Fix crashes on malformed destructuring assignments during emit - #64651
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Mateusz Burzyński (Andarist) wants to merge 2 commits into
Open
Mateusz Burzyński (Andarist) wants to merge 2 commits into
Mateusz Burzyński (Andarist) wants to merge 2 commits into
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Mateusz Burzyński (Andarist)
October 6, 2026 06:57
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🟡 Changes recommended
The removed debug assertions should be broadened to valid container-level invariants rather than eliminated.
Review effort: Balanced
Findings: 3
Open (3)
What changed in this PR
Prevents compiler emit crashes on malformed destructuring assignments across decorator and class-field transforms.
Changes:
- Allows malformed assignment elements to continue through transform visitors.
- Adds regression coverage for array/object targets, decorators, private fields, and
super. - Adds diagnostic, emit, type, and symbol baselines.
| File | Description |
|---|---|
tsc/internal/transformers/estransforms/esdecorator.go |
Relaxes assignment-element visitor assertions. |
tsc/internal/transformers/estransforms/classfields.go |
Relaxes object-assignment visitor assertion. |
tsc/testdata/tests/cases/compiler/malformedSuperDestructuringInDecoratedClassStaticBlock.ts |
Tests malformed super destructuring. |
tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentESDecorators.ts |
Tests malformed object targets with decorators. |
tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts |
Tests malformed private-field syntax. |
tsc/testdata/tests/cases/compiler/malformedDestructuringAssignmentTransformVariants.ts |
Covers transform and target variants. |
tsc/testdata/baselines/reference/compiler/malformedSuperDestructuringInDecoratedClassStaticBlock.types |
Type baseline. |
tsc/testdata/baselines/reference/compiler/malformedSuperDestructuringInDecoratedClassStaticBlock.symbols |
Symbol baseline. |
tsc/testdata/baselines/reference/compiler/malformedSuperDestructuringInDecoratedClassStaticBlock.js |
Emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedSuperDestructuringInDecoratedClassStaticBlock.errors.txt |
Diagnostic baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentESDecorators.types |
Type baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentESDecorators.symbols |
Symbol baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentESDecorators.js |
Emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentESDecorators.errors.txt |
Diagnostic baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.types |
Type baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.symbols |
Symbol baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.js |
Emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.errors.txt |
Diagnostic baseline. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=true,target=es2022).js |
Legacy-decorator ES2022 emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=true,target=es2022).errors.txt |
Legacy-decorator ES2022 diagnostics. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=true,target=es2015).js |
Legacy-decorator ES2015 emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=true,target=es2015).errors.txt |
Legacy-decorator ES2015 diagnostics. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=false,target=es2022).js |
ES-decorator ES2022 emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=false,target=es2022).errors.txt |
ES-decorator ES2022 diagnostics. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=false,target=es2015).js |
ES-decorator ES2015 emit baseline. |
tsc/testdata/baselines/reference/compiler/malformedDestructuringAssignmentTransformVariants(experimentaldecorators=false,target=es2015).errors.txt |
ES-decorator ES2015 diagnostics. |
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supersedes #63972 #63973 and #64472
fixes a crash reported here: #64458 (comment)
Those removed asserts assume a non-malformed source code. But those transformer paths still run over malformed nodes and it's the easiest to accept such subtrees given those malformed trees legitimately reach those visitors.
Alternatively, the fix could check if the target is valid or not and skip those "strict" (with asserts) visitors. But honestly, that seems like a more work/specialcasing and from what I've seen in the past the similar codepaths are just usually tolerant when it comes to malformed inputs like this so I think removing those asserts would match the preexisting style~