re PR c++/51312 ([C++0x] Wrong interpretation of converted constant expressions…

re PR c++/51312 ([C++0x] Wrong interpretation of converted constant expressions (for enumerator initializers))

/cp
2014-08-07  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51312
	* decl.c (build_enumerator): Handle class types with conversion
	operators via perform_implicit_conversion_flags and
	build_expr_type_conversion.

	* cvt.c (build_expr_type_conversion): Replace pair of errors
	with error + inform.

/testsuite
2014-08-07  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/51312
	* g++.dg/cpp0x/enum29.C: New.

From-SVN: r213736

gcc/cp/ChangeLog

+2014-08-07  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51312
+	* decl.c (build_enumerator): Handle class types with conversion
+	operators via perform_implicit_conversion_flags and
+	build_expr_type_conversion.
+
+	* cvt.c (build_expr_type_conversion): Replace pair of errors
+	with error + inform.
+
 2014-08-07  Jason Merrill  <jason@redhat.com>
 
 	PR c++/62043

gcc/cp/cvt.c

@@ -1658,7 +1658,8 @@ build_expr_type_conversion (int desires, tree expr, bool complain)
 		    {
 		      error ("ambiguous default type conversion from %qT",
 			     basetype);
-		      error ("  candidate conversions include %qD and %qD",
+		      inform (input_location,
+			      "  candidate conversions include %qD and %qD",
 			      winner, cand);
 		    }
 		  return error_mark_node;

gcc/cp/decl.c

@@ -12966,6 +12966,23 @@ build_enumerator (tree name, tree value, tree enumtype, location_t loc)
       /* Validate and default VALUE.  */
       if (value != NULL_TREE)
 	{
+	  if (!ENUM_UNDERLYING_TYPE (enumtype))
+	    {
+	      tree tmp_value = build_expr_type_conversion (WANT_INT | WANT_ENUM,
+							   value, true);
+	      if (tmp_value)
+		value = tmp_value;
+	    }
+	  else if (! INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (value)))
+	    value = perform_implicit_conversion_flags
+	      (ENUM_UNDERLYING_TYPE (enumtype), value, tf_warning_or_error,
+	       LOOKUP_IMPLICIT | LOOKUP_NO_NARROWING);
+
+	  if (value == error_mark_node)
+	    value = NULL_TREE;
+
+	  if (value != NULL_TREE)
+	    {
 	      value = cxx_constant_value (value);
 
 	      if (TREE_CODE (value) != INTEGER_CST
@@ -12976,6 +12993,7 @@ build_enumerator (tree name, tree value, tree enumtype, location_t loc)
 		  value = NULL_TREE;
 		}
 	    }
+	}
 
       /* Default based on previous value.  */
       if (value == NULL_TREE)

gcc/testsuite/ChangeLog

+2014-08-07  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/51312
+	* g++.dg/cpp0x/enum29.C: New.
+
 2014-08-07  John David Anglin  <danglin@gcc.gnu.org>
 
 	* gcc.dg/atomic/c11-atomic-exec-4.c: Undefine _POSIX_C_SOURCE before

gcc/testsuite/g++.dg/cpp0x/enum29.C

+// PR c++/51312
+// { dg-do compile { target c++11 } }
+
+struct X0
+{
+  constexpr operator int() const { return 1; }
+};
+
+struct X1
+{
+  enum RE1 { re1 = 1 };
+  constexpr operator RE1() const { return re1; }
+};
+
+struct X2
+{
+  constexpr operator int() const { return __INT_MAX__; }
+};
+
+struct X3
+{
+  enum RE3 { re3 = __INT_MAX__ };
+  constexpr operator RE3() const { return re3; }
+};
+
+struct X4
+{
+  constexpr operator double() const { return 1.0; }
+};
+
+struct X5
+{
+  constexpr operator int() const { return __INT_MAX__; }
+  constexpr operator unsigned() const { return __INT_MAX__ * 2U + 1; }
+};
+
+enum E0 { e0 = X0() };
+enum E1 { e1 = X1() };
+enum E2 { e2 = X2() };
+enum E3 { e3 = X3() };
+enum E4 { e4 = X4() };  // { dg-error "integer constant" }
+enum E5 { e5 = X5() };  // { dg-error "ambiguous" }
+
+enum F0 : int { f0 = X0() };
+enum F1 : int { f1 = X1() };
+enum F2 : int { f2 = X2() };
+enum F3 : int { f3 = X3() };
+enum F4 : int { f4 = X4() };  // { dg-error "narrowing" }
+enum F5 : int { f5 = X5() };
+
+enum G0 : signed char { g0 = X0() };
+enum G1 : signed char { g1 = X1() };
+enum G2 : signed char { g2 = X2() };  // { dg-error "narrowing" }
+// { dg-warning "overflow" "" { target *-*-* } 53 }
+enum G3 : signed char { g3 = X3() };  // { dg-error "narrowing" }
+// { dg-warning "overflow" "" { target *-*-* } 55 }
+enum G4 : signed char { g4 = X4() };  // { dg-error "narrowing" }
+enum G5 : signed char { g5 = X5() };  // { dg-error "ambiguous" }