Add support for member pointers to const_cast.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63055 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaNamedCast.cpp

@@ -133,7 +133,10 @@ CheckConstCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
     SrcType = SrcExpr->getType();
   }
 
-  if (!DestType->isPointerType()) {
+  // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
+  //   the rules for const_cast are the same as those used for pointers.
+
+  if (!DestType->isPointerType() && !DestType->isMemberPointerType()) {
     // Cannot cast to non-pointer, non-reference type. Note that, if DestType
     // was a reference type, we converted it to a pointer above.
     // C++ 5.2.11p3: For two pointer types [...]
@@ -141,7 +144,8 @@ CheckConstCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
       << OrigDestType << DestRange;
     return;
   }
-  if (DestType->isFunctionPointerType()) {
+  if (DestType->isFunctionPointerType() ||
+      DestType->isMemberFunctionPointerType()) {
     // Cannot cast direct function pointers.
     // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
     // T is the ultimate pointee of source and target type.

test/SemaCXX/const-cast.cpp

@@ -1,5 +1,7 @@
 // RUN: clang -fsyntax-only -verify %s
 
+struct A {};
+
 // See if aliasing can confuse this baby.
 typedef char c;
 typedef c *cp;
@@ -33,6 +35,9 @@ char ***good_const_cast_test(ccvpcvpp var)
   f fp = 0;
   // Don't misidentify fn** as a function pointer.
   f *fpp = const_cast<f*>(&fp);
+  int const A::* const A::*icapcap = 0;
+  int A::* A::* iapap = const_cast<int A::* A::*>(icapcap);
+
   return var4;
 }
 
@@ -52,5 +57,7 @@ short *bad_const_cast_test(char const *volatile *const volatile *var)
   f fp1 = 0;
   // Function pointers.
   f fp2 = const_cast<f>(fp1); // expected-error {{const_cast to 'f', which is not a reference, pointer-to-object, or pointer-to-data-member}}
+  void (A::*mfn)() = 0;
+  (void)const_cast<void (A::*)()>(mfn); // expected-error {{const_cast to 'void (struct A::*)(void)', which is not a reference, pointer-to-object, or pointer-to-data-member}}
   return **var3;
 }

www/cxx_status.html

@@ -587,10 +587,10 @@ welcome!</p>
 <tr>
   <td>&nbsp;&nbsp;&nbsp;&nbsp;5.2.11 [expr.const.cast]</td>
   <td class="complete" align="center">&#x2713;</td>
-  <td class="advanced" align="center"></td>
-  <td class="advanced" align="center"></td>
+  <td class="complete" align="center">&#x2713;</td>
+  <td class="complete" align="center">&#x2713;</td>
+  <td></td>
   <td></td>
-  <td>Missing member pointer conversions</td>  
 </tr>
 <tr><td>&nbsp;&nbsp;5.3 [expr.unary]</td><td></td><td></td><td></td><td></td><td></td></tr>
 <tr><td>&nbsp;&nbsp;&nbsp;&nbsp;5.3.1 [expr.unary.op]</td><td></td><td></td><td></td><td></td><td></td></tr>