From: Jason Merrill <jason@redhat.com>
Date: Tue, 9 Jul 2013 17:56:32 +0000 (-0400)
Subject: re PR c++/57437 (C++11: mutable lambdas)
X-Git-Tag: releases/gcc-4.9.0~5059
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f9f91ddcf76a01b80f8b194f7402aedc40e8af79;p=thirdparty%2Fgcc.git

re PR c++/57437 (C++11: mutable lambdas)

	PR c++/57437
	* typeck.c (check_return_expr): Lambda proxies aren't eligible
	for nrv or return by move.

From-SVN: r200843
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 2d6fa73d0117..68c6a09cff93 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2013-07-09  Jason Merrill  <jason@redhat.com>
 
+	PR c++/57437
+	* typeck.c (check_return_expr): Lambda proxies aren't eligible
+	for nrv or return by move.
+
 	PR c++/57532
 	* parser.c (cp_parser_ref_qualifier_opt): Don't tentatively parse
 	a ref-qualifier in C++98 mode.
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 462abdd5039d..6f7d48928791 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -8399,7 +8399,8 @@ check_return_expr (tree retval, bool *no_warning)
      && VAR_P (retval)
      && DECL_CONTEXT (retval) == current_function_decl
      && ! TREE_STATIC (retval)
-     && ! DECL_ANON_UNION_VAR_P (retval)
+     /* And not a lambda or anonymous union proxy.  */
+     && !DECL_HAS_VALUE_EXPR_P (retval)
      && (DECL_ALIGN (retval) <= DECL_ALIGN (result))
      /* The cv-unqualified type of the returned value must be the
         same as the cv-unqualified return type of the
@@ -8444,7 +8445,7 @@ check_return_expr (tree retval, bool *no_warning)
          Note that these conditions are similar to, but not as strict as,
 	 the conditions for the named return value optimization.  */
       if ((cxx_dialect != cxx98)
-          && (VAR_P (retval)
+          && ((VAR_P (retval) && !DECL_HAS_VALUE_EXPR_P (retval))
 	      || TREE_CODE (retval) == PARM_DECL)
 	  && DECL_CONTEXT (retval) == current_function_decl
 	  && !TREE_STATIC (retval)
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-return1.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-return1.C
new file mode 100644
index 000000000000..4b353b64c37e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-return1.C
@@ -0,0 +1,26 @@
+// PR c++/57437
+// { dg-require-effective-target c++11 }
+
+struct A {
+  int i;
+
+  A(): i(42) {}
+  A(const A&) = default;
+  A(A&& a): i(a.i) { a.i = 0; }
+};
+
+int main()
+{
+  A x;
+
+  auto y = [x] () mutable {
+    x.i++;
+    return x;
+  };
+
+  if (y().i != 43)
+    __builtin_abort ();
+
+  if (y().i != 44)
+    __builtin_abort ();
+}