[C++ PATCH] Fix constexpr C++11 handling with lambdas (PR c++/65075)

[Jakub Jelinek]

Hi!

If there are lambdas in C++11 constexpr return-stmts, we get implicit
typedefs of the lambda types, but those are artificial and we should ignore
them.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2015-02-16  Paolo Carlini  <paolo.carlini@oracle.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR c++/65075
	* constexpr.c (check_constexpr_bind_expr_vars): Allow
	implicit typedefs for lambda types.

	* g++.dg/cpp0x/pr65075.C: New test.

--- gcc/cp/constexpr.c.jj	2015-02-14 00:19:49.000000000 +0100
+++ gcc/cp/constexpr.c	2015-02-16 15:12:06.260262857 +0100
@@ -416,7 +416,8 @@ check_constexpr_bind_expr_vars (tree t)
 
   for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var))
     if (TREE_CODE (var) == TYPE_DECL
-	&& DECL_IMPLICIT_TYPEDEF_P (var))
+	&& DECL_IMPLICIT_TYPEDEF_P (var)
+	&& !LAMBDA_TYPE_P (TREE_TYPE (var)))
       return false;
   return true;
 }
--- gcc/testsuite/g++.dg/cpp0x/pr65075.C.jj	2015-02-16 15:09:48.405517062 +0100
+++ gcc/testsuite/g++.dg/cpp0x/pr65075.C	2015-02-16 15:09:23.000000000 +0100
@@ -0,0 +1,17 @@
+// PR c++/65075
+// { dg-do compile { target c++11 } }
+
+typedef void (*E) ();
+template <class T>
+constexpr E
+bar (bool a)
+{
+  return a ? []() {} : []() {};
+}
+
+void
+foo ()
+{
+  (bar<int> (false)) ();
+  (bar<int> (true)) ();
+}

	Jakub