Fix build when Qt is used in an automatic reference-counted environment

When automatic reference-counting (ARC) is enabled on Darwin platforms
the NSAutoReleasePool class should not be used directly, which caused a
build error if qglobal.h was included after the Foundation.h in client
code.

The preferred alternative for ARC is the scoped @autoreleasepool
construct, which allows the compiler to reason about needing to
insert _objc_autoreleasePoolPush and _objc_autoreleasePoolPop
calls.

Note that ARC translation units can be combined with non-ARC translation
units, so Qt and the QMacAutoReleasePool class can still be used in
ARC client code even if Qt is not built with ARC.

Task-number: QTBUG-51332
Change-Id: I7ef1c3146aa416a9d6a1dc299ce7b17f22f889e5
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@theqtcompany.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/corelib/kernel/qcore_mac_objc.mm b/src/corelib/kernel/qcore_mac_objc.mm
index 1a2b047041..e1480a36d5 100644
--- a/src/corelib/kernel/qcore_mac_objc.mm
+++ b/src/corelib/kernel/qcore_mac_objc.mm
@@ -150,7 +150,7 @@ QMacAutoReleasePool::~QMacAutoReleasePool()
     // Drain behaves the same as release, with the advantage that
     // if we're ever used in a garbage-collected environment, the
     // drain acts as a hint to the garbage collector to collect.
-    [pool drain];
+    [static_cast<NSAutoreleasePool*>(pool) drain];
 }
 
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