X.Protocol is an instance of Y.Type only if X conforms to Y. Since X
is a protocol, this is only true if X contains Y and Y is
self-conforming.
Note that this updates some tests that actually contained invalid code.
Fixes <rdar://problem/20915927>.
Swift SVN r29349
Rename existentialConformsToSelf() to existentialTypeSupported(). This
predicate is the "protocol has no Self or associated type requirements"
check, which is a looser condition than self-conformance. This was being
tested to see if the user could refer to the protocol via an existential
type.
The new existentialConformsToSelf() now checks for protocol being @objc,
and for the absence of static methods. This is used as part of the
argument type matching logic in matchType() to determine if the
existential can be bound to a generic type parameter.
The latter condition is stricter, for two reasons:
1) We allow binding existentials to multiple type parameters all sharing
the same generic type parameter T, so we don't want the user to be
able to see any static methods on T.
2) There is an IRGen limitation whereby only existentials without witness
tables can be passed in this manner.
Using the above, the representsNonTrivialGenericParameter() function
has been renamed to canBindGenericParamToExistential(). It now allows
an existential type to be bound to a generic type parameter only under
the following circumstances:
A) If the generic type parameter has no conformances, the match is allowed.
B) If the generic type parameter has at least one conformance, then all
of the conformances on the generic type parameter must be
existentialConformsToSelf() (condition 1 above), and all conformances
on the existential must be @objc (condition 2 above).
Fixes <rdar://problem/18378390> and <rdar://problem/18683843>, and lays
the groundwork for fixing a few other related issues.
Swift SVN r29337
The last remaining case was apparently @objc generic classes, which
seem to work now.
Also nuke the IRGen/unimplemented_objc_generic_class.swift test,
this is now implemented and we have other tests that test this
functionality.
Swift SVN r29260
Resolves a few compiler crashes on invalid. One could imagine this
triggering on well-formed code, but I was unable to form such a test
case.
Swift SVN r29149
The last remaining case was apparently @objc generic classes, which
seem to work now.
Also nuke the IRGen/unimplemented_objc_generic_class.swift test,
this is now implemented and we have other tests that test this
functionality.
Swift SVN r29138
We only attempt to access such nested types in ill-formed code, but
this helps maintain AST invariants. Fixes rdar://problem/20593294 and
resolves 18 compiler crashers.
Swift SVN r29135
The aforementioned commit didn't really fix the problem, but it happened
to avoid the crash, so I've tweaked the tests to continue crashing. In
order to keep in sync with upstream practical swift, I renamed the
tweaked tests and copied the original ones into "fixed".
Swift SVN r29033
The protocol is still needed in order to make sure mixed signed/unsigned
arithmetic doesn't compile, but after pulling all its "real"
requirements into UnsignedIntegerType, that's now its only function.
Thus, rename it to _DisallowMixedSignArithmetic.
Swift SVN r28980
