);
doStmt()
  matches 'do {} while(true)'

Matches explicit cast expressions.

Matches any cast expression written in user code, whether it be a
C-style cast, a functional-style cast, or a keyword cast.

Does not match implicit conversions.

Note: the name "explicitCast" is chosen to match Clang's terminology, as
Clang uses the term "cast" to apply to implicit conversions as well as to
actual cast expressions.

See also: hasDestinationType.

Example: matches all five of the casts in
  int((int)(reinterpret_cast<int>(static_cast<int>(const_cast<int>(42)))))
but does not match the implicit conversion in
  long ell = 42;

Matches expressions.

Example matches x()
  void f() { x(); }

Matches expressions that introduce cleanups to be run at the end
of the sub-expression's evaluation.

Example matches std::string()
  const std::string str = std::string();

Matches fixed point literals

Matches float literals of all sizes / encodings, e.g.
1.0, 1.0f, 1.0L and 1e10.

Does not match implicit conversions such as
  float a = 10;

Matches for statements.

Example matches 'for (;;) {}'
  for (;;) {}
  int i[] =  {1, 2, 3}; for (auto a : i);

Matches C11 _Generic expression.

Matches GNU __null expression.

Matches goto statements.

Given
  goto FOO;
  FOO: bar();
gotoStmt()
  matches 'goto FOO'

Matches if statements.

Example matches 'if (x) {}'
  if (x) {}

Matches imaginary literals, which are based on integer and floating
point literals e.g.: 1i, 1.0i

Matches the implicit cast nodes of Clang's AST.

This matches many different places, including function call return value
eliding, as well as any type conversions.

Matches implicit initializers of init list expressions.

Given
  point ptarray[10] = { [2].y = 1.0, [2].x = 2.0, [0].x = 1.0 };
implicitValueInitExpr()
  matches "[0].y" (implicitly)

Matches init list expressions.

Given
  int a[] = { 1, 2 };
  struct B { int x, y; };
  B b = { 5, 6 };
initListExpr()
  matches "{ 1, 2 }" and "{ 5, 6 }"

Matches integer literals of all sizes / encodings, e.g.
1, 1L, 0x1 and 1U.

Does not match character-encoded integers such as L'a'.

Matches label statements.

Given
  goto FOO;
  FOO: bar();
labelStmt()
  matches 'FOO:'

Matches lambda expressions.

Example matches [&](){return 5;}
  [&](){return 5;}

Matches nodes where temporaries are materialized.

Example: Given
  struct T {void func();};
  T f();
  void g(T);
materializeTemporaryExpr() matches 'f()' in these statements
  T u(f());
  g(f());
  f().func();
but does not match
  f();

Matches member expressions.

Given
  class Y {
    void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
    int a; static int b;
  };
memberExpr()
  matches this->x, x, y.x, a, this->b

Matches null statements.

  foo();;
nullStmt()
  matches the second ';'

Matches Objective-C @catch statements.

Example matches @catch
  @try {}
  @catch (...) {}

Matches Objective-C @finally statements.

Example matches @finally
  @try {}
  @finally {}

Matches a reference to an ObjCIvar.

Example: matches "a" in "init" method:
@implementation A {
  NSString *a;
}
- (void) init {
  a = @"hello";
}

Matches ObjectiveC Message invocation expressions.

The innermost message send invokes the "alloc" class method on the
NSString class, while the outermost message send invokes the
"initWithString" instance method on the object returned from
NSString's "alloc". This matcher should match both message sends.
  [[NSString alloc] initWithString:@"Hello"]

Matches Objective-C statements.

Example matches @throw obj;

Matches Objective-C @try statements.

Example matches @try
  @try {}
  @catch (...) {}

Matches any ``#pragma omp`` executable directive.

Given

  #pragma omp parallel
  #pragma omp parallel default(none)
  #pragma omp taskyield

``ompExecutableDirective()`` matches ``omp parallel``,
``omp parallel default(none)`` and ``omp taskyield``.

Matches opaque value expressions. They are used as helpers
to reference another expressions and can be met
in BinaryConditionalOperators, for example.

Example matches 'a'
  (a ?: c) + 42;

Matches parentheses used in expressions.

Example matches (foo() + 1)
  int foo() { return 1; }
  int a = (foo() + 1);

Matches paren list expressions.
ParenListExprs don't have a predefined type and are used for late parsing.
In the final AST, they can be met in template declarations.

Given
  template<typename T> class X {
    void f() {
      X x(*this);
      int a = 0, b = 1; int i = (a, b);
    }
  };
parenListExpr() matches "*this" but NOT matches (a, b) because (a, b)
has a predefined type and is a ParenExpr, not a ParenListExpr.

Matches predefined identifier expressions [C99 6.4.2.2].

Example: Matches __func__
  printf("%s", __func__);

Matches return statements.

Given
  return 1;
returnStmt()
  matches 'return 1'

Matches statements.

Given
  { ++a; }
stmt()
  matches both the compound statement '{ ++a; }' and '++a'.

Matches statement expression (GNU extension).

Example match: ({ int X = 4; X; })
  int C = ({ int X = 4; X; });

Matches string literals (also matches wide string literals).

Example matches "abcd", L"abcd"
  char *s = "abcd";
  wchar_t *ws = L"abcd";

Matches substitutions of non-type template parameters.

Given
  template <int N>
  struct A { static const int n = N; };
  struct B : public A<42> {};
substNonTypeTemplateParmExpr()
  matches "N" in the right-hand side of "static const int n = N;"

Matches case and default statements inside switch statements.

Given
  switch(a) { case 42: break; default: break; }
switchCase()
  matches 'case 42:' and 'default:'.

Matches switch statements.

Given
  switch(a) { case 42: break; default: break; }
switchStmt()
  matches 'switch(a)'.

Matches sizeof (C99), alignof (C++11) and vec_step (OpenCL)

Given
  Foo x = bar;
  int y = sizeof(x) + alignof(x);
unaryExprOrTypeTraitExpr()
  matches sizeof(x) and alignof(x)

Matches unary operator expressions.

Example matches !a
  !a || b

Matches reference to a name that can be looked up during parsing
but could not be resolved to a specific declaration.

Given
  template<typename T>
  T foo() { T a; return a; }
  template<typename T>
  void bar() {
    foo<T>();
  }
unresolvedLookupExpr()
  matches foo<T>() 

Matches unresolved member expressions.

Given
  struct X {
    template <class T> void f();
    void g();
  };
  template <class T> void h() { X x; x.f<T>(); x.g(); }
unresolvedMemberExpr()
  matches x.f<T>

Matches user defined literal operator call.

Example match: "foo"_suffix

Matches while statements.

Given
  while (true) {}
whileStmt()
  matches 'while (true) {}'.

Matches template arguments (with location info).

Given
  template <typename T> struct C {};
  C<int> c;
templateArgumentLoc()
  matches 'int' in C<int>.

Matches template arguments.

Given
  template <typename T> struct C {};
  C<int> c;
templateArgument()
  matches 'int' in C<int>.

Matches template name.

Given
  template <typename T> class X { };
  X<int> xi;
templateName()
  matches 'X' in X<int>.

Matches C or C++ elaborated `TypeLoc`s.

Given
  struct s {};
  struct s ss;
elaboratedTypeLoc()
  matches the `TypeLoc` of the variable declaration of `ss`.

Matches pointer `TypeLoc`s.

Given
  int* x;
pointerTypeLoc()
  matches `int*`.

Matches `QualifiedTypeLoc`s in the clang AST.

Given
  const int x = 0;
qualifiedTypeLoc()
  matches `const int`.

Matches reference `TypeLoc`s.

Given
  int x = 3;
  int& l = x;
  int&& r = 3;
referenceTypeLoc()
  matches `int&` and `int&&`.

Matches template specialization `TypeLoc`s.

Given
  template <typename T> class C {};
  C<char> var;
varDecl(hasTypeLoc(templateSpecializationTypeLoc(typeLoc())))
  matches `C<char> var`.

Matches TypeLocs in the clang AST.

Matches all kinds of arrays.

Given
  int a[] = { 2, 3 };
  int b[4];
  void f() { int c[a[0]]; }
arrayType()
  matches "int a[]", "int b[4]" and "int c[a[0]]";

Matches atomic types.

Given
  _Atomic(int) i;
atomicType()
  matches "_Atomic(int) i"

Matches types nodes representing C++11 auto types.

Given:
  auto n = 4;
  int v[] = { 2, 3 }
  for (auto i : v) { }
autoType()
  matches "auto n" and "auto i"

Matches block pointer types, i.e. types syntactically represented as
"void (^)(int)".

The pointee is always required to be a FunctionType.

Matches builtin Types.

Given
  struct A {};
  A a;
  int b;
  float c;
  bool d;
builtinType()
  matches "int b", "float c" and "bool d"

Matches C99 complex types.

Given
  _Complex float f;
complexType()
  matches "_Complex float f"

Matches C arrays with a specified constant size.

Given
  void() {
    int a[2];
    int b[] = { 2, 3 };
    int c[b[0]];
  }
constantArrayType()
  matches "int a[2]"

Matches decayed type
Example matches i[] in declaration of f.
    (matcher = valueDecl(hasType(decayedType(hasDecayedType(pointerType())))))
Example matches i[1].
    (matcher = expr(hasType(decayedType(hasDecayedType(pointerType())))))
  void f(int i[]) {
    i[1] = 0;
  }

Matches types nodes representing C++11 decltype(<expr>) types.

Given:
  short i = 1;
  int j = 42;
  decltype(i + j) result = i + j;
decltypeType()
  matches "decltype(i + j)"

Matches C++17 deduced template specialization types, e.g. deduced class
template types.

Given
  template <typename T>
  class C { public: C(T); };

  C c(123);
deducedTemplateSpecializationType() matches the type in the declaration
of the variable c.

Matches C++ arrays whose size is a value-dependent expression.

Given
  template<typename T, int Size>
  class array {
    T data[Size];
  };
dependentSizedArrayType
  matches "T data[Size]"

Matches types specified with an elaborated type keyword or with a
qualified name.

Given
  namespace N {
    namespace M {
      class D {};
    }
  }
  class C {};

  class C c;
  N::M::D d;

elaboratedType() matches the type of the variable declarations of both
c and d.

Matches enum types.

Given
  enum C { Green };
  enum class S { Red };

  C c;
  S s;

enumType() matches the type of the variable declarations of both c and
s.

Matches FunctionProtoType nodes.

Given
  int (*f)(int);
  void g();
functionProtoType()
  matches "int (*f)(int)" and the type of "g" in C++ mode.
  In C mode, "g" is not matched because it does not contain a prototype.

Matches FunctionType nodes.

Given
  int (*f)(int);
  void g();
functionType()
  matches "int (*f)(int)" and the type of "g".

Matches C arrays with unspecified size.

Given
  int a[] = { 2, 3 };
  int b[42];
  void f(int c[]) { int d[a[0]]; };
incompleteArrayType()
  matches "int a[]" and "int c[]"

Matches injected class name types.

Example matches S s, but not S<T> s.
    (matcher = parmVarDecl(hasType(injectedClassNameType())))
  template <typename T> struct S {
    void f(S s);
    void g(S<T> s);
  };

Matches lvalue reference types.

Given:
  int *a;
  int &b = *a;
  int &&c = 1;
  auto &d = b;
  auto &&e = c;
  auto &&f = 2;
  int g = 5;

lValueReferenceType() matches the types of b, d, and e. e is
matched since the type is deduced as int& by reference collapsing rules.

Matches member pointer types.
Given
  struct A { int i; }
  A::* ptr = A::i;
memberPointerType()
  matches "A::* ptr"

Matches an Objective-C object pointer type, which is different from
a pointer type, despite being syntactically similar.

Given
  int *a;

  @interface Foo
  @end
  Foo *f;
pointerType()
  matches "Foo *f", but does not match "int *a".

Matches ParenType nodes.

Given
  int (*ptr_to_array)[4];
  int *array_of_ptrs[4];

varDecl(hasType(pointsTo(parenType()))) matches ptr_to_array but not
array_of_ptrs.

Matches pointer types, but does not match Objective-C object pointer
types.

Given
  int *a;
  int &b = *a;
  int c = 5;

  @interface Foo
  @end
  Foo *f;
pointerType()
  matches "int *a", but does not match "Foo *f".

Matches rvalue reference types.

Given:
  int *a;
  int &b = *a;
  int &&c = 1;
  auto &d = b;
  auto &&e = c;
  auto &&f = 2;
  int g = 5;

rValueReferenceType() matches the types of c and f. e is not
matched as it is deduced to int& by reference collapsing rules.

Matches record types (e.g. structs, classes).

Given
  class C {};
  struct S {};

  C c;
  S s;

recordType() matches the type of the variable declarations of both c
and s.

Matches both lvalue and rvalue reference types.

Given
  int *a;
  int &b = *a;
  int &&c = 1;
  auto &d = b;
  auto &&e = c;
  auto &&f = 2;
  int g = 5;

referenceType() matches the types of b, c, d, e, and f.

Matches types that represent the result of substituting a type for a
template type parameter.

Given
  template <typename T>
  void F(T t) {
    int i = 1 + t;
  }

substTemplateTypeParmType() matches the type of 't' but not '1'

Matches tag types (record and enum types).

Given
  enum E {};
  class C {};

  E e;
  C c;

tagType() matches the type of the variable declarations of both e
and c.

Matches template specialization types.

Given
  template <typename T>
  class C { };

  template class C<int>;  // A
  C<char> var;            // B

templateSpecializationType() matches the type of the explicit
instantiation in A and the type of the variable declaration in B.

Matches template type parameter types.

Example matches T, but not int.
    (matcher = templateTypeParmType())
  template <typename T> void f(int i);

Matches Types in the clang AST.

Matches typedef types.

Given
  typedef int X;
typedefType()
  matches "typedef int X"

Matches types nodes representing unary type transformations.

Given:
  typedef __underlying_type(T) type;
unaryTransformType()
  matches "__underlying_type(T)"

Matches C arrays with a specified size that is not an
integer-constant-expression.

Given
  void f() {
    int a[] = { 2, 3 }
    int b[42];
    int c[a[0]];
  }
variableArrayType()
  matches "int c[a[0]]"

Matches if all given matchers match.

Usable as: Any Matcher

Matches if any of the given matchers matches.

Usable as: Any Matcher

Matches any node.

Useful when another matcher requires a child matcher, but there's no
additional constraint. This will often be used with an explicit conversion
to an internal::Matcher<> type such as TypeMatcher.

Example: DeclarationMatcher(anything()) matches all declarations, e.g.,
"int* p" and "void f()" in
  int* p;
  void f();

Usable as: Any Matcher

Matches any of the NodeMatchers with InnerMatchers nested within

Given
  if (true);
  for (; true; );
with the matcher
  mapAnyOf(ifStmt, forStmt).with(
    hasCondition(cxxBoolLiteralExpr(equals(true)))
    ).bind("trueCond")
matches the if and the for. It is equivalent to:
  auto trueCond = hasCondition(cxxBoolLiteralExpr(equals(true)));
  anyOf(
    ifStmt(trueCond).bind("trueCond"),
    forStmt(trueCond).bind("trueCond")
    );

The with() chain-call accepts zero or more matchers which are combined
as-if with allOf() in each of the node matchers.
Usable as: Any Matcher

Matches if the provided matcher does not match.

Example matches Y (matcher = cxxRecordDecl(unless(hasName("X"))))
  class X {};
  class Y {};

Usable as: Any Matcher

Matches an entity that has been implicitly added by the compiler (e.g.
implicit default/copy constructors).

Matches operator expressions (binary or unary) that have any of the
specified names.

   hasAnyOperatorName("+", "-")
 Is equivalent to
   anyOf(hasOperatorName("+"), hasOperatorName("-"))

Matches the operator Name of operator expressions (binary or
unary).

Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
  !(a || b)

Matches all kinds of assignment operators.

Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 = s2
           (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
  struct S { S& operator=(const S&); };
  void x() { S s1, s2; s1 = s2; }

Matches comparison operators.

Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 < s2
           (matcher = cxxOperatorCallExpr(isComparisonOperator()))
  struct S { bool operator<(const S& other); };
  void x(S s1, S s2) { bool b1 = s1 < s2; }

Matches private C++ declarations and C++ base specifers that specify private
inheritance.

Examples:
  class C {
  public:    int a;
  protected: int b;
  private:   int c; // fieldDecl(isPrivate()) matches 'c'
  };

  struct Base {};
  struct Derived1 : private Base {}; // matches 'Base'
  class Derived2 : Base {}; // matches 'Base'

Matches protected C++ declarations and C++ base specifers that specify
protected inheritance.

Examples:
  class C {
  public:    int a;
  protected: int b; // fieldDecl(isProtected()) matches 'b'
  private:   int c;
  };

  class Base {};
  class Derived : protected Base {}; // matches 'Base'

Matches public C++ declarations and C++ base specifers that specify public
inheritance.

Examples:
  class C {
  public:    int a; // fieldDecl(isPublic()) matches 'a'
  protected: int b;
  private:   int c;
  };

  class Base {};
  class Derived1 : public Base {}; // matches 'Base'
  struct Derived2 : Base {}; // matches 'Base'

Matches declarations of virtual methods and C++ base specifers that specify
virtual inheritance.

Example:
  class A {
   public:
    virtual void x(); // matches x
  };

Example:
  class Base {};
  class DirectlyDerived : virtual Base {}; // matches Base
  class IndirectlyDerived : DirectlyDerived, Base {}; // matches Base

Usable as: Matcher<CXXMethodDecl>, Matcher<CXXBaseSpecifier>

Matches literals that are equal to the given value of type ValueT.

Given
  f('false, 3.14, 42);
characterLiteral(equals(0))
  matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
  match false
floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
  match 3.14
integerLiteral(equals(42))
  matches 42

Note that you cannot directly match a negative numeric literal because the
minus sign is not part of the literal: It is a unary operator whose operand
is the positive numeric literal. Instead, you must use a unaryOperator()
matcher to match the minus sign:

unaryOperator(hasOperatorName("-"),
              hasUnaryOperand(integerLiteral(equals(13))))

Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
           Matcher<FloatingLiteral>, Matcher<IntegerLiteral>

Matches a C++ catch statement that has a catch-all handler.

Given
  try {
    // ...
  } catch (int) {
    // ...
  } catch (...) {
    // ...
  }
cxxCatchStmt(isCatchAll()) matches catch(...) but not catch(int).

Checks that a call expression or a constructor call expression has
a specific number of arguments (including absent default arguments).

Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
  void f(int x, int y);
  f(0, 0);

Matches a constructor call expression which uses list initialization.

Matches a constructor call expression which requires
zero initialization.

Given
void foo() {
  struct point { double x; double y; };
  point pt[2] = { { 1.0, 2.0 } };
}
initListExpr(has(cxxConstructExpr(requiresZeroInitialization()))
will match the implicit array filler for pt[1].

Matches constructor declarations that are copy constructors.

Given
  struct S {
    S(); // #1
    S(const S &); // #2
    S(S &&); // #3
  };
cxxConstructorDecl(isCopyConstructor()) will match #2, but not #1 or #3.

Matches constructor declarations that are default constructors.

Given
  struct S {
    S(); // #1
    S(const S &); // #2
    S(S &&); // #3
  };
cxxConstructorDecl(isDefaultConstructor()) will match #1, but not #2 or #3.

Matches constructors that delegate to another constructor.

Given
  struct S {
    S(); // #1
    S(int) {} // #2
    S(S &&) : S() {} // #3
  };
  S::S() : S(0) {} // #4
cxxConstructorDecl(isDelegatingConstructor()) will match #3 and #4, but not
#1 or #2.

Matches constructor, conversion function, and deduction guide declarations
that have an explicit specifier if this explicit specifier is resolved to
true.

Given
  template<bool b>
  struct S {
    S(int); // #1
    explicit S(double); // #2
    operator int(); // #3
    explicit operator bool(); // #4
    explicit(false) S(bool) // # 7
    explicit(true) S(char) // # 8
    explicit(b) S(S) // # 9
  };
  S(int) -> S<true> // #5
  explicit S(double) -> S<false> // #6
cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
cxxConversionDecl(isExplicit()) will match #4, but not #3.
cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.

Matches constructor declarations that are move constructors.

Given
  struct S {
    S(); // #1
    S(const S &); // #2
    S(S &&); // #3
  };
cxxConstructorDecl(isMoveConstructor()) will match #3, but not #1 or #2.

Matches constructor, conversion function, and deduction guide declarations
that have an explicit specifier if this explicit specifier is resolved to
true.

Given
  template<bool b>
  struct S {
    S(int); // #1
    explicit S(double); // #2
    operator int(); // #3
    explicit operator bool(); // #4
    explicit(false) S(bool) // # 7
    explicit(true) S(char) // # 8
    explicit(b) S(S) // # 9
  };
  S(int) -> S<true> // #5
  explicit S(double) -> S<false> // #6
cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
cxxConversionDecl(isExplicit()) will match #4, but not #3.
cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.

Matches a constructor initializer if it is initializing a base, as
opposed to a member.

Given
  struct B {};
  struct D : B {
    int I;
    D(int i) : I(i) {}
  };
  struct E : B {
    E() : B() {}
  };
cxxConstructorDecl(hasAnyConstructorInitializer(isBaseInitializer()))
  will match E(), but not match D(int).

Matches a constructor initializer if it is initializing a member, as
opposed to a base.

Given
  struct B {};
  struct D : B {
    int I;
    D(int i) : I(i) {}
  };
  struct E : B {
    E() : B() {}
  };
cxxConstructorDecl(hasAnyConstructorInitializer(isMemberInitializer()))
  will match D(int), but not match E().

Matches a constructor initializer if it is explicitly written in
code (as opposed to implicitly added by the compiler).

Given
  struct Foo {
    Foo() { }
    Foo(int) : foo_("A") { }
    string foo_;
  };
cxxConstructorDecl(hasAnyConstructorInitializer(isWritten()))
  will match Foo(int), but not Foo()

Matches constructor, conversion function, and deduction guide declarations
that have an explicit specifier if this explicit specifier is resolved to
true.

Given
  template<bool b>
  struct S {
    S(int); // #1
    explicit S(double); // #2
    operator int(); // #3
    explicit operator bool(); // #4
    explicit(false) S(bool) // # 7
    explicit(true) S(char) // # 8
    explicit(b) S(S) // # 9
  };
  S(int) -> S<true> // #5
  explicit S(double) -> S<false> // #6
cxxConstructorDecl(isExplicit()) will match #2 and #8, but not #1, #7 or #9.
cxxConversionDecl(isExplicit()) will match #4, but not #3.
cxxDeductionGuideDecl(isExplicit()) will match #6, but not #5.

Matches template-dependent, but known, member names.

In template declarations, dependent members are not resolved and so can
not be matched to particular named declarations.

This matcher allows to match on the known name of members.

Given
  template <typename T>
  struct S {
      void mem();
  };
  template <typename T>
  void x() {
      S<T> s;
      s.mem();
  }
cxxDependentScopeMemberExpr(hasMemberName("mem")) matches `s.mem()`

Matches member expressions that are called with '->' as opposed
to '.'.

Member calls on the implicit this pointer match as called with '->'.

Given
  class Y {
    void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
    template <class T> void f() { this->f<T>(); f<T>(); }
    int a;
    static int b;
  };
  template <class T>
  class Z {
    void x() { this->m; }
  };
memberExpr(isArrow())
  matches this->x, x, y.x, a, this->b
cxxDependentScopeMemberExpr(isArrow())
  matches this->m
unresolvedMemberExpr(isArrow())
  matches this->f<T>, f<T>

Matches template-dependent, but known, member names against an already-bound
node

In template declarations, dependent members are not resolved and so can
not be matched to particular named declarations.

This matcher allows to match on the name of already-bound VarDecl, FieldDecl
and CXXMethodDecl nodes.

Given
  template <typename T>
  struct S {
      void mem();
  };
  template <typename T>
  void x() {
      S<T> s;
      s.mem();
  }
The matcher
@code
cxxDependentScopeMemberExpr(
  hasObjectExpression(declRefExpr(hasType(templateSpecializationType(
      hasDeclaration(classTemplateDecl(has(cxxRecordDecl(has(
          cxxMethodDecl(hasName("mem")).bind("templMem")
          )))))
      )))),
  memberHasSameNameAsBoundNode("templMem")
  )
@endcode
first matches and binds the @c mem member of the @c S template, then
compares its name to the usage in @c s.mem() in the @c x function template

Matches if the given method declaration is const.

Given
struct A {
  void foo() const;
  void bar();
};

cxxMethodDecl(isConst()) matches A::foo() but not A::bar()

Matches if the given method declaration declares a copy assignment
operator.

Given
struct A {
  A &operator=(const A &);
  A &operator=(A &&);
};

cxxMethodDecl(isCopyAssignmentOperator()) matches the first method but not
the second one.

Matches if the given method or class declaration is final.

Given:
  class A final {};

  struct B {
    virtual void f();
  };

  struct C : B {
    void f() final;
  };
matches A and C::f, but not B, C, or B::f

Matches if the given method declaration declares a move assignment
operator.

Given
struct A {
  A &operator=(const A &);
  A &operator=(A &&);
};

cxxMethodDecl(isMoveAssignmentOperator()) matches the second method but not
the first one.

Matches if the given method declaration overrides another method.

Given
  class A {
   public:
    virtual void x();
  };
  class B : public A {
   public:
    virtual void x();
  };
  matches B::x

Matches if the given method declaration is pure.

Given
  class A {
   public:
    virtual void x() = 0;
  };
  matches A::x

Matches method declarations that are user-provided.

Given
  struct S {
    S(); // #1
    S(const S &) = default; // #2
    S(S &&) = delete; // #3
  };
cxxConstructorDecl(isUserProvided()) will match #1, but not #2 or #3.

Matches declarations of virtual methods and C++ base specifers that specify
virtual inheritance.

Example:
  class A {
   public:
    virtual void x(); // matches x
  };

Example:
  class Base {};
  class DirectlyDerived : virtual Base {}; // matches Base
  class IndirectlyDerived : DirectlyDerived, Base {}; // matches Base

Usable as: Matcher<CXXMethodDecl>, Matcher<CXXBaseSpecifier>

Matches if the given method declaration has an explicit "virtual".

Given
  class A {
   public:
    virtual void x();
  };
  class B : public A {
   public:
    void x();
  };
  matches A::x but not B::x

Matches array new expressions.

Given:
  MyClass *p1 = new MyClass[10];
cxxNewExpr(isArray())
  matches the expression 'new MyClass[10]'.

Matches operator expressions (binary or unary) that have any of the
specified names.

   hasAnyOperatorName("+", "-")
 Is equivalent to
   anyOf(hasOperatorName("+"), hasOperatorName("-"))

Matches overloaded operator names.

Matches overloaded operator names specified in strings without the
"operator" prefix: e.g. "<<".

  hasAnyOverloadedOperatorName("+", "-")
Is equivalent to
  anyOf(hasOverloadedOperatorName("+"), hasOverloadedOperatorName("-"))

Matches the operator Name of operator expressions (binary or
unary).

Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
  !(a || b)

Matches overloaded operator names.

Matches overloaded operator names specified in strings without the
"operator" prefix: e.g. "<<".

Given:
  class A { int operator*(); };
  const A &operator<<(const A &a, const A &b);
  A a;
  a << a;   // <-- This matches

cxxOperatorCallExpr(hasOverloadedOperatorName("<<"))) matches the
specified line and
cxxRecordDecl(hasMethod(hasOverloadedOperatorName("*")))
matches the declaration of A.

Usable as: Matcher<CXXOperatorCallExpr>, Matcher<FunctionDecl>

Matches all kinds of assignment operators.

Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 = s2
           (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
  struct S { S& operator=(const S&); };
  void x() { S s1, s2; s1 = s2; }

Matches comparison operators.

Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 < s2
           (matcher = cxxOperatorCallExpr(isComparisonOperator()))
  struct S { bool operator<(const S& other); };
  void x(S s1, S s2) { bool b1 = s1 < s2; }

Matches a class declaration that is defined.

Example matches x (matcher = cxxRecordDecl(hasDefinition()))
class x {};
class y;

Overloaded method as shortcut for isDerivedFrom(hasName(...)).

Overloaded method as shortcut for isDirectlyDerivedFrom(hasName(...)).

Matches explicit template specializations of function, class, or
static member variable template instantiations.

Given
  template<typename T> void A(T t) { }
  template<> void A(int N) { }
functionDecl(isExplicitTemplateSpecialization())
  matches the specialization A<int>().

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches if the given method or class declaration is final.

Given:
  class A final {};

  struct B {
    virtual void f();
  };

  struct C : B {
    void f() final;
  };
matches A and C::f, but not B, C, or B::f

Matches the generated class of lambda expressions.

Given:
  auto x = []{};

cxxRecordDecl(isLambda()) matches the implicit class declaration of
decltype(x)

Overloaded method as shortcut for
isSameOrDerivedFrom(hasName(...)).

Matches template instantiations of function, class, or static
member variable template instantiations.

Given
  template <typename T> class X {}; class A {}; X<A> x;
or
  template <typename T> class X {}; class A {}; template class X<A>;
or
  template <typename T> class X {}; class A {}; extern template class X<A>;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  matches the template instantiation of X<A>.

But given
  template <typename T>  class X {}; class A {};
  template <> class X<A> {}; X<A> x;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  does not match, as X<A> is an explicit template specialization.

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches operator expressions (binary or unary) that have any of the
specified names.

   hasAnyOperatorName("+", "-")
 Is equivalent to
   anyOf(hasOperatorName("+"), hasOperatorName("-"))

Matches the operator Name of operator expressions (binary or
unary).

Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
  !(a || b)

Matches all kinds of assignment operators.

Example 1: matches a += b (matcher = binaryOperator(isAssignmentOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 = s2
           (matcher = cxxOperatorCallExpr(isAssignmentOperator()))
  struct S { S& operator=(const S&); };
  void x() { S s1, s2; s1 = s2; }

Matches comparison operators.

Example 1: matches a == b (matcher = binaryOperator(isComparisonOperator()))
  if (a == b)
    a += b;

Example 2: matches s1 < s2
           (matcher = cxxOperatorCallExpr(isComparisonOperator()))
  struct S { bool operator<(const S& other); };
  void x(S s1, S s2) { bool b1 = s1 < s2; }

Checks that a call expression or a constructor call expression has
a specific number of arguments (including absent default arguments).

Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
  void f(int x, int y);
  f(0, 0);

Checks that a call expression or a constructor call expression has
a specific number of arguments (including absent default arguments).

Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
  void f(int x, int y);
  f(0, 0);

Matches call expressions which were resolved using ADL.

Example matches y(x) but not y(42) or NS::y(x).
  namespace NS {
    struct X {};
    void y(X);
  }

  void y(...);

  void test() {
    NS::X x;
    y(x); // Matches
    NS::y(x); // Doesn't match
    y(42); // Doesn't match
    using NS::y;
    y(x); // Found by both unqualified lookup and ADL, doesn't match
   }

Matches casts that has a given cast kind.

Example: matches the implicit cast around 0
(matcher = castExpr(hasCastKind(CK_NullToPointer)))
  int *p = 0;

If the matcher is use from clang-query, CastKind parameter
should be passed as a quoted string. e.g., hasCastKind("CK_NullToPointer").

Matches literals that are equal to the given value of type ValueT.

Given
  f('false, 3.14, 42);
characterLiteral(equals(0))
  matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
  match false
floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
  match 3.14
integerLiteral(equals(42))
  matches 42

Note that you cannot directly match a negative numeric literal because the
minus sign is not part of the literal: It is a unary operator whose operand
is the positive numeric literal. Instead, you must use a unaryOperator()
matcher to match the minus sign:

unaryOperator(hasOperatorName("-"),
              hasUnaryOperand(integerLiteral(equals(13))))

Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
           Matcher<FloatingLiteral>, Matcher<IntegerLiteral>

Matches if the number of template arguments equals N.

Given
  template<typename T> struct C {};
  C<int> c;
classTemplateSpecializationDecl(templateArgumentCountIs(1))
  matches C<int>.

Checks that a compound statement contains a specific number of
child statements.

Example: Given
  { for (;;) {} }
compoundStmt(statementCountIs(0)))
  matches '{}'
  but does not match the outer compound statement.

Matches nodes that have the specified size.

Given
  int a[42];
  int b[2 * 21];
  int c[41], d[43];
  char *s = "abcd";
  wchar_t *ws = L"abcd";
  char *w = "a";
constantArrayType(hasSize(42))
  matches "int a[42]" and "int b[2 * 21]"
stringLiteral(hasSize(4))
  matches "abcd", L"abcd"

Matches declaration statements that contain a specific number of
declarations.

Example: Given
  int a, b;
  int c;
  int d = 2, e;
declCountIs(2)
  matches 'int a, b;' and 'int d = 2, e;', but not 'int c;'.

Matches if a node equals a previously bound node.

Matches a node if it equals the node previously bound to ID.

Given
  class X { int a; int b; };
cxxRecordDecl(
    has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
    has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
  matches the class X, as a and b have the same type.

Note that when multiple matches are involved via forEach* matchers,
equalsBoundNodes acts as a filter.
For example:
compoundStmt(
    forEachDescendant(varDecl().bind("d")),
    forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
will trigger a match for each combination of variable declaration
and reference to that variable declaration within a compound statement.

Matches if a node equals another node.

Decl has pointer identity in the AST.

Matches declaration that has a given attribute.

Given
  __attribute__((device)) void f() { ... }
decl(hasAttr(clang::attr::CUDADevice)) matches the function declaration of
f. If the matcher is used from clang-query, attr::Kind parameter should be
passed as a quoted string. e.g., hasAttr("attr::CUDADevice").

Matches statements that are (transitively) expanded from the named macro.
Does not match if only part of the statement is expanded from that macro or
if different parts of the statement are expanded from different
appearances of the macro.

Matches AST nodes that were expanded within files whose name is
partially matching a given regex.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
  #include "ASTMatcher.h"
  class X {};
ASTMatcher.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

If the matcher is used in clang-query, RegexFlags parameter
should be passed as a quoted string. e.g: "NoFlags".
Flags can be combined with '|' example "IgnoreCase | BasicRegex"

Matches AST nodes that were expanded within the main-file.

Example matches X but not Y
  (matcher = cxxRecordDecl(isExpansionInMainFile())
  #include <Y.h>
  class X {};
Y.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches AST nodes that were expanded within system-header-files.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInSystemHeader())
  #include <SystemHeader.h>
  class X {};
SystemHeader.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches an entity that has been implicitly added by the compiler (e.g.
implicit default/copy constructors).

Matches declarations in the namespace `std`, but not in nested namespaces.

Given
  class vector {};
  namespace foo {
    class vector {};
    namespace std {
      class vector {};
    }
  }
  namespace std {
    inline namespace __1 {
      class vector {}; // #1
      namespace experimental {
        class vector {};
      }
    }
  }
cxxRecordDecl(hasName("vector"), isInStdNamespace()) will match only #1.

Matches declarations that are template instantiations or are inside
template instantiations.

Given
  template<typename T> void A(T t) { T i; }
  A(0);
  A(0U);
functionDecl(isInstantiated())
  matches 'A(int) {...};' and 'A(unsigned) {...}'.

Matches private C++ declarations and C++ base specifers that specify private
inheritance.

Examples:
  class C {
  public:    int a;
  protected: int b;
  private:   int c; // fieldDecl(isPrivate()) matches 'c'
  };

  struct Base {};
  struct Derived1 : private Base {}; // matches 'Base'
  class Derived2 : Base {}; // matches 'Base'

Matches protected C++ declarations and C++ base specifers that specify
protected inheritance.

Examples:
  class C {
  public:    int a;
  protected: int b; // fieldDecl(isProtected()) matches 'b'
  private:   int c;
  };

  class Base {};
  class Derived : protected Base {}; // matches 'Base'

Matches public C++ declarations and C++ base specifers that specify public
inheritance.

Examples:
  class C {
  public:    int a; // fieldDecl(isPublic()) matches 'a'
  protected: int b;
  private:   int c;
  };

  class Base {};
  class Derived1 : public Base {}; // matches 'Base'
  struct Derived2 : Base {}; // matches 'Base'

Matches designated initializer expressions that contain
a specific number of designators.

Example: Given
  point ptarray[10] = { [2].y = 1.0, [0].x = 1.0 };
  point ptarray2[10] = { [2].y = 1.0, [2].x = 0.0, [0].x = 1.0 };
designatorCountIs(2)
  matches '{ [2].y = 1.0, [0].x = 1.0 }',
  but not '{ [2].y = 1.0, [2].x = 0.0, [0].x = 1.0 }'.

Matches C++11 scoped enum declaration.

Example matches Y (matcher = enumDecl(isScoped()))
enum X {};
enum class Y {};

Matches expressions that are instantiation-dependent even if it is
neither type- nor value-dependent.

In the following example, the expression sizeof(sizeof(T() + T()))
is instantiation-dependent (since it involves a template parameter T),
but is neither type- nor value-dependent, since the type of the inner
sizeof is known (std::size_t) and therefore the size of the outer
sizeof is known.
  template<typename T>
  void f(T x, T y) { sizeof(sizeof(T() + T()); }
expr(isInstantiationDependent()) matches sizeof(sizeof(T() + T())

Matches expressions that are type-dependent because the template type
is not yet instantiated.

For example, the expressions "x" and "x + y" are type-dependent in
the following code, but "y" is not type-dependent:
  template<typename T>
  void add(T x, int y) {
    x + y;
  }
expr(isTypeDependent()) matches x + y

Matches expression that are value-dependent because they contain a
non-type template parameter.

For example, the array bound of "Chars" in the following example is
value-dependent.
  template<int Size> int f() { return Size; }
expr(isValueDependent()) matches return Size

Matches expressions that resolve to a null pointer constant, such as
GNU's __null, C++11's nullptr, or C's NULL macro.

Given:
  void *v1 = NULL;
  void *v2 = nullptr;
  void *v3 = __null; // GNU extension
  char *cp = (char *)0;
  int *ip = 0;
  int i = 0;
expr(nullPointerConstant())
  matches the initializer for v1, v2, v3, cp, and ip. Does not match the
  initializer for i.

Matches non-static data members that are bit-fields of the specified
bit width.

Given
  class C {
    int a : 2;
    int b : 4;
    int c : 2;
  };
fieldDecl(hasBitWidth(2))
  matches 'int a;' and 'int c;' but not 'int b;'.

Matches non-static data members that are bit-fields.

Given
  class C {
    int a : 2;
    int b;
  };
fieldDecl(isBitField())
  matches 'int a;' but not 'int b;'.

Matches literals that are equal to the given value of type ValueT.

Given
  f('false, 3.14, 42);
characterLiteral(equals(0))
  matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
  match false
floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
  match 3.14
integerLiteral(equals(42))
  matches 42

Note that you cannot directly match a negative numeric literal because the
minus sign is not part of the literal: It is a unary operator whose operand
is the positive numeric literal. Instead, you must use a unaryOperator()
matcher to match the minus sign:

unaryOperator(hasOperatorName("-"),
              hasUnaryOperand(integerLiteral(equals(13))))

Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
           Matcher<FloatingLiteral>, Matcher<IntegerLiteral>

Matches overloaded operator names.

Matches overloaded operator names specified in strings without the
"operator" prefix: e.g. "<<".

  hasAnyOverloadedOperatorName("+", "-")
Is equivalent to
  anyOf(hasOverloadedOperatorName("+"), hasOverloadedOperatorName("-"))

Matches functions that have a dynamic exception specification.

Given:
  void f();
  void g() noexcept;
  void h() noexcept(true);
  void i() noexcept(false);
  void j() throw();
  void k() throw(int);
  void l() throw(...);
functionDecl(hasDynamicExceptionSpec()) and
  functionProtoType(hasDynamicExceptionSpec())
  match the declarations of j, k, and l, but not f, g, h, or i.

Matches overloaded operator names.

Matches overloaded operator names specified in strings without the
"operator" prefix: e.g. "<<".

Given:
  class A { int operator*(); };
  const A &operator<<(const A &a, const A &b);
  A a;
  a << a;   // <-- This matches

cxxOperatorCallExpr(hasOverloadedOperatorName("<<"))) matches the
specified line and
cxxRecordDecl(hasMethod(hasOverloadedOperatorName("*")))
matches the declaration of A.

Usable as: Matcher<CXXOperatorCallExpr>, Matcher<FunctionDecl>

Matches a function declared with a trailing return type.

Example matches Y (matcher = functionDecl(hasTrailingReturn()))
int X() {}
auto Y() -> int {}

Matches consteval function declarations and if consteval/if ! consteval
statements.

Given:
  consteval int a();
  void b() { if consteval {} }
  void c() { if ! consteval {} }
  void d() { if ! consteval {} else {} }
functionDecl(isConsteval())
  matches the declaration of "int a()".
ifStmt(isConsteval())
  matches the if statement in "void b()", "void c()", "void d()".

Matches constexpr variable and function declarations,
       and if constexpr.

Given:
  constexpr int foo = 42;
  constexpr int bar();
  void baz() { if constexpr(1 > 0) {} }
varDecl(isConstexpr())
  matches the declaration of foo.
functionDecl(isConstexpr())
  matches the declaration of bar.
ifStmt(isConstexpr())
  matches the if statement in baz.

Matches defaulted function declarations.

Given:
  class A { ~A(); };
  class B { ~B() = default; };
functionDecl(isDefaulted())
  matches the declaration of ~B, but not ~A.

Matches if a declaration has a body attached.

Example matches A, va, fa
  class A {};
  class B;  // Doesn't match, as it has no body.
  int va;
  extern int vb;  // Doesn't match, as it doesn't define the variable.
  void fa() {}
  void fb();  // Doesn't match, as it has no body.
  @interface X
  - (void)ma; // Doesn't match, interface is declaration.
  @end
  @implementation X
  - (void)ma {}
  @end

Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
  Matcher<ObjCMethodDecl>

Matches deleted function declarations.

Given:
  void Func();
  void DeletedFunc() = delete;
functionDecl(isDeleted())
  matches the declaration of DeletedFunc, but not Func.

Matches explicit template specializations of function, class, or
static member variable template instantiations.

Given
  template<typename T> void A(T t) { }
  template<> void A(int N) { }
functionDecl(isExplicitTemplateSpecialization())
  matches the specialization A<int>().

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches extern "C" function or variable declarations.

Given:
  extern "C" void f() {}
  extern "C" { void g() {} }
  void h() {}
  extern "C" int x = 1;
  extern "C" int y = 2;
  int z = 3;
functionDecl(isExternC())
  matches the declaration of f and g, but not the declaration of h.
varDecl(isExternC())
  matches the declaration of x and y, but not the declaration of z.

Matches function and namespace declarations that are marked with
the inline keyword.

Given
  inline void f();
  void g();
  namespace n {
  inline namespace m {}
  }
functionDecl(isInline()) will match ::f().
namespaceDecl(isInline()) will match n::m.

Determines whether the function is "main", which is the entry point
into an executable program.

Matches FunctionDecls that have a noreturn attribute.

Given
  void nope();
  [[noreturn]] void a();
  __attribute__((noreturn)) void b();
  struct c { [[noreturn]] c(); };
functionDecl(isNoReturn())
  matches all of those except
  void nope();

Matches functions that have a non-throwing exception specification.

Given:
  void f();
  void g() noexcept;
  void h() throw();
  void i() throw(int);
  void j() noexcept(false);
functionDecl(isNoThrow()) and functionProtoType(isNoThrow())
  match the declarations of g, and h, but not f, i or j.

Matches variable/function declarations that have "static" storage
class specifier ("static" keyword) written in the source.

Given:
  static void f() {}
  static int i = 0;
  extern int j;
  int k;
functionDecl(isStaticStorageClass())
  matches the function declaration f.
varDecl(isStaticStorageClass())
  matches the variable declaration i.

Matches template instantiations of function, class, or static
member variable template instantiations.

Given
  template <typename T> class X {}; class A {}; X<A> x;
or
  template <typename T> class X {}; class A {}; template class X<A>;
or
  template <typename T> class X {}; class A {}; extern template class X<A>;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  matches the template instantiation of X<A>.

But given
  template <typename T>  class X {}; class A {};
  template <> class X<A> {}; X<A> x;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  does not match, as X<A> is an explicit template specialization.

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches if a function declaration is variadic.

Example matches f, but not g or h. The function i will not match, even when
compiled in C mode.
  void f(...);
  void g(int);
  template <typename... Ts> void h(Ts...);
  void i();

Matches weak function declarations.

Given:
  void foo() __attribute__((__weakref__("__foo")));
  void bar();
functionDecl(isWeak())
  matches the weak declaration "foo", but not "bar".

Matches FunctionDecls and FunctionProtoTypes that have a
specific parameter count.

Given
  void f(int i) {}
  void g(int i, int j) {}
  void h(int i, int j);
  void j(int i);
  void k(int x, int y, int z, ...);
functionDecl(parameterCountIs(2))
  matches g and h
functionProtoType(parameterCountIs(2))
  matches g and h
functionProtoType(parameterCountIs(3))
  matches k

Matches functions that have a dynamic exception specification.

Given:
  void f();
  void g() noexcept;
  void h() noexcept(true);
  void i() noexcept(false);
  void j() throw();
  void k() throw(int);
  void l() throw(...);
functionDecl(hasDynamicExceptionSpec()) and
  functionProtoType(hasDynamicExceptionSpec())
  match the declarations of j, k, and l, but not f, g, h, or i.

Matches functions that have a non-throwing exception specification.

Given:
  void f();
  void g() noexcept;
  void h() throw();
  void i() throw(int);
  void j() noexcept(false);
functionDecl(isNoThrow()) and functionProtoType(isNoThrow())
  match the declarations of g, and h, but not f, i or j.

Matches FunctionDecls and FunctionProtoTypes that have a
specific parameter count.

Given
  void f(int i) {}
  void g(int i, int j) {}
  void h(int i, int j);
  void j(int i);
  void k(int x, int y, int z, ...);
functionDecl(parameterCountIs(2))
  matches g and h
functionProtoType(parameterCountIs(2))
  matches g and h
functionProtoType(parameterCountIs(3))
  matches k

Matches consteval function declarations and if consteval/if ! consteval
statements.

Given:
  consteval int a();
  void b() { if consteval {} }
  void c() { if ! consteval {} }
  void d() { if ! consteval {} else {} }
functionDecl(isConsteval())
  matches the declaration of "int a()".
ifStmt(isConsteval())
  matches the if statement in "void b()", "void c()", "void d()".

Matches constexpr variable and function declarations,
       and if constexpr.

Given:
  constexpr int foo = 42;
  constexpr int bar();
  void baz() { if constexpr(1 > 0) {} }
varDecl(isConstexpr())
  matches the declaration of foo.
functionDecl(isConstexpr())
  matches the declaration of bar.
ifStmt(isConstexpr())
  matches the if statement in baz.

Matches literals that are equal to the given value of type ValueT.

Given
  f('false, 3.14, 42);
characterLiteral(equals(0))
  matches 'cxxBoolLiteral(equals(false)) and cxxBoolLiteral(equals(0))
  match false
floatLiteral(equals(3.14)) and floatLiteral(equals(314e-2))
  match 3.14
integerLiteral(equals(42))
  matches 42

Note that you cannot directly match a negative numeric literal because the
minus sign is not part of the literal: It is a unary operator whose operand
is the positive numeric literal. Instead, you must use a unaryOperator()
matcher to match the minus sign:

unaryOperator(hasOperatorName("-"),
              hasUnaryOperand(integerLiteral(equals(13))))

Usable as: Matcher<CharacterLiteral>, Matcher<CXXBoolLiteralExpr>,
           Matcher<FloatingLiteral>, Matcher<IntegerLiteral>

Matches a `LambdaCapture` that refers to 'this'.

Given
class C {
  int cc;
  int f() {
    auto l = [this]() { return cc; };
    return l();
  }
};
lambdaExpr(hasAnyCapture(lambdaCapture(capturesThis())))
  matches `[this]() { return cc; }`.

Matches an entity that has been implicitly added by the compiler (e.g.
implicit default/copy constructors).

Matches member expressions that are called with '->' as opposed
to '.'.

Member calls on the implicit this pointer match as called with '->'.

Given
  class Y {
    void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
    template <class T> void f() { this->f<T>(); f<T>(); }
    int a;
    static int b;
  };
  template <class T>
  class Z {
    void x() { this->m; }
  };
memberExpr(isArrow())
  matches this->x, x, y.x, a, this->b
cxxDependentScopeMemberExpr(isArrow())
  matches this->m
unresolvedMemberExpr(isArrow())
  matches this->f<T>, f<T>

Matches NamedDecl nodes that have any of the specified names.

This matcher is only provided as a performance optimization of hasName.
    hasAnyName(a, b, c)
 is equivalent to, but faster than
    anyOf(hasName(a), hasName(b), hasName(c))

Matches a declaration that has external formal linkage.

Example matches only z (matcher = varDecl(hasExternalFormalLinkage()))
void f() {
  int x;
  static int y;
}
int z;

Example matches f() because it has external formal linkage despite being
unique to the translation unit as though it has internal likage
(matcher = functionDecl(hasExternalFormalLinkage()))

namespace {
void f() {}
}

Matches NamedDecl nodes that have the specified name.

Supports specifying enclosing namespaces or classes by prefixing the name
with '<enclosing>::'.
Does not match typedefs of an underlying type with the given name.

Example matches X (Name == "X")
  class X;

Example matches X (Name is one of "::a::b::X", "a::b::X", "b::X", "X")
  namespace a { namespace b { class X; } }

Matches NamedDecl nodes whose fully qualified names contain
a substring matched by the given RegExp.

Supports specifying enclosing namespaces or classes by
prefixing the name with '<enclosing>::'.  Does not match typedefs
of an underlying type with the given name.

Example matches X (regexp == "::X")
  class X;

Example matches X (regexp is one of "::X", "^foo::.*X", among others)
  namespace foo { namespace bar { class X; } }

If the matcher is used in clang-query, RegexFlags parameter
should be passed as a quoted string. e.g: "NoFlags".
Flags can be combined with '|' example "IgnoreCase | BasicRegex"

Matches anonymous namespace declarations.

Given
  namespace n {
  namespace {} // #1
  }
namespaceDecl(isAnonymous()) will match #1 but not ::n.

Matches function and namespace declarations that are marked with
the inline keyword.

Given
  inline void f();
  void g();
  namespace n {
  inline namespace m {}
  }
functionDecl(isInline()) will match ::f().
namespaceDecl(isInline()) will match n::m.

Matches if the OpenMP ``default`` clause has ``firstprivate`` kind
specified.

Given

  #pragma omp parallel
  #pragma omp parallel default(none)
  #pragma omp parallel default(shared)
  #pragma omp parallel default(firstprivate)

``ompDefaultClause(isFirstPrivateKind())`` matches only
``default(firstprivate)``.

Matches if the OpenMP ``default`` clause has ``none`` kind specified.

Given

  #pragma omp parallel
  #pragma omp parallel default(none)
  #pragma omp parallel default(shared)
  #pragma omp parallel default(firstprivate)

``ompDefaultClause(isNoneKind())`` matches only ``default(none)``.

Matches if the OpenMP ``default`` clause has ``shared`` kind specified.

Given

  #pragma omp parallel
  #pragma omp parallel default(none)
  #pragma omp parallel default(shared)
  #pragma omp parallel default(firstprivate)

``ompDefaultClause(isSharedKind())`` matches only ``default(shared)``.

Matches if the OpenMP directive is allowed to contain the specified OpenMP
clause kind.

Given

  #pragma omp parallel
  #pragma omp parallel for
  #pragma omp          for

`ompExecutableDirective(isAllowedToContainClause(OMPC_default))`` matches
``omp parallel`` and ``omp parallel for``.

If the matcher is use from clang-query, ``OpenMPClauseKind`` parameter
should be passed as a quoted string. e.g.,
``isAllowedToContainClauseKind("OMPC_default").``

Matches standalone OpenMP directives,
i.e., directives that can't have a structured block.

Given

  #pragma omp parallel
  {}
  #pragma omp taskyield

``ompExecutableDirective(isStandaloneDirective()))`` matches
``omp taskyield``.

Overloaded method as shortcut for isDerivedFrom(hasName(...)).

Overloaded method as shortcut for isDirectlyDerivedFrom(hasName(...)).

Overloaded method as shortcut for
isSameOrDerivedFrom(hasName(...)).

Checks that a call expression or a constructor call expression has
a specific number of arguments (including absent default arguments).

Example matches f(0, 0) (matcher = callExpr(argumentCountIs(2)))
  void f(int x, int y);
  f(0, 0);

Matches when at least one of the supplied string equals to the
Selector.getAsString()

 matcher = objCMessageExpr(hasSelector("methodA:", "methodB:"));
 matches both of the expressions below:
    [myObj methodA:argA];
    [myObj methodB:argB];

Matches when the selector is a keyword selector

objCMessageExpr(hasKeywordSelector()) matches the generated setFrame
message expression in

  UIWebView *webView = ...;
  CGRect bodyFrame = webView.frame;
  bodyFrame.size.height = self.bodyContentHeight;
  webView.frame = bodyFrame;
  //     ^---- matches here

Matches when the selector is the empty selector

Matches only when the selector of the objCMessageExpr is NULL. This may
represent an error condition in the tree!

Matches when BaseName == Selector.getAsString()

 matcher = objCMessageExpr(hasSelector("loadHTMLString:baseURL:"));
 matches the outer message expr in the code below, but NOT the message
 invocation for self.bodyView.
    [self.bodyView loadHTMLString:html baseURL:NULL];

Matches when the selector is a Unary Selector

 matcher = objCMessageExpr(matchesSelector(hasUnarySelector());
 matches self.bodyView in the code below, but NOT the outer message
 invocation of "loadHTMLString:baseURL:".
    [self.bodyView loadHTMLString:html baseURL:NULL];

Returns true when the Objective-C message is sent to a class.

Example
matcher = objcMessageExpr(isClassMessage())
matches
  [NSString stringWithFormat:@"format"];
but not
  NSString *x = @"hello";
  [x containsString:@"h"];

Returns true when the Objective-C message is sent to an instance.

Example
matcher = objcMessageExpr(isInstanceMessage())
matches
  NSString *x = @"hello";
  [x containsString:@"h"];
but not
  [NSString stringWithFormat:@"format"];

Matches ObjC selectors whose name contains
a substring matched by the given RegExp.
 matcher = objCMessageExpr(matchesSelector("loadHTMLStringmatches the outer message expr in the code below, but NOT the message
 invocation for self.bodyView.
    [self.bodyView loadHTMLString:html baseURL:NULL];

If the matcher is used in clang-query, RegexFlags parameter
should be passed as a quoted string. e.g: "NoFlags".
Flags can be combined with '|' example "IgnoreCase | BasicRegex"

Matches when the selector has the specified number of arguments

 matcher = objCMessageExpr(numSelectorArgs(0));
 matches self.bodyView in the code below

 matcher = objCMessageExpr(numSelectorArgs(2));
 matches the invocation of "loadHTMLString:baseURL:" but not that
 of self.bodyView
    [self.bodyView loadHTMLString:html baseURL:NULL];

Returns true when the Objective-C method declaration is a class method.

Example
matcher = objcMethodDecl(isClassMethod())
matches
@interface I + (void)foo; @end
but not
@interface I - (void)bar; @end

Matches if a declaration has a body attached.

Example matches A, va, fa
  class A {};
  class B;  // Doesn't match, as it has no body.
  int va;
  extern int vb;  // Doesn't match, as it doesn't define the variable.
  void fa() {}
  void fb();  // Doesn't match, as it has no body.
  @interface X
  - (void)ma; // Doesn't match, interface is declaration.
  @end
  @implementation X
  - (void)ma {}
  @end

Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
  Matcher<ObjCMethodDecl>

Returns true when the Objective-C method declaration is an instance method.

Example
matcher = objcMethodDecl(isInstanceMethod())
matches
@interface I - (void)bar; @end
but not
@interface I + (void)foo; @end

Matches a declaration that has default arguments.

Example matches y (matcher = parmVarDecl(hasDefaultArgument()))
void x(int val) {}
void y(int val = 0) {}

Deprecated. Use hasInitializer() instead to be able to
match on the contents of the default argument.  For example:

void x(int val = 7) {}
void y(int val = 42) {}
parmVarDecl(hasInitializer(integerLiteral(equals(42))))
  matches the parameter of y

A matcher such as
  parmVarDecl(hasInitializer(anything()))
is equivalent to parmVarDecl(hasDefaultArgument()).

Matches the ParmVarDecl nodes that are at the N'th position in the parameter
list. The parameter list could be that of either a block, function, or
objc-method.


Given

void f(int a, int b, int c) {
}

``parmVarDecl(isAtPosition(0))`` matches ``int a``.

``parmVarDecl(isAtPosition(1))`` matches ``int b``.

Matches if the matched type is represented by the given string.

Given
  class Y { public: void x(); };
  void z() { Y* y; y->x(); }
cxxMemberCallExpr(on(hasType(asString("class Y *"))))
  matches y->x()

Matches if a node equals a previously bound node.

Matches a node if it equals the node previously bound to ID.

Given
  class X { int a; int b; };
cxxRecordDecl(
    has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
    has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
  matches the class X, as a and b have the same type.

Note that when multiple matches are involved via forEach* matchers,
equalsBoundNodes acts as a filter.
For example:
compoundStmt(
    forEachDescendant(varDecl().bind("d")),
    forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
will trigger a match for each combination of variable declaration
and reference to that variable declaration within a compound statement.

Matches QualType nodes that have local CV-qualifiers attached to
the node, not hidden within a typedef.

Given
  typedef const int const_int;
  const_int i;
  int *const j;
  int *volatile k;
  int m;
varDecl(hasType(hasLocalQualifiers())) matches only j and k.
i is const-qualified but the qualifier is not local.

Matches QualType nodes that are of character type.

Given
  void a(char);
  void b(wchar_t);
  void c(double);
functionDecl(hasAnyParameter(hasType(isAnyCharacter())))
matches "a(char)", "b(wchar_t)", but not "c(double)".

Matches QualType nodes that are of any pointer type; this includes
the Objective-C object pointer type, which is different despite being
syntactically similar.

Given
  int *i = nullptr;

  @interface Foo
  @end
  Foo *f;

  int j;
varDecl(hasType(isAnyPointer()))
  matches "int *i" and "Foo *f", but not "int j".

Matches QualType nodes that are const-qualified, i.e., that
include "top-level" const.

Given
  void a(int);
  void b(int const);
  void c(const int);
  void d(const int*);
  void e(int const) {};
functionDecl(hasAnyParameter(hasType(isConstQualified())))
  matches "void b(int const)", "void c(const int)" and
  "void e(int const) {}". It does not match d as there
  is no top-level const on the parameter type "const int *".

Matches QualType nodes that are of integer type.

Given
  void a(int);
  void b(long);
  void c(double);
functionDecl(hasAnyParameter(hasType(isInteger())))
matches "a(int)", "b(long)", but not "c(double)".

Matches QualType nodes that are of signed integer type.

Given
  void a(int);
  void b(unsigned long);
  void c(double);
functionDecl(hasAnyParameter(hasType(isSignedInteger())))
matches "a(int)", but not "b(unsigned long)" and "c(double)".

Matches QualType nodes that are of unsigned integer type.

Given
  void a(int);
  void b(unsigned long);
  void c(double);
functionDecl(hasAnyParameter(hasType(isUnsignedInteger())))
matches "b(unsigned long)", but not "a(int)" and "c(double)".

Matches QualType nodes that are volatile-qualified, i.e., that
include "top-level" volatile.

Given
  void a(int);
  void b(int volatile);
  void c(volatile int);
  void d(volatile int*);
  void e(int volatile) {};
functionDecl(hasAnyParameter(hasType(isVolatileQualified())))
  matches "void b(int volatile)", "void c(volatile int)" and
  "void e(int volatile) {}". It does not match d as there
  is no top-level volatile on the parameter type "volatile int *".

Matches if a node equals a previously bound node.

Matches a node if it equals the node previously bound to ID.

Given
  class X { int a; int b; };
cxxRecordDecl(
    has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
    has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
  matches the class X, as a and b have the same type.

Note that when multiple matches are involved via forEach* matchers,
equalsBoundNodes acts as a filter.
For example:
compoundStmt(
    forEachDescendant(varDecl().bind("d")),
    forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
will trigger a match for each combination of variable declaration
and reference to that variable declaration within a compound statement.

Matches if a node equals another node.

Stmt has pointer identity in the AST.

Matches statements that are (transitively) expanded from the named macro.
Does not match if only part of the statement is expanded from that macro or
if different parts of the statement are expanded from different
appearances of the macro.

Matches AST nodes that were expanded within files whose name is
partially matching a given regex.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
  #include "ASTMatcher.h"
  class X {};
ASTMatcher.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

If the matcher is used in clang-query, RegexFlags parameter
should be passed as a quoted string. e.g: "NoFlags".
Flags can be combined with '|' example "IgnoreCase | BasicRegex"

Matches AST nodes that were expanded within the main-file.

Example matches X but not Y
  (matcher = cxxRecordDecl(isExpansionInMainFile())
  #include <Y.h>
  class X {};
Y.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches AST nodes that were expanded within system-header-files.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInSystemHeader())
  #include <SystemHeader.h>
  class X {};
SystemHeader.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches statements inside of a template instantiation.

Given
  int j;
  template<typename T> void A(T t) { T i; j += 42;}
  A(0);
  A(0U);
declStmt(isInTemplateInstantiation())
  matches 'int i;' and 'unsigned i'.
unless(stmt(isInTemplateInstantiation()))
  will NOT match j += 42; as it's shared between the template definition and
  instantiation.

Matches nodes that have the specified size.

Given
  int a[42];
  int b[2 * 21];
  int c[41], d[43];
  char *s = "abcd";
  wchar_t *ws = L"abcd";
  char *w = "a";
constantArrayType(hasSize(42))
  matches "int a[42]" and "int b[2 * 21]"
stringLiteral(hasSize(4))
  matches "abcd", L"abcd"

Matches TagDecl object that are spelled with "class."

Example matches C, but not S, U or E.
  struct S {};
  class C {};
  union U {};
  enum E {};

Matches if a declaration has a body attached.

Example matches A, va, fa
  class A {};
  class B;  // Doesn't match, as it has no body.
  int va;
  extern int vb;  // Doesn't match, as it doesn't define the variable.
  void fa() {}
  void fb();  // Doesn't match, as it has no body.
  @interface X
  - (void)ma; // Doesn't match, interface is declaration.
  @end
  @implementation X
  - (void)ma {}
  @end

Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
  Matcher<ObjCMethodDecl>

Matches TagDecl object that are spelled with "enum."

Example matches E, but not C, S or U.
  struct S {};
  class C {};
  union U {};
  enum E {};

Matches TagDecl object that are spelled with "struct."

Example matches S, but not C, U or E.
  struct S {};
  class C {};
  union U {};
  enum E {};

Matches TagDecl object that are spelled with "union."

Example matches U, but not C, S or E.
  struct S {};
  class C {};
  union U {};
  enum E {};

Matches a TemplateArgument of integral type with a given value.

Note that 'Value' is a string as the template argument's value is
an arbitrary precision integer. 'Value' must be euqal to the canonical
representation of that integral value in base 10.

Given
  template<int T> struct C {};
  C<42> c;
classTemplateSpecializationDecl(
  hasAnyTemplateArgument(equalsIntegralValue("42")))
  matches the implicit instantiation of C in C<42>.

Matches a TemplateArgument that is an integral value.

Given
  template<int T> struct C {};
  C<42> c;
classTemplateSpecializationDecl(
  hasAnyTemplateArgument(isIntegral()))
  matches the implicit instantiation of C in C<42>
  with isIntegral() matching 42.

Matches if the number of template arguments equals N.

Given
  template<typename T> struct C {};
  C<int> c;
classTemplateSpecializationDecl(templateArgumentCountIs(1))
  matches C<int>.

Matches statements that are (transitively) expanded from the named macro.
Does not match if only part of the statement is expanded from that macro or
if different parts of the statement are expanded from different
appearances of the macro.

Matches AST nodes that were expanded within files whose name is
partially matching a given regex.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInFileMatching("AST.*"))
  #include "ASTMatcher.h"
  class X {};
ASTMatcher.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

If the matcher is used in clang-query, RegexFlags parameter
should be passed as a quoted string. e.g: "NoFlags".
Flags can be combined with '|' example "IgnoreCase | BasicRegex"

Matches AST nodes that were expanded within the main-file.

Example matches X but not Y
  (matcher = cxxRecordDecl(isExpansionInMainFile())
  #include <Y.h>
  class X {};
Y.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches AST nodes that were expanded within system-header-files.

Example matches Y but not X
    (matcher = cxxRecordDecl(isExpansionInSystemHeader())
  #include <SystemHeader.h>
  class X {};
SystemHeader.h:
  class Y {};

Usable as: Matcher<Decl>, Matcher<Stmt>, Matcher<TypeLoc>

Matches type bool.

Given
 struct S { bool func(); };
functionDecl(returns(booleanType()))
  matches "bool func();"

Matches if a node equals a previously bound node.

Matches a node if it equals the node previously bound to ID.

Given
  class X { int a; int b; };
cxxRecordDecl(
    has(fieldDecl(hasName("a"), hasType(type().bind("t")))),
    has(fieldDecl(hasName("b"), hasType(type(equalsBoundNode("t"))))))
  matches the class X, as a and b have the same type.

Note that when multiple matches are involved via forEach* matchers,
equalsBoundNodes acts as a filter.
For example:
compoundStmt(
    forEachDescendant(varDecl().bind("d")),
    forEachDescendant(declRefExpr(to(decl(equalsBoundNode("d"))))))
will trigger a match for each combination of variable declaration
and reference to that variable declaration within a compound statement.

Matches if a node equals another node.

Type has pointer identity in the AST.

Matches any real floating-point type (float, double, long double).

Given
  int i;
  float f;
realFloatingPointType()
  matches "float f" but not "int i"

Matches type void.

Given
 struct S { void func(); };
functionDecl(returns(voidType()))
  matches "void func();"

Matches unary expressions of a certain kind.

Given
  int x;
  int s = sizeof(x) + alignof(x)
unaryExprOrTypeTraitExpr(ofKind(UETT_SizeOf))
  matches sizeof(x)

If the matcher is use from clang-query, UnaryExprOrTypeTrait parameter
should be passed as a quoted string. e.g., ofKind("UETT_SizeOf").

Matches operator expressions (binary or unary) that have any of the
specified names.

   hasAnyOperatorName("+", "-")
 Is equivalent to
   anyOf(hasOperatorName("+"), hasOperatorName("-"))

Matches the operator Name of operator expressions (binary or
unary).

Example matches a || b (matcher = binaryOperator(hasOperatorName("||")))
  !(a || b)

Matches member expressions that are called with '->' as opposed
to '.'.

Member calls on the implicit this pointer match as called with '->'.

Given
  class Y {
    void x() { this->x(); x(); Y y; y.x(); a; this->b; Y::b; }
    template <class T> void f() { this->f<T>(); f<T>(); }
    int a;
    static int b;
  };
  template <class T>
  class Z {
    void x() { this->m; }
  };
memberExpr(isArrow())
  matches this->x, x, y.x, a, this->b
cxxDependentScopeMemberExpr(isArrow())
  matches this->m
unresolvedMemberExpr(isArrow())
  matches this->f<T>, f<T>

Matches a variable declaration that has automatic storage duration.

Example matches x, but not y, z, or a.
(matcher = varDecl(hasAutomaticStorageDuration())
void f() {
  int x;
  static int y;
  thread_local int z;
}
int a;

Matches a variable declaration that does not have local storage.

Example matches y and z (matcher = varDecl(hasGlobalStorage())
void f() {
  int x;
  static int y;
}
int z;

Matches a variable declaration that has function scope and is a
non-static local variable.

Example matches x (matcher = varDecl(hasLocalStorage())
void f() {
  int x;
  static int y;
}
int z;

Matches a variable declaration that has static storage duration.
It includes the variable declared at namespace scope and those declared
with "static" and "extern" storage class specifiers.

void f() {
  int x;
  static int y;
  thread_local int z;
}
int a;
static int b;
extern int c;
varDecl(hasStaticStorageDuration())
  matches the function declaration y, a, b and c.

Matches a variable declaration that has thread storage duration.

Example matches z, but not x, z, or a.
(matcher = varDecl(hasThreadStorageDuration())
void f() {
  int x;
  static int y;
  thread_local int z;
}
int a;

Matches constexpr variable and function declarations,
       and if constexpr.

Given:
  constexpr int foo = 42;
  constexpr int bar();
  void baz() { if constexpr(1 > 0) {} }
varDecl(isConstexpr())
  matches the declaration of foo.
functionDecl(isConstexpr())
  matches the declaration of bar.
ifStmt(isConstexpr())
  matches the if statement in baz.

Matches constinit variable declarations.

Given:
  constinit int foo = 42;
  constinit const char* bar = "baz";
  int baz = 42;
  [[clang::require_constant_initialization]] int xyz = 42;
varDecl(isConstinit())
  matches the declaration of `foo` and `bar`, but not `baz` and `xyz`.

Matches if a declaration has a body attached.

Example matches A, va, fa
  class A {};
  class B;  // Doesn't match, as it has no body.
  int va;
  extern int vb;  // Doesn't match, as it doesn't define the variable.
  void fa() {}
  void fb();  // Doesn't match, as it has no body.
  @interface X
  - (void)ma; // Doesn't match, interface is declaration.
  @end
  @implementation X
  - (void)ma {}
  @end

Usable as: Matcher<TagDecl>, Matcher<VarDecl>, Matcher<FunctionDecl>,
  Matcher<ObjCMethodDecl>

Matches a variable declaration that is an exception variable from
a C++ catch block, or an Objective-C statement.

Example matches x (matcher = varDecl(isExceptionVariable())
void f(int y) {
  try {
  } catch (int x) {
  }
}

Matches explicit template specializations of function, class, or
static member variable template instantiations.

Given
  template<typename T> void A(T t) { }
  template<> void A(int N) { }
functionDecl(isExplicitTemplateSpecialization())
  matches the specialization A<int>().

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches extern "C" function or variable declarations.

Given:
  extern "C" void f() {}
  extern "C" { void g() {} }
  void h() {}
  extern "C" int x = 1;
  extern "C" int y = 2;
  int z = 3;
functionDecl(isExternC())
  matches the declaration of f and g, but not the declaration of h.
varDecl(isExternC())
  matches the declaration of x and y, but not the declaration of z.

Matches a variable serving as the implicit variable for a lambda init-
capture.

Example matches x (matcher = varDecl(isInitCapture()))
auto f = [x=3]() { return x; };

Matches a static variable with local scope.

Example matches y (matcher = varDecl(isStaticLocal()))
void f() {
  int x;
  static int y;
}
static int z;

Matches variable/function declarations that have "static" storage
class specifier ("static" keyword) written in the source.

Given:
  static void f() {}
  static int i = 0;
  extern int j;
  int k;
functionDecl(isStaticStorageClass())
  matches the function declaration f.
varDecl(isStaticStorageClass())
  matches the variable declaration i.

Matches template instantiations of function, class, or static
member variable template instantiations.

Given
  template <typename T> class X {}; class A {}; X<A> x;
or
  template <typename T> class X {}; class A {}; template class X<A>;
or
  template <typename T> class X {}; class A {}; extern template class X<A>;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  matches the template instantiation of X<A>.

But given
  template <typename T>  class X {}; class A {};
  template <> class X<A> {}; X<A> x;
cxxRecordDecl(hasName("::X"), isTemplateInstantiation())
  does not match, as X<A> is an explicit template specialization.

Usable as: Matcher<FunctionDecl>, Matcher<VarDecl>, Matcher<CXXRecordDecl>

Matches nodes which can be used with binary operators.

The code
  var1 != var2;
might be represented in the clang AST as a binaryOperator, a
cxxOperatorCallExpr or a cxxRewrittenBinaryOperator, depending on

* whether the types of var1 and var2 are fundamental (binaryOperator) or at
  least one is a class type (cxxOperatorCallExpr)
* whether the code appears in a template declaration, if at least one of the
  vars is a dependent-type (binaryOperator)
* whether the code relies on a rewritten binary operator, such as a
spaceship operator or an inverted equality operator
(cxxRewrittenBinaryOperator)

This matcher elides details in places where the matchers for the nodes are
compatible.

Given
  binaryOperation(
    hasOperatorName("!="),
    hasLHS(expr().bind("lhs")),
    hasRHS(expr().bind("rhs"))
  )
matches each use of "!=" in:
  struct S{
      bool operator!=(const S&) const;
  };

  void foo()
  {
     1 != 2;
     S() != S();
  }

  template<typename T>
  void templ()
  {
     1 != 2;
     T() != S();
  }
  struct HasOpEq
  {
      bool operator==(const HasOpEq &) const;
  };

  void inverse()
  {
      HasOpEq s1;
      HasOpEq s2;
      if (s1 != s2)
          return;
  }

  struct HasSpaceship
  {
      bool operator<=>(const HasOpEq &) const;
  };

  void use_spaceship()
  {
      HasSpaceship s1;
      HasSpaceship s2;
      if (s1 != s2)
          return;
  }

Matches if any of the given matchers matches.

Unlike anyOf, eachOf will generate a match result for each
matching submatcher.

For example, in:
  class A { int a; int b; };
The matcher:
  cxxRecordDecl(eachOf(has(fieldDecl(hasName("a")).bind("v")),
                       has(fieldDecl(hasName("b")).bind("v"))))
will generate two results binding "v", the first of which binds
the field declaration of a, the second the field declaration of
b.

Usable as: Any Matcher

Matches if the node or any descendant matches.

Generates results for each match.

For example, in:
  class A { class B {}; class C {}; };
The matcher:
  cxxRecordDecl(hasName("::A"),
                findAll(cxxRecordDecl(isDefinition()).bind("m")))
will generate results for A, B and C.

Usable as: Any Matcher

Matches AST nodes that have descendant AST nodes that match the
provided matcher.

Example matches X, A, A::X, B, B::C, B::C::X
  (matcher = cxxRecordDecl(forEachDescendant(cxxRecordDecl(hasName("X")))))
  class X {};
  class A { class X {}; };  // Matches A, because A::X is a class of name
                            // X inside A.
  class B { class C { class X {}; }; };

DescendantT must be an AST base type.

As opposed to 'hasDescendant', 'forEachDescendant' will cause a match for
each result that matches instead of only on the first one.

Note: Recursively combined ForEachDescendant can cause many matches:
  cxxRecordDecl(forEachDescendant(cxxRecordDecl(
    forEachDescendant(cxxRecordDecl())
  )))
will match 10 times (plus injected class name matches) on:
  class A { class B { class C { class D { class E {}; }; }; }; };

Usable as: Any Matcher

Matches AST nodes that have child AST nodes that match the
provided matcher.

Example matches X, Y, Y::X, Z::Y, Z::Y::X
  (matcher = cxxRecordDecl(forEach(cxxRecordDecl(hasName("X")))
  class X {};
  class Y { class X {}; };  // Matches Y, because Y::X is a class of name X
                            // inside Y.
  class Z { class Y { class X {}; }; };  // Does not match Z.

ChildT must be an AST base type.

As opposed to 'has', 'forEach' will cause a match for each result that
matches instead of only on the first one.

Usable as: Any Matcher

Matches AST nodes that have an ancestor that matches the provided
matcher.

Given
void f() { if (true) { int x = 42; } }
void g() { for (;;) { int x = 43; } }
expr(integerLiteral(hasAncestor(ifStmt()))) matches 42, but not 43.

Usable as: Any Matcher

Matches AST nodes that have descendant AST nodes that match the
provided matcher.

Example matches X, Y, Z
    (matcher = cxxRecordDecl(hasDescendant(cxxRecordDecl(hasName("X")))))
  class X {};  // Matches X, because X::X is a class of name X inside X.
  class Y { class X {}; };
  class Z { class Y { class X {}; }; };

DescendantT must be an AST base type.

Usable as: Any Matcher

Matches AST nodes that have child AST nodes that match the
provided matcher.

Example matches X, Y
  (matcher = cxxRecordDecl(has(cxxRecordDecl(hasName("X")))
  class X {};  // Matches X, because X::X is a class of name X inside X.
  class Y { class X {}; };
  class Z { class Y { class X {}; }; };  // Does not match Z.

ChildT must be an AST base type.

Usable as: Any Matcher
Note that has is direct matcher, so it also matches things like implicit
casts and paren casts. If you are matching with expr then you should
probably consider using ignoringParenImpCasts like:
has(ignoringParenImpCasts(expr())).

Matches AST nodes that have a parent that matches the provided
matcher.

Given
void f() { for (;;) { int x = 42; if (true) { int x = 43; } } }
compoundStmt(hasParent(ifStmt())) matches "{ int x = 43; }".

Usable as: Any Matcher

Matches function calls and constructor calls

Because CallExpr and CXXConstructExpr do not share a common
base class with API accessing arguments etc, AST Matchers for code
which should match both are typically duplicated. This matcher
removes the need for duplication.

Given code
struct ConstructorTakesInt
{
  ConstructorTakesInt(int i) {}
};

void callTakesInt(int i)
{
}

void doCall()
{
  callTakesInt(42);
}

void doConstruct()
{
  ConstructorTakesInt cti(42);
}

The matcher
invocation(hasArgument(0, integerLiteral(equals(42))))
matches the expression in both doCall and doConstruct

Matches any node regardless of the submatcher.

However, optionally will retain any bindings generated by the submatcher.
Useful when additional information which may or may not present about a main
matching node is desired.

For example, in:
  class Foo {
    int bar;
  }
The matcher:
  cxxRecordDecl(
    optionally(has(
      fieldDecl(hasName("bar")).bind("var")
  ))).bind("record")
will produce a result binding for both "record" and "var".
The matcher will produce a "record" binding for even if there is no data
member named "bar" in that class.

Usable as: Any Matcher

Causes all nested matchers to be matched with the specified traversal kind.

Given
  void foo()
  {
      int i = 3.0;
  }
The matcher
  traverse(TK_IgnoreUnlessSpelledInSource,
    varDecl(hasInitializer(floatLiteral().bind("init")))
  )
matches the variable declaration with "init" bound to the "3.0".

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}

Matches the false branch expression of a conditional operator
(binary or ternary).

Example matches b
  condition ? a : b
  condition ?: b

Matches the true branch expression of a conditional operator.

Example 1 (conditional ternary operator): matches a
  condition ? a : b

Example 2 (conditional binary operator): matches opaqueValueExpr(condition)
  condition ?: b

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches the base expression of an array subscript expression.

Given
  int i[5];
  void f() { i[1] = 42; }
arraySubscriptExpression(hasBase(implicitCastExpr(
    hasSourceExpression(declRefExpr()))))
  matches i[1] with the declRefExpr() matching i

Matches the index expression of an array subscript expression.

Given
  int i[5];
  void f() { i[1] = 42; }
arraySubscriptExpression(hasIndex(integerLiteral()))
  matches i[1] with the integerLiteral() matching 1

Matches the left hand side of binary operator expressions.

Example matches a (matcher = binaryOperator(hasLHS()))
  a || b

Matches the right hand side of binary operator expressions.

Example matches b (matcher = binaryOperator(hasRHS()))
  a || b

Matches arrays and C99 complex types that have a specific element
type.

Given
  struct A {};
  A a[7];
  int b[7];
arrayType(hasElementType(builtinType()))
  matches "int b[7]"

Usable as: Matcher<ArrayType>, Matcher<ComplexType>

Matches atomic types with a specific value type.

Given
  _Atomic(int) i;
  _Atomic(float) f;
atomicType(hasValueType(isInteger()))
 matches "_Atomic(int) i"

Usable as: Matcher<AtomicType>

Matches AutoType nodes where the deduced type is a specific type.

Note: There is no TypeLoc for the deduced type and thus no
getDeducedLoc() matcher.

Given
  auto a = 1;
  auto b = 2.0;
autoType(hasDeducedType(isInteger()))
  matches "auto a"

Usable as: Matcher<AutoType>

Matches any using shadow declaration.

Given
  namespace X { void b(); }
  using X::b;
usingDecl(hasAnyUsingShadowDecl(hasName("b"))))
  matches using X::b 

Matches if either the left hand side or the right hand side of a
binary operator matches.

Matches the left hand side of binary operator expressions.

Example matches a (matcher = binaryOperator(hasLHS()))
  a || b

Matches if both matchers match with opposite sides of the binary operator.

Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                             integerLiteral(equals(2)))
  1 + 2 // Match
  2 + 1 // Match
  1 + 1 // No match
  2 + 2 // No match

Matches the right hand side of binary operator expressions.

Example matches b (matcher = binaryOperator(hasRHS()))
  a || b

Matches the DecompositionDecl the binding belongs to.

For example, in:
void foo()
{
    int arr[3];
    auto &[f, s, t] = arr;

    f = 42;
}
The matcher:
  bindingDecl(hasName("f"),
                forDecomposition(decompositionDecl())
matches 'f' in 'auto &[f, s, t]'.

Matches any parameter of a function or an ObjC method declaration or a
block.

Does not match the 'this' parameter of a method.

Given
  class X { void f(int x, int y, int z) {} };
cxxMethodDecl(hasAnyParameter(hasName("y")))
  matches f(int x, int y, int z) {}
with hasAnyParameter(...)
  matching int y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
matches the declaration of method f with hasParameter
matching y.

For blocks, given
  b = ^(int y) { printf("%d", y) };

the matcher blockDecl(hasAnyParameter(hasName("y")))
matches the declaration of the block b with hasParameter
matching y.

Matches the n'th parameter of a function or an ObjC method
declaration or a block.

Given
  class X { void f(int x) {} };
cxxMethodDecl(hasParameter(0, hasType(varDecl())))
  matches f(int x) {}
with hasParameter(...)
  matching int x

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasParameter(0, hasName("y")))
matches the declaration of method f with hasParameter
matching y.

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Narrows PointerType (and similar) matchers to those where the
pointee matches a given matcher.

Given
  int *a;
  int const *b;
  float const *f;
pointerType(pointee(isConstQualified(), isInteger()))
  matches "int const *b"

Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
  Matcher<PointerType>, Matcher<ReferenceType>

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Overloaded to match the declaration of the expression's or value
declaration's type.

In case of a value declaration (for example a variable declaration),
this resolves one layer of indirection. For example, in the value
declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
declaration of x.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              cxxRecordDecl(hasName("X"))))
 class X {};
 void y(X &x) { x; X z; }
 class Y { friend class X; };
 class Z : public virtual X {};

Example matches class Derived
(matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
class Base {};
class Derived : Base {};

Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
Matcher<CXXBaseSpecifier>

Matches if the expression's or declaration's type matches a type
matcher.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and U (matcher = typedefDecl(hasType(asString("int")))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              asString("class X")))
 class X {};
 void y(X &x) { x; X z; }
 typedef int U;
 class Y { friend class X; };
 class Z : public virtual X {};

Matches all arguments and their respective ParmVarDecl.

Given
  void f(int i);
  int y;
  f(y);
callExpr(
  forEachArgumentWithParam(
    declRefExpr(to(varDecl(hasName("y")))),
    parmVarDecl(hasType(isInteger()))
))
  matches f(y);
with declRefExpr(...)
  matching int y
and parmVarDecl(...)
  matching int i

Matches all arguments and their respective types for a CallExpr or
CXXConstructExpr. It is very similar to forEachArgumentWithParam but
it works on calls through function pointers as well.

The difference is, that function pointers do not provide access to a
ParmVarDecl, but only the QualType for each argument.

Given
  void f(int i);
  int y;
  f(y);
  void (*f_ptr)(int) = f;
  f_ptr(y);
callExpr(
  forEachArgumentWithParamType(
    declRefExpr(to(varDecl(hasName("y")))),
    qualType(isInteger()).bind("type)
))
  matches f(y) and f_ptr(y)
with declRefExpr(...)
  matching int y
and qualType(...)
  matching int

Matches any argument of a call expression or a constructor call
expression, or an ObjC-message-send expression.

Given
  void x(int, int, int) { int y; x(1, y, 42); }
callExpr(hasAnyArgument(declRefExpr()))
  matches x(1, y, 42)
with hasAnyArgument(...)
  matching y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end
  void foo(I *i) { [i f:12]; }
objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
  matches [i f:12]

Matches the n'th argument of a call expression or a constructor
call expression.

Example matches y in x(y)
    (matcher = callExpr(hasArgument(0, declRefExpr())))
  void x(int) { int y; x(y); }

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches each constructor initializer in a constructor definition.

Given
  class A { A() : i(42), j(42) {} int i; int j; };
cxxConstructorDecl(forEachConstructorInitializer(
  forField(decl().bind("x"))
))
  will trigger two matches, binding for 'i' and 'j' respectively.

Matches a constructor initializer.

Given
  struct Foo {
    Foo() : foo_(1) { }
    int foo_;
  };
cxxRecordDecl(has(cxxConstructorDecl(
  hasAnyConstructorInitializer(anything())
)))
  record matches Foo, hasAnyConstructorInitializer matches foo_(1)

Matches the field declaration of a constructor initializer.

Given
  struct Foo {
    Foo() : foo_(1) { }
    int foo_;
  };
cxxRecordDecl(has(cxxConstructorDecl(hasAnyConstructorInitializer(
    forField(hasName("foo_"))))))
  matches Foo
with forField matching foo_

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches the initializer expression of a constructor initializer.

Given
  struct Foo {
    Foo() : foo_(1) { }
    int foo_;
  };
cxxRecordDecl(has(cxxConstructorDecl(hasAnyConstructorInitializer(
    withInitializer(integerLiteral(equals(1)))))))
  matches Foo
with withInitializer matching (1)

Matches a member expression where the object expression is matched by a
given matcher. Implicit object expressions are included; that is, it matches
use of implicit `this`.

Given
  struct X {
    int m;
    int f(X x) { x.m; return m; }
  };
memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
  matches `x.m`, but not `m`; however,
memberExpr(hasObjectExpression(hasType(pointsTo(
     cxxRecordDecl(hasName("X"))))))
  matches `m` (aka. `this->m`), but not `x.m`.

Matches selection statements with initializer.

Given:
 void foo() {
   if (int i = foobar(); i > 0) {}
   switch (int i = foobar(); i) {}
   for (auto& a = get_range(); auto& x : a) {}
 }
 void bar() {
   if (foobar() > 0) {}
   switch (foobar()) {}
   for (auto& x : get_range()) {}
 }
ifStmt(hasInitStatement(anything()))
  matches the if statement in foo but not in bar.
switchStmt(hasInitStatement(anything()))
  matches the switch statement in foo but not in bar.
cxxForRangeStmt(hasInitStatement(anything()))
  matches the range for statement in foo but not in bar.

Matches the initialization statement of a for loop.

Example:
    forStmt(hasLoopVariable(anything()))
matches 'int x' in
    for (int x : a) { }

Matches the range initialization statement of a for loop.

Example:
    forStmt(hasRangeInit(anything()))
matches 'a' in
    for (int x : a) { }

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches on the implicit object argument of a member call expression. Unlike
`on`, matches the argument directly without stripping away anything.

Given
  class Y { public: void m(); };
  Y g();
  class X : public Y { void g(); };
  void z(Y y, X x) { y.m(); x.m(); x.g(); (g()).m(); }
cxxMemberCallExpr(onImplicitObjectArgument(hasType(
    cxxRecordDecl(hasName("Y")))))
  matches `y.m()`, `x.m()` and (g()).m(), but not `x.g()`.
cxxMemberCallExpr(on(callExpr()))
  does not match `(g()).m()`, because the parens are not ignored.

FIXME: Overload to allow directly matching types?

Matches on the implicit object argument of a member call expression, after
stripping off any parentheses or implicit casts.

Given
  class Y { public: void m(); };
  Y g();
  class X : public Y {};
  void z(Y y, X x) { y.m(); (g()).m(); x.m(); }
cxxMemberCallExpr(on(hasType(cxxRecordDecl(hasName("Y")))))
  matches `y.m()` and `(g()).m()`.
cxxMemberCallExpr(on(hasType(cxxRecordDecl(hasName("X")))))
  matches `x.m()`.
cxxMemberCallExpr(on(callExpr()))
  matches `(g()).m()`.

FIXME: Overload to allow directly matching types?

Overloaded to match the type's declaration.

Matches if the type of the expression's implicit object argument either
matches the InnerMatcher, or is a pointer to a type that matches the
InnerMatcher.

Given
  class Y { public: void m(); };
  class X : public Y { void g(); };
  void z() { Y y; y.m(); Y *p; p->m(); X x; x.m(); x.g(); }
cxxMemberCallExpr(thisPointerType(hasDeclaration(
    cxxRecordDecl(hasName("Y")))))
  matches `y.m()`, `p->m()` and `x.m()`.
cxxMemberCallExpr(thisPointerType(hasDeclaration(
    cxxRecordDecl(hasName("X")))))
  matches `x.g()`.

Matches each method overridden by the given method. This matcher may
produce multiple matches.

Given
  class A { virtual void f(); };
  class B : public A { void f(); };
  class C : public B { void f(); };
cxxMethodDecl(ofClass(hasName("C")),
              forEachOverridden(cxxMethodDecl().bind("b"))).bind("d")
  matches once, with "b" binding "A::f" and "d" binding "C::f" (Note
  that B::f is not overridden by C::f).

The check can produce multiple matches in case of multiple inheritance, e.g.
  class A1 { virtual void f(); };
  class A2 { virtual void f(); };
  class C : public A1, public A2 { void f(); };
cxxMethodDecl(ofClass(hasName("C")),
              forEachOverridden(cxxMethodDecl().bind("b"))).bind("d")
  matches twice, once with "b" binding "A1::f" and "d" binding "C::f", and
  once with "b" binding "A2::f" and "d" binding "C::f".

Matches the class declaration that the given method declaration
belongs to.

FIXME: Generalize this for other kinds of declarations.
FIXME: What other kind of declarations would we need to generalize
this to?

Example matches A() in the last line
    (matcher = cxxConstructExpr(hasDeclaration(cxxMethodDecl(
        ofClass(hasName("A"))))))
  class A {
   public:
    A();
  };
  A a = A();

Matches any placement new expression arguments.

Given:
  MyClass *p1 = new (Storage) MyClass();
cxxNewExpr(hasAnyPlacementArg(anything()))
  matches the expression 'new (Storage, 16) MyClass()'.

Matches array new expressions with a given array size.

Given:
  MyClass *p1 = new MyClass[10];
cxxNewExpr(hasArraySize(integerLiteral(equals(10))))
  matches the expression 'new MyClass[10]'.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches placement new expression arguments.

Given:
  MyClass *p1 = new (Storage, 16) MyClass();
cxxNewExpr(hasPlacementArg(1, integerLiteral(equals(16))))
  matches the expression 'new (Storage, 16) MyClass()'.

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches if either the left hand side or the right hand side of a
binary operator matches.

Matches the left hand side of binary operator expressions.

Example matches a (matcher = binaryOperator(hasLHS()))
  a || b

Matches if both matchers match with opposite sides of the binary operator.

Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                             integerLiteral(equals(2)))
  1 + 2 // Match
  2 + 1 // Match
  1 + 1 // No match
  2 + 2 // No match

Matches the right hand side of binary operator expressions.

Example matches b (matcher = binaryOperator(hasRHS()))
  a || b

Matches if the operand of a unary operator matches.

Example matches true (matcher = hasUnaryOperand(
                                  cxxBoolLiteral(equals(true))))
  !true

Matches C++ classes that have a direct or indirect base matching BaseSpecMatcher.

Example:
matcher hasAnyBase(hasType(cxxRecordDecl(hasName("SpecialBase"))))
  class Foo;
  class Bar : Foo {};
  class Baz : Bar {};
  class SpecialBase;
  class Proxy : SpecialBase {};  // matches Proxy
  class IndirectlyDerived : Proxy {};  //matches IndirectlyDerived

FIXME: Refactor this and isDerivedFrom to reuse implementation.

Matches C++ classes that have a direct base matching BaseSpecMatcher.

Example:
matcher hasDirectBase(hasType(cxxRecordDecl(hasName("SpecialBase"))))
  class Foo;
  class Bar : Foo {};
  class Baz : Bar {};
  class SpecialBase;
  class Proxy : SpecialBase {};  // matches Proxy
  class IndirectlyDerived : Proxy {};  // doesn't match

Matches the first method of a class or struct that satisfies InnerMatcher.

Given:
  class A { void func(); };
  class B { void member(); };

cxxRecordDecl(hasMethod(hasName("func"))) matches the declaration of
A but not B.

Matches C++ classes that are directly or indirectly derived from a class
matching Base, or Objective-C classes that directly or indirectly
subclass a class matching Base.

Note that a class is not considered to be derived from itself.

Example matches Y, Z, C (Base == hasName("X"))
  class X;
  class Y : public X {};  // directly derived
  class Z : public Y {};  // indirectly derived
  typedef X A;
  typedef A B;
  class C : public B {};  // derived from a typedef of X

In the following example, Bar matches isDerivedFrom(hasName("X")):
  class Foo;
  typedef Foo X;
  class Bar : public Foo {};  // derived from a type that X is a typedef of

In the following example, Bar matches isDerivedFrom(hasName("NSObject"))
  @interface NSObject @end
  @interface Bar : NSObject @end

Usable as: Matcher<CXXRecordDecl>, Matcher<ObjCInterfaceDecl>

Matches C++ or Objective-C classes that are directly derived from a class
matching Base.

Note that a class is not considered to be derived from itself.

Example matches Y, C (Base == hasName("X"))
  class X;
  class Y : public X {};  // directly derived
  class Z : public Y {};  // indirectly derived
  typedef X A;
  typedef A B;
  class C : public B {};  // derived from a typedef of X

In the following example, Bar matches isDerivedFrom(hasName("X")):
  class Foo;
  typedef Foo X;
  class Bar : public Foo {};  // derived from a type that X is a typedef of

Similar to isDerivedFrom(), but also matches classes that directly
match Base.

Matches if either the left hand side or the right hand side of a
binary operator matches.

Matches the left hand side of binary operator expressions.

Example matches a (matcher = binaryOperator(hasLHS()))
  a || b

Matches if both matchers match with opposite sides of the binary operator.

Example matcher = binaryOperator(hasOperands(integerLiteral(equals(1),
                                             integerLiteral(equals(2)))
  1 + 2 // Match
  2 + 1 // Match
  1 + 1 // No match
  2 + 2 // No match

Matches the right hand side of binary operator expressions.

Example matches b (matcher = binaryOperator(hasRHS()))
  a || b

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches any argument of a call expression or a constructor call
expression, or an ObjC-message-send expression.

Given
  void x(int, int, int) { int y; x(1, y, 42); }
callExpr(hasAnyArgument(declRefExpr()))
  matches x(1, y, 42)
with hasAnyArgument(...)
  matching y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end
  void foo(I *i) { [i f:12]; }
objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
  matches [i f:12]

Matches the n'th argument of a call expression or a constructor
call expression.

Example matches y in x(y)
    (matcher = callExpr(hasArgument(0, declRefExpr())))
  void x(int) { int y; x(y); }

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches if the call expression's callee's declaration matches the
given matcher.

Example matches y.x() (matcher = callExpr(callee(
                                   cxxMethodDecl(hasName("x")))))
  class Y { public: void x(); };
  void z() { Y y; y.x(); }

Matches if the call expression's callee expression matches.

Given
  class Y { void x() { this->x(); x(); Y y; y.x(); } };
  void f() { f(); }
callExpr(callee(expr()))
  matches this->x(), x(), y.x(), f()
with callee(...)
  matching this->x, x, y.x, f respectively

Note: Callee cannot take the more general internal::Matcher<Expr>
because this introduces ambiguous overloads with calls to Callee taking a
internal::Matcher<Decl>, as the matcher hierarchy is purely
implemented in terms of implicit casts.

Matches all arguments and their respective ParmVarDecl.

Given
  void f(int i);
  int y;
  f(y);
callExpr(
  forEachArgumentWithParam(
    declRefExpr(to(varDecl(hasName("y")))),
    parmVarDecl(hasType(isInteger()))
))
  matches f(y);
with declRefExpr(...)
  matching int y
and parmVarDecl(...)
  matching int i

Matches all arguments and their respective types for a CallExpr or
CXXConstructExpr. It is very similar to forEachArgumentWithParam but
it works on calls through function pointers as well.

The difference is, that function pointers do not provide access to a
ParmVarDecl, but only the QualType for each argument.

Given
  void f(int i);
  int y;
  f(y);
  void (*f_ptr)(int) = f;
  f_ptr(y);
callExpr(
  forEachArgumentWithParamType(
    declRefExpr(to(varDecl(hasName("y")))),
    qualType(isInteger()).bind("type)
))
  matches f(y) and f_ptr(y)
with declRefExpr(...)
  matching int y
and qualType(...)
  matching int

Matches any argument of a call expression or a constructor call
expression, or an ObjC-message-send expression.

Given
  void x(int, int, int) { int y; x(1, y, 42); }
callExpr(hasAnyArgument(declRefExpr()))
  matches x(1, y, 42)
with hasAnyArgument(...)
  matching y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end
  void foo(I *i) { [i f:12]; }
objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
  matches [i f:12]

Matches the n'th argument of a call expression or a constructor
call expression.

Example matches y in x(y)
    (matcher = callExpr(hasArgument(0, declRefExpr())))
  void x(int) { int y; x(y); }

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

If the given case statement does not use the GNU case range
extension, matches the constant given in the statement.

Given
  switch (1) { case 1: case 1+1: case 3 ... 4: ; }
caseStmt(hasCaseConstant(integerLiteral()))
  matches "case 1:"

Matches if the cast's source expression
or opaque value's source expression matches the given matcher.

Example 1: matches "a string"
(matcher = castExpr(hasSourceExpression(cxxConstructExpr())))
class URL { URL(string); };
URL url = "a string";

Example 2: matches 'b' (matcher =
opaqueValueExpr(hasSourceExpression(implicitCastExpr(declRefExpr())))
int a = b ?: 1;

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl that have at least one TemplateArgument matching the given
InnerMatcher.

Given
  template<typename T> class A {};
  template<> class A<double> {};
  A<int> a;

  template<typename T> f() {};
  void func() { f<int>(); };

classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToType(asString("int"))))
  matches the specialization A<int>

functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
  matches the specialization f<int>

Matches the specialized template of a specialization declaration.

Given
  template<typename T> class A {}; #1
  template<> class A<int> {}; #2
classTemplateSpecializationDecl(hasSpecializedTemplate(classTemplateDecl()))
  matches '#2' with classTemplateDecl() matching the class template
  declaration of 'A' at #1.

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

Given
  template<typename T, typename U> class A {};
  A<bool, int> b;
  A<int, bool> c;

  template<typename T> void f() {}
  void func() { f<int>(); };
classTemplateSpecializationDecl(hasTemplateArgument(
    1, refersToType(asString("int"))))
  matches the specialization A<bool, int>

functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
  matches the specialization f<int>

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches arrays and C99 complex types that have a specific element
type.

Given
  struct A {};
  A a[7];
  int b[7];
arrayType(hasElementType(builtinType()))
  matches "int b[7]"

Usable as: Matcher<ArrayType>, Matcher<ComplexType>

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches compound statements where at least one substatement matches
a given matcher. Also matches StmtExprs that have CompoundStmt as children.

Given
  { {}; 1+2; }
hasAnySubstatement(compoundStmt())
  matches '{ {}; 1+2; }'
with compoundStmt()
  matching '{}'

Matches the decayed type, whoes decayed type matches InnerMatcher

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches template specialization `TypeLoc`s where the n'th
`TemplateArgumentLoc` matches the given `InnerMatcher`.

Given
  template<typename T, typename U> class A {};
  A<double, int> b;
  A<int, double> c;
varDecl(hasTypeLoc(templateSpecializationTypeLoc(hasTemplateArgumentLoc(0,
  hasTypeLoc(loc(asString("double")))))))
  matches `A<double, int> b`, but not `A<int, double> c`.

Matches a DeclRefExpr that refers to a declaration through a
specific using shadow declaration.

Given
  namespace a { void f() {} }
  using a::f;
  void g() {
    f();     // Matches this ..
    a::f();  // .. but not this.
  }
declRefExpr(throughUsingDecl(anything()))
  matches f()

Matches a DeclRefExpr that refers to a declaration that matches the
specified matcher.

Example matches x in if(x)
    (matcher = declRefExpr(to(varDecl(hasName("x")))))
  bool x;
  if (x) {}

Matches the n'th declaration of a declaration statement.

Note that this does not work for global declarations because the AST
breaks up multiple-declaration DeclStmt's into multiple single-declaration
DeclStmt's.
Example: Given non-global declarations
  int a, b = 0;
  int c;
  int d = 2, e;
declStmt(containsDeclaration(
      0, varDecl(hasInitializer(anything()))))
  matches only 'int d = 2, e;', and
declStmt(containsDeclaration(1, varDecl()))
  matches 'int a, b = 0' as well as 'int d = 2, e;'
  but 'int c;' is not matched.

Matches the Decl of a DeclStmt which has a single declaration.

Given
  int a, b;
  int c;
declStmt(hasSingleDecl(anything()))
  matches 'int c;' but not 'int a, b;'.

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches declarations whose declaration context, interpreted as a
Decl, matches InnerMatcher.

Given
  namespace N {
    namespace M {
      class D {};
    }
  }

cxxRcordDecl(hasDeclContext(namedDecl(hasName("M")))) matches the
declaration of class D.

Matches DecltypeType nodes to find out the underlying type.

Given
  decltype(1) a = 1;
  decltype(2.0) b = 2.0;
decltypeType(hasUnderlyingType(isInteger()))
  matches the type of "a"

Usable as: Matcher<DecltypeType>

Matches any binding of a DecompositionDecl.

For example, in:
void foo()
{
    int arr[3];
    auto &[f, s, t] = arr;

    f = 42;
}
The matcher:
  decompositionDecl(hasAnyBinding(bindingDecl(hasName("f").bind("fBinding"))))
matches the decomposition decl with 'f' bound to "fBinding".

Matches the Nth binding of a DecompositionDecl.

For example, in:
void foo()
{
    int arr[3];
    auto &[f, s, t] = arr;

    f = 42;
}
The matcher:
  decompositionDecl(hasBinding(0,
  bindingDecl(hasName("f").bind("fBinding"))))
matches the decomposition decl with 'f' bound to "fBinding".

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}

Matches elaborated `TypeLoc`s that have a named `TypeLoc` matching
`InnerMatcher`.

Given
  template <typename T>
  class C {};
  class C<int> c;

  class D {};
  class D d;
elaboratedTypeLoc(hasNamedTypeLoc(templateSpecializationTypeLoc()));
  matches the `TypeLoc` of the variable declaration of `c`, but not `d`.

Matches ElaboratedTypes whose qualifier, a NestedNameSpecifier,
matches InnerMatcher if the qualifier exists.

Given
  namespace N {
    namespace M {
      class D {};
    }
  }
  N::M::D d;

elaboratedType(hasQualifier(hasPrefix(specifiesNamespace(hasName("N"))))
matches the type of the variable declaration of d.

Matches ElaboratedTypes whose named type matches InnerMatcher.

Given
  namespace N {
    namespace M {
      class D {};
    }
  }
  N::M::D d;

elaboratedType(namesType(recordType(
hasDeclaration(namedDecl(hasName("D")))))) matches the type of the variable
declaration of d.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches casts whose destination type matches a given matcher.

(Note: Clang's AST refers to other conversions as "casts" too, and calls
actual casts "explicit" casts.)

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Overloaded to match the declaration of the expression's or value
declaration's type.

In case of a value declaration (for example a variable declaration),
this resolves one layer of indirection. For example, in the value
declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
declaration of x.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              cxxRecordDecl(hasName("X"))))
 class X {};
 void y(X &x) { x; X z; }
 class Y { friend class X; };
 class Z : public virtual X {};

Example matches class Derived
(matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
class Base {};
class Derived : Base {};

Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
Matcher<CXXBaseSpecifier>

Matches if the expression's or declaration's type matches a type
matcher.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and U (matcher = typedefDecl(hasType(asString("int")))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              asString("class X")))
 class X {};
 void y(X &x) { x; X z; }
 typedef int U;
 class Y { friend class X; };
 class Z : public virtual X {};

Matches expressions that match InnerMatcher that are possibly wrapped in an
elidable constructor and other corresponding bookkeeping nodes.

In C++17, elidable copy constructors are no longer being generated in the
AST as it is not permitted by the standard. They are, however, part of the
AST in C++14 and earlier. So, a matcher must abstract over these differences
to work in all language modes. This matcher skips elidable constructor-call
AST nodes, `ExprWithCleanups` nodes wrapping elidable constructor-calls and
various implicit nodes inside the constructor calls, all of which will not
appear in the C++17 AST.

Given

struct H {};
H G();
void f() {
  H D = G();
}

``varDecl(hasInitializer(ignoringElidableConstructorCall(callExpr())))``
matches ``H D = G()`` in C++11 through C++17 (and beyond).

Matches expressions that match InnerMatcher after any implicit casts
are stripped off.

Parentheses and explicit casts are not discarded.
Given
  int arr[5];
  int a = 0;
  char b = 0;
  const int c = a;
  int *d = arr;
  long e = (long) 0l;
The matchers
   varDecl(hasInitializer(ignoringImpCasts(integerLiteral())))
   varDecl(hasInitializer(ignoringImpCasts(declRefExpr())))
would match the declarations for a, b, c, and d, but not e.
While
   varDecl(hasInitializer(integerLiteral()))
   varDecl(hasInitializer(declRefExpr()))
only match the declarations for a.

Matches expressions that match InnerMatcher after any implicit AST
nodes are stripped off.

Parentheses and explicit casts are not discarded.
Given
  class C {};
  C a = C();
  C b;
  C c = b;
The matchers
   varDecl(hasInitializer(ignoringImplicit(cxxConstructExpr())))
would match the declarations for a, b, and c.
While
   varDecl(hasInitializer(cxxConstructExpr()))
only match the declarations for b and c.

Matches expressions that match InnerMatcher after parentheses and
casts are stripped off.

Implicit and non-C Style casts are also discarded.
Given
  int a = 0;
  char b = (0);
  void* c = reinterpret_cast<char*>(0);
  char d = char(0);
The matcher
   varDecl(hasInitializer(ignoringParenCasts(integerLiteral())))
would match the declarations for a, b, c, and d.
while
   varDecl(hasInitializer(integerLiteral()))
only match the declaration for a.

Matches expressions that match InnerMatcher after implicit casts and
parentheses are stripped off.

Explicit casts are not discarded.
Given
  int arr[5];
  int a = 0;
  char b = (0);
  const int c = a;
  int *d = (arr);
  long e = ((long) 0l);
The matchers
   varDecl(hasInitializer(ignoringParenImpCasts(integerLiteral())))
   varDecl(hasInitializer(ignoringParenImpCasts(declRefExpr())))
would match the declarations for a, b, c, and d, but not e.
while
   varDecl(hasInitializer(integerLiteral()))
   varDecl(hasInitializer(declRefExpr()))
would only match the declaration for a.

Overload ignoringParens for Expr.

Given
  const char* str = ("my-string");
The matcher
  implicitCastExpr(hasSourceExpression(ignoringParens(stringLiteral())))
would match the implicit cast resulting from the assignment.

Matches non-static data members that have an in-class initializer.

Given
  class C {
    int a = 2;
    int b = 3;
    int c;
  };
fieldDecl(hasInClassInitializer(integerLiteral(equals(2))))
  matches 'int a;' but not 'int b;'.
fieldDecl(hasInClassInitializer(anything()))
  matches 'int a;' and 'int b;' but not 'int c;'.

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}

Matches the increment statement of a for loop.

Example:
    forStmt(hasIncrement(unaryOperator(hasOperatorName("++"))))
matches '++x' in
    for (x; x < N; ++x) { }

Matches the initialization statement of a for loop.

Example:
    forStmt(hasLoopInit(declStmt()))
matches 'int x = 0' in
    for (int x = 0; x < N; ++x) { }

Overloaded to match the declaration of the expression's or value
declaration's type.

In case of a value declaration (for example a variable declaration),
this resolves one layer of indirection. For example, in the value
declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
declaration of x.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              cxxRecordDecl(hasName("X"))))
 class X {};
 void y(X &x) { x; X z; }
 class Y { friend class X; };
 class Z : public virtual X {};

Example matches class Derived
(matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
class Base {};
class Derived : Base {};

Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
Matcher<CXXBaseSpecifier>

Matches if the expression's or declaration's type matches a type
matcher.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and U (matcher = typedefDecl(hasType(asString("int")))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              asString("class X")))
 class X {};
 void y(X &x) { x; X z; }
 typedef int U;
 class Y { friend class X; };
 class Z : public virtual X {};

Matches a function declaration that has a given body present in the AST.
Note that this matcher matches all the declarations of a function whose
body is present in the AST.

Given
  void f();
  void f() {}
  void g();
functionDecl(hasAnyBody(compoundStmt()))
  matches both 'void f();'
  and 'void f() {}'
with compoundStmt()
  matching '{}'
  but does not match 'void g();'

Matches any parameter of a function or an ObjC method declaration or a
block.

Does not match the 'this' parameter of a method.

Given
  class X { void f(int x, int y, int z) {} };
cxxMethodDecl(hasAnyParameter(hasName("y")))
  matches f(int x, int y, int z) {}
with hasAnyParameter(...)
  matching int y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
matches the declaration of method f with hasParameter
matching y.

For blocks, given
  b = ^(int y) { printf("%d", y) };

the matcher blockDecl(hasAnyParameter(hasName("y")))
matches the declaration of the block b with hasParameter
matching y.

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl that have at least one TemplateArgument matching the given
InnerMatcher.

Given
  template<typename T> class A {};
  template<> class A<double> {};
  A<int> a;

  template<typename T> f() {};
  void func() { f<int>(); };

classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToType(asString("int"))))
  matches the specialization A<int>

functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
  matches the specialization f<int>

Matches the expression in an explicit specifier if present in the given
declaration.

Given
  template<bool b>
  struct S {
    S(int); // #1
    explicit S(double); // #2
    operator int(); // #3
    explicit operator bool(); // #4
    explicit(false) S(bool) // # 7
    explicit(true) S(char) // # 8
    explicit(b) S(S) // # 9
  };
  S(int) -> S<true> // #5
  explicit S(double) -> S<false> // #6
cxxConstructorDecl(hasExplicitSpecifier(constantExpr())) will match #7, #8 and #9, but not #1 or #2.
cxxConversionDecl(hasExplicitSpecifier(constantExpr())) will not match #3 or #4.
cxxDeductionGuideDecl(hasExplicitSpecifier(constantExpr())) will not match #5 or #6.

Matches the n'th parameter of a function or an ObjC method
declaration or a block.

Given
  class X { void f(int x) {} };
cxxMethodDecl(hasParameter(0, hasType(varDecl())))
  matches f(int x) {}
with hasParameter(...)
  matching int x

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasParameter(0, hasName("y")))
matches the declaration of method f with hasParameter
matching y.

Matches a function declared with the specified return `TypeLoc`.

Given
  int f() { return 5; }
  void g() {}
functionDecl(hasReturnTypeLoc(loc(asString("int"))))
  matches the declaration of `f`, but not `g`.

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

Given
  template<typename T, typename U> class A {};
  A<bool, int> b;
  A<int, bool> c;

  template<typename T> void f() {}
  void func() { f<int>(); };
classTemplateSpecializationDecl(hasTemplateArgument(
    1, refersToType(asString("int"))))
  matches the specialization A<bool, int>

functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
  matches the specialization f<int>

Matches the return type of a function declaration.

Given:
  class X { int f() { return 1; } };
cxxMethodDecl(returns(asString("int")))
  matches int f() { return 1; }

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}

Matches the condition variable statement in an if statement.

Given
  if (A* a = GetAPointer()) {}
hasConditionVariableStatement(...)
  matches 'A* a = GetAPointer()'.

Matches the else-statement of an if statement.

Examples matches the if statement
  (matcher = ifStmt(hasElse(cxxBoolLiteral(equals(true)))))
  if (false) false; else true;

Matches selection statements with initializer.

Given:
 void foo() {
   if (int i = foobar(); i > 0) {}
   switch (int i = foobar(); i) {}
   for (auto& a = get_range(); auto& x : a) {}
 }
 void bar() {
   if (foobar() > 0) {}
   switch (foobar()) {}
   for (auto& x : get_range()) {}
 }
ifStmt(hasInitStatement(anything()))
  matches the if statement in foo but not in bar.
switchStmt(hasInitStatement(anything()))
  matches the switch statement in foo but not in bar.
cxxForRangeStmt(hasInitStatement(anything()))
  matches the range for statement in foo but not in bar.

Matches the then-statement of an if statement.

Examples matches the if statement
  (matcher = ifStmt(hasThen(cxxBoolLiteral(equals(true)))))
  if (false) true; else false;

Matches implicit casts whose destination type matches a given
matcher.

FIXME: Unit test this matcher

Matches the n'th item of an initializer list expression.

Example matches y.
    (matcher = initListExpr(hasInit(0, expr())))
  int x{y}.

Matches the syntactic form of init list expressions
(if expression have it).

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches a `LambdaCapture` that refers to the specified `VarDecl`. The
`VarDecl` can be a separate variable that is captured by value or
reference, or a synthesized variable if the capture has an initializer.

Given
  void foo() {
    int x;
    auto f = [x](){};
    auto g = [x = 1](){};
  }
In the matcher
lambdaExpr(hasAnyCapture(lambdaCapture(capturesVar(hasName("x")))),
capturesVar(hasName("x")) matches `x` and `x = 1`.

Matches each lambda capture in a lambda expression.

Given
  int main() {
    int x, y;
    float z;
    auto f = [=]() { return x + y + z; };
  }
lambdaExpr(forEachLambdaCapture(
    lambdaCapture(capturesVar(varDecl(hasType(isInteger()))))))
will trigger two matches, binding for 'x' and 'y' respectively.

Matches any capture in a lambda expression.

Given
  void foo() {
    int t = 5;
    auto f = [=](){ return t; };
  }
lambdaExpr(hasAnyCapture(lambdaCapture())) and
lambdaExpr(hasAnyCapture(lambdaCapture(refersToVarDecl(hasName("t")))))
  both match `[=](){ return t; }`.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches a member expression where the object expression is matched by a
given matcher. Implicit object expressions are included; that is, it matches
use of implicit `this`.

Given
  struct X {
    int m;
    int f(X x) { x.m; return m; }
  };
memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
  matches `x.m`, but not `m`; however,
memberExpr(hasObjectExpression(hasType(pointsTo(
     cxxRecordDecl(hasName("X"))))))
  matches `m` (aka. `this->m`), but not `x.m`.

Matches a member expression where the member is matched by a
given matcher.

Given
  struct { int first, second; } first, second;
  int i(second.first);
  int j(first.second);
memberExpr(member(hasName("first")))
  matches second.first
  but not first.second (because the member name there is "second").

Narrows PointerType (and similar) matchers to those where the
pointee matches a given matcher.

Given
  int *a;
  int const *b;
  float const *f;
pointerType(pointee(isConstQualified(), isInteger()))
  matches "int const *b"

Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
  Matcher<PointerType>, Matcher<ReferenceType>

Matches a NamedDecl whose underlying declaration matches the given
matcher.

Given
  namespace N { template<class T> void f(T t); }
  template <class T> void g() { using N::f; f(T()); }
unresolvedLookupExpr(hasAnyDeclaration(
    namedDecl(hasUnderlyingDecl(hasName("::N::f")))))
  matches the use of f in g() .

Matches on the prefix of a NestedNameSpecifierLoc.

Given
  struct A { struct B { struct C {}; }; };
  A::B::C c;
nestedNameSpecifierLoc(hasPrefix(loc(specifiesType(asString("struct A")))))
  matches "A::"

Matches NestedNameSpecifierLocs for which the given inner
NestedNameSpecifier-matcher matches.

Matches nested name specifier locs that specify a type matching the
given TypeLoc.

Given
  struct A { struct B { struct C {}; }; };
  A::B::C c;
nestedNameSpecifierLoc(specifiesTypeLoc(loc(type(
  hasDeclaration(cxxRecordDecl(hasName("A")))))))
  matches "A::"

Matches on the prefix of a NestedNameSpecifier.

Given
  struct A { struct B { struct C {}; }; };
  A::B::C c;
nestedNameSpecifier(hasPrefix(specifiesType(asString("struct A")))) and
  matches "A::"

Matches nested name specifiers that specify a namespace matching the
given namespace matcher.

Given
  namespace ns { struct A {}; }
  ns::A a;
nestedNameSpecifier(specifiesNamespace(hasName("ns")))
  matches "ns::"

Matches nested name specifiers that specify a type matching the
given QualType matcher without qualifiers.

Given
  struct A { struct B { struct C {}; }; };
  A::B::C c;
nestedNameSpecifier(specifiesType(
  hasDeclaration(cxxRecordDecl(hasName("A")))
))
  matches "A::"

Matches any clause in an OpenMP directive.

Given

  #pragma omp parallel
  #pragma omp parallel default(none)

``ompExecutableDirective(hasAnyClause(anything()))`` matches
``omp parallel default(none)``.

Matches the structured-block of the OpenMP executable directive

Prerequisite: the executable directive must not be standalone directive.
If it is, it will never match.

Given

   #pragma omp parallel
   ;
   #pragma omp parallel
   {}

``ompExecutableDirective(hasStructuredBlock(nullStmt()))`` will match ``;``

Matches C++ classes that are directly or indirectly derived from a class
matching Base, or Objective-C classes that directly or indirectly
subclass a class matching Base.

Note that a class is not considered to be derived from itself.

Example matches Y, Z, C (Base == hasName("X"))
  class X;
  class Y : public X {};  // directly derived
  class Z : public Y {};  // indirectly derived
  typedef X A;
  typedef A B;
  class C : public B {};  // derived from a typedef of X

In the following example, Bar matches isDerivedFrom(hasName("X")):
  class Foo;
  typedef Foo X;
  class Bar : public Foo {};  // derived from a type that X is a typedef of

In the following example, Bar matches isDerivedFrom(hasName("NSObject"))
  @interface NSObject @end
  @interface Bar : NSObject @end

Usable as: Matcher<CXXRecordDecl>, Matcher<ObjCInterfaceDecl>

Matches C++ or Objective-C classes that are directly derived from a class
matching Base.

Note that a class is not considered to be derived from itself.

Example matches Y, C (Base == hasName("X"))
  class X;
  class Y : public X {};  // directly derived
  class Z : public Y {};  // indirectly derived
  typedef X A;
  typedef A B;
  class C : public B {};  // derived from a typedef of X

In the following example, Bar matches isDerivedFrom(hasName("X")):
  class Foo;
  typedef Foo X;
  class Bar : public Foo {};  // derived from a type that X is a typedef of

Similar to isDerivedFrom(), but also matches classes that directly
match Base.

Matches any argument of a call expression or a constructor call
expression, or an ObjC-message-send expression.

Given
  void x(int, int, int) { int y; x(1, y, 42); }
callExpr(hasAnyArgument(declRefExpr()))
  matches x(1, y, 42)
with hasAnyArgument(...)
  matching y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end
  void foo(I *i) { [i f:12]; }
objcMessageExpr(hasAnyArgument(integerLiteral(equals(12))))
  matches [i f:12]

Matches the n'th argument of a call expression or a constructor
call expression.

Example matches y in x(y)
    (matcher = callExpr(hasArgument(0, declRefExpr())))
  void x(int) { int y; x(y); }

Matches if the Objective-C message is sent to an instance,
and the inner matcher matches on that instance.

For example the method call in
  NSString *x = @"hello";
  [x containsString:@"h"];
is matched by
objcMessageExpr(hasReceiver(declRefExpr(to(varDecl(hasName("x"))))))

Matches on the receiver of an ObjectiveC Message expression.

Example
matcher = objCMessageExpr(hasReceiverType(asString("UIWebView *")));
matches the [webView ...] message invocation.
  NSString *webViewJavaScript = ...
  UIWebView *webView = ...
  [webView stringByEvaluatingJavaScriptFromString:webViewJavascript];

Matches any parameter of a function or an ObjC method declaration or a
block.

Does not match the 'this' parameter of a method.

Given
  class X { void f(int x, int y, int z) {} };
cxxMethodDecl(hasAnyParameter(hasName("y")))
  matches f(int x, int y, int z) {}
with hasAnyParameter(...)
  matching int y

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasAnyParameter(hasName("y")))
matches the declaration of method f with hasParameter
matching y.

For blocks, given
  b = ^(int y) { printf("%d", y) };

the matcher blockDecl(hasAnyParameter(hasName("y")))
matches the declaration of the block b with hasParameter
matching y.

Matches the n'th parameter of a function or an ObjC method
declaration or a block.

Given
  class X { void f(int x) {} };
cxxMethodDecl(hasParameter(0, hasType(varDecl())))
  matches f(int x) {}
with hasParameter(...)
  matching int x

For ObjectiveC, given
  @interface I - (void) f:(int) y; @end

the matcher objcMethodDecl(hasParameter(0, hasName("y")))
matches the declaration of method f with hasParameter
matching y.

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches if the cast's source expression
or opaque value's source expression matches the given matcher.

Example 1: matches "a string"
(matcher = castExpr(hasSourceExpression(cxxConstructExpr())))
class URL { URL(string); };
URL url = "a string";

Example 2: matches 'b' (matcher =
opaqueValueExpr(hasSourceExpression(implicitCastExpr(declRefExpr())))
int a = b ?: 1;

Matches an OverloadExpr if any of the declarations in the set of
overloads matches the given matcher.

Given
  template <typename T> void foo(T);
  template <typename T> void bar(T);
  template <typename T> void baz(T t) {
    foo(t);
    bar(t);
  }
unresolvedLookupExpr(hasAnyDeclaration(
    functionTemplateDecl(hasName("foo"))))
  matches foo in foo(t); but not bar in bar(t);

Matches ParenType nodes where the inner type is a specific type.

Given
  int (*ptr_to_array)[4];
  int (*ptr_to_func)(int);

varDecl(hasType(pointsTo(parenType(innerType(functionType()))))) matches
ptr_to_func but not ptr_to_array.

Usable as: Matcher<ParenType>

Matches pointer `TypeLoc`s that have a pointee `TypeLoc` matching
`PointeeMatcher`.

Given
  int* x;
pointerTypeLoc(hasPointeeLoc(loc(asString("int"))))
  matches `int*`.

Narrows PointerType (and similar) matchers to those where the
pointee matches a given matcher.

Given
  int *a;
  int const *b;
  float const *f;
pointerType(pointee(isConstQualified(), isInteger()))
  matches "int const *b"

Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
  Matcher<PointerType>, Matcher<ReferenceType>

Matches QualTypes whose canonical type matches InnerMatcher.

Given:
  typedef int &int_ref;
  int a;
  int_ref b = a;

varDecl(hasType(qualType(referenceType()))))) will not match the
declaration of b but varDecl(hasType(qualType(hasCanonicalType(referenceType())))))) does.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches types that match InnerMatcher after any parens are stripped.

Given
  void (*fp)(void);
The matcher
  varDecl(hasType(pointerType(pointee(ignoringParens(functionType())))))
would match the declaration for fp.

Overloaded to match the pointee type's declaration.

Matches if the matched type is a pointer type and the pointee type
matches the specified matcher.

Example matches y->x()
  (matcher = cxxMemberCallExpr(on(hasType(pointsTo
     cxxRecordDecl(hasName("Y")))))))
  class Y { public: void x(); };
  void z() { Y *y; y->x(); }

Overloaded to match the referenced type's declaration.

Matches if the matched type is a reference type and the referenced
type matches the specified matcher.

Example matches X &x and const X &y
    (matcher = varDecl(hasType(references(cxxRecordDecl(hasName("X"))))))
  class X {
    void a(X b) {
      X &x = b;
      const X &y = b;
    }
  };

Matches `QualifiedTypeLoc`s that have an unqualified `TypeLoc` matching
`InnerMatcher`.

Given
  int* const x;
  const int y;
qualifiedTypeLoc(hasUnqualifiedLoc(pointerTypeLoc()))
  matches the `TypeLoc` of the variable declaration of `x`, but not `y`.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches reference `TypeLoc`s that have a referent `TypeLoc` matching
`ReferentMatcher`.

Given
  int x = 3;
  int& xx = x;
referenceTypeLoc(hasReferentLoc(loc(asString("int"))))
  matches `int&`.

Narrows PointerType (and similar) matchers to those where the
pointee matches a given matcher.

Given
  int *a;
  int const *b;
  float const *f;
pointerType(pointee(isConstQualified(), isInteger()))
  matches "int const *b"

Usable as: Matcher<BlockPointerType>, Matcher<MemberPointerType>,
  Matcher<PointerType>, Matcher<ReferenceType>

Matches the return value expression of a return statement

Given
  return a + b;
hasReturnValue(binaryOperator())
  matches 'return a + b'
with binaryOperator()
  matching 'a + b'

Matches compound statements where at least one substatement matches
a given matcher. Also matches StmtExprs that have CompoundStmt as children.

Given
  { {}; 1+2; }
hasAnySubstatement(compoundStmt())
  matches '{ {}; 1+2; }'
with compoundStmt()
  matching '{}'

Same as unaryExprOrTypeTraitExpr, but only matching
alignof.

Matches declaration of the function, method, or block the statement
belongs to.

Given:
F& operator=(const F& o) {
  std::copy_if(o.begin(), o.end(), begin(), [](V v) { return v > 0; });
  return *this;
}
returnStmt(forCallable(functionDecl(hasName("operator="))))
  matches 'return *this'
  but does not match 'return v > 0'

Given:
-(void) foo {
  int x = 1;
  dispatch_sync(queue, ^{ int y = 2; });
}
declStmt(forCallable(objcMethodDecl()))
  matches 'int x = 1'
  but does not match 'int y = 2'.
whereas declStmt(forCallable(blockDecl()))
  matches 'int y = 2'
  but does not match 'int x = 1'.

Matches declaration of the function the statement belongs to.

Deprecated. Use forCallable() to correctly handle the situation when
the declaration is not a function (but a block or an Objective-C method).
forFunction() not only fails to take non-functions into account but also
may match the wrong declaration in their presence.

Given:
F& operator=(const F& o) {
  std::copy_if(o.begin(), o.end(), begin(), [](V v) { return v > 0; });
  return *this;
}
returnStmt(forFunction(hasName("operator=")))
  matches 'return *this'
  but does not match 'return v > 0'

Same as unaryExprOrTypeTraitExpr, but only matching
sizeof.

Matches template type parameter substitutions that have a replacement
type that matches the provided matcher.

Given
  template <typename T>
  double F(T t);
  int i;
  double j = F(i);

substTemplateTypeParmType(hasReplacementType(type())) matches int

Matches each case or default statement belonging to the given switch
statement. This matcher may produce multiple matches.

Given
  switch (1) { case 1: case 2: default: switch (2) { case 3: case 4: ; } }
switchStmt(forEachSwitchCase(caseStmt().bind("c"))).bind("s")
  matches four times, with "c" binding each of "case 1:", "case 2:",
"case 3:" and "case 4:", and "s" respectively binding "switch (1)",
"switch (1)", "switch (2)" and "switch (2)".

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}

Matches selection statements with initializer.

Given:
 void foo() {
   if (int i = foobar(); i > 0) {}
   switch (int i = foobar(); i) {}
   for (auto& a = get_range(); auto& x : a) {}
 }
 void bar() {
   if (foobar() > 0) {}
   switch (foobar()) {}
   for (auto& x : get_range()) {}
 }
ifStmt(hasInitStatement(anything()))
  matches the if statement in foo but not in bar.
switchStmt(hasInitStatement(anything()))
  matches the switch statement in foo but not in bar.
cxxForRangeStmt(hasInitStatement(anything()))
  matches the range for statement in foo but not in bar.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches a sugar TemplateArgument that refers to a certain expression.

Given
  struct B { int next; };
  template<int(B::*next_ptr)> struct A {};
  A<&B::next> a;
templateSpecializationType(hasAnyTemplateArgument(
  isExpr(hasDescendant(declRefExpr(to(fieldDecl(hasName("next"))))))))
  matches the specialization A<&B::next> with fieldDecl(...) matching
    B::next

Matches a canonical TemplateArgument that refers to a certain
declaration.

Given
  struct B { int next; };
  template<int(B::*next_ptr)> struct A {};
  A<&B::next> a;
classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToDeclaration(fieldDecl(hasName("next")))))
  matches the specialization A<&B::next> with fieldDecl(...) matching
    B::next

Matches a TemplateArgument that refers to an integral type.

Given
  template<int T> struct C {};
  C<42> c;
classTemplateSpecializationDecl(
  hasAnyTemplateArgument(refersToIntegralType(asString("int"))))
  matches the implicit instantiation of C in C<42>.

Matches a TemplateArgument that refers to a certain template.

Given
  template<template <typename> class S> class X {};
  template<typename T> class Y {};
  X<Y> xi;
classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToTemplate(templateName())))
  matches the specialization X<Y>

Matches a TemplateArgument that refers to a certain type.

Given
  struct X {};
  template<typename T> struct A {};
  A<X> a;
classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToType(class(hasName("X")))))
  matches the specialization A<X>

Matches template specialization `TypeLoc`s that have at least one
`TemplateArgumentLoc` matching the given `InnerMatcher`.

Given
  template<typename T> class A {};
  A<int> a;
varDecl(hasTypeLoc(templateSpecializationTypeLoc(hasAnyTemplateArgumentLoc(
  hasTypeLoc(loc(asString("int")))))))
  matches `A<int> a`.

Matches template specialization `TypeLoc`s where the n'th
`TemplateArgumentLoc` matches the given `InnerMatcher`.

Given
  template<typename T, typename U> class A {};
  A<double, int> b;
  A<int, double> c;
varDecl(hasTypeLoc(templateSpecializationTypeLoc(hasTemplateArgumentLoc(0,
  hasTypeLoc(loc(asString("double")))))))
  matches `A<double, int> b`, but not `A<int, double> c`.

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl that have at least one TemplateArgument matching the given
InnerMatcher.

Given
  template<typename T> class A {};
  template<> class A<double> {};
  A<int> a;

  template<typename T> f() {};
  void func() { f<int>(); };

classTemplateSpecializationDecl(hasAnyTemplateArgument(
    refersToType(asString("int"))))
  matches the specialization A<int>

functionDecl(hasAnyTemplateArgument(refersToType(asString("int"))))
  matches the specialization f<int>

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches classTemplateSpecializations, templateSpecializationType and
functionDecl where the n'th TemplateArgument matches the given InnerMatcher.

Given
  template<typename T, typename U> class A {};
  A<bool, int> b;
  A<int, bool> c;

  template<typename T> void f() {}
  void func() { f<int>(); };
classTemplateSpecializationDecl(hasTemplateArgument(
    1, refersToType(asString("int"))))
  matches the specialization A<bool, int>

functionDecl(hasTemplateArgument(0, refersToType(asString("int"))))
  matches the specialization f<int>

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches TypeLocs for which the given inner
QualType-matcher matches.

Matches if the type location of a node matches the inner matcher.

Examples:
  int x;
declaratorDecl(hasTypeLoc(loc(asString("int"))))
  matches int x

auto x = int(3);
cxxTemporaryObjectExpr(hasTypeLoc(loc(asString("int"))))
  matches int(3)

struct Foo { Foo(int, int); };
auto x = Foo(1, 2);
cxxFunctionalCastExpr(hasTypeLoc(loc(asString("struct Foo"))))
  matches Foo(1, 2)

Usable as: Matcher<BlockDecl>, Matcher<CXXBaseSpecifier>,
  Matcher<CXXCtorInitializer>, Matcher<CXXFunctionalCastExpr>,
  Matcher<CXXNewExpr>, Matcher<CXXTemporaryObjectExpr>,
  Matcher<CXXUnresolvedConstructExpr>,
  Matcher<ClassTemplateSpecializationDecl>, Matcher<CompoundLiteralExpr>,
  Matcher<DeclaratorDecl>, Matcher<ExplicitCastExpr>,
  Matcher<ObjCPropertyDecl>, Matcher<TemplateArgumentLoc>,
  Matcher<TypedefNameDecl>

Matches if the expression's or declaration's type matches a type
matcher.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and U (matcher = typedefDecl(hasType(asString("int")))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              asString("class X")))
 class X {};
 void y(X &x) { x; X z; }
 typedef int U;
 class Y { friend class X; };
 class Z : public virtual X {};

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches if the matched type matches the unqualified desugared
type of the matched node.

For example, in:
  class A {};
  using B = A;
The matcher type(hasUnqualifiedDesugaredType(recordType())) matches
both B and A.

Matches unary expressions that have a specific type of argument.

Given
  int a, c; float b; int s = sizeof(a) + sizeof(b) + alignof(c);
unaryExprOrTypeTraitExpr(hasArgumentOfType(asString("int"))
  matches sizeof(a) and alignof(c)

Matches if the operand of a unary operator matches.

Example matches true (matcher = hasUnaryOperand(
                                  cxxBoolLiteral(equals(true))))
  !true

Matches a member expression where the object expression is matched by a
given matcher. Implicit object expressions are included; that is, it matches
use of implicit `this`.

Given
  struct X {
    int m;
    int f(X x) { x.m; return m; }
  };
memberExpr(hasObjectExpression(hasType(cxxRecordDecl(hasName("X")))))
  matches `x.m`, but not `m`; however,
memberExpr(hasObjectExpression(hasType(pointsTo(
     cxxRecordDecl(hasName("X"))))))
  matches `m` (aka. `this->m`), but not `x.m`.

Matches a node if the declaration associated with that node
matches the given matcher.

The associated declaration is:
- for type nodes, the declaration of the underlying type
- for CallExpr, the declaration of the callee
- for MemberExpr, the declaration of the referenced member
- for CXXConstructExpr, the declaration of the constructor
- for CXXNewExpr, the declaration of the operator new
- for ObjCIvarExpr, the declaration of the ivar

For type nodes, hasDeclaration will generally match the declaration of the
sugared type. Given
  class X {};
  typedef X Y;
  Y y;
in varDecl(hasType(hasDeclaration(decl()))) the decl will match the
typedefDecl. A common use case is to match the underlying, desugared type.
This can be achieved by using the hasUnqualifiedDesugaredType matcher:
  varDecl(hasType(hasUnqualifiedDesugaredType(
      recordType(hasDeclaration(decl())))))
In this matcher, the decl will match the CXXRecordDecl of class X.

Usable as: Matcher<AddrLabelExpr>, Matcher<CallExpr>,
  Matcher<CXXConstructExpr>, Matcher<CXXNewExpr>, Matcher<DeclRefExpr>,
  Matcher<EnumType>, Matcher<InjectedClassNameType>, Matcher<LabelStmt>,
  Matcher<MemberExpr>, Matcher<QualType>, Matcher<RecordType>,
  Matcher<TagType>, Matcher<TemplateSpecializationType>,
  Matcher<TemplateTypeParmType>, Matcher<TypedefType>,
  Matcher<UnresolvedUsingType>

Matches a using shadow declaration where the target declaration is
matched by the given matcher.

Given
  namespace X { int a; void b(); }
  using X::a;
  using X::b;
usingDecl(hasAnyUsingShadowDecl(hasTargetDecl(functionDecl())))
  matches using X::b but not using X::a 

Overloaded to match the declaration of the expression's or value
declaration's type.

In case of a value declaration (for example a variable declaration),
this resolves one layer of indirection. For example, in the value
declaration "X x;", cxxRecordDecl(hasName("X")) matches the declaration of
X, while varDecl(hasType(cxxRecordDecl(hasName("X")))) matches the
declaration of x.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              cxxRecordDecl(hasName("X"))))
 class X {};
 void y(X &x) { x; X z; }
 class Y { friend class X; };
 class Z : public virtual X {};

Example matches class Derived
(matcher = cxxRecordDecl(hasAnyBase(hasType(cxxRecordDecl(hasName("Base"))))))
class Base {};
class Derived : Base {};

Usable as: Matcher<Expr>, Matcher<FriendDecl>, Matcher<ValueDecl>,
Matcher<CXXBaseSpecifier>

Matches if the expression's or declaration's type matches a type
matcher.

Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
            and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
            and U (matcher = typedefDecl(hasType(asString("int")))
            and friend class X (matcher = friendDecl(hasType("X"))
            and public virtual X (matcher = cxxBaseSpecifier(hasType(
                                              asString("class X")))
 class X {};
 void y(X &x) { x; X z; }
 typedef int U;
 class Y { friend class X; };
 class Z : public virtual X {};

Matches a variable declaration that has an initializer expression
that matches the given matcher.

Example matches x (matcher = varDecl(hasInitializer(callExpr())))
  bool y() { return true; }
  bool x = y();

Matches VariableArrayType nodes that have a specific size
expression.

Given
  void f(int b) {
    int a[b];
  }
variableArrayType(hasSizeExpr(ignoringImpCasts(declRefExpr(to(
  varDecl(hasName("b")))))))
  matches "int a[b]"

Matches the condition expression of an if statement, for loop,
switch statement or conditional operator.

Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
  if (true) {}