re PR c++/51912 ([C++11] G++ accepts floating point case labels)

/cp
2013-08-14  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51912
	* cp-tree.h (LOOKUP_NO_NON_INTEGRAL): Add.
	* decl.c (case_conversion): Use it.
	* call.c (standard_conversion): Likewise.
	(implicit_conversion): Adjust.

/testsuite
2013-08-14  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51912
	* g++.dg/cpp0x/enum28.C: New.
	* g++.dg/cpp0x/enum15.C: Adjust.

From-SVN: r201754

gcc/cp/ChangeLog

+2013-08-14  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51912
+	* cp-tree.h (LOOKUP_NO_NON_INTEGRAL): Add.
+	* decl.c (case_conversion): Use it.
+	* call.c (standard_conversion): Likewise.
+	(implicit_conversion): Adjust.
+
 2013-08-13  Adam Butcher  <adam@jessamine.co.uk>
 
 	* pt.c: Grammar fix in comments ("it's" to "its").

gcc/cp/call.c

@@ -1314,7 +1314,8 @@ standard_conversion (tree to, tree from, tree expr, bool c_cast_p,
   /* As an extension, allow conversion to complex type.  */
   else if (ARITHMETIC_TYPE_P (to))
     {
-      if (! (INTEGRAL_CODE_P (fcode) || fcode == REAL_TYPE)
+      if (! (INTEGRAL_CODE_P (fcode)
+	     || (fcode == REAL_TYPE && !(flags & LOOKUP_NO_NON_INTEGRAL)))
           || SCOPED_ENUM_P (from))
 	return NULL;
       conv = build_conv (ck_std, to, conv);
@@ -1681,7 +1682,7 @@ implicit_conversion (tree to, tree from, tree expr, bool c_cast_p,
      resolution, or after we've chosen one.  */
   flags &= (LOOKUP_ONLYCONVERTING|LOOKUP_NO_CONVERSION|LOOKUP_COPY_PARM
 	    |LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND|LOOKUP_PREFER_RVALUE
-	    |LOOKUP_NO_NARROWING|LOOKUP_PROTECT);
+	    |LOOKUP_NO_NARROWING|LOOKUP_PROTECT|LOOKUP_NO_NON_INTEGRAL);
 
   /* FIXME: actually we don't want warnings either, but we can't just
      have 'complain &= ~(tf_warning|tf_error)' because it would cause

gcc/cp/cp-tree.h

@@ -4510,6 +4510,8 @@ enum overload_flags { NO_SPECIAL = 0, DTOR_FLAG, TYPENAME_FLAG };
 #define LOOKUP_EXPLICIT_TMPL_ARGS (LOOKUP_ALREADY_DIGESTED << 1)
 /* Like LOOKUP_NO_TEMP_BIND, but also prevent binding to xvalues.  */
 #define LOOKUP_NO_RVAL_BIND (LOOKUP_EXPLICIT_TMPL_ARGS << 1)
+/* Used by case_conversion to disregard non-integral conversions.  */
+#define LOOKUP_NO_NON_INTEGRAL (LOOKUP_NO_RVAL_BIND << 1)
 
 #define LOOKUP_NAMESPACES_ONLY(F)  \
   (((F) & LOOKUP_PREFER_NAMESPACES) && !((F) & LOOKUP_PREFER_TYPES))

gcc/cp/decl.c

@@ -3103,7 +3103,9 @@ case_conversion (tree type, tree value)
     {
       if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type))
 	type = type_promotes_to (type);
-      value = perform_implicit_conversion (type, value, tf_warning_or_error);
+      value = (perform_implicit_conversion_flags
+	       (type, value, tf_warning_or_error,
+		LOOKUP_IMPLICIT | LOOKUP_NO_NON_INTEGRAL));
     }
   return cxx_constant_value (value);
 }

gcc/testsuite/ChangeLog

+2013-08-14  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51912
+	* g++.dg/cpp0x/enum28.C: New.
+	* g++.dg/cpp0x/enum15.C: Adjust.
+
 2013-08-14  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	PR target/57949

gcc/testsuite/g++.dg/cpp0x/enum15.C

@@ -15,6 +15,6 @@ void foo (A a, int i)
     {
     case A::Val0: break;	// { dg-error "" }
     case 1: break;
-    case 2.0: break;
+    case 2.0: break;            // { dg-error "" }
     }
 }

gcc/testsuite/g++.dg/cpp0x/enum28.C

+// PR c++/51912
+// { dg-do compile { target c++11 } }
+
+constexpr double g() { return 2.0; }
+
+void f(int i)
+{
+  switch (i)
+    {
+    case 1.0:;    // { dg-error "could not convert" }
+    }
+
+  switch (i)
+    {
+    case g():;    // { dg-error "could not convert" }
+    }
+}