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Sema: Don't crash when key path literals appear in PartialKeyPath context.

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And make an attempt to use the constraint system's contextualType to bind type information; this makes things better but doesn't seem to be a complete solution for contextually typing key paths.
This commit is contained in:
Joe Groff
2017-05-23 16:48:58 -07:00
parent b3a3b52783
commit a6fb6d6f15
6 changed files with 117 additions and 41 deletions
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34
lib/Sema/CSSimplify.cpp
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@@ -3776,7 +3776,7 @@ ConstraintSystem::simplifyKeyPathConstraint(Type keyPathTy,
keyPathTy = getFixedTypeRecursive(keyPathTy, /*want rvalue*/ true);
auto tryMatchRootAndValueFromKeyPathType =
[&](BoundGenericType *bgt) -> SolutionKind {
[&](BoundGenericType *bgt, bool allowPartial) -> SolutionKind {
Type boundRoot, boundValue;
// We can get root and value from a concrete key path type.
@@ -3786,9 +3786,13 @@ ConstraintSystem::simplifyKeyPathConstraint(Type keyPathTy,
boundRoot = bgt->getGenericArgs()[0];
boundValue = bgt->getGenericArgs()[1];
} else if (bgt->getDecl() == getASTContext().getPartialKeyPathDecl()) {
// We can still get the root from a PartialKeyPath.
boundRoot = bgt->getGenericArgs()[0];
boundValue = Type();
if (allowPartial) {
// We can still get the root from a PartialKeyPath.
boundRoot = bgt->getGenericArgs()[0];
boundValue = Type();
} else {
return SolutionKind::Error;
}
} else {
// We can't bind anything from this type.
return SolutionKind::Solved;
@@ -3804,14 +3808,26 @@ ConstraintSystem::simplifyKeyPathConstraint(Type keyPathTy,
return SolutionKind::Solved;
};
// If the key path type is bound from context, feed that into the root and
// value types.
// If we're fixed to a bound generic type, trying harvesting context from it.
// However, we don't want a solution that fixes the expression type to
// PartialKeyPath; we'd rather that be represented using an upcast conversion.
if (auto keyPathBGT = keyPathTy->getAs<BoundGenericType>()) {
if (tryMatchRootAndValueFromKeyPathType(keyPathBGT) == SolutionKind::Error)
if (tryMatchRootAndValueFromKeyPathType(keyPathBGT, /*allowPartial*/false)
== SolutionKind::Error)
return SolutionKind::Error;
}
// If the expression has contextual type information, try using that too.
if (auto contextualTy = getContextualType(keyPath)) {
if (auto contextualBGT = contextualTy->getAs<BoundGenericType>()) {
if (tryMatchRootAndValueFromKeyPathType(contextualBGT,
/*allowPartial*/true)
== SolutionKind::Error)
return SolutionKind::Error;
}
}
// See if we resolved overloads for all the components involved.
enum {
ReadOnly,
@@ -3824,7 +3840,7 @@ ConstraintSystem::simplifyKeyPathConstraint(Type keyPathTy,
switch (component.getKind()) {
case KeyPathExpr::Component::Kind::Invalid:
return SolutionKind::Error;
break;
case KeyPathExpr::Component::Kind::UnresolvedProperty:
case KeyPathExpr::Component::Kind::UnresolvedSubscript: {