Issues

• es/minifier: reassociates float multiplications without unsafe_math, changing moment and luxon results

  swc-project/swc#12634 · Filter by author baltasarblanco opened on Oct 30, 2026

• Wtf8Atom serde: parse() then print() drops a backslash from strings containing \\u followed by a non-hex character

  swc-project/swc#12625 · Filter by author cainrus opened on Oct 28, 2026
  1

• Segfault in napi_register_module_v1 when a second worker_thread loads @swc/core (regression in 1.16.17, still in 1.16.20)

  swc-project/swc#12623 · Filter by author Eyalm321 opened on Oct 27, 2026

• es/minifier: keep_class_names allows mangled method parameters to shadow the preserved inner class name

  swc-project/swc#12618 · Filter by author shafiktanbir opened on Oct 26, 2026

• React development __source locations do not follow inputSourceMap

  C-bug
  swc-project/swc#12613 · Filter by author alexeyr-ci6 opened on Oct 26, 2026

• Generated CommonJS require calls have no source mapping at the callee

  C-bug
  swc-project/swc#12611 · Filter by author alexeyr-ci6 opened on Oct 26, 2026
  2

• React Compiler (jsc.transform.reactCompiler): source map has no mappings inside compiled functions

  swc-project/swc#12602 · Filter by author MatthieuBrouillard opened on Oct 23, 2026
  1

• @swc/core ≥ 1.16.17 crashes with SIGSEGV on macOS arm64 when @stylexswc/rs-compiler is loaded first (1.16.13 works)

  C-bug
  swc-project/swc#12591 · Filter by author j-choriki opened on Oct 22, 2026

• es/fixer: drops the parentheses of (let)[0], turning the statement into a let declaration

  swc-project/swc#12589 · Filter by author baltasarblanco opened on Oct 21, 2026
  1

• es/fixer: prints (-0).x = 0 as -0..x=0, an invalid assignment target

  swc-project/swc#12588 · Filter by author baltasarblanco opened on Oct 21, 2026
  1

• es/fixer: drops the parentheses of ("use strict");, turning it into a directive

  swc-project/swc#12587 · Filter by author baltasarblanco opened on Oct 21, 2026

• es/minifier: drops an unused object whose spread calls a getter

  swc-project/swc#12586 · Filter by author baltasarblanco opened on Oct 21, 2026
  1

• es/minifier: a shorthand property of an undeclared global reads a later value or loses its ReferenceError

  swc-project/swc#12578 · Filter by author baltasarblanco opened on Oct 20, 2026

• Implement format.wrap_func_args / wrap_iife

  enhancement
  swc-project/swc#12572 · Filter by author ebidelman opened on Oct 19, 2026

• es/minifier: moves a use of a variable past a later var redeclaration that reassigns it

  swc-project/swc#12564 · Filter by author baltasarblanco opened on Oct 19, 2026

• emitIsolatedDts emits no declaration files since swc_typescript became optional

  swc-project/swc#12556 · Filter by author jbedard opened on Oct 17, 2026

• Default config parses .mts/.cts as ES, not TypeScript

  swc-project/swc#12555 · Filter by author jbedard opened on Oct 17, 2026

• emitIsolatedDts writes .d.ts for .mts/.cts inputs instead of .d.mts/.d.cts

  swc-project/swc#12554 · Filter by author jbedard opened on Oct 17, 2026

• using lowering emits new _SuppressedError(...) but declares _SuppressedError1 (regression since 1.15.46)

  C-bug
  swc-project/swc#12531 · Filter by author msc117 opened on Oct 13, 2026
  1

• Named function expression renamed when a global with the same name is referenced (Map → Map1)

  C-bug
  swc-project/swc#12528 · Filter by author slowcheetah opened on Oct 13, 2026
  1

  

• Wrong behavior of using and await using in for-of heads

  C-bug
  swc-project/swc#12494 · Filter by author TrickyPi opened on Oct 8, 2026

• Reset expression errors when object literal is a member base

  swc-project/swc#12486 · Filter by author JLHwung opened on Oct 5, 2026

• @swc/core fails to load on wasm32 runtimes: @swc/core-wasm32-wasi is referenced by the loader but never published

  enhancement
  swc-project/swc#12466 · Filter by author michaelkremenetsky opened on Oct 2, 2026

• Source maps do not account for U+2028 and U+2029 line terminators

  C-bug
  swc-project/swc#12454 · Filter by author gb-jos opened on Oct 1, 2026
  2

• es/minifier: shadowed undefined parameter renamed to undefined1, leaving an undeclared reference

  C-bug
  swc-project/swc#12438 · Filter by author bminer opened on Sep 29, 2026