re PR c++/12242 (g++ should warn about out-of-range int->enum conversions)

2008-08-09  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c++/12242
cp/
	* cvt.c (ocp_convert): Warn for out-of-range conversions to enum.

testsuite/
	* g++.dg/warn/pr12242.C: New.

From-SVN: r138898

gcc/cp/ChangeLog

 2008-08-09  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
+	PR c++/12242
+	* cvt.c (ocp_convert): Warn for out-of-range conversions to enum.
+
+2008-08-09  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
 	PR 36901
 	* cp-tree.h (struct diagnostic_context, struct diagnostic_info):
 	Delete forward declarations. Check that toplev.h has not been

gcc/cp/cvt.c

@@ -638,19 +638,35 @@ ocp_convert (tree type, tree expr, int convtype, int flags)
   if (INTEGRAL_CODE_P (code))
     {
       tree intype = TREE_TYPE (e);
-      /* enum = enum, enum = int, enum = float, (enum)pointer are all
-	 errors.  */
-      if (TREE_CODE (type) == ENUMERAL_TYPE
-	  && (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
+
+      if (TREE_CODE (type) == ENUMERAL_TYPE)
+	{
+	  /* enum = enum, enum = int, enum = float, (enum)pointer are all
+	     errors.  */
+	  if (((INTEGRAL_OR_ENUMERATION_TYPE_P (intype)
 		|| TREE_CODE (intype) == REAL_TYPE)
 	       && ! (convtype & CONV_STATIC))
-	      || TREE_CODE (intype) == POINTER_TYPE))
-	{
-	  if (flags & LOOKUP_COMPLAIN)
-	    permerror ("conversion from %q#T to %q#T", intype, type);
+	      || TREE_CODE (intype) == POINTER_TYPE)
+	    {
+	      if (flags & LOOKUP_COMPLAIN)
+		permerror ("conversion from %q#T to %q#T", intype, type);
 
-	  if (!flag_permissive)
-	    return error_mark_node;
+	      if (!flag_permissive)
+		return error_mark_node;
+	    }
+
+	  /* [expr.static.cast]
+
+	     8. A value of integral or enumeration type can be explicitly
+	     converted to an enumeration type. The value is unchanged if
+	     the original value is within the range of the enumeration
+	     values. Otherwise, the resulting enumeration value is
+	     unspecified.  */
+	  if (TREE_CODE (expr) == INTEGER_CST && !int_fits_type_p (expr, type))
+	    warning (OPT_Wconversion, 
+		     "the result of the conversion is unspecified because "
+		     "%qE is outside the range of type %qT",
+		     expr, type);
 	}
       if (MAYBE_CLASS_TYPE_P (intype))
 	{

gcc/testsuite/ChangeLog

 2008-08-09  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
+	PR c++/12242
+	* g++.dg/warn/pr12242.C: New.
+	
+2008-08-09  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
 	PR 36901
 	* gcc.dg/pr36901-1.c: New.
 	* gcc.dg/pr36901-3.c: New.

gcc/testsuite/g++.dg/warn/pr12242.C

+// PR 12242: should warn about out-of-range int->enum conversions
+// { dg-do compile }
+// { dg-options "-Wconversion -fpermissive" }
+enum X { A };
+enum Y { B, C, D };
+
+void example ()
+{
+  int i = 5;
+  X x;
+  Y y;
+  
+  x = 10;  // { dg-warning "warning: invalid conversion from .int. to .X." }
+           // { dg-warning "warning:\[^\n\]*unspecified" "" { target *-*-* } 13 }
+  x = 1;   // { dg-warning "warning: invalid conversion from .int. to .X." }
+  x = C;   // { dg-error "error: cannot convert .Y. to .X. in assignment" }  
+  x = D;   // { dg-error "error: cannot convert .Y. to .X. in assignment" }  
+  y = A;   // { dg-error "error: cannot convert .X. to .Y. in assignment" }  
+  x = y;   // { dg-error "error: cannot convert .Y. to .X. in assignment" }  
+  x = i;   // { dg-warning "warning: invalid conversion from .int. to .X."  }
+}
+
+void foo () 
+{
+  X a = static_cast<X> (10); // { dg-warning "warning:\[^\n\]*unspecified" }
+  X b = static_cast<X> (0);
+  X c = static_cast<X> (1);
+  X d = static_cast<X> (2); // { dg-warning "warning:\[^\n\]*unspecified" }
+  X f = static_cast<X> ((int)A);
+  X g = static_cast<X> (B);
+  X h = static_cast<X> (C);
+  X e = static_cast<X> (D); // { dg-warning "warning\[^\n\]*unspecified" }
+}
+
+enum QEvent { x = 42 }; 
+ 
+int bar()
+{ 
+  QEvent x = ( QEvent ) 42000; // { dg-warning "warning\[^\n\]*unspecified" }
+  return ( int ) x; 
+}
+
+enum W {a,b,c};
+enum Z {d,e,f,g};
+void bazz (int, int, int, int);
+
+void baz() {
+  int three = 3;
+  int four = 4;
+  bazz (
+	W(three), 
+	W(3), 
+	Z(four), 
+	Z(4) // { dg-warning "warning\[^\n\]*unspecified" }
+	);
+}
+