Keep track of objc method redeclarations in the same interface.

Avoid possible infinite loop when iterating over an ObjCMethod's redeclarations.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141946 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/PCH/method-redecls.m b/test/PCH/method-redecls.m
new file mode 100644
index 0000000..14ce3ac
--- /dev/null
+++ b/test/PCH/method-redecls.m
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -x objective-c -emit-pch -o %t
+
+// Avoid infinite loop because of method redeclarations.
+
+@interface Foo
+-(void)meth;
+-(void)meth;
+-(void)meth;
+@end
+
+@implementation Foo
+-(void)meth { }
+@end