Author: rsmith
Date: Mon Jul 2 16:25:22 2018
New Revision: 336153
URL: http://llvm.org/viewvc/llvm-project?rev=336153&view=rev
Log:
Per C++ [over.match.copy]p1, direct-initialization of a reference can
only invoke converting constructors of the reference's underlying type.
Modified:
cfe/trunk/lib/Sema/SemaInit.cpp
cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5.cpp
Modified: cfe/trunk/lib/Sema/SemaInit.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=336153&r1=336152&r2=336153&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaInit.cpp (original)
+++ cfe/trunk/lib/Sema/SemaInit.cpp Mon Jul 2 16:25:22 2018
@@ -4224,9 +4224,11 @@ static OverloadingResult TryRefInitWithC
OverloadCandidateSet &CandidateSet = Sequence.getFailedCandidateSet();
CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
- // Determine whether we are allowed to call explicit constructors or
- // explicit conversion operators.
- bool AllowExplicit = Kind.AllowExplicit();
+ // Determine whether we are allowed to call explicit conversion operators.
+ // Note that none of [over.match.copy], [over.match.conv], nor
+ // [over.match.ref] permit an explicit constructor to be chosen when
+ // initializing a reference, not even for direct-initialization.
+ bool AllowExplicitCtors = false;
bool AllowExplicitConvs =
Kind.allowExplicitConversionFunctionsInRefBinding();
const RecordType *T1RecordType = nullptr;
@@ -4242,7 +4244,7 @@ static OverloadingResult TryRefInitWithC
continue;
if (!Info.Constructor->isInvalidDecl() &&
- Info.Constructor->isConvertingConstructor(AllowExplicit)) {
+ Info.Constructor->isConvertingConstructor(AllowExplicitCtors)) {
if (Info.ConstructorTmpl)
S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
/*ExplicitArgs*/ nullptr,
Modified: cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5.cpp?rev=336153&r1=336152&r2=336153&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5.cpp (original)
+++ cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5.cpp Mon Jul 2
16:25:22 2018
@@ -61,3 +61,12 @@ namespace test3 {
unsigned &t9 = (a->bitY += 3); // expected-error {{non-const reference
cannot bind to bit-field 'bitY'}}
}
}
+
+namespace explicit_ctor {
+ struct A {};
+ struct B { // expected-note 2{{candidate}}
+ explicit B(const A&);
+ };
+ A a;
+ const B &b(a); // expected-error {{no viable conversion}}
+}
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