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fix JS regex literal parsing in char classes #7790

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Merged
merged 4 commits into from
Aug 28, 2025
+50 −277
Merged

fix JS regex literal parsing in char classes #7790

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f2d3e4c
fix JS regex literal parsing in char classes
zth Aug 22, 2025
fe5e0f9
Merge branch 'master' into fix-regex-char-classes
mediremi Aug 27, 2025
88efa86
Simplify regex character class parsing and reject more invalid regexes
mediremi Aug 27, 2025
16412d8
Add CHANGELOG entry
mediremi Aug 27, 2025
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@

#### :bug: Bug fix

- Fix JS regex literal parsing in character classes. https://github.com/rescript-lang/rescript/pull/7790
- Fix creating interface for functions with upper bounded polymorphic args. https://github.com/rescript-lang/rescript/pull/7786

#### :memo: Documentation
Expand Down
14 changes: 10 additions & 4 deletions compiler/syntax/src/res_scanner.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -584,9 +584,9 @@ let scan_regex scanner =
bring_buf_up_to_date ~start_offset:last_char_offset;
Buffer.contents buf)
in
let rec scan () =
let rec scan ?(in_char_class = false) () =
match scanner.ch with
| '/' ->
| '/' when not in_char_class ->
let last_char_offset = scanner.offset in
next scanner;
let pattern = result ~first_char_offset ~last_char_offset in
Expand All @@ -610,10 +610,16 @@ let scan_regex scanner =
| '\\' ->
next scanner;
next scanner;
scan ()
scan ~in_char_class ()
| '[' when not in_char_class ->
next scanner;
scan ~in_char_class:true ()
| ']' when in_char_class ->
next scanner;
scan ~in_char_class:false ()
| _ ->
next scanner;
scan ()
scan ~in_char_class ()
in
let pattern, flags = scan () in
let end_pos = position scanner in
Expand Down
20 changes: 20 additions & 0 deletions tests/syntax_tests/data/parsing/errors/expressions/expected/regexCharacterClasses.res.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@

Syntax error!
syntax_tests/data/parsing/errors/expressions/regexCharacterClasses.res:1:14

1 │ let re = /[]/]/
2 │

I'm not sure what to parse here when looking at "]".


Syntax error!
syntax_tests/data/parsing/errors/expressions/regexCharacterClasses.res:1:16

1 │ let re = /[]/]/
2 │

unterminated regex

let re = [%re {js|/[]/|js}]
;;[%re {js|//|js}]
1 change: 1 addition & 0 deletions tests/syntax_tests/data/parsing/errors/expressions/regexCharacterClasses.res
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@@ -0,0 +1 @@
let re = /[]/]/
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Added an error test for an invalid use of character classes

142 changes: 7 additions & 135 deletions tests/syntax_tests/data/parsing/grammar/expressions/expected/regex.res.txt
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Expand Up @@ -76,10 +76,7 @@ let re = [%re {js|/a[b-d]/|js}]
let re = [%re {js|/a[-b]/|js}]
let re = [%re {js|/a[\\-b]/|js}]
let re = [%re {js|/a[]b/|js}]
let re = [%re {js|/a[/|js}]
let re = [%re {js|/a\\/|js}]
let re = [%re {js|/abc)/|js}]
let re = [%re {js|/(abc/|js}]
let re = [%re {js|/a]/|js}]
let re = [%re {js|/a[]]b/|js}]
let re = [%re {js|/a[\\]]b/|js}]
Expand Down Expand Up @@ -239,7 +236,6 @@ let re = [%re {js|/a[-b]/|js}]
let re = [%re {js|/a[b-]/|js}]
let re = [%re {js|/a[b-a]/|js}]
let re = [%re {js|/a[]b/|js}]
let re = [%re {js|/a[/|js}]
let re = [%re {js|/a]/|js}]
let re = [%re {js|/a[]]b/|js}]
let re = [%re {js|/a[^bc]d/|js}]
Expand All @@ -258,8 +254,6 @@ let re = [%re {js|/a\\(b/|js}]
let re = [%re {js|/a\\(*b/|js}]
let re = [%re {js|/a\\(*b/|js}]
let re = [%re {js|/a\\\\b/|js}]
let re = [%re {js|/abc)/|js}]
let re = [%re {js|/(abc/|js}]
let re = [%re {js|/((a))/|js}]
let re = [%re {js|/(a)b(c)/|js}]
let re = [%re {js|/a+b+c/|js}]
Expand Down Expand Up @@ -317,134 +311,6 @@ let re = [%re {js|/[k]/|js}]
let re = [%re {js|/a[-]?c/|js}]
let re = [%re {js|/(abc)\\1/|js}]
let re = [%re {js|/([a-c]*)\\1/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)ab*c/|js}]
let re = [%re {js|/(?i)ab*bc/|js}]
let re = [%re {js|/(?i)ab*bc/|js}]
let re = [%re {js|/(?i)ab*?bc/|js}]
let re = [%re {js|/(?i)ab{0,}?bc/|js}]
let re = [%re {js|/(?i)ab+?bc/|js}]
let re = [%re {js|/(?i)ab+bc/|js}]
let re = [%re {js|/(?i)ab+bc/|js}]
let re = [%re {js|/(?i)ab{1,}bc/|js}]
let re = [%re {js|/(?i)ab+bc/|js}]
let re = [%re {js|/(?i)ab{1,}?bc/|js}]
let re = [%re {js|/(?i)ab{1,3}?bc/|js}]
let re = [%re {js|/(?i)ab{3,4}?bc/|js}]
let re = [%re {js|/(?i)ab{4,5}?bc/|js}]
let re = [%re {js|/(?i)ab??bc/|js}]
let re = [%re {js|/(?i)ab??bc/|js}]
let re = [%re {js|/(?i)ab{0,1}?bc/|js}]
let re = [%re {js|/(?i)ab??bc/|js}]
let re = [%re {js|/(?i)ab??c/|js}]
let re = [%re {js|/(?i)ab{0,1}?c/|js}]
let re = [%re {js|/(?i)^abc$/|js}]
let re = [%re {js|/(?i)^abc$/|js}]
let re = [%re {js|/(?i)^abc/|js}]
let re = [%re {js|/(?i)^abc$/|js}]
let re = [%re {js|/(?i)abc$/|js}]
let re = [%re {js|/(?i)^/|js}]
let re = [%re {js|/(?i)$/|js}]
let re = [%re {js|/(?i)a.c/|js}]
let re = [%re {js|/(?i)a.c/|js}]
let re = [%re {js|/(?i)a.*?c/|js}]
let re = [%re {js|/(?i)a.*c/|js}]
let re = [%re {js|/(?i)a[bc]d/|js}]
let re = [%re {js|/(?i)a[bc]d/|js}]
let re = [%re {js|/(?i)a[b-d]e/|js}]
let re = [%re {js|/(?i)a[b-d]e/|js}]
let re = [%re {js|/(?i)a[b-d]/|js}]
let re = [%re {js|/(?i)a[-b]/|js}]
let re = [%re {js|/(?i)a[b-]/|js}]
let re = [%re {js|/(?i)a[b-a]/|js}]
let re = [%re {js|/(?i)a[]b/|js}]
let re = [%re {js|/(?i)a[/|js}]
let re = [%re {js|/(?i)a]/|js}]
let re = [%re {js|/(?i)a[]]b/|js}]
let re = [%re {js|/(?i)a[^bc]d/|js}]
let re = [%re {js|/(?i)a[^bc]d/|js}]
let re = [%re {js|/(?i)a[^-b]c/|js}]
let re = [%re {js|/(?i)a[^-b]c/|js}]
let re = [%re {js|/(?i)a[^]b]c/|js}]
let re = [%re {js|/(?i)a[^]b]c/|js}]
let re = [%re {js|/(?i)ab|cd/|js}]
let re = [%re {js|/(?i)ab|cd/|js}]
let re = [%re {js|/(?i)()ef/|js}]
let re = [%re {js|/(?i)*a/|js}]
let re = [%re {js|/(?i)(*)b/|js}]
let re = [%re {js|/(?i)$b/|js}]
let re = [%re {js|/(?i)a\\/|js}]
let re = [%re {js|/(?i)a\\(b/|js}]
let re = [%re {js|/(?i)a\\(*b/|js}]
let re = [%re {js|/(?i)a\\(*b/|js}]
let re = [%re {js|/(?i)a\\\\b/|js}]
let re = [%re {js|/(?i)abc)/|js}]
let re = [%re {js|/(?i)(abc/|js}]
let re = [%re {js|/(?i)((a))/|js}]
let re = [%re {js|/(?i)(a)b(c)/|js}]
let re = [%re {js|/(?i)a+b+c/|js}]
let re = [%re {js|/(?i)a{1,}b{1,}c/|js}]
let re = [%re {js|/(?i)a**/|js}]
let re = [%re {js|/(?i)a.+?c/|js}]
let re = [%re {js|/(?i)a.*?c/|js}]
let re = [%re {js|/(?i)a.{0,5}?c/|js}]
let re = [%re {js|/(?i)(a+|b)*/|js}]
let re = [%re {js|/(?i)(a+|b){0,}/|js}]
let re = [%re {js|/(?i)(a+|b)+/|js}]
let re = [%re {js|/(?i)(a+|b){1,}/|js}]
let re = [%re {js|/(?i)(a+|b)?/|js}]
let re = [%re {js|/(?i)(a+|b){0,1}/|js}]
let re = [%re {js|/(?i)(a+|b){0,1}?/|js}]
let re = [%re {js|/(?i))(/|js}]
let re = [%re {js|/(?i)[^ab]*/|js}]
let re = [%re {js|/(?i)abc/|js}]
let re = [%re {js|/(?i)a*/|js}]
let re = [%re {js|/(?i)([abc])*d/|js}]
let re = [%re {js|/(?i)([abc])*bcd/|js}]
let re = [%re {js|/(?i)a|b|c|d|e/|js}]
let re = [%re {js|/(?i)(a|b|c|d|e)f/|js}]
let re = [%re {js|/(?i)abcd*efg/|js}]
let re = [%re {js|/(?i)ab*/|js}]
let re = [%re {js|/(?i)ab*/|js}]
let re = [%re {js|/(?i)(ab|cd)e/|js}]
let re = [%re {js|/(?i)[abhgefdc]ij/|js}]
let re = [%re {js|/(?i)^(ab|cd)e/|js}]
let re = [%re {js|/(?i)(abc|)ef/|js}]
let re = [%re {js|/(?i)(a|b)c*d/|js}]
let re = [%re {js|/(?i)(ab|ab*)bc/|js}]
let re = [%re {js|/(?i)a([bc]*)c*/|js}]
let re = [%re {js|/(?i)a([bc]*)(c*d)/|js}]
let re = [%re {js|/(?i)a([bc]+)(c*d)/|js}]
let re = [%re {js|/(?i)a([bc]*)(c+d)/|js}]
let re = [%re {js|/(?i)a[bcd]*dcdcde/|js}]
let re = [%re {js|/(?i)a[bcd]+dcdcde/|js}]
let re = [%re {js|/(?i)(ab|a)b*c/|js}]
let re = [%re {js|/(?i)((a)(b)c)(d)/|js}]
let re = [%re {js|/(?i)[a-zA-Z_][a-zA-Z0-9_]*/|js}]
let re = [%re {js|/(?i)^a(bc+|b[eh])g|.h$/|js}]
let re = [%re {js|/(?i)(bc+d$|ef*g.|h?i(j|k))/|js}]
let re = [%re {js|/(?i)(bc+d$|ef*g.|h?i(j|k))/|js}]
let re = [%re {js|/(?i)(bc+d$|ef*g.|h?i(j|k))/|js}]
let re = [%re {js|/(?i)(bc+d$|ef*g.|h?i(j|k))/|js}]
let re = [%re {js|/(?i)(bc+d$|ef*g.|h?i(j|k))/|js}]
let re = [%re {js|/(?i)((((((((((a))))))))))/|js}]
let re = [%re {js|/(?i)((((((((((a))))))))))\\10/|js}]
let re = [%re {js|/(?i)(((((((((a)))))))))/|js}]
let re = [%re {js|/(?i)(?:(?:(?:(?:(?:(?:(?:(?:(?:(a))))))))))/|js}]
let re = [%re {js|/(?i)(?:(?:(?:(?:(?:(?:(?:(?:(?:(a|b|c))))))))))/|js}]
let re = [%re {js|/(?i)multiple words of text/|js}]
let re = [%re {js|/(?i)multiple words/|js}]
let re = [%re {js|/(?i)(.*)c(.*)/|js}]
let re = [%re {js|/(?i)\\((.*), (.*)\\)/|js}]
let re = [%re {js|/(?i)[k]/|js}]
let re = [%re {js|/(?i)a[-]?c/|js}]
let re = [%re {js|/(?i)(abc)\\1/|js}]
let re = [%re {js|/(?i)([a-c]*)\\1/|js}]
let re = [%re {js|/a(?!b)./|js}]
let re = [%re {js|/a(?=d)./|js}]
let re = [%re {js|/a(?=c|d)./|js}]
Expand Down Expand Up @@ -499,4 +365,10 @@ let re = [%re {js|/^a*?$/|js}]
let re = [%re {js|/^((a)c)?(ab)$/|js}]
let re = [%re {js|/^([ab]*?)(?=(b)?)c/|js}]
let re = [%re {js|/^([ab]*?)(?!(b))c/|js}]
let re = [%re {js|/^([ab]*?)(?<!(a))c/|js}]
let re = [%re {js|/^([ab]*?)(?<!(a))c/|js}]
let re = [%re {js|/\.[^/.]+$/|js}]
let re = [%re {js|/[^]]/|js}]
let re = [%re {js|/[/]/|js}]
let re = [%re {js|/[]]/|js}]
let re = [%re {js|/[\]]/|js}]
let re = [%re {js|/[[]]/|js}]
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