From patchwork Thu Dec  6 14:34:27 2012
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Subject: C++ PATCH for c++/55015 (undefined lambda conv op)
Date: Thu, 06 Dec 2012 04:34:27 -0000
From: Jason Merrill <jason@redhat.com>
X-Patchwork-Id: 204249
Message-Id: <50C0ACF3.1020603@redhat.com>
To: gcc-patches List <gcc-patches@gcc.gnu.org>

My earlier patch to change the linkage of the lambda conversion operator 
was wrong; the problem was that we were failing to mark members of a 
local class in a template as comdat.  So I've fixed that and reverted 
the earlier change.

Tested x86_64-pc-linux-gnu, applying to trunk and 4.7.


commit 98abf95dad4ba214f04fb30d2e8c756b9d209797
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Dec 5 17:33:27 2012 -0500

    	PR c++/55015
    	PR c++/53821
    	* semantics.c (maybe_add_lambda_conv_op): Revert earlier change.
    	* decl.c (start_preparsed_function): Make local class methods comdat
    	in templates, too.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index bae48ce..cdda2f4 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13199,10 +13199,9 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
       if (DECL_NOT_REALLY_EXTERN (decl1))
 	DECL_EXTERNAL (decl1) = 0;
 
-      if (ctx != NULL_TREE && DECL_DECLARED_INLINE_P (ctx)
-	  && TREE_PUBLIC (ctx))
+      if (ctx != NULL_TREE && vague_linkage_p (ctx))
 	/* This is a function in a local class in an extern inline
-	   function.  */
+	   or template function.  */
 	comdat_linkage (decl1);
     }
   /* If this function belongs to an interface, it is public.
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index eaf7069..53e849a 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -9419,6 +9419,8 @@ maybe_add_lambda_conv_op (tree type)
   DECL_NOT_REALLY_EXTERN (fn) = 1;
   DECL_DECLARED_INLINE_P (fn) = 1;
   DECL_ARGUMENTS (fn) = build_this_parm (fntype, TYPE_QUAL_CONST);
+  if (nested)
+    DECL_INTERFACE_KNOWN (fn) = 1;
 
   add_method (type, fn, NULL_TREE);
 
@@ -9449,6 +9451,8 @@ maybe_add_lambda_conv_op (tree type)
   DECL_ARGUMENTS (fn) = copy_list (DECL_CHAIN (DECL_ARGUMENTS (callop)));
   for (arg = DECL_ARGUMENTS (fn); arg; arg = DECL_CHAIN (arg))
     DECL_CONTEXT (arg) = fn;
+  if (nested)
+    DECL_INTERFACE_KNOWN (fn) = 1;
 
   add_method (type, fn, NULL_TREE);
 
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv6.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv6.C
new file mode 100644
index 0000000..bd90437
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-conv6.C
@@ -0,0 +1,7 @@
+// PR c++/55015
+// { dg-do link }
+// { dg-options -std=c++11 }
+
+typedef void (*VoidFunc)();
+inline VoidFunc GetFunc() { return [](){}; }
+int main() { VoidFunc func = GetFunc(); }