From: Akira Hatanaka <ahatanaka@apple.com>
Date: Thu, 26 Jul 2018 17:51:13 +0000 (+0000)
Subject: [Sema][ObjC] Do not propagate the nullability specifier on the receiver
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=dcd0309c08ba6c3c39bb75ed975fcf95ca63ad7f;p=clang

[Sema][ObjC] Do not propagate the nullability specifier on the receiver
to the result type of a message send if the result type cannot have a
nullability specifier.

Previously, clang would print the following message when the code in
nullability.m was compiled:

"incompatible integer to pointer conversion initializing 'int *' with
an expression of type 'int _Nullable'"

This is wrong as 'int' isn't supposed to have any nullability
specifiers.

rdar://problem/40830514

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@338048 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index bf9d081bb9..bf0ffeba06 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1357,6 +1357,11 @@ QualType Sema::getMessageSendResultType(QualType ReceiverType,
   if (isClassMessage)
     return resultType;
 
+  // There is nothing left to do if the result type cannot have a nullability
+  // specifier.
+  if (!resultType->canHaveNullability())
+    return resultType;
+
   // Map the nullability of the result into a table index.
   unsigned receiverNullabilityIdx = 0;
   if (auto nullability = ReceiverType->getNullability(Context))
diff --git a/test/SemaObjC/nullability.m b/test/SemaObjC/nullability.m
index cbfe132d14..93f4d1d499 100644
--- a/test/SemaObjC/nullability.m
+++ b/test/SemaObjC/nullability.m
@@ -279,3 +279,14 @@ void test(ArraysInMethods *obj) {
   [obj simpleSugar:0]; // expected-warning {{null passed to a callee that requires a non-null argument}}
   [obj sugarWithTypedef:0]; // expected-warning {{null passed to a callee that requires a non-null argument}}
 }
+
+// Check that we don't propagate the nullability specifier on the receiver to
+// the result type of a message send if the result type cannot have a
+// nullability specifier.
+@interface C0
+-(int) count;
+@end
+
+void testMessageSendResultType(C0 * _Nullable c0) {
+  int *p = [c0 count]; // expected-warning {{incompatible integer to pointer conversion initializing 'int *' with an expression of type 'int'}}
+}