swift

e4ac2e0d - Sema: Suppress -require-explicit-availability diagnostics for @_implementationOnly decls.

Sema: Suppress -require-explicit-availability diagnostics for @_implementationOnly decls. A decl marked `@_implementationOnly` isn't really part of the module's public API, so it shouldn't be flagged by -require-explicit-availability. Resolves rdar://176476752.