Fix Issue 11025 - case-insensitive backreferences in std.regex#11070
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niy-ati wants to merge 2 commits into
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Fix Issue 11025 - case-insensitive backreferences in std.regex#11070niy-ati wants to merge 2 commits into
niy-ati wants to merge 2 commits into
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Under /i, literals are casefolded at parse time but IR.Backref still compared codepoints with ==. Use simple case folding when matching backrefs in the backtracking and Thompson engines (and ctRegex).
rikkimax
reviewed
Jul 18, 2026
| TestVectors( `[adzУ-Я]{4}`, "DzюЯ", "y", "$&", "DzюЯ", "i"), | ||
| TestVectors( `\p{L}\p{Lu}{10}`, "абвгдеЖЗИКЛ", "y", "$&", "абвгдеЖЗИКЛ", "i"), | ||
| TestVectors( `(?:Dåb){3}`, "DåbDÅBdÅb", "y", "$&", "DåbDÅBdÅb", "i"), | ||
| // Issue 11025: backrefs must casefold under /i |
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Suggested change
| // Issue 11025: backrefs must casefold under /i | |
| // https://github.com/dlang/phobos/issues/11025 backrefs must casefold under /i |
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updated the comment to link the issue.
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Summary
/i,IR.Backrefcompared captures with==, so(.)\1matchedBBbut notAa.RegexOption.casefoldis set (backtracking, Thompson, and ctRegex).Fixes #11025
Test plan
TestVectorsforAa/aA/BB/ non-match / multi-char /(?i).