1 files changed, 15 insertions, 3 deletions
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 3941643893..11fed28b52 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -1658,12 +1658,24 @@ static void markEscapingByrefs(const FunctionScopeInfo &FSI, Sema &S) {
   // Set the EscapingByref flag of __block variables captured by
   // escaping blocks.
   for (const BlockDecl *BD : FSI.Blocks) {
-    if (BD->doesNotEscape())
-      continue;
     for (const BlockDecl::Capture &BC : BD->captures()) {
       VarDecl *VD = BC.getVariable();
-      if (VD->hasAttr<BlocksAttr>())
+      if (VD->hasAttr<BlocksAttr>()) {
+        // Nothing to do if this is a __block variable captured by a
+        // non-escaping block.
+        if (BD->doesNotEscape())
+          continue;
         VD->setEscapingByref();
+      }
+      // Check whether the captured variable is or contains an object of
+      // non-trivial C union type.
+      QualType CapType = BC.getVariable()->getType();
+      if (CapType.hasNonTrivialToPrimitiveDestructCUnion() ||
+          CapType.hasNonTrivialToPrimitiveCopyCUnion())
+        S.checkNonTrivialCUnion(BC.getVariable()->getType(),
+                                BD->getCaretLocation(),
+                                Sema::NTCUC_BlockCapture,
+                                Sema::NTCUK_Destruct|Sema::NTCUK_Copy);
     }
   }