llvm-project/clang/test/SemaObjCXX/Inputs/nullability-pragmas-generic...

#pragma clang assume_nonnull begin

__attribute__((objc_root_class))
@interface B
@end

@interface C : B
@end

__attribute__((objc_root_class))
@interface NSGeneric<T : B *> // expected-note{{type parameter 'T' declared here}}
- (T)tee;
- (nullable T)maybeTee;
@end

typedef NSGeneric<C *> *Generic_with_C;

#pragma clang assume_nonnull end

@interface NSGeneric<T : C *>(Blah) // expected-error{{type bound 'C *' for type parameter 'T' conflicts with previous bound 'B *'}}
@end
Substitute type arguments into uses of Objective-C interface members. When messaging a method that was defined in an Objective-C class (or category or extension thereof) that has type parameters, substitute the type arguments for those type parameters. Similarly, substitute into property accesses, instance variables, and other references. This includes general infrastructure for substituting the type arguments associated with an ObjCObject(Pointer)Type into a type referenced within a particular context, handling all of the substitutions required to deal with (e.g.) inheritance involving parameterized classes. In cases where no type arguments are available (e.g., because we're messaging via some unspecialized type, id, etc.), we substitute in the type bounds for the type parameters instead. Example: @interface NSSet<T : id<NSCopying>> : NSObject <NSCopying> - (T)firstObject; @end void f(NSSet<NSString > stringSet, NSSet anySet) { [stringSet firstObject]; // produces NSString [anySet firstObject]; // produces id<NSCopying> (the bound) } When substituting for the type parameters given an unspecialized context (i.e., no specific type arguments were given), substituting the type bounds unconditionally produces type signatures that are too strong compared to the pre-generics signatures. Instead, use the following rule: - In covariant positions, such as method return types, replace type parameters with “id” or “Class” (the latter only when the type parameter bound is “Class” or qualified class, e.g, “Class<NSCopying>”) - In other positions (e.g., parameter types), replace type parameters with their type bounds. - When a specialized Objective-C object or object pointer type contains a type parameter in its type arguments (e.g., NSArray<T>, but not NSArray<NSString > ), replace the entire object/object pointer type with its unspecialized version (e.g., NSArray ). llvm-svn: 241543 2015-07-07 11:57:53 +08:00			`#pragma clang assume_nonnull begin`

			`__attribute__((objc_root_class))`
			`@interface B`
			`@end`

			`@interface C : B`
			`@end`

			`__attribute__((objc_root_class))`
			`@interface NSGeneric<T : B *> // expected-note{{type parameter 'T' declared here}}`
			`- (T)tee;`
			`- (nullable T)maybeTee;`
			`@end`

			`typedef NSGeneric<C > Generic_with_C;`

			`#pragma clang assume_nonnull end`

			`@interface NSGeneric<T : C >(Blah) // expected-error{{type bound 'C ' for type parameter 'T' conflicts with previous bound 'B *'}}`
			`@end`