tree 2a92da4058feaafa78baad885b1155874b1c5ca1
parent f22e9f3eba041f4750bf5746e3c876fbac31f755
author Jordan Rose <jordan_rose@apple.com> 1490401034 -0700
committer Jordan Rose <jordan_rose@apple.com> 1490401126 -0700

[APINotes] Don't apply API notes to non-definitions of structs. (#69)

There are two reasons for this:

- It doesn't really seem appropriate for forward-declared structs to
  pick up attributes.

- In a proper definition `struct X { ... }`, the first `struct X`
  counts as a declaration, which means the API note attributes can get
  added ahead of time. Later on, when we try to add them /again/,
  they'll replace the attribute added at the first point rather than
  whatever the user wrote in source after the close brace. This also
  applies if there are any forward declarations before the definition.

There is a downside: API notes now can't affect tag types that are
/never/ defined (for example, structs that are forward-declared for
use in pointers). Any annotations one might want to apply to such
a type must be written in source.

rdar://problem/29981732
(cherry picked from commit 911df2f93842d956d2848d8c10366b742cc4eef2)