A protocol conformance of a class A to a protocol P can be inherited
by a subclass B of A unless
- A requirement of P refers to Self (not an associated type thereof)
in its signature,
+ *except* when Self is the result type of the method in P and the
corresponding witness for A's conformance to B is a DynamicSelf
method.
Remove the uses of DynamicSelf from the literal protocols, going back
to Self. The fact that the conformances of NSDictionary, NSArray,
NSString, etc. to the corresponding literal protocols use witnesses
that return DynamicSelf makes NSMutableDictionary, NSMutableArray,
NSMutableString, and other subclasses still conform to the
protocol. We also correctly reject attempts to (for example) create an
NSDecimalNumber from a numeric literal, because NSNumber doesn't
provide a suitable factory method by which any subclass can be literal
convertible.
Swift SVN r14204
Take DynamicSelf as a keyword, but parse it as a type-identifier.
Teach function declaration checking to sniff out and validate
DynamicSelf early, with appropriate QoI for references to DynamicSelf
that appear in other places.
As a temporary hack, DynamicSelf resolves to an alias for 'Self' in a
protocol or the enclosing nominal type.
Swift SVN r12708
protocol BaseProto {
typealias AssocTy
}
var a: BaseProto.AssocTy // error!
While this could be interpreted to mean "a is an existential bounded by
whatever AssocTy is bounded by", we don't actually support this in any
other contexts; if a protocol has a function that returns an associated type,
it can only be used in a concrete or generic context, not an existential one.
<rdar://problem/15850024>
Swift SVN r12600
An initializer outside of the class's defining module won't
necessarily have access to all of the stored properties of the class
to initialize them (and wouldn't be resilient against changes even if
it did), so it must delegate.
Swift SVN r12302
As part of this, take away the poor attempt at recovering by adding an
explicit protocol conformance. The recovery mode isn't all that useful
in a system with only explicit conformance, and it messes with
diagnostics further down the line. We can bring it back later once
we're happy with explicit conformance checking.
Swift SVN r11503
There's a lot more work to do here, but start to categorize tests
along the lines of what a specification might look like, with
directories (chapters) for basic concepts, declarations, expressions,
statements, etc.
Swift SVN r9958
Break cycles agressively when we find circular class inheritance. The
stronger AST invariants prevent us from having to check for loops
everywhere in the front end.
Swift SVN r7325
Detect duplicate and multiple inheritance, clean up diagnostics, and
unify the code that checks the types in the inheritance clause with
the code that sets the superclass and protocol lists.
Swift SVN r6706
