Re: [C++ Patch] PR 64644 (""warning: anonymous union with no members" should be an error with -pedantic-errors")

[Paolo Carlini]

Hi,

gently pinging this. As you can see certainly isn't an high priority 
issue but resolving it one way or the other seems pretty simple...


On 16/06/2017 15:47, Paolo Carlini wrote:

Hi,

submitter and Manuel analyzed this a while ago and came to the 
conclusion - which I think is still valid vs the current working draft 
- that strictly speaking this kind of code violates [dcl.dcl], thus a 
pedwarn seems more suited than a plain warning. The below one-liner, 
suggested by Manuel at the time, passes testing on x86_64-linux 
together with my testsuite changes.


https://gcc.gnu.org/ml/gcc-patches/2017-06/msg01193.html

Thanks!
Paolo.

[C++ Patch] PR 64644 (""warning: anonymous union with no members" should be an error with -pedantic-errors")

[Paolo Carlini]

Hi,

submitter and Manuel analyzed this a while ago and came to the 
conclusion - which I think is still valid vs the current working draft - 
that strictly speaking this kind of code violates [dcl.dcl], thus a 
pedwarn seems more suited than a plain warning. The below one-liner, 
suggested by Manuel at the time, passes testing on x86_64-linux together 
with my testsuite changes.


Thanks,

Paolo.

//

/cp
2017-06-16  Manuel Lopez-Ibanez  
Paolo Carlini  

PR c++/64644
* decl2.c (finish_anon_union): Complain about "anonymous union with
no members" with a pedwarn.

/testsuite
2017-06-16  Manuel Lopez-Ibanez  
Paolo Carlini  

PR c++/64644
* g++.dg/other/anon-union4.C: New.
* g++.old-deja/g++.law/union4.C: Adjust.
* g++.old-deja/g++.other/anon1.C: Likewise.
Index: cp/decl2.c
===
--- cp/decl2.c  (revision 249233)
+++ cp/decl2.c  (working copy)
@@ -1559,7 +1559,7 @@ finish_anon_union (tree anon_union_decl)
 return;
   if (main_decl == NULL_TREE)
 {
-  warning (0, "anonymous union with no members");
+  pedwarn (input_location, 0, "anonymous union with no members");
   return;
 }
 
Index: testsuite/g++.dg/other/anon-union4.C
===
--- testsuite/g++.dg/other/anon-union4.C(revision 0)
+++ testsuite/g++.dg/other/anon-union4.C(working copy)
@@ -0,0 +1,3 @@
+// PR c++/64644
+
+static union { };  // { dg-error "anonymous union with no members" }
Index: testsuite/g++.old-deja/g++.law/union4.C
===
--- testsuite/g++.old-deja/g++.law/union4.C (revision 249233)
+++ testsuite/g++.old-deja/g++.law/union4.C (working copy)
@@ -10,4 +10,4 @@ static union {
 struct SS {
 int ss;
 };
-};// { dg-warning "no members" }
+};// { dg-error "no members" }
Index: testsuite/g++.old-deja/g++.other/anon1.C
===
--- testsuite/g++.old-deja/g++.other/anon1.C(revision 249233)
+++ testsuite/g++.old-deja/g++.other/anon1.C(working copy)
@@ -3,4 +3,4 @@
 static union {
   union {
   };
-}; // { dg-warning "" } anonymous union with no members
+}; // { dg-error "" } anonymous union with no members