[PATCH] D128031: Don't emit `-Wnullability-completeness` warnings on `weak` Objective-C properties.

[Michael Wyman via Phabricator via cfe-commits]

mwyman created this revision.
mwyman added reviewers: dmaclach, stephanemoore.
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Zeroing weak references are by definition `nullable`, and adding `nonnull` or `_Nonnull` yields a mutual-exclusivity error. However, when `-Wnullability-completeness` is enabled, in non-audited header regions it's necessary to add the `nullable` property keyword to avoid a warning. It should not be necessary to add code clutter to restate the nullability of a `weak` property even under `-Wnullability-completeness`.

Additionally, the fix-it hints are both non-idiomatic Objective-C (adding `_Nullable` to the property's pointer type rather than in the `@property` attributes) and suggest the option of adding `_Nonnull` (which would be an error).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D128031

Files:
  clang/lib/Sema/SemaType.cpp
  clang/test/SemaObjCXX/Inputs/nullability-consistency-2.h


Index: clang/test/SemaObjCXX/Inputs/nullability-consistency-2.h
===================================================================
--- clang/test/SemaObjCXX/Inputs/nullability-consistency-2.h
+++ clang/test/SemaObjCXX/Inputs/nullability-consistency-2.h
@@ -19,13 +19,9 @@
 @property (retain,nullable) SomeClass *property2;
 - (nullable SomeClass *)method1;
 - (void)method2:(nonnull SomeClass *)param;
- at property (readonly, weak) SomeClass *property3; // expected-warning{{missing a nullability type specifier}}
-// expected-note at -1 {{insert '_Nullable' if the pointer may be null}}
-// expected-note at -2 {{insert '_Nonnull' if the pointer should never be null}}
+ at property (readonly, weak) SomeClass *property3;
 @end
 
 @interface SomeClass ()
- at property (readonly, weak) SomeClass *property4; // expected-warning{{missing a nullability type specifier}}
-// expected-note at -1 {{insert '_Nullable' if the pointer may be null}}
-// expected-note at -2 {{insert '_Nonnull' if the pointer should never be null}}
+ at property (readonly, weak) SomeClass *property4;
 @end
Index: clang/lib/Sema/SemaType.cpp
===================================================================
--- clang/lib/Sema/SemaType.cpp
+++ clang/lib/Sema/SemaType.cpp
@@ -4683,8 +4683,13 @@
       }
 
       // Weak properties are inferred to be nullable.
-      if (state.getDeclarator().isObjCWeakProperty() && inAssumeNonNullRegion) {
-        inferNullability = NullabilityKind::Nullable;
+      if (state.getDeclarator().isObjCWeakProperty()) {
+        // Weak properties cannot be nonnull, and should not complain about
+        // missing nullable attributes during completeness checks.
+        complainAboutMissingNullability = CAMN_No;
+        if (inAssumeNonNullRegion) {
+          inferNullability = NullabilityKind::Nullable;
+        }
         break;
       }
 


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