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Remove the assumption that constructing a T always produces a T.

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With failable initializers, it will be able to produce a T? or T!.


Swift SVN r21294
This commit is contained in:
Doug Gregor
2014-08-19 21:01:10 +00:00
parent 42dc448e7e
commit 0777d6dd6f
5 changed files with 30 additions and 25 deletions
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36
lib/Sema/CSSimplify.cpp
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@@ -2066,7 +2066,8 @@ commit_to_conversions:
}
ConstraintSystem::SolutionKind
ConstraintSystem::simplifyConstructionConstraint(Type valueType, Type argType,
ConstraintSystem::simplifyConstructionConstraint(Type valueType,
FunctionType *fnType,
unsigned flags,
ConstraintLocator *locator) {
// Desugar the value type.
@@ -2083,6 +2084,9 @@ ConstraintSystem::simplifyConstructionConstraint(Type valueType, Type argType,
}
}
Type argType = fnType->getInput();
Type resultType = fnType->getResult();
switch (desugarValueType->getKind()) {
#define SUGARED_TYPE(id, parent) case TypeKind::id:
#define TYPE(id, parent)
@@ -2107,6 +2111,14 @@ ConstraintSystem::simplifyConstructionConstraint(Type valueType, Type argType,
case TypeKind::Tuple: {
// Tuple construction is simply tuple conversion.
if (matchTypes(resultType, desugarValueType,
TypeMatchKind::BindType,
flags,
ConstraintLocatorBuilder(locator)
.withPathElement(ConstraintLocator::ApplyFunction))
== SolutionKind::Error)
return SolutionKind::Error;
return matchTypes(argType, valueType, TypeMatchKind::Conversion,
flags|TMF_GenerateConstraints, locator);
}
@@ -2166,11 +2178,10 @@ ConstraintSystem::simplifyConstructionConstraint(Type valueType, Type argType,
TVO_CanBindToLValue|TVO_PrefersSubtypeBinding);
// The constructor will have function type T -> T2, for a fresh type
// variable T. Note that these constraints specifically require a
// match on the result type because the constructors for enums and struct
// types always return a value of exactly that type.
// variable T. T2 is the result type provided via the construction
// constraint itself.
addValueMemberConstraint(valueType, name,
FunctionType::get(tv, valueType),
FunctionType::get(tv, resultType),
getConstraintLocator(
locator,
ConstraintLocator::ConstructorMember));
@@ -3190,18 +3201,8 @@ retry:
// For a metatype, perform a construction.
if (auto meta2 = dyn_cast<AnyMetatypeType>(desugar2)) {
auto instanceTy2 = meta2->getInstanceType();
// Bind the result type to the instance type.
if (matchTypes(func1->getResult(), instanceTy2,
TypeMatchKind::BindType,
flags,
locator.withPathElement(ConstraintLocator::ApplyFunction))
== SolutionKind::Error)
return SolutionKind::Error;
// Construct the instance from the input arguments.
addConstraint(ConstraintKind::Construction, func1->getInput(), instanceTy2,
addConstraint(ConstraintKind::Construction, func1, meta2->getInstanceType(),
getConstraintLocator(outerLocator));
return SolutionKind::Solved;
}
@@ -3983,7 +3984,8 @@ ConstraintSystem::simplifyConstraint(const Constraint &constraint) {
case ConstraintKind::Construction:
return simplifyConstructionConstraint(constraint.getSecondType(),
constraint.getFirstType(),
constraint.getFirstType()
->castTo<FunctionType>(),
TMF_None,
constraint.getLocator());