PR45521: Preserve the value kind when performing a standard conversion

sequence on a glvalue expression.

If the sequence is supposed to perform an lvalue-to-rvalue conversion,
then one will be specified as the first conversion in the sequence.
Otherwise, one should not be invented.

clang/lib/Sema/SemaExprCXX.cpp

@@ -4203,8 +4203,8 @@ Sema::PerformImplicitConversion(Expr *From, QualType ToType,
     break;
 
   case ICK_Compatible_Conversion:
-      From = ImpCastExprToType(From, ToType, CK_NoOp,
-                               VK_RValue, /*BasePath=*/nullptr, CCK).get();
+    From = ImpCastExprToType(From, ToType, CK_NoOp, From->getValueKind(),
+                             /*BasePath=*/nullptr, CCK).get();
     break;
 
   case ICK_Writeback_Conversion:
@@ -4441,11 +4441,7 @@ Sema::PerformImplicitConversion(Expr *From, QualType ToType,
     break;
 
   case ICK_Qualification: {
-    // The qualification keeps the category of the inner expression, unless the
-    // target type isn't a reference.
-    ExprValueKind VK =
-        ToType->isReferenceType() ? From->getValueKind() : VK_RValue;
-
+    ExprValueKind VK = From->getValueKind();
     CastKind CK = CK_NoOp;
 
     if (ToType->isReferenceType() &&

clang/lib/Sema/SemaOverload.cpp

@@ -4709,7 +4709,7 @@ TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
                               Sema::ReferenceConversions::NestedQualification)
                              ? ICK_Qualification
                              : ICK_Identity;
-    ICS.Standard.FromTypePtr = T2.getAsOpaquePtr();
+    ICS.Standard.setFromType(T2);
     ICS.Standard.setToType(0, T2);
     ICS.Standard.setToType(1, T1);
     ICS.Standard.setToType(2, T1);

clang/test/SemaCXX/references.cpp

@@ -201,3 +201,9 @@ namespace RefCollapseTypePrinting {
   template void add_rref<const int&>(); // expected-note {{instantiation of}}
   template void add_rref<const int&&>(); // expected-note {{instantiation of}}
 }
+
+namespace PR45521 {
+  struct a { template<class b> a(const b * const&); };
+  int *d;
+  const a &r = d;
+}