diff mbox

[C++] PR 65977

Message ID 5591A9A0.2040803@oracle.com
State New
Headers show

Commit Message

Paolo Carlini June 29, 2015, 8:25 p.m. UTC 
Hi,

given in particular Richard Smith' analysis here:

http://stackoverflow.com/questions/29871138/constexpr-is-not-allowed-in-declaration-of-friend-template-specialization/29957648#29957648

I think it's pretty straightforward that we don't have a good reason to 
reject constexpr friend declarations. In practice the most recent 
compilers I have at hand all agree.

Tested x86_64-linux.

Thanks,
Paolo.

///////////////////////
/cp
2015-06-29  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/65977
	* decl.c (grokfndecl): Allow constexpr declarations of friend
	template specializations.


/testsuite
2015-06-29  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/65977
	* g++.dg/cpp0x/constexpr-friend-3.C: New.
	* g++.dg/cpp0x/constexpr-friend-2.C: Adjust.

Comments

Jason Merrill June 29, 2015, 9:55 p.m. UTC | #1 
OK.

Jason
diff mbox

Patch

Index: cp/decl.c
===================================================================
--- cp/decl.c	(revision 225123)
+++ cp/decl.c	(working copy)
@@ -7738,15 +7738,12 @@  grokfndecl (tree ctype,
 	    }
 
 	  if (inlinep & 1)
-	    error ("%<inline%> is not allowed in declaration of friend "
-		   "template specialization %qD",
-		   decl);
-	  if (inlinep & 2)
-	    error ("%<constexpr%> is not allowed in declaration of friend "
-		   "template specialization %qD",
-		   decl);
-	  if (inlinep)
-	    return NULL_TREE;
+	    {
+	      error ("%<inline%> is not allowed in declaration of friend "
+		     "template specialization %qD",
+		     decl);
+	      return NULL_TREE;
+	    }
 	}
     }
 
Index: testsuite/g++.dg/cpp0x/constexpr-friend-2.C
===================================================================
--- testsuite/g++.dg/cpp0x/constexpr-friend-2.C	(revision 225123)
+++ testsuite/g++.dg/cpp0x/constexpr-friend-2.C	(working copy)
@@ -3,5 +3,5 @@ 
 template<typename T> void f(T);
 
 template <class T> class A {
-  friend constexpr void f<>(int);  // { dg-error "'constexpr' is not allowed" }
+  friend constexpr void f<>(int);
 };
Index: testsuite/g++.dg/cpp0x/constexpr-friend-3.C
===================================================================
--- testsuite/g++.dg/cpp0x/constexpr-friend-3.C	(revision 0)
+++ testsuite/g++.dg/cpp0x/constexpr-friend-3.C	(working copy)
@@ -0,0 +1,21 @@ 
+// PR c++/65977
+// { dg-do compile { target c++11 } }
+
+template<__SIZE_TYPE__>
+class bitset;
+
+template<__SIZE_TYPE__ N>
+constexpr bool operator==(const bitset<N>&, const bitset<N>&) noexcept;
+
+template<__SIZE_TYPE__ N>
+class bitset
+{
+  friend constexpr bool operator== <>(const bitset<N>&,
+				      const bitset<N>&) noexcept;
+};
+
+template<__SIZE_TYPE__ N>
+constexpr bool operator==(const bitset<N>&, const bitset<N>&) noexcept
+{
+  return true;
+}