Index: lib/AST/Type.cpp
===================================================================
--- lib/AST/Type.cpp
+++ lib/AST/Type.cpp
@@ -2035,7 +2035,18 @@
 
     case Qualifiers::OCL_None:
       break;
-    }        
+    }
+  } else if (Context.getLangOpts().ObjCWeak) {
+    switch (getObjCLifetime()) {
+    case Qualifiers::OCL_Weak:
+      return false;
+
+    case Qualifiers::OCL_None:
+    case Qualifiers::OCL_ExplicitNone:
+    case Qualifiers::OCL_Strong:
+    case Qualifiers::OCL_Autoreleasing:
+      break;
+    }
   }
   
   QualType CanonicalType = getTypePtr()->CanonicalType;
@@ -2099,7 +2110,18 @@
       if ((*this)->isObjCLifetimeType())
         return false;
       break;
-    }        
+    }
+  } else if (Context.getLangOpts().ObjCWeak) {
+    switch (getObjCLifetime()) {
+    case Qualifiers::OCL_Weak:
+      return false;
+
+    case Qualifiers::OCL_None:
+    case Qualifiers::OCL_ExplicitNone:
+    case Qualifiers::OCL_Strong:
+    case Qualifiers::OCL_Autoreleasing:
+      break;
+    }
   }
   
   QualType CanonicalType = getTypePtr()->CanonicalType;
@@ -2151,7 +2173,18 @@
       if ((*this)->isObjCLifetimeType())
         return false;
       break;
-    }        
+    }
+  } else if (Context.getLangOpts().ObjCWeak) {
+    switch (getObjCLifetime()) {
+    case Qualifiers::OCL_Weak:
+      return false;
+
+    case Qualifiers::OCL_None:
+    case Qualifiers::OCL_ExplicitNone:
+    case Qualifiers::OCL_Strong:
+    case Qualifiers::OCL_Autoreleasing:
+      break;
+    }
   }
 
   // C++11 [basic.types]p9
@@ -2310,7 +2343,18 @@
 
     case Qualifiers::OCL_None:
       break;
-    }        
+    }
+  } else if (Context.getLangOpts().ObjCWeak) {
+    switch (getObjCLifetime()) {
+    case Qualifiers::OCL_Weak:
+      return false;
+
+    case Qualifiers::OCL_ExplicitNone:
+    case Qualifiers::OCL_Strong:
+    case Qualifiers::OCL_Autoreleasing:
+    case Qualifiers::OCL_None:
+      break;
+    }
   }
 
   // C++11 [basic.types]p9:
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4648,10 +4648,12 @@
       return S.canThrow(Result.get()) == CT_Cannot;
 
     if (Kind == clang::TT_IsTriviallyConstructible) {
-      // Under Objective-C ARC, if the destination has non-trivial Objective-C
-      // lifetime, this is a non-trivial construction.
-      if (S.getLangOpts().ObjCAutoRefCount &&
-          hasNontrivialObjCLifetime(T.getNonReferenceType()))
+      // Under Objective-C ARC and Weak, if the destination has non-trivial
+      // Objective-C lifetime, this is a non-trivial construction.
+      if ((S.getLangOpts().ObjCAutoRefCount &&
+           hasNontrivialObjCLifetime(T.getNonReferenceType())) ||
+          (S.getLangOpts().ObjCWeak &&
+           T.getNonReferenceType().getObjCLifetime() == Qualifiers::OCL_Weak))
         return false;
 
       // The initialization succeeded; now make sure there are no non-trivial
@@ -4870,10 +4872,13 @@
       return Self.canThrow(Result.get()) == CT_Cannot;
 
     if (BTT == BTT_IsTriviallyAssignable) {
-      // Under Objective-C ARC, if the destination has non-trivial Objective-C
-      // lifetime, this is a non-trivial assignment.
-      if (Self.getLangOpts().ObjCAutoRefCount &&
-          hasNontrivialObjCLifetime(LhsT.getNonReferenceType()))
+      // Under Objective-C ARC and Weak, if the destination has non-trivial
+      // Objective-C lifetime, this is a non-trivial assignment.
+      if ((Self.getLangOpts().ObjCAutoRefCount &&
+           hasNontrivialObjCLifetime(LhsT.getNonReferenceType())) ||
+          (Self.getLangOpts().ObjCWeak &&
+           LhsT.getNonReferenceType().getObjCLifetime() ==
+               Qualifiers::OCL_Weak))
         return false;
 
       return !Result.get()->hasNonTrivialCall(Self.Context);
Index: test/SemaObjCXX/objc-weak-type-traits.mm
===================================================================
--- /dev/null
+++ test/SemaObjCXX/objc-weak-type-traits.mm
@@ -0,0 +1,210 @@
+// RUN: %clang_cc1 -fsyntax-only -fobjc-weak -fobjc-runtime-has-weak -verify -std=c++11 %s
+// expected-no-diagnostics
+
+// Check the results of the various type-trait query functions on
+// lifetime-qualified types in ObjC Weak.
+
+#define TRAIT_IS_TRUE(Trait, Type) static_assert(Trait(Type), "")
+#define TRAIT_IS_FALSE(Trait, Type) static_assert(!Trait(Type), "")
+#define TRAIT_IS_TRUE_2(Trait, Type1, Type2) static_assert(Trait(Type1, Type2), "")
+#define TRAIT_IS_FALSE_2(Trait, Type1, Type2) static_assert(!Trait(Type1, Type2), "")
+  
+struct HasStrong { id obj; };
+struct HasWeak { __weak id obj; };
+struct HasUnsafeUnretained { __unsafe_unretained id obj; };
+
+// __has_nothrow_assign
+TRAIT_IS_TRUE(__has_nothrow_assign, __strong id);
+TRAIT_IS_TRUE(__has_nothrow_assign, __weak id);
+TRAIT_IS_TRUE(__has_nothrow_assign, __autoreleasing id);
+TRAIT_IS_TRUE(__has_nothrow_assign, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_nothrow_assign, HasStrong);
+TRAIT_IS_TRUE(__has_nothrow_assign, HasWeak);
+TRAIT_IS_TRUE(__has_nothrow_assign, HasUnsafeUnretained);
+
+// __has_nothrow_copy
+TRAIT_IS_TRUE(__has_nothrow_copy, __strong id);
+TRAIT_IS_TRUE(__has_nothrow_copy, __weak id);
+TRAIT_IS_TRUE(__has_nothrow_copy, __autoreleasing id);
+TRAIT_IS_TRUE(__has_nothrow_copy, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_nothrow_copy, HasStrong);
+TRAIT_IS_TRUE(__has_nothrow_copy, HasWeak);
+TRAIT_IS_TRUE(__has_nothrow_copy, HasUnsafeUnretained);
+
+// __has_nothrow_constructor
+TRAIT_IS_TRUE(__has_nothrow_constructor, __strong id);
+TRAIT_IS_TRUE(__has_nothrow_constructor, __weak id);
+TRAIT_IS_TRUE(__has_nothrow_constructor, __autoreleasing id);
+TRAIT_IS_TRUE(__has_nothrow_constructor, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_nothrow_constructor, HasStrong);
+TRAIT_IS_TRUE(__has_nothrow_constructor, HasWeak);
+TRAIT_IS_TRUE(__has_nothrow_constructor, HasUnsafeUnretained);
+
+// __has_trivial_assign
+TRAIT_IS_TRUE(__has_trivial_assign, __strong id);
+TRAIT_IS_FALSE(__has_trivial_assign, __weak id);
+TRAIT_IS_TRUE(__has_trivial_assign, __autoreleasing id);
+TRAIT_IS_TRUE(__has_trivial_assign, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_trivial_assign, HasStrong);
+TRAIT_IS_FALSE(__has_trivial_assign, HasWeak);
+TRAIT_IS_TRUE(__has_trivial_assign, HasUnsafeUnretained);
+
+// __has_trivial_copy
+TRAIT_IS_TRUE(__has_trivial_copy, __strong id);
+TRAIT_IS_FALSE(__has_trivial_copy, __weak id);
+TRAIT_IS_TRUE(__has_trivial_copy, __autoreleasing id);
+TRAIT_IS_TRUE(__has_trivial_copy, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_trivial_copy, HasStrong);
+TRAIT_IS_FALSE(__has_trivial_copy, HasWeak);
+TRAIT_IS_TRUE(__has_trivial_copy, HasUnsafeUnretained);
+
+// __has_trivial_constructor
+TRAIT_IS_TRUE(__has_trivial_constructor, __strong id);
+TRAIT_IS_FALSE(__has_trivial_constructor, __weak id);
+TRAIT_IS_TRUE(__has_trivial_constructor, __autoreleasing id);
+TRAIT_IS_TRUE(__has_trivial_constructor, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_trivial_constructor, HasStrong);
+TRAIT_IS_FALSE(__has_trivial_constructor, HasWeak);
+TRAIT_IS_TRUE(__has_trivial_constructor, HasUnsafeUnretained);
+
+// __has_trivial_destructor
+TRAIT_IS_TRUE(__has_trivial_destructor, __strong id);
+TRAIT_IS_FALSE(__has_trivial_destructor, __weak id);
+TRAIT_IS_TRUE(__has_trivial_destructor, __autoreleasing id);
+TRAIT_IS_TRUE(__has_trivial_destructor, __unsafe_unretained id);
+TRAIT_IS_TRUE(__has_trivial_destructor, HasStrong);
+TRAIT_IS_FALSE(__has_trivial_destructor, HasWeak);
+TRAIT_IS_TRUE(__has_trivial_destructor, HasUnsafeUnretained);
+
+// __is_literal
+TRAIT_IS_TRUE(__is_literal, __strong id);
+TRAIT_IS_TRUE(__is_literal, __weak id);
+TRAIT_IS_TRUE(__is_literal, __autoreleasing id);
+TRAIT_IS_TRUE(__is_literal, __unsafe_unretained id);
+
+// __is_literal_type
+TRAIT_IS_TRUE(__is_literal_type, __strong id);
+TRAIT_IS_TRUE(__is_literal_type, __weak id);
+TRAIT_IS_TRUE(__is_literal_type, __autoreleasing id);
+TRAIT_IS_TRUE(__is_literal_type, __unsafe_unretained id);
+
+// __is_pod
+TRAIT_IS_TRUE(__is_pod, __strong id);
+TRAIT_IS_FALSE(__is_pod, __weak id);
+TRAIT_IS_TRUE(__is_pod, __autoreleasing id);
+TRAIT_IS_TRUE(__is_pod, __unsafe_unretained id);
+TRAIT_IS_TRUE(__is_pod, HasStrong);
+TRAIT_IS_FALSE(__is_pod, HasWeak);
+TRAIT_IS_TRUE(__is_pod, HasUnsafeUnretained);
+
+// __is_trivial
+TRAIT_IS_TRUE(__is_trivial, __strong id);
+TRAIT_IS_FALSE(__is_trivial, __weak id);
+TRAIT_IS_TRUE(__is_trivial, __autoreleasing id);
+TRAIT_IS_TRUE(__is_trivial, __unsafe_unretained id);
+TRAIT_IS_TRUE(__is_trivial, HasStrong);
+TRAIT_IS_FALSE(__is_trivial, HasWeak);
+TRAIT_IS_TRUE(__is_trivial, HasUnsafeUnretained);
+
+// __is_scalar
+TRAIT_IS_TRUE(__is_scalar, __strong id);
+TRAIT_IS_FALSE(__is_scalar, __weak id);
+TRAIT_IS_TRUE(__is_scalar, __autoreleasing id);
+TRAIT_IS_TRUE(__is_scalar, __unsafe_unretained id);
+
+// __is_standard_layout
+TRAIT_IS_TRUE(__is_standard_layout, __strong id);
+TRAIT_IS_TRUE(__is_standard_layout, __weak id);
+TRAIT_IS_TRUE(__is_standard_layout, __autoreleasing id);
+TRAIT_IS_TRUE(__is_standard_layout, __unsafe_unretained id);
+
+// __is_trivally_assignable
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __strong id&, __unsafe_unretained id&&);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __strong id);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __weak id);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __autoreleasing id);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __unsafe_unretained id);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __strong id&&);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __weak id&&);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __autoreleasing id&&);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, __weak id&, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __autoreleasing id&, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, __unsafe_unretained id&, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_assignable, HasStrong&, HasStrong);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, HasStrong&, HasStrong&&);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, HasWeak&, HasWeak);
+TRAIT_IS_FALSE_2(__is_trivially_assignable, HasWeak&, HasWeak&&);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, HasUnsafeUnretained&, HasUnsafeUnretained);
+TRAIT_IS_TRUE_2(__is_trivially_assignable, HasUnsafeUnretained&, HasUnsafeUnretained&&);
+
+// __is_trivally_constructible
+TRAIT_IS_TRUE(__is_trivially_constructible, __strong id);
+TRAIT_IS_FALSE(__is_trivially_constructible, __weak id);
+TRAIT_IS_TRUE(__is_trivially_constructible, __autoreleasing id);
+TRAIT_IS_TRUE(__is_trivially_constructible, __unsafe_unretained id);
+
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __strong id, __unsafe_unretained id&&);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __strong id);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __weak id);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __autoreleasing id);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __unsafe_unretained id);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __strong id&&);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __weak id&&);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __autoreleasing id&&);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, __weak id, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __autoreleasing id, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __strong id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __weak id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __autoreleasing id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __unsafe_unretained id);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __strong id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __weak id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __autoreleasing id&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, __unsafe_unretained id, __unsafe_unretained id&&);
+
+TRAIT_IS_TRUE_2(__is_trivially_constructible, HasStrong, HasStrong);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, HasStrong, HasStrong&&);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak);
+TRAIT_IS_FALSE_2(__is_trivially_constructible, HasWeak, HasWeak&&);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained);
+TRAIT_IS_TRUE_2(__is_trivially_constructible, HasUnsafeUnretained, HasUnsafeUnretained&&);