Pending further discussion, re-enable warnings for Objective C

covariant/contravariant overrides and implementations, but do so under
control of a new flag (-Wno-objc-covariant-overrides, which yes does cover
contravariance too).

*At least* the covariance cases will probably be enabled by default shortly,
but that's not totally uncontroversial.

llvm-svn: 117346

3 files changed, 51 insertions, 6 deletions

diff --git a/clang/test/SemaObjC/method-conflict-1.m b/clang/test/SemaObjC/method-conflict-1.m
index b8789fa807e..fb62e2ef354 100644
--- a/clang/test/SemaObjC/method-conflict-1.m
+++ b/clang/test/SemaObjC/method-conflict-1.m
@@ -7,12 +7,13 @@
 
 @interface MyClass : NSObject {
 }
-- (void)myMethod:(NSArray *)object; 
+- (void)myMethod:(NSArray *)object; // expected-note {{previous definition is here}}
 - (void)myMethod1:(NSObject *)object; // expected-note {{previous definition is here}}
 @end
 
 @implementation MyClass
-- (void)myMethod:(NSObject *)object { 
+// Warn about this contravariant use for now:
+- (void)myMethod:(NSObject *)object { // expected-warning {{conflicting parameter types in implementation of 'myMethod:': 'NSArray *' vs 'NSObject *'}}
 }
 - (void)myMethod1:(NSArray *)object { // expected-warning {{conflicting parameter types in implementation of 'myMethod1:': 'NSObject *' vs 'NSArray *'}}
 }
diff --git a/clang/test/SemaObjC/method-conflict-2.m b/clang/test/SemaObjC/method-conflict-2.m
new file mode 100644
index 00000000000..fd472824559
--- /dev/null
+++ b/clang/test/SemaObjC/method-conflict-2.m
@@ -0,0 +1,44 @@
+// RUN: %clang_cc1 -Wno-objc-covariant-overrides -fsyntax-only -verify %s
+
+@interface A @end
+@interface B : A @end
+
+@interface Test1 {}
+- (void) test1:(A*) object; // expected-note {{previous definition is here}} 
+- (void) test2:(B*) object;
+@end
+
+@implementation Test1
+- (void) test1:(B*) object {} // expected-warning {{conflicting parameter types in implementation of 'test1:': 'A *' vs 'B *'}}
+- (void) test2:(A*) object {}
+@end
+
+@interface Test2 {}
+- (void) test1:(id) object; // expected-note {{previous definition is here}} 
+- (void) test2:(A*) object;
+@end
+
+@implementation Test2
+- (void) test1:(A*) object {} // expected-warning {{conflicting parameter types in implementation of 'test1:': 'id' vs 'A *'}}
+- (void) test2:(id) object {}
+@end
+
+@interface Test3 {}
+- (A*) test1;
+- (B*) test2; // expected-note {{previous definition is here}} 
+@end
+
+@implementation Test3
+- (B*) test1 { return 0; }
+- (A*) test2 { return 0; } // expected-warning {{conflicting return type in implementation of 'test2': 'B *' vs 'A *'}}
+@end
+
+// The particular case of overriding with an id return is white-listed.
+@interface Test4 {}
+- (id) test1;
+- (A*) test2;
+@end
+@implementation Test4
+- (A*) test1 { return 0; }
+- (id) test2 { return 0; }
+@end
diff --git a/clang/test/SemaObjC/method-typecheck-3.m b/clang/test/SemaObjC/method-typecheck-3.m
index 629889c3ad5..23036e65d51 100644
--- a/clang/test/SemaObjC/method-typecheck-3.m
+++ b/clang/test/SemaObjC/method-typecheck-3.m
@@ -1,8 +1,8 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
 
 @interface A
-- (id)obj;
-- (A*)a;
+- (id)obj; // expected-note {{previous definition is here}}
+- (A*)a; // expected-note {{previous definition is here}}
 - (void)takesA: (A*)a; // expected-note {{previous definition is here}}
 - (void)takesId: (id)a; // expected-note {{previous definition is here}}
 @end
@@ -12,8 +12,8 @@
 @end
 
 @implementation B
-- (B*)obj {return self;}
-- (B*)a { return self;} 
+- (B*)obj {return self;} // expected-warning {{conflicting return type in implementation of 'obj'}}
+- (B*)a { return self;}  // expected-warning {{conflicting return type in implementation of 'a'}}
 - (void)takesA: (B*)a  // expected-warning {{conflicting parameter types in implementation of 'takesA:'}}
 {}
 - (void)takesId: (B*)a // expected-warning {{conflicting parameter types in implementation of 'takesId:'}}