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[ResultBuilder] AST transform: don't try type erasure of result expressions #60449

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Merged
merged 2 commits into from
Aug 9, 2022
Merged

[ResultBuilder] AST transform: don't try type erasure of result expressions #60449

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8f4658f
[CSClosure] Start using recorded targets for `ReturnStmt`s
xedin Aug 8, 2022
422dbe4
[ResultBuilder] AST transform: don't try type erasure of result expre…
xedin Aug 8, 2022
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9 changes: 1 addition & 8 deletions lib/Sema/BuilderTransform.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -919,8 +919,6 @@ class ResultBuilderTransform

using UnsupportedElt = SkipUnhandledConstructInResultBuilder::UnhandledNode;

/// The constraint system this transform is associated with.
ConstraintSystem &CS;
/// The result type of this result builder body.
Type ResultType;

Expand All @@ -930,8 +928,7 @@ class ResultBuilderTransform
public:
ResultBuilderTransform(ConstraintSystem &cs, DeclContext *dc,
Type builderType, Type resultTy)
: BuilderTransformerBase(&cs, dc, builderType), CS(cs),
ResultType(resultTy) {}
: BuilderTransformerBase(&cs, dc, builderType), ResultType(resultTy) {}

UnsupportedElt getUnsupportedElement() const { return FirstUnsupported; }

Expand Down Expand Up @@ -1180,10 +1177,6 @@ class ResultBuilderTransform
{buildBlockResult}, {Identifier()});
}

// Type erase return if the result type requires it.
buildBlockResult = CS.buildTypeErasedExpr(buildBlockResult, dc,
ResultType, CTP_ReturnStmt);

elements.push_back(new (ctx) ReturnStmt(resultLoc, buildBlockResult,
/*Implicit=*/true));
}
Expand Down
27 changes: 19 additions & 8 deletions lib/Sema/CSClosure.cpp
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Expand Up @@ -1584,6 +1584,8 @@ class SyntacticElementSolutionApplication
}

ASTNode visitReturnStmt(ReturnStmt *returnStmt) {
auto &cs = solution.getConstraintSystem();

if (!returnStmt->hasResult()) {
// If contextual is not optional, there is nothing to do here.
if (resultType->isVoid())
Expand All @@ -1598,8 +1600,6 @@ class SyntacticElementSolutionApplication
assert(resultType->getOptionalObjectType() &&
resultType->lookThroughAllOptionalTypes()->isVoid());

auto &cs = solution.getConstraintSystem();

auto target = *cs.getSolutionApplicationTarget(returnStmt);
returnStmt->setResult(target.getAsExpr());
}
Expand Down Expand Up @@ -1629,13 +1629,24 @@ class SyntacticElementSolutionApplication
mode = convertToResult;
}

SolutionApplicationTarget resultTarget(
resultExpr, context.getAsDeclContext(),
mode == convertToResult ? CTP_ReturnStmt : CTP_Unused,
mode == convertToResult ? resultType : Type(),
/*isDiscarded=*/false);
if (auto newResultTarget = rewriteTarget(resultTarget))
Optional<SolutionApplicationTarget> resultTarget;
if (auto target = cs.getSolutionApplicationTarget(returnStmt)) {
resultTarget = *target;
} else {
// Single-expression closures have to handle returns in a special
// way so the target has to be created for them during solution
// application based on the resolved type.
assert(isSingleExpression);
resultTarget = SolutionApplicationTarget(
resultExpr, context.getAsDeclContext(),
mode == convertToResult ? CTP_ReturnStmt : CTP_Unused,
mode == convertToResult ? resultType : Type(),
/*isDiscarded=*/false);
}

if (auto newResultTarget = rewriteTarget(*resultTarget)) {
resultExpr = newResultTarget->getAsExpr();
}

switch (mode) {
case convertToResult:
Expand Down