fix(transformer/typescript): inline const enum members through type-cast wrappers

[Dunqing]

Closes #22444.

Phase.idle as Phase, Phase.idle satisfies Phase, Phase.idle!, and <Phase>Phase.idle failed to inline under optimizeConstEnums. The const enum declaration was stripped while the member access was left as Phase.idle, producing a runtime ReferenceError.

Cause

The enum inliner's enter_expression matched only bare StaticMemberExpression/ComputedMemberExpression. annotations.rs strips TS-only wrappers in its own enter_expression, but walk_expression only calls enter_expression once per node — after the strip the inner Phase.idle was never revisited.

Fix

Peek through the wrappers via Expression::get_inner_expression_mut() (it already handles TSAsExpression, TSSatisfiesExpression, TSNonNullExpression, TSTypeAssertion, TSInstantiationExpression, ParenthesizedExpression). The outer *expr = … replacement then drops the wrapper along with the inlined value.

Example

const enum Phase { idle, active }

class Foo {
  #foo = Phase.idle as Phase;
}

Before:

class Foo {
  #foo = Phase.idle;  // dangling reference
}

After:

class Foo {
  #foo = 0;
}

Verification

New fixtures cover all wrapper shapes for const + regular enums:

• babel-plugin-transform-typescript/const-enum-type-cast/
• babel-plugin-transform-typescript/optimize-enums/type-cast/

[Dunqing]

• fix(transformer): sync scoping after lowering an enum to IIFE #22502
• fix(transformer/typescript): keep enum IIFE when a non-inlinable value reference remains #22501
• fix(transformer/typescript): inline const enum members through type-cast wrappers #22500 👈 (View in Graphite)
• main

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[codspeed-hq]

Merging this PR will not alter performance

✅ 44 untouched benchmarks
⏩ 7 skipped benchmarks¹

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_{Comparing fix/transformer-const-enum-type-cast (62376dd) with main (c9f506e)}

Footnotes

1. 7 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[graphite-app]

Merge activity

• May 18, 2:18 AM UTC: Dunqing added this pull request to the Graphite merge queue.
• May 18, 2:23 AM UTC: Merged by the Graphite merge queue.