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Sema: Check for invalid reference *before* checking for unsupported existential member access

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This commit is contained in:
Anthony Latsis
2021-08-13 20:08:04 +03:00
parent 64b8f61b13
commit e49ca21bf0
2 changed files with 61 additions and 40 deletions
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73
lib/Sema/CSSimplify.cpp
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@@ -7322,7 +7322,7 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
// Dig out the instance type and figure out what members of the instance type
// we are going to see.
auto baseTy = candidate.getBaseType();
auto baseObjTy = baseTy->getRValueType();
const auto baseObjTy = baseTy->getRValueType();
bool hasInstanceMembers = false;
bool hasInstanceMethods = false;
@@ -7369,18 +7369,6 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
hasInstanceMethods = true;
}
// If our base is an existential type, we can't make use of any
// member whose signature involves associated types.
if (instanceTy->isExistentialType()) {
if (auto *proto = decl->getDeclContext()->getSelfProtocolDecl()) {
if (!proto->isAvailableInExistential(decl)) {
result.addUnviable(candidate,
MemberLookupResult::UR_UnavailableInExistential);
return;
}
}
}
// If the invocation's argument expression has a favored type,
// use that information to determine whether a specific overload for
// the candidate should be favored.
@@ -7400,6 +7388,20 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
}
}
const auto isUnsupportedExistentialMemberAccess = [&] {
// If our base is an existential type, we can't make use of any
// member whose signature involves associated types.
if (instanceTy->isExistentialType()) {
if (auto *proto = decl->getDeclContext()->getSelfProtocolDecl()) {
if (!proto->isAvailableInExistential(decl)) {
return true;
}
}
}
return false;
};
// See if we have an instance method, instance member or static method,
// and check if it can be accessed on our base type.
@@ -7413,20 +7415,35 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
? candidate
: OverloadChoice(instanceTy, decl,
FunctionRefKind::SingleApply);
// If this is an instance member referenced from metatype
// let's add unviable result to the set because it could be
// either curried reference or an invalid call.
//
// New candidate shouldn't affect performance because such
// choice would only be attempted when solver is in diagnostic mode.
result.addUnviable(choice, MemberLookupResult::UR_InstanceMemberOnType);
bool invalidMethodRef = isa<FuncDecl>(decl) && !hasInstanceMethods;
bool invalidMemberRef = !isa<FuncDecl>(decl) && !hasInstanceMembers;
// If this is definitely an invalid way to reference a method or member
// on the metatype, let's stop here.
if (invalidMethodRef || invalidMemberRef)
const bool invalidMethodRef = isa<FuncDecl>(decl) && !hasInstanceMethods;
const bool invalidMemberRef = !isa<FuncDecl>(decl) && !hasInstanceMembers;
if (invalidMethodRef || invalidMemberRef) {
// If this is definitely an invalid way to reference a method or member
// on the metatype, let's stop here.
result.addUnviable(choice,
MemberLookupResult::UR_InstanceMemberOnType);
return;
} else if (isUnsupportedExistentialMemberAccess()) {
// If the member reference itself is legal, but it turns out to be an
// unsupported existential member access, do not make further
// assumptions about the correctness of a potential call -- let
// the unsupported member access error prevail.
result.addUnviable(candidate,
MemberLookupResult::UR_UnavailableInExistential);
return;
} else {
// Otherwise, still add an unviable result to the set, because it
// could be an invalid call that was supposed to be performed on an
// instance of the type.
//
// New candidate shouldn't affect performance because such
// choice would only be attempted when solver is in diagnostic mode.
result.addUnviable(choice,
MemberLookupResult::UR_InstanceMemberOnType);
}
}
// If the underlying type of a typealias is fully concrete, it is legal
@@ -7477,6 +7494,12 @@ performMemberLookup(ConstraintKind constraintKind, DeclNameRef memberName,
}
}
if (isUnsupportedExistentialMemberAccess()) {
result.addUnviable(candidate,
MemberLookupResult::UR_UnavailableInExistential);
return;
}
// If we have an rvalue base, make sure that the result isn't 'mutating'
// (only valid on lvalues).
if (!baseTy->is<AnyMetatypeType>() &&