re PR c++/35711 (bad text in -Wcast-qual warning (forgets volatile))

2009-04-21  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c++/35711
cp/
	* typeck.c (check_for_casting_away_constness): We diagnose casting
	away any qualifiers not just constness.
	(casts_away_constness): Mention that it handles more than just
	constness.
testsuite/
	* g++.dg/warn/pr35711.C: New.
	* g++.dg/conversion/ptrmem2.C: Update.

From-SVN: r146537

gcc/cp/ChangeLog

@@ -1,3 +1,11 @@
+2009-04-21  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c++/35711
+	* typeck.c (check_for_casting_away_constness): We diagnose casting
+	away any qualifiers not just constness.
+	(casts_away_constness): Mention that it handles more than just
+	constness.
+	
 2009-04-21  Joseph Myers  <joseph@codesourcery.com>
 
 	* ChangeLog, ChangeLog-1993, ChangeLog-1994, ChangeLog-1995,

gcc/cp/typeck.c

@@ -5038,7 +5038,12 @@ cp_build_compound_expr (tree lhs, tree rhs, tsubst_flags_t complain)
 }
 
 /* Issue a diagnostic message if casting from SRC_TYPE to DEST_TYPE
-   casts away constness.  CAST gives the type of cast.  */
+   casts away constness.  CAST gives the type of cast.  
+
+   ??? This function warns for casting away any qualifier not just
+   const.  We would like to specify exactly what qualifiers are casted
+   away.
+*/
 
 static void
 check_for_casting_away_constness (tree src_type, tree dest_type,
@@ -5049,27 +5054,29 @@ check_for_casting_away_constness (tree src_type, tree dest_type,
   if (cast == CAST_EXPR && !warn_cast_qual)
       return;
   
-  if (casts_away_constness (src_type, dest_type))
-    switch (cast)
-      {
-      case CAST_EXPR:
-	warning (OPT_Wcast_qual, 
-                 "cast from type %qT to type %qT casts away constness",
-		 src_type, dest_type);
-	return;
-	
-      case STATIC_CAST_EXPR:
-	error ("static_cast from type %qT to type %qT casts away constness",
+  if (!casts_away_constness (src_type, dest_type))
+    return;
+
+  switch (cast)
+    {
+    case CAST_EXPR:
+      warning (OPT_Wcast_qual, 
+	       "cast from type %qT to type %qT casts away qualifiers",
 	       src_type, dest_type);
-	return;
-	
-      case REINTERPRET_CAST_EXPR:
-	error ("reinterpret_cast from type %qT to type %qT casts away constness",
-	       src_type, dest_type);
-	return;
-      default:
-	gcc_unreachable();
-      }
+      return;
+      
+    case STATIC_CAST_EXPR:
+      error ("static_cast from type %qT to type %qT casts away qualifiers",
+	     src_type, dest_type);
+      return;
+      
+    case REINTERPRET_CAST_EXPR:
+      error ("reinterpret_cast from type %qT to type %qT casts away qualifiers",
+	     src_type, dest_type);
+      return;
+    default:
+      gcc_unreachable();
+    }
 }
 
 /* Convert EXPR (an expression with pointer-to-member type) to TYPE
@@ -7362,7 +7369,12 @@ casts_away_constness_r (tree *t1, tree *t2)
 }
 
 /* Returns nonzero if casting from TYPE1 to TYPE2 casts away
-   constness.  */
+   constness.  
+
+   ??? This function returns non-zero if casting away qualifiers not
+   just const.  We would like to return to the caller exactly which
+   qualifiers are casted away to give more accurate diagnostics.
+*/
 
 static bool
 casts_away_constness (tree t1, tree t2)

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2009-04-21  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR c++/35711
+	* g++.dg/warn/pr35711.C: New.
+	* g++.dg/conversion/ptrmem2.C: Update.
+
 2009-04-21  Joseph Myers  <joseph@codesourcery.com>
 
 	* ChangeLog, ChangeLog-1993-2007, ChangeLog-2008, ChangeLog.ptr,

gcc/testsuite/g++.dg/conversion/ptrmem2.C

@@ -31,8 +31,8 @@ const int B::*p9 = static_cast<const int B::*>(&D::x);
 const int D::*p10 = static_cast<const int D::*>(&B::x);
 
 // Invalid conversions which decrease cv-qualification.
-int B::*p11 = static_cast<int B::*>(p10); // { dg-error "casts away constness" }
-int D::*p12 = static_cast<int D::*>(p9);  // { dg-error "casts away constness" }
+int B::*p11 = static_cast<int B::*>(p10); // { dg-error "casts away qualifiers" }
+int D::*p12 = static_cast<int D::*>(p9);  // { dg-error "casts away qualifiers" }
 
 // Attempts to change member type.
 float B::*p13 = static_cast<float B::*>(&D::x); // { dg-error "" }

gcc/testsuite/g++.dg/warn/pr35711.C

@@ -0,0 +1,8 @@
+// PR 35711
+// { dg-do compile }
+// { dg-options "-Wcast-qual" }
+
+int* foo (volatile int *p)
+{
+  return (int*)p; // { dg-warning "cast from type 'volatile int\\*' to type 'int\\*' casts away qualifiers" }
+}