Merging r295150:

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r295150 | ahatanak | 2017-02-14 21:15:28 -0800 (Tue, 14 Feb 2017) | 13 lines

[Sema] Disallow returning a __block variable via a move.

r274291 made changes to prefer calling a move constructor to calling a
copy constructor when returning from a function. This caused programs to
crash when a __block variable in the heap was moved out and used later.

This commit fixes the bug by disallowing moving out of __block variables
implicitly.

rdar://problem/28181080

Differential Revision: https://reviews.llvm.org/D29908

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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_40@295234 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 1 deletions

diff --git a/test/SemaObjCXX/blocks.mm b/test/SemaObjCXX/blocks.mm
index 09d614d372..3f901cc0a8 100644
--- a/test/SemaObjCXX/blocks.mm
+++ b/test/SemaObjCXX/blocks.mm
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -fblocks -Wno-objc-root-class %s
+// RUN: %clang_cc1 -fsyntax-only -verify -fblocks -Wno-objc-root-class -std=c++11 %s
 @protocol NSObject;
 
 void bar(id(^)(void));
@@ -144,3 +144,17 @@ namespace DependentReturn {
 
   template void f<X>(X);
 }
+
+namespace MoveBlockVariable {
+struct B0 {
+};
+
+struct B1 { // expected-note 2 {{candidate constructor (the implicit}}
+  B1(B0&&); // expected-note {{candidate constructor not viable}}
+};
+
+B1 test_move() {
+  __block B0 b;
+  return b; // expected-error {{no viable conversion from returned value of type 'MoveBlockVariable::B0' to function return type 'MoveBlockVariable::B1'}}
+}
+}