PR17295: Do not allow explicit conversion functions to be used in cases where
an additional conversion (other than a qualification conversion) would be
required after the explicit conversion.
Conversely, do allow explicit conversion functions to be used when initializing
a temporary for a reference binding in direct-list-initialization.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191150 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 1c33c32..afd9393 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -3346,6 +3346,33 @@
return;
}
}
+ if (S.getLangOpts().CPlusPlus && !DestType->isAggregateType() &&
+ InitList->getNumInits() == 1 &&
+ InitList->getInit(0)->getType()->isRecordType()) {
+ // - Otherwise, if the initializer list has a single element of type E
+ // [...references are handled above...], the object or reference is
+ // initialized from that element; if a narrowing conversion is required
+ // to convert the element to T, the program is ill-formed.
+ //
+ // Per core-24034, this is direct-initialization if we were performing
+ // direct-list-initialization and copy-initialization otherwise.
+ // We can't use InitListChecker for this, because it always performs
+ // copy-initialization. This only matters if we might use an 'explicit'
+ // conversion operator, so we only need to handle the cases where the source
+ // is of record type.
+ InitializationKind SubKind =
+ Kind.getKind() == InitializationKind::IK_DirectList
+ ? InitializationKind::CreateDirect(Kind.getLocation(),
+ InitList->getLBraceLoc(),
+ InitList->getRBraceLoc())
+ : Kind;
+ Expr *SubInit[1] = { InitList->getInit(0) };
+ Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
+ /*TopLevelOfInitList*/true);
+ if (Sequence)
+ Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
+ return;
+ }
InitListChecker CheckInitList(S, Entity, InitList,
DestType, /*VerifyOnly=*/true);
@@ -4366,6 +4393,14 @@
MultiExprArg Args,
bool TopLevelOfInitList)
: FailedCandidateSet(Kind.getLocation()) {
+ InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList);
+}
+
+void InitializationSequence::InitializeFrom(Sema &S,
+ const InitializedEntity &Entity,
+ const InitializationKind &Kind,
+ MultiExprArg Args,
+ bool TopLevelOfInitList) {
ASTContext &Context = S.Context;
// Eliminate non-overload placeholder types in the arguments. We