[C++ Patch] PR 60978

[Paolo Carlini]

Hi,

another simple issue: this one argues that the warning is overeager when 
anonymous enums are involved, which often are just used as named 
constants. Details: maybe write the conditional in a different way; 
maybe even use && instead of ||. Tested x86_64-linux.

Thanks,
Paolo.

//////////////////////
/cp
2014-12-02  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/60978
        * call.c (build_conditional_expr_1): Do not -Wenum-compare warn
        for anonymous enums.

/testsuite
2014-12-02  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/60978
        * g++.dg/warn/Wenum-compare-2.C: New.
Index: cp/call.c
===================================================================
--- cp/call.c   (revision 218278)
+++ cp/call.c   (working copy)
@@ -5014,6 +5014,10 @@ build_conditional_expr_1 (location_t loc, tree arg
              && DECL_CONTEXT (orig_arg2) == DECL_CONTEXT (orig_arg3))
            /* Two enumerators from the same enumeration can have different
               types when the enumeration is still being defined.  */;
+         else if (TYPE_ANONYMOUS_P (arg2_type)
+                  || TYPE_ANONYMOUS_P (arg3_type))
+           /* Avoid warning for anonymous enums, probably just used as
+              named constants.  */;
           else if (complain & tf_warning)
             warning_at (loc, OPT_Wenum_compare, "enumeral mismatch in "
                        "conditional expression: %qT vs %qT",
Index: testsuite/g++.dg/warn/Wenum-compare-2.C
===================================================================
--- testsuite/g++.dg/warn/Wenum-compare-2.C     (revision 0)
+++ testsuite/g++.dg/warn/Wenum-compare-2.C     (working copy)
@@ -0,0 +1,10 @@
+// PR c++/60978
+// { dg-options "-Wenum-compare" }
+
+enum { A };
+enum { B };
+
+int foo(int x)
+{
+  return x ? A : B;
+}