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[ConstraintSystem] Fix a property wrapper constraint generation crash. #36611

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Merged
merged 1 commit into from
Mar 29, 2021
Merged

[ConstraintSystem] Fix a property wrapper constraint generation crash. #36611

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33 changes: 14 additions & 19 deletions lib/Sema/CSGen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3560,9 +3560,7 @@ static bool generateWrappedPropertyTypeConstraints(
Type propertyType) {
auto dc = wrappedVar->getInnermostDeclContext();

Type wrapperType = LValueType::get(initializerType);
Type wrappedValueType;

auto wrapperAttributes = wrappedVar->getAttachedPropertyWrappers();
for (unsigned i : indices(wrapperAttributes)) {
// FIXME: We should somehow pass an OpenUnboundGenericTypeFn to
Expand All @@ -3573,16 +3571,20 @@ static bool generateWrappedPropertyTypeConstraints(
if (rawWrapperType->hasError() || !wrapperInfo)
return true;

// The former wrappedValue type must be equal to the current wrapper type
if (wrappedValueType) {
auto *typeRepr = wrapperAttributes[i]->getTypeRepr();
auto *locator =
cs.getConstraintLocator(typeRepr, LocatorPathElt::ContextualType());
wrapperType = cs.replaceInferableTypesWithTypeVars(rawWrapperType,
locator);
auto *typeExpr = wrapperAttributes[i]->getTypeExpr();
auto *locator = cs.getConstraintLocator(typeExpr);
auto wrapperType = cs.replaceInferableTypesWithTypeVars(rawWrapperType, locator);
cs.setType(typeExpr, wrapperType);

if (!wrappedValueType) {
// Equate the outermost wrapper type to the initializer type.
if (initializerType)
cs.addConstraint(ConstraintKind::Equal, wrapperType, initializerType, locator);
} else {
// The former wrappedValue type must be equal to the current wrapper type
cs.addConstraint(ConstraintKind::Equal, wrapperType, wrappedValueType,
locator);
cs.setContextualType(typeRepr, TypeLoc::withoutLoc(wrappedValueType),
cs.getConstraintLocator(locator, LocatorPathElt::ContextualType()));
cs.setContextualType(typeExpr, TypeLoc::withoutLoc(wrappedValueType),
CTP_ComposedPropertyWrapper);
}

Expand Down Expand Up @@ -3888,19 +3890,12 @@ bool ConstraintSystem::generateConstraints(

case SolutionApplicationTarget::Kind::uninitializedWrappedVar: {
auto *wrappedVar = target.getAsUninitializedWrappedVar();
auto *outermostWrapper = wrappedVar->getAttachedPropertyWrappers().front();
auto *typeExpr = outermostWrapper->getTypeExpr();
auto backingType = replaceInferableTypesWithTypeVars(
outermostWrapper->getType(),getConstraintLocator(typeExpr));

setType(typeExpr, backingType);

auto propertyType = getVarType(wrappedVar);
if (propertyType->hasError())
return true;

return generateWrappedPropertyTypeConstraints(
*this, backingType, wrappedVar, propertyType);
*this, /*initializerType=*/Type(), wrappedVar, propertyType);
}
}
}
Expand Down
17 changes: 17 additions & 0 deletions test/decl/var/property_wrappers.swift
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Expand Up @@ -2076,3 +2076,20 @@ struct OptionalWrapper<T> {
struct UseOptionalWrapper {
@OptionalWrapper var p: Int?? // Okay
}

@propertyWrapper
struct WrapperWithFailableInit<Value> {
var wrappedValue: Value

init(_ base: WrapperWithFailableInit<Value>) { fatalError() }

init?(_ base: WrapperWithFailableInit<Value?>) { fatalError() }
}

struct TestInitError {
// FIXME: bad diagnostics when a wrapper does not support init from wrapped value

// expected-error@+2 {{extraneous argument label 'wrappedValue:' in call}}
// expected-error@+1 {{cannot convert value of type 'Int' to specified type 'WrapperWithFailableInit<Int>'}}
@WrapperWithFailableInit var value: Int = 10
}