Tracking issue for the remaining Prettier conformance test failures (tested against Prettier 3.8.1).

Every failure listed below has a corresponding issue filed in the Prettier repository. These are cases where Prettier produces incorrect output, and oxfmt intentionally produces the correct output. The tests will pass once Prettier releases the fixes.

Status

Compatibility 100% — all remaining failures are known Prettier issues, not oxfmt issues. These are rare edge cases, mostly related to comment placement.

JavaScript (7 failing)

• js/comments/15661.js
  Unnecessary parentheses wrapping for BinaryExpression in UnaryExpression prettier/prettier#18802
• js/comments/empty-statements.js
  missing line break after trailing comments of empty statement prettier/prettier#18842
• js/comments/function-declaration.js ✅
  Keep comments after arrow in body prettier/prettier#18775
• js/comments/return-statement.js
  Leading comment in parenthesized return expression moves to incorrect place in member chain prettier/prettier#18843
• js/explicit-resource-management/valid-await-using-comments.js
  inconsistent semicolon placement with trailing block comments on variable declarations prettier/prettier#18832
• js/for/9812-unstable.js ✅
  @ts-expect-error comment is being shifted so it breaks prettier/prettier#9812
• js/last-argument-expansion/dangling-comment-in-arrow-function.js ✅
  Comment within the arrow function's empty parameters was placed incorrectly after the fat arrow operator prettier/prettier#18208

TypeScript (11 failing)

• typescript/arrow/comments.ts
  inconsistent semicolon placement with trailing block comments on variable declarations prettier/prettier#18832
• typescript/arrow/comments/issue-11100.ts
  Comment within the arrow function's empty parameters was placed incorrectly after the fat arrow operator prettier/prettier#18208
• typescript/as/break-after-keyword/18148.ts
  Incorrectly calculated line width prettier/prettier#18148
• typescript/class/empty-method-body.ts
  Trailing comment after empty method signature moves before parentheses prettier/prettier#18835
• typescript/comments/mapped_types.ts
  Inline block comment in mapped type incorrectly moved to separate line prettier/prettier#18730
• typescript/comments/method_types.ts
  Trailing comment after empty method signature moves before parentheses prettier/prettier#18835
• typescript/mapped-type/issue-11098.ts
  Inline block comment in mapped type incorrectly moved to separate line prettier/prettier#18730
• typescript/property-signature/consistent-with-flow/comments.ts
  Inconsistent formatting logic of PropertySignature and ObjectProperty prettier/prettier#18209
• typescript/union/comments/18106.ts
  Improve comment attach in union type prettier/prettier#18828
• typescript/union/comments/18389.ts
  Inconsistent comment placement in nested unions vs unions in intersections prettier/prettier#18778
  jsdoc comment in union type isn't being aligned prettier/prettier#18787
• typescript/union/single-type/single-type.ts
  Comments in the single item union type are placed incorrectly in the TSTypeAliasDeclaration prettier/prettier#18834