re PR c++/48450 ([C++0x][SFINAE] Hard errors with static_cast expressions)

	PR c++/48450
	* typeck.c (check_for_casting_away_constness): Take complain.
	(build_static_cast_1, build_reinterpret_cast_1): Pass it.
	(build_const_cast_1): Pass it.  Take full complain parm.
	(build_const_cast, cp_build_c_cast): Adjust.

From-SVN: r172145

gcc/cp/ChangeLog

 2011-04-07  Jason Merrill  <jason@redhat.com>
 
+	PR c++/48450
+	* typeck.c (check_for_casting_away_constness): Take complain.
+	(build_static_cast_1, build_reinterpret_cast_1): Pass it.
+	(build_const_cast_1): Pass it.  Take full complain parm.
+	(build_const_cast, cp_build_c_cast): Adjust.
+
 	* tree.c (build_aggr_init_expr): Always return error_mark_node
 	on abstract violation.
 

gcc/cp/typeck.c

@@ -5579,42 +5579,47 @@ 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.  Returns true
+   if the cast is ill-formed, false if it is well-formed.
 
    ??? This function warns for casting away any qualifier not just
    const.  We would like to specify exactly what qualifiers are casted
    away.
 */
 
-static void
+static bool
 check_for_casting_away_constness (tree src_type, tree dest_type,
-				  enum tree_code cast)
+				  enum tree_code cast, tsubst_flags_t complain)
 {
   /* C-style casts are allowed to cast away constness.  With
      WARN_CAST_QUAL, we still want to issue a warning.  */
   if (cast == CAST_EXPR && !warn_cast_qual)
-      return;
+    return false;
   
   if (!casts_away_constness (src_type, dest_type))
-    return;
+    return false;
 
   switch (cast)
     {
     case CAST_EXPR:
-      warning (OPT_Wcast_qual, 
-	       "cast from type %qT to type %qT casts away qualifiers",
-	       src_type, dest_type);
-      return;
+      if (complain & tf_warning)
+	warning (OPT_Wcast_qual,
+		 "cast from type %qT to type %qT casts away qualifiers",
+		 src_type, dest_type);
+      return false;
       
     case STATIC_CAST_EXPR:
-      error ("static_cast from type %qT to type %qT casts away qualifiers",
-	     src_type, dest_type);
-      return;
+      if (complain & tf_error)
+	error ("static_cast from type %qT to type %qT casts away qualifiers",
+	       src_type, dest_type);
+      return true;
       
     case REINTERPRET_CAST_EXPR:
-      error ("reinterpret_cast from type %qT to type %qT casts away qualifiers",
-	     src_type, dest_type);
-      return;
+      if (complain & tf_error)
+	error ("reinterpret_cast from type %qT to type %qT casts away qualifiers",
+	       src_type, dest_type);
+      return true;
+
     default:
       gcc_unreachable();
     }
@@ -5832,8 +5837,10 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
     {
       tree base;
 
-      if (!c_cast_p)
-	check_for_casting_away_constness (intype, type, STATIC_CAST_EXPR);
+      if (!c_cast_p
+	  && check_for_casting_away_constness (intype, type, STATIC_CAST_EXPR,
+					       complain))
+	return error_mark_node;
       base = lookup_base (TREE_TYPE (type), TREE_TYPE (intype),
 			  c_cast_p ? ba_unique : ba_check,
 			  NULL);
@@ -5868,10 +5875,13 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
 	}
       if (can_convert (t1, t2) || can_convert (t2, t1))
 	{
-	  if (!c_cast_p)
-	    check_for_casting_away_constness (intype, type, STATIC_CAST_EXPR);
+	  if (!c_cast_p
+	      && check_for_casting_away_constness (intype, type,
+						   STATIC_CAST_EXPR,
+						   complain))
+	    return error_mark_node;
 	  return convert_ptrmem (type, expr, /*allow_inverse_p=*/1,
-				 c_cast_p, tf_warning_or_error);
+				 c_cast_p, complain);
 	}
     }
 
@@ -5885,8 +5895,10 @@ build_static_cast_1 (tree type, tree expr, bool c_cast_p,
       && VOID_TYPE_P (TREE_TYPE (intype))
       && TYPE_PTROB_P (type))
     {
-      if (!c_cast_p)
-	check_for_casting_away_constness (intype, type, STATIC_CAST_EXPR);
+      if (!c_cast_p
+	  && check_for_casting_away_constness (intype, type, STATIC_CAST_EXPR,
+					       complain))
+	return error_mark_node;
       return build_nop (type, expr);
     }
 
@@ -6090,8 +6102,11 @@ build_reinterpret_cast_1 (tree type, tree expr, bool c_cast_p,
     {
       tree sexpr = expr;
 
-      if (!c_cast_p)
-	check_for_casting_away_constness (intype, type, REINTERPRET_CAST_EXPR);
+      if (!c_cast_p
+	  && check_for_casting_away_constness (intype, type,
+					       REINTERPRET_CAST_EXPR,
+					       complain))
+	return error_mark_node;
       /* Warn about possible alignment problems.  */
       if (STRICT_ALIGNMENT && warn_cast_align
           && (complain & tf_warning)
@@ -6168,7 +6183,7 @@ build_reinterpret_cast (tree type, tree expr, tsubst_flags_t complain)
    whether or not the conversion succeeded.  */
 
 static tree
-build_const_cast_1 (tree dst_type, tree expr, bool complain,
+build_const_cast_1 (tree dst_type, tree expr, tsubst_flags_t complain,
 		    bool *valid_p)
 {
   tree src_type;
@@ -6187,7 +6202,7 @@ build_const_cast_1 (tree dst_type, tree expr, bool complain,
 
   if (!POINTER_TYPE_P (dst_type) && !TYPE_PTRMEM_P (dst_type))
     {
-      if (complain)
+      if (complain & tf_error)
 	error ("invalid use of const_cast with type %qT, "
 	       "which is not a pointer, "
 	       "reference, nor a pointer-to-data-member type", dst_type);
@@ -6196,7 +6211,7 @@ build_const_cast_1 (tree dst_type, tree expr, bool complain,
 
   if (TREE_CODE (TREE_TYPE (dst_type)) == FUNCTION_TYPE)
     {
-      if (complain)
+      if (complain & tf_error)
 	error ("invalid use of const_cast with type %qT, which is a pointer "
 	       "or reference to a function type", dst_type);
       return error_mark_node;
@@ -6221,7 +6236,7 @@ build_const_cast_1 (tree dst_type, tree expr, bool complain,
       reference_type = dst_type;
       if (! real_lvalue_p (expr))
 	{
-	  if (complain)
+	  if (complain & tf_error)
 	    error ("invalid const_cast of an rvalue of type %qT to type %qT",
 		   src_type, dst_type);
 	  return error_mark_node;
@@ -6248,12 +6263,12 @@ build_const_cast_1 (tree dst_type, tree expr, bool complain,
 	  *valid_p = true;
 	  /* This cast is actually a C-style cast.  Issue a warning if
 	     the user is making a potentially unsafe cast.  */
-	  check_for_casting_away_constness (src_type, dst_type, CAST_EXPR);
+	  check_for_casting_away_constness (src_type, dst_type, CAST_EXPR,
+					    complain);
 	}
       if (reference_type)
 	{
-	  expr = cp_build_addr_expr (expr,
-				     complain ? tf_warning_or_error : tf_none);
+	  expr = cp_build_addr_expr (expr, complain);
 	  expr = build_nop (reference_type, expr);
 	  return convert_from_reference (expr);
 	}
@@ -6270,7 +6285,7 @@ build_const_cast_1 (tree dst_type, tree expr, bool complain,
 	}
     }
 
-  if (complain)
+  if (complain & tf_error)
     error ("invalid const_cast from type %qT to type %qT",
 	   src_type, dst_type);
   return error_mark_node;
@@ -6293,7 +6308,7 @@ build_const_cast (tree type, tree expr, tsubst_flags_t complain)
       return convert_from_reference (t);
     }
 
-  return build_const_cast_1 (type, expr, complain & tf_error,
+  return build_const_cast_1 (type, expr, complain,
 			     /*valid_p=*/NULL);
 }
 
@@ -6379,7 +6394,7 @@ cp_build_c_cast (tree type, tree expr, tsubst_flags_t complain)
 		"cast to pointer from integer of different size");
 
   /* A C-style cast can be a const_cast.  */
-  result = build_const_cast_1 (type, value, /*complain=*/false,
+  result = build_const_cast_1 (type, value, complain & tf_warning,
 			       &valid_p);
   if (valid_p)
     return result;

gcc/testsuite/ChangeLog

 2011-04-07  Jason Merrill  <jason@redhat.com>
 
+	* c-c++-common/Wcast-qual-1.c: Move here from...
+	* gcc.dg/cast-qual-3.c: ...here, and...
+	* g++.dg/warn/Wcast-qual2.C: ...here.
+
 	* g++.dg/cpp0x/sfinae8.C: New.
 
 	* g++.dg/cpp0x/sfinae7.C: New.

gcc/testsuite/g++.dg/warn/Wcast-qual2.C → gcc/testsuite/c-c++-common/Wcast-qual-1.c

 /* { dg-do compile } */
 /* { dg-options "-Wcast-qual" } */
 
-/* The files gcc.dg/cast-qual-3.c and g++.dg/warn/Wcast-qual2.c are
-   duals.  they are intended to show that gcc -Wcast-qual and g++
-   -Wcast-qual emit warnings in the same cases.  If you change this
-   file, please also change the other one.  */
-
 void
 f1 (void *bar)
 {

gcc/testsuite/gcc.dg/cast-qual-3.c

-/* { dg-do compile } */
-/* { dg-options "-Wcast-qual" } */
-
-/* The files gcc.dg/cast-qual-3.c and g++.dg/warn/Wcast-qual2.c are
-   duals.  they are intended to show that gcc -Wcast-qual and g++
-   -Wcast-qual emit warnings in the same cases.  If you change this
-   file, please also change the other one.  */
-
-void
-f1 (void *bar)
-{
-  const void *p1 = (const void *) bar;
-  const char *p2 = (const char *) bar;
-  const void **p3 = (const void **) bar;
-  const char **p4 = (const char **) bar;
-  const void * const *p5 = (const void * const *) bar;
-  const char * const *p6 = (const char * const *) bar;
-  void * const *p7 = (void * const *) bar;
-  char * const *p8 = (char * const *) bar;
-  const void ***p9 = (const void ***) bar;
-  const char ***p10 = (const char ***) bar;
-  void * const **p11 = (void * const **) bar;
-  char * const **p12 = (char * const **) bar;
-  void ** const *p13 = (void ** const *) bar;
-  char ** const *p14 = (char ** const *) bar;
-  const void * const **p15 = (const void * const **) bar;
-  const char * const **p16 = (const char * const **) bar;
-  const void ** const *p17 = (const void ** const *) bar;
-  const char ** const *p18 = (const char ** const *) bar;
-  void * const * const * p19 = (void * const * const *) bar;
-  char * const * const * p20 = (char * const * const *) bar;
-  const void * const * const *p21 = (const void * const * const *) bar;
-  const char * const * const *p22 = (const char * const * const *) bar;
-}
-
-void
-f2 (void **bar)
-{
-  const void *p1 = (const void *) bar;
-  const char *p2 = (const char *) bar;
-  const void **p3 = (const void **) bar; /* { dg-warning "cast" } */
-  const char **p4 = (const char **) bar;
-  const void * const *p5 = (const void * const *) bar;
-  const char * const *p6 = (const char * const *) bar;
-  void * const *p7 = (void * const *) bar;
-  char * const *p8 = (char * const *) bar;
-  const void ***p9 = (const void ***) bar;
-  const char ***p10 = (const char ***) bar;
-  void * const **p11 = (void * const **) bar;
-  char * const **p12 = (char * const **) bar;
-  void ** const *p13 = (void ** const *) bar;
-  char ** const *p14 = (char ** const *) bar;
-  const void * const **p15 = (const void * const **) bar;
-  const char * const **p16 = (const char * const **) bar;
-  const void ** const *p17 = (const void ** const *) bar;
-  const char ** const *p18 = (const char ** const *) bar;
-  void * const * const * p19 = (void * const * const *) bar;
-  char * const * const * p20 = (char * const * const *) bar;
-  const void * const * const *p21 = (const void * const * const *) bar;
-  const char * const * const *p22 = (const char * const * const *) bar;
-}
-
-void
-f3 (void ***bar)
-{
-  const void *p1 = (const void *) bar;
-  const char *p2 = (const char *) bar;
-  const void **p3 = (const void **) bar;
-  const char **p4 = (const char **) bar;
-  const void * const *p5 = (const void * const *) bar;
-  const char * const *p6 = (const char * const *) bar;
-  void * const *p7 = (void * const *) bar;
-  char * const *p8 = (char * const *) bar;
-  const void ***p9 = (const void ***) bar; /* { dg-warning "cast" } */
-  const char ***p10 = (const char ***) bar;
-  void * const **p11 = (void * const **) bar; /* { dg-warning "cast" } */
-  char * const **p12 = (char * const **) bar;
-  void ** const *p13 = (void ** const *) bar;
-  char ** const *p14 = (char ** const *) bar;
-  const void * const **p15 = (const void * const **) bar; /* { dg-warning "cast" } */
-  const char * const **p16 = (const char * const **) bar;
-  const void ** const *p17 = (const void ** const *) bar; /* { dg-warning "cast" } */
-  const char ** const *p18 = (const char ** const *) bar;
-  void * const * const * p19 = (void * const * const *) bar;
-  char * const * const * p20 = (char * const * const *) bar;
-  const void * const * const *p21 = (const void * const * const *) bar;
-  const char * const * const *p22 = (const char * const * const *) bar;
-}
-
-void
-f4 (void * const **bar)
-{
-  const void ***p9 = (const void ***) bar; /* { dg-warning "cast" } */
-  void * const **p11 = (void * const **) bar;
-  void ** const *p13 = (void ** const *) bar; /* { dg-warning "cast" } */
-  const void * const **p15 = (const void * const **) bar; /* { dg-warning "cast" } */
-  const void ** const *p17 = (const void ** const *) bar; /* { dg-warning "cast" } */
-  void * const * const * p19 = (void * const * const *) bar;
-  const void * const * const *p21 = (const void * const * const *) bar;
-}
-
-void
-f5 (char ***bar)
-{
-  volatile const char ***p9 = (volatile const char ***) bar; /* { dg-warning "cast" } */
-  volatile char * const **p11 = (volatile char * const **) bar; /* { dg-warning "cast" } */
-  volatile char ** const *p13 = (volatile char ** const *) bar; /* { dg-warning "cast" } */
-  volatile const char * const **p15 = (volatile const char * const **) bar; /* { dg-warning "cast" } */
-  volatile const char ** const *p17 = (volatile const char ** const *) bar; /* { dg-warning "cast" } */
-  volatile char * const * const * p19 = (volatile char * const * const *) bar;
-  volatile const char * const * const *p21 = (volatile const char * const * const *) bar;
-}
-
-void
-f6 (char ***bar)
-{
-  const char * volatile **p9 = (const char * volatile **) bar; /* { dg-warning "cast" } */
-  char * volatile const **p11 = (char * volatile const **) bar; /* { dg-warning "cast" } */
-  char * volatile * const *p13 = (char * volatile * const *) bar;
-  const char * volatile const **p15 = (const char * volatile const **) bar; /* { dg-warning "cast" } */
-  const char * volatile * const *p17 = (const char * volatile * const *) bar; /* { dg-warning "cast" } */
-  char * volatile const * const * p19 = (char * volatile const * const *) bar;
-  const char * volatile const * const *p21 = (const char * volatile const * const *) bar;
-}
-
-void
-f7 (char ***bar)
-{
-  const char ** volatile *p9 = (const char ** volatile *) bar; /* { dg-warning "cast" } */
-  char * const * volatile *p11 = (char * const * volatile *) bar; /* { dg-warning "cast" } */
-  char ** volatile const *p13 = (char ** volatile const *) bar;
-  const char * const * volatile *p15 = (const char * const * volatile *) bar; /* { dg-warning "cast" } */
-  const char ** volatile const *p17 = (const char ** volatile const *) bar; /* { dg-warning "cast" } */
-  char * const * volatile const * p19 = (char * const * volatile const *) bar;
-  const char * const * volatile const *p21 = (const char * const * volatile const *) bar;
-}
-
-typedef int (intfn) (int);
-typedef intfn *pintfn;
-typedef const intfn *constfn;
-
-void
-f8 (constfn ***bar)
-{
-  const constfn *p1 = (const constfn *) bar;
-  const pintfn *p2 = (const pintfn *) bar;
-  const constfn **p3 = (const constfn **) bar;
-  const pintfn **p4 = (const pintfn **) bar;
-  const constfn * const *p5 = (const constfn * const *) bar;
-  const pintfn * const *p6 = (const pintfn * const *) bar;
-  constfn * const *p7 = (constfn * const *) bar;
-  pintfn * const *p8 = (pintfn * const *) bar;
-  const constfn ***p9 = (const constfn ***) bar; /* { dg-warning "cast" } */
-  const pintfn ***p10 = (const pintfn ***) bar; /* { dg-warning "cast" } */
-  constfn * const **p11 = (constfn * const **) bar; /* { dg-warning "cast" } */
-  pintfn * const **p12 = (pintfn * const **) bar; /* { dg-warning "cast" } */
-  constfn ** const *p13 = (constfn ** const *) bar;
-  pintfn ** const *p14 = (pintfn ** const *) bar;
-  const constfn * const **p15 = (const constfn * const **) bar; /* { dg-warning "cast" } */
-  const pintfn * const **p16 = (const pintfn * const **) bar; /* { dg-warning "cast" } */
-  const constfn ** const *p17 = (const constfn ** const *) bar; /* { dg-warning "cast" } */
-  const pintfn ** const *p18 = (const pintfn ** const *) bar; /* { dg-warning "cast" } */
-  constfn * const * const * p19 = (constfn * const * const *) bar;
-  pintfn * const * const * p20 = (pintfn * const * const *) bar;
-  const constfn * const * const *p21 = (const constfn * const * const *) bar;
-  const pintfn * const * const *p22 = (const pintfn * const * const *) bar;
-}