This is accomplished by recognizing this specific situation and
replacing the 'objc' attribute with a hidden '_objcRuntimeName'
attribute. This /only/ applies to classes that are themselves
non-generic (including any enclosing generic context) but that have
generic ancestry, and thus cannot be exposed directly to Objective-C.
This commit also eliminates '@NSKeyedArchiverClassName'. It was
decided that the distinction between '@NSKeyedArchiverClassName' and
'@objc' was too subtle to be worth explaining to developers, and that
any case where you'd use '@NSKeyedArchiverClassName' was already a
place where the ObjC name wasn't visible at compile time.
This commit does not update diagnostics to reflect this change; we're
going to change them anyway.
rdar://problem/32414557
The warnings about deprecated @objc inference in Swift 3 mode can be a
bit annoying; and are mostly relevant to the migration workflow. Make
the warning emission a three-state switch:
* None (the default): don't warn about these issues.
* Minimal (-warn-swift3-objc-inference-minimal): warn about direct
uses of @objc entrypoints and provide "@objc" Fix-Its for them.
* Complete (-warn-swift3-objc-inference-complete): warn about all
cases where Swift 3 infers @objc but Swift 4 will not.
Fixes rdar://problem/31922278.
Split the warning into two warnings, because we want different Fix-It behavior.
* For the ‘dynamic’ warning, drop the “in Swift 4” part and keep the @objc Fix-It on the main warning. This is always auto-applyable.
* For the inferred-for-members-of-Objective-C-derived-classes warning, drop the “in Swift 4” part. More importantly, split off two notes: one with the @objc Fix-It (Swift 3 behavior) and one with the @nonobjc Fix-It (Swift 4 behavior). This makes it clearer that there is a choice, and neither is “obviously” correct.
When in Swift 3 compatibility mode without
`-warn-swift3-objc-inference`, warn on the *uses* of declarations that
depend on the Objective-C runtime that became `@objc` due to the
deprecated inference rule. This far more directly captures important
uses of the deprecated Objective-C entrypoints. We diagnose:
* `#selector` expressions that refer to one of these `@objc` members
* `#keyPath` expressions that refer to one of these `@objc` members
* Dynamic lookup (i.e., member access via `AnyObject`) that refers to
one of these `@objc` members.
Introduce an opt-in warning (enabled by the frontend option
-warn-swift3-objc-inference) for each declaration for which @objc is
inferred based on Swift 3 rules that no longer apply after SE-0160.