When converting from a type to itself or one of its base classes via a

constructor call, the conversion is only a standard conversion
sequence if that constructor is a copy constructor. This fixes PR5834
in a semi-lame way, because the "real" fix will be to move over to
InitializationSequence. That will happen "soonish", but not now.

llvm-svn: 91861

2 files changed, 16 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index fbcb8074289..66aa4845b12 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -451,7 +451,8 @@ Sema::TryImplicitConversion(Expr* From, QualType ToType,
       QualType FromCanon
         = Context.getCanonicalType(From->getType().getUnqualifiedType());
       QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
-      if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) {
+      if (Constructor->isCopyConstructor(Context) &&
+          (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) {
         // Turn this into a "standard" conversion sequence, so that it
         // gets ranked with standard conversion sequences.
         ICS.ConversionKind = ImplicitConversionSequence::StandardConversion;
diff --git a/clang/test/CodeGenCXX/PR5834-constructor-conversion.cpp b/clang/test/CodeGenCXX/PR5834-constructor-conversion.cpp
new file mode 100644
index 00000000000..044d8e555d7
--- /dev/null
+++ b/clang/test/CodeGenCXX/PR5834-constructor-conversion.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -emit-llvm -o - %s
+
+// PR5834
+struct ASTMultiMover {};
+struct ASTMultiPtr {
+  ASTMultiPtr();
+  ASTMultiPtr(ASTMultiPtr&);
+  ASTMultiPtr(ASTMultiMover mover);
+  operator ASTMultiMover();
+};
+void f1() {
+  extern void f0(ASTMultiPtr);
+  f0(ASTMultiPtr());
+}