Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Percentage text admits values beyond its grammar · case 01
Percentage text admits values beyond its grammar.
Percentage text admits values beyond its grammar · case 02
Percentage text admits values beyond its grammar.
Percentage text admits values beyond its grammar · case 03
Percentage text admits values beyond its grammar.
Percentage text admits values beyond its grammar · case 04
Percentage text admits values beyond its grammar.
Percentage text admits values beyond its grammar · case 05
Percentage text admits values beyond its grammar.
A UUID-shaped identifier accepts misplaced separators · case 01
A UUID-shaped identifier accepts misplaced separators.
A UUID-shaped identifier accepts misplaced separators · case 02
A UUID-shaped identifier accepts misplaced separators.
A UUID-shaped identifier accepts misplaced separators · case 03
A UUID-shaped identifier accepts misplaced separators.
A UUID-shaped identifier accepts misplaced separators · case 04
A UUID-shaped identifier accepts misplaced separators.
A UUID-shaped identifier accepts misplaced separators · case 05
A UUID-shaped identifier accepts misplaced separators.
A byte address mixes colon and hyphen separators · case 01
A byte address mixes colon and hyphen separators.
A byte address mixes colon and hyphen separators · case 02
A byte address mixes colon and hyphen separators.
A byte address mixes colon and hyphen separators · case 03
A byte address mixes colon and hyphen separators.
A byte address mixes colon and hyphen separators · case 04
A byte address mixes colon and hyphen separators.
A byte address mixes colon and hyphen separators · case 05
A byte address mixes colon and hyphen separators.
A slug contains adjacent or terminal separators · case 01
A slug contains adjacent or terminal separators.
A slug contains adjacent or terminal separators · case 02
A slug contains adjacent or terminal separators.
A slug contains adjacent or terminal separators · case 03
A slug contains adjacent or terminal separators.
A slug contains adjacent or terminal separators · case 04
A slug contains adjacent or terminal separators.
A slug contains adjacent or terminal separators · case 05
A slug contains adjacent or terminal separators.
A dotted name admits empty identifiers · case 01
A dotted name admits empty identifiers.
A dotted name admits empty identifiers · case 02
A dotted name admits empty identifiers.
A dotted name admits empty identifiers · case 03
A dotted name admits empty identifiers.
A dotted name admits empty identifiers · case 04
A dotted name admits empty identifiers.
A dotted name admits empty identifiers · case 05
A dotted name admits empty identifiers.
A reserved word passes lexical identifier validation · case 01
A reserved word passes lexical identifier validation.
A reserved word passes lexical identifier validation · case 02
A reserved word passes lexical identifier validation.
A reserved word passes lexical identifier validation · case 03
A reserved word passes lexical identifier validation.
A reserved word passes lexical identifier validation · case 04
A reserved word passes lexical identifier validation.
A reserved word passes lexical identifier validation · case 05
A reserved word passes lexical identifier validation.
An unknown escape is admitted in a quoted token · case 01
An unknown escape is admitted in a quoted token.
An unknown escape is admitted in a quoted token · case 02
An unknown escape is admitted in a quoted token.
An unknown escape is admitted in a quoted token · case 03
An unknown escape is admitted in a quoted token.
An unknown escape is admitted in a quoted token · case 04
An unknown escape is admitted in a quoted token.
An unknown escape is admitted in a quoted token · case 05
An unknown escape is admitted in a quoted token.
SQL-style strings treat backslash as a quote escape · case 01
SQL-style strings treat backslash as a quote escape.
SQL-style strings treat backslash as a quote escape · case 02
SQL-style strings treat backslash as a quote escape.
SQL-style strings treat backslash as a quote escape · case 03
SQL-style strings treat backslash as a quote escape.
SQL-style strings treat backslash as a quote escape · case 04
SQL-style strings treat backslash as a quote escape.
SQL-style strings treat backslash as a quote escape · case 05
SQL-style strings treat backslash as a quote escape.
A block comment terminates at the last closing marker · case 01
A block comment terminates at the last closing marker.
A block comment terminates at the last closing marker · case 02
A block comment terminates at the last closing marker.
A block comment terminates at the last closing marker · case 03
A block comment terminates at the last closing marker.
A block comment terminates at the last closing marker · case 04
A block comment terminates at the last closing marker.
A block comment terminates at the last closing marker · case 05
A block comment terminates at the last closing marker.
A line comment swallows the following record · case 01
A line comment swallows the following record.
A line comment swallows the following record · case 02
A line comment swallows the following record.
A line comment swallows the following record · case 03
A line comment swallows the following record.
A line comment swallows the following record · case 04
A line comment swallows the following record.
A line comment swallows the following record · case 05
A line comment swallows the following record.
A code fence closes with a shorter delimiter · case 01
A code fence closes with a shorter delimiter.
A code fence closes with a shorter delimiter · case 02
A code fence closes with a shorter delimiter.
A code fence closes with a shorter delimiter · case 03
A code fence closes with a shorter delimiter.
A code fence closes with a shorter delimiter · case 04
A code fence closes with a shorter delimiter.
A code fence closes with a shorter delimiter · case 05
A code fence closes with a shorter delimiter.
A flat Markdown link allows an unmatched destination parenthesis · case 01
A flat Markdown link allows an unmatched destination parenthesis.
A flat Markdown link allows an unmatched destination parenthesis · case 02
A flat Markdown link allows an unmatched destination parenthesis.
A flat Markdown link allows an unmatched destination parenthesis · case 03
A flat Markdown link allows an unmatched destination parenthesis.
A flat Markdown link allows an unmatched destination parenthesis · case 04
A flat Markdown link allows an unmatched destination parenthesis.
A flat Markdown link allows an unmatched destination parenthesis · case 05
A flat Markdown link allows an unmatched destination parenthesis.
A hashtag begins with a digit or underscore · case 01
A hashtag begins with a digit or underscore.
A hashtag begins with a digit or underscore · case 02
A hashtag begins with a digit or underscore.
A hashtag begins with a digit or underscore · case 03
A hashtag begins with a digit or underscore.
A hashtag begins with a digit or underscore · case 04
A hashtag begins with a digit or underscore.
A hashtag begins with a digit or underscore · case 05
A hashtag begins with a digit or underscore.
An at-mention accepts punctuation inside its name · case 01
An at-mention accepts punctuation inside its name.
An at-mention accepts punctuation inside its name · case 02
An at-mention accepts punctuation inside its name.
An at-mention accepts punctuation inside its name · case 03
An at-mention accepts punctuation inside its name.
An at-mention accepts punctuation inside its name · case 04
An at-mention accepts punctuation inside its name.
An at-mention accepts punctuation inside its name · case 05
An at-mention accepts punctuation inside its name.
A language label has an empty or overlong subtag · case 01
A language label has an empty or overlong subtag.
A language label has an empty or overlong subtag · case 02
A language label has an empty or overlong subtag.
A language label has an empty or overlong subtag · case 03
A language label has an empty or overlong subtag.
A language label has an empty or overlong subtag · case 04
A language label has an empty or overlong subtag.
A language label has an empty or overlong subtag · case 05
A language label has an empty or overlong subtag.
A media type lacks exactly one separator · case 01
A media type lacks exactly one separator.
A media type lacks exactly one separator · case 02
A media type lacks exactly one separator.
A media type lacks exactly one separator · case 03
A media type lacks exactly one separator.
A media type lacks exactly one separator · case 04
A media type lacks exactly one separator.
A media type lacks exactly one separator · case 05
A media type lacks exactly one separator.
A key-value parameter permits an empty key · case 01
A key-value parameter permits an empty key.
A key-value parameter permits an empty key · case 02
A key-value parameter permits an empty key.
A key-value parameter permits an empty key · case 03
A key-value parameter permits an empty key.
A key-value parameter permits an empty key · case 04
A key-value parameter permits an empty key.
A key-value parameter permits an empty key · case 05
A key-value parameter permits an empty key.
A boolean token is accepted by truthiness · case 01
A boolean token is accepted by truthiness.
A boolean token is accepted by truthiness · case 02
A boolean token is accepted by truthiness.
A boolean token is accepted by truthiness · case 03
A boolean token is accepted by truthiness.
A boolean token is accepted by truthiness · case 04
A boolean token is accepted by truthiness.
A boolean token is accepted by truthiness · case 05
A boolean token is accepted by truthiness.
A null literal accepts aliases from another language · case 01
A null literal accepts aliases from another language.
A null literal accepts aliases from another language · case 02
A null literal accepts aliases from another language.
A null literal accepts aliases from another language · case 03
A null literal accepts aliases from another language.
A null literal accepts aliases from another language · case 04
A null literal accepts aliases from another language.
A null literal accepts aliases from another language · case 05
A null literal accepts aliases from another language.
A braced quantifier admits a missing lower bound · case 01
A braced quantifier admits a missing lower bound.
A braced quantifier admits a missing lower bound · case 02
A braced quantifier admits a missing lower bound.
A braced quantifier admits a missing lower bound · case 03
A braced quantifier admits a missing lower bound.
A braced quantifier admits a missing lower bound · case 04
A braced quantifier admits a missing lower bound.
A braced quantifier admits a missing lower bound · case 05
A braced quantifier admits a missing lower bound.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗