[clang] [clang][ExtractAPI] Compute inherited availability information (PR #103040)

[Cyndy Ishida via cfe-commits]

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@@ -0,0 +1,149 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -extract-api --pretty-sgf --emit-sgf-symbol-labels-for-testing -triple arm64-apple-macosx \
+// RUN:   -x objective-c-header %s -o %t/output.symbols.json -verify
+
+
+// RUN: FileCheck %s --input-file %t/output.symbols.json --check-prefix A
+__attribute__((availability(macos, introduced=9.0, deprecated=12.0, obsoleted=20.0)))
+ at interface A
----------------
cyndyishida wrote:

What's the expected availability information emitted when the enclosing entity doesn't have one defined? 
```
@interface A
@property int moreRestrictive __attribute__((availability(macos, introduced=10.0, deprecated=11.0, obsoleted=19.0)));
@end 
```

https://github.com/llvm/llvm-project/pull/103040