fix rvalue to lvalue binding

Author: cor3ntin

clang/include/clang/Sema/Overload.h

@@ -408,8 +408,15 @@ class Sema;
     }
 
     bool isPerfect(const ASTContext &C) const {
-      return isIdentityConversion() &&
-             (!ReferenceBinding || C.hasSameType(getFromType(), getToType(2)));
+      if(!isIdentityConversion())
+        return false;
+      if(!ReferenceBinding)
+        return true;
+      if(!C.hasSameType(getFromType(), getToType(2)))
+        return false;
+      if(BindsToRvalue && IsLvalueReference)
+        return false;
+      return true;
     }
 
     ImplicitConversionRank getRank() const;

clang/lib/Sema/SemaOverload.cpp

@@ -11031,6 +11031,8 @@ void OverloadCandidateSet::AddDeferredMethodTemplateCandidate(
     bool SuppressUserConversions, bool PartialOverloading,
     OverloadCandidateParamOrder PO) {
 
+  assert(!isa<CXXConstructorDecl>(MethodTmpl->getTemplatedDecl()));
+
   auto *C =
       allocateDeferredCandidate<DeferredMethodTemplateOverloadCandidate>();
 

clang/test/SemaCXX/overload-resolution-deferred-templates.cpp

@@ -128,6 +128,27 @@ struct Test {
 static_assert(__is_constructible(S, Test));
 }
 
+namespace RefBinding {
+
+template <typename> struct remove_reference;
+template <typename _Tp> struct remove_reference<_Tp &> {
+  using type = _Tp;
+};
+template <typename _Tp> remove_reference<_Tp>::type move(_Tp &&);
+template <typename _Head> struct _Head_base {
+  _Head_base(_Head &__h) : _M_head_impl(__h) {}
+  template <typename _UHead> _Head_base(_UHead &&);
+  _Head _M_head_impl;
+};
+
+template <typename _Elements> void forward_as_tuple(_Elements &&) {
+  _Head_base<_Elements &&>(_Elements{});
+}
+struct StringRef {
+  void operator[](const StringRef __k) { forward_as_tuple((move)(__k)); }
+};
+
+}
 
 namespace GH62096 {
 template <typename T>