[clang] [WebKit checkers] Recognize NS_RETURNS_RETAINED and CF_RETURNS_RETAINED. (PR #157629)

[Rashmi Mudduluru via cfe-commits]

================
@@ -438,6 +438,20 @@ void use_const_local() {
 
 } // namespace const_global
 
+namespace ns_retained_return_value {
+
+NSString *provideNS() NS_RETURNS_RETAINED;
+CFDictionaryRef provideCF() CF_RETURNS_RETAINED;
+void consumeNS(NSString *);
+void consumeCF(CFDictionaryRef);
+
+void foo() {
+  consumeNS(provideNS());
+  consumeCF(provideCF());
+}
+
+} // namespace ns_retained_return_value
+
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t-rasmud wrote:

I'm fairly certain this works, but can we have a test case with inheritance (sub class calls `provideNS` defined in super class) for the sake of completion?

https://github.com/llvm/llvm-project/pull/157629