Warn about confusable identifiers, i.e. identifiers that are visually close to each other, but use different Unicode characters. This detects a potential attack described in CVE-2021-42574.


int fo; // Initial character is U+0066 (LATIN SMALL LETTER F).
int 𝐟o; // Initial character is U+1D41F (MATHEMATICAL BOLD SMALL F) not U+0066 (LATIN SMALL LETTER F).