--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/test/SemaObjC/method-undef-extension-warn-1.m	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class %s
+
+@interface MyClass
+@end
+
+@protocol P
+- (void)Pmeth;
+- (void)Pmeth1; // expected-note {{method 'Pmeth1' declared here}}
+@end
+
+// Class extension
+@interface MyClass () <P>
+- (void)meth2; // expected-note {{method 'meth2' declared here}}
+@end
+
+// Add a category to test that clang does not emit warning for this method.
+@interface MyClass (Category) 
+- (void)categoryMethod;
+@end
+
+@implementation MyClass // expected-warning {{method 'Pmeth1' in protocol 'P' not implemented}} \
+                        // expected-warning {{method definition for 'meth2' not found}}
+- (void)Pmeth {}
+@end