Port TS#62283: Clear SkipGenericFunctions in yield expression checking

[Copilot]

Ports microsoft/TypeScript#62283.

silentNeverType was leaking into inferred generator types when yield expressions contained inner generic function calls. The CheckModeSkipGenericFunctions flag was being passed through to checkExpression for yield operands, causing generic calls to return silentNeverType instead of being properly resolved.

• Clear CheckModeSkipGenericFunctions from checkMode in checkAndAggregateYieldOperandTypes when checking yield expressions, matching the existing pattern used for return expressions and arrow body expressions
• The other two parts of TS#62283 (removing silentNeverIterationTypes and early silentNeverType returns) were already absent in the Go port

// Before
yieldExprType = c.checkExpressionEx(yieldExpr.Expression(), checkMode)
// After
yieldExprType = c.checkExpressionEx(yieldExpr.Expression(), checkMode & ^CheckModeSkipGenericFunctions)

Baseline impact: genericCallAtYieldExpressionInGenericCall1 drops from 7 errors to 3 (removes spurious TS2488 errors), generator types correctly infer number instead of any/never. genericCallAtYieldExpressionInGenericCall2 error diff eliminated entirely.

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[Copilot]

Pull request overview

This PR ports TypeScript#62283, fixing a type inference bug where silentNeverType was leaking into generator return types when yield expressions contained generic function calls. The fix clears the CheckModeSkipGenericFunctions flag when checking yield operands, matching the existing pattern used for return statements and arrow function bodies.

Changes:

• Clear CheckModeSkipGenericFunctions in checkAndAggregateYieldOperandTypes when checking yield expression operands to prevent silentNeverType from incorrectly propagating into inferred generator types

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/checker/checker.go	Added flag clearing (checkMode & ^CheckModeSkipGenericFunctions) when checking yield expression operands in checkAndAggregateYieldOperandTypes, matching the pattern used for return and arrow expressions
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall2.errors.txt	Removed spurious TS2488 error (entire error file now empty)
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall2.errors.txt.diff	Reflects removal of spurious TS2488 error
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall1.errors.txt	Error count reduced from 7 to 3, removing spurious TS2488 errors from yield expressions
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall1.errors.txt.diff	Shows reduction in errors and correction of type inference (Generator instead of Generator)
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall1.types	Generator types now correctly infer number instead of any for yield type parameter
testdata/baselines/reference/submodule/compiler/genericCallAtYieldExpressionInGenericCall1.types.diff	Shows improved type inference in generator return types

[jakebailey]

I'll note that this also "ports" microsoft/TypeScript#61317 in that microsoft/TypeScript#62283 effectively reverted the former and used a different fix.