[PATCH] D23236: When ARC is enabled, no warning will be generated when a method1. Returns 'nil' in a method that is attributed to return a 'nonnull'2. The return-statement is a ConditionalOperator, where the lhs is nil and rhs an objC-method-call (or the other...

[Hendrik von Prince via cfe-commits]

parallaxe updated this revision to Diff 69000.
parallaxe added a comment.

Moved the tests into `nullability_nullonly.mm` according to @dcoughlin.
Applied the changes according to @aaron.ballman.


https://reviews.llvm.org/D23236

Files:
  lib/Sema/SemaStmt.cpp
  test/Analysis/nullability_nullonly.mm
  test/SemaObjC/nullability.m

Index: test/SemaObjC/nullability.m
===================================================================
--- test/SemaObjC/nullability.m
+++ test/SemaObjC/nullability.m
@@ -82,7 +82,7 @@
 }
 - (NSFoo *)redundantMethod1 {
   int *ip = 0;
-  return ip; // expected-warning{{result type 'NSFoo * _Nonnull'}}
+  return ip; // expected-warning{{incompatible pointer types returning 'int *' from a function with result type 'NSFoo *'}}
 }
 @end
 
@@ -96,7 +96,7 @@
 @implementation NSMerge
 - (NSFoo *)methodA:(NSFoo*)foo {
   int *ptr = foo; // expected-warning{{incompatible pointer types initializing 'int *' with an expression of type 'NSFoo * _Nonnull'}}
-  return ptr; // expected-warning{{result type 'NSFoo * _Nonnull'}}
+  return ptr; // expected-warning{{incompatible pointer types returning 'int *' from a function with result type 'NSFoo *'}}
 }
 
 - (nullable NSFoo *)methodB:(null_unspecified NSFoo*)foo { // expected-error{{nullability specifier 'nullable' conflicts with existing specifier 'nonnull'}} \
@@ -106,7 +106,7 @@
 
 - (nonnull NSFoo *)methodC:(nullable NSFoo*)foo {
   int *ip = 0;
-  return ip; // expected-warning{{result type 'NSFoo * _Nonnull'}}
+  return ip; // expected-warning{{incompatible pointer types returning 'int *' from a function with result type 'NSFoo *'}}
 }
 @end
 
@@ -191,7 +191,7 @@
 @implementation NSResettable // expected-warning{{synthesized setter 'setResettable4:' for null_resettable property 'resettable4' does not handle nil}}
 - (NSResettable *)resettable1 {
   int *ip = 0;
-  return ip; // expected-warning{{result type 'NSResettable * _Nonnull'}}
+  return ip; // expected-warning{{incompatible pointer types returning 'int *' from a function with result type 'NSResettable *'}}
 }
 
 - (void)setResettable1:(NSResettable *)param {
Index: test/Analysis/nullability_nullonly.mm
===================================================================
--- test/Analysis/nullability_nullonly.mm
+++ test/Analysis/nullability_nullonly.mm
@@ -64,6 +64,10 @@
   }
 }
 
+NSString *_Nonnull testNullReturnInTernaryOperator(int x) {
+  return x > 3 ? nil : [@"" stringByAppendingString:@""]; // expected-warning {{Null is returned from a function that is expected to return a non-null value}}
+}
+
 void testPreconditionViolationInInlinedFunction(Dummy *p) {
   doNotWarnWhenPreconditionIsViolated(p);
 }
@@ -145,6 +149,10 @@
   else
     return p; // no-warning
 }
+
+- (NSString * _Nonnull)testNullReturnInTernaryOperator:(int)x {
+  return x > 3 ? nil : [@"" stringByAppendingString:@""]; // expected-warning {{Null is returned from a method that is expected to return a non-null value}}
+}
 @end
 
 
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -3340,7 +3340,17 @@
     assert(RetValExp || HasDependentReturnType);
     const VarDecl *NRVOCandidate = nullptr;
 
-    QualType RetType = RelatedRetType.isNull() ? FnRetType : RelatedRetType;
+    QualType RetType;
+    if (RelatedRetType.isNull()) {
+      RetType = FnRetType;
+      // The nullability-attributes of the return-type of a function/method
+      // is not necessarily conforming to the nullability-attributes of
+      // the expression itself, so we remove the nullability-attributes.
+      if(const auto *AttrType = RetType->getAs<AttributedType>())
+        RetType = AttrType->desugar();
+    } else {
+      RetType = RelatedRetType;
+    }
 
     // C99 6.8.6.4p3(136): The return statement is not an assignment. The
     // overlap restriction of subclause 6.5.16.1 does not apply to the case of


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