llvm-project/clang/test/SemaObjC/protocol-id-test-1.m

// RUN: %clang_cc1 -verify -Wno-objc-root-class %s

@interface FF
- (void) Meth;
@end

@protocol P
@end

@interface INTF<P> // expected-note {{receiver is instance of class declared here}}
- (void)IMeth;
@end

@implementation INTF
- (void)IMeth {INTF<P> *pi;  [pi Meth]; } // expected-warning {{instance method '-Meth' not found (return type defaults to 'id'); did you mean '-IMeth'?}}
@end