Open Radar

 
28-Jun-2012 04:34 PM Heath Borders:
Summary:
Clang doesn't not warn that a class doesn't implement a required protocol method when that protocol method has an id parameter with a protocol and the implementing class only has the parameter as id.

Steps to Reproduce:

Compile the following in a .m file.

@protocol Foo <NSObject>

@end

@protocol Bar <NSObject>

- (void) barWithFoo: (id<Foo>) foo;

@end

@interface MyBar <Bar>

@end

@implementation

- (void) barWithFoo: (id) foo;

@end

Expected Results:
Clang should issue a warning that -[Bar barWithFoo:] is unimplemented

Actual Results:
Clang issues no warning.

Regression:

Notes:

05-Jul-2012 01:20 PM Heath Borders:
The following scenario occurred that I expected the compiler to catch.

I originally had:

@protocol Bar <NSObject>

- (void) barWithFoo: (id) foo;

@end

@interface MyBar <Bar>

@end

@implementation

- (void) barWithFoo: (id) foo;

@end

Then, I decided I wanted to create a Foo protocol:

@protocol Foo <NSObject>

- (void) doStuff;

@end

@protocol Bar <NSObject>

- (void) barWithFoo: (id<Foo>) foo;

@end

@interface MyBar <Bar>

@end

@implementation

- (void) barWithFoo: (id) foo {
  [foo doStuff];
}

@end

Later, I changed my Foo protocol method's name, but forgot to change the selector call in -{Bar barWithFoo:], which I expected the compiler to catch for me.  This caused a crash.

@protocol Foo <NSObject>

- (void) doDifferentStuff;

@end

@protocol Bar <NSObject>

- (void) barWithFoo: (id<Foo>) foo;

@end

@interface MyBar <Bar>

@end

@implementation

- (void) barWithFoo: (id) foo {
  [foo doStuff]; // selector missing!
}

@end