Crash: malformed `super` destructuring in a decorated class static block panics

[daniellockyer]

🔎 Search Terms

visitArrayAssignmentElement, esDecorator super destructuring, static block decorator crash, IsArrayBindingOrAssignmentElement, "Debug failure. False expression"

🕗 Version & Regression Information

• This is a crash
• This changed between TypeScript 6.0.3 (JS) and 7.1.0-dev (main, Go): 6.0.3 reports error TS1005 and exits but the Go rewrite panics

⏯ Playground Link

I cannot provide a link because the TypeScript playground does not have v7.

💻 Code

(@c
class extends B{static{[super.x 0]=[1];}});

🙁 Actual behavior

panic: Debug failure. False expression. [recovered, repanicked]

goroutine 50 [running]:
sync.(*WaitGroup).Go.func1.1()
        sync/waitgroup.go:251 +0x48
panic({0x1061c58e0?, 0x176c0104340?})
        runtime/panic.go:860 +0x12c
github.com/microsoft/TypeScript/tsc/internal/debug.Fail(...)
        github.com/microsoft/TypeScript/tsc/internal/debug/debug.go:14
github.com/microsoft/TypeScript/tsc/internal/debug.assertSlow(...)
        github.com/microsoft/TypeScript/tsc/internal/debug/debug.go:60 +0x5c
github.com/microsoft/TypeScript/tsc/internal/debug.Assert(...)
        github.com/microsoft/TypeScript/tsc/internal/debug/debug.go:49
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).visitArrayAssignmentElement(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:2201 +0x90
github.com/microsoft/TypeScript/tsc/internal/ast.(*NodeVisitor).VisitSlice(...)
        github.com/microsoft/TypeScript/tsc/internal/ast/visitor.go:171 +0x19c
github.com/microsoft/TypeScript/tsc/internal/ast.(*NodeVisitor).VisitNodes(...)
        github.com/microsoft/TypeScript/tsc/internal/ast/visitor.go:99 +0x3c
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).visitAssignmentPattern(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:2281 +0x58
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).visitBinaryExpression(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:1915 +0x5b4
... 36 lines truncated ...
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).visitClassStaticBlockDeclaration(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:1538 +0x2f0
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).transformClassLike(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:705 +0xa60
github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms.(*esDecoratorTransformer).visitClassExpression(...)
        github.com/microsoft/TypeScript/tsc/internal/transformers/estransforms/esdecorator.go:1109 +0x138
... 108 lines truncated ...
github.com/microsoft/TypeScript/tsc/internal/compiler.(*emitter).emitJSFile(...)
        github.com/microsoft/TypeScript/tsc/internal/compiler/emitter.go:200 +0x198
github.com/microsoft/TypeScript/tsc/internal/compiler.(*emitter).emit(...)
        github.com/microsoft/TypeScript/tsc/internal/compiler/emitter.go:50 +0xec
github.com/microsoft/TypeScript/tsc/internal/compiler.(*Program).Emit.func2()
        github.com/microsoft/TypeScript/tsc/internal/compiler/program.go:1851 +0x1c0

🙂 Expected behavior

The compiler should not crash 😊

Additional information about the issue

Disclosure: This crash was found with a custom mutation fuzzer and AI assistance (Kimi K3). The input was minimized and then verified by hand against TypeScript 7.1.0-dev (main) and TypeScript 6.0.3.