@objc enums have special requirements on the raw type, which were
enforced as part of checking the raw type of the enum. Rework the
checking here so that the additional constraints are part of resolving
whether the enum is exposed to Objective-C. This keeps raw-type
computation more independent and “lower-level” than @objc computation.
Once reworked, eliminate the “CIntegerTypes” cache from TypeChecker:
it probably doesn't matter, and the caching should be performed by the
request-evaluator rather than the type checker.
In Swift 4, constructors had the same name as properties,
methods and enum cases named `init`. This meant that you
could use constructor syntax to call such a member, which
caused some confusing behavior.
Recently I added a special declname for `init` so that
constructors have unique names distinct from any name you
can spell, and "foo.init" syntax would look for a member
with the special name rather than one named `init`.
Unfortunately people actually had code where they defined
members named `init` and then use them via normal member
lookup syntax, like this:
enum E {
case `init`
}
let e: E = E.init
So to maintain backward compatibility, hack member lookup
to also find members named `init` when looking up the special
declname for constructors.
The workaround is only enabled in Swift 4 and 4.2 mode;
in Swift 5 mode you are expected to write "foo.`init`" to access
non-constructor members named `init`.
Fixes <rdar://problem/38682258>.
This fixes a 4.2 regression where enums and subscripts could not
contain single-argument function types with an 'inout' parameter,
because we erroneously diagnosed the 'inout' as if it appeared
at the top level of the enum case or subscript index type.
Fixes <https://bugs.swift.org/browse/SR-7890>.
Continue to emit notes for the candidates, but use different text.
Note that we can emit a typo correction fix-it even if there are
multiple candidates with the same name.
Also, disable typo correction in the migrator, since the operation
is quite expensive, the notes are never presented to the user, and
the fix-its can interfere with the migrator's own edits.
Our general guidance is that fix-its should be added on the main
diagnostic only when the fix-it is highly likely to be correct.
The exact threshold is debateable. Typo correction is certainly
capable of making mistakes, but most of its edits are right, and
when it's wrong it's usually obviously wrong. On balance, I think
this is the right thing to do. For what it's worth, it's also
what we do in Clang.
I tried doing this directly from typeCheckDecl(), but it breaks
associated type inference. We can figure this out later when
declaration checking becomes lazier and more incremental.
Note that typo correction does not force witnesses of
synthesized conformances. This means that a typo correction
from a top-level form will no longer pick up synthesized
witnesses, and will find the protocol requirement instead.
To give a test the same behavior as before, I put the
expression in a function body instead of a top-level form.
Note that we already had the same behavior with typo
correction from pattern binding initializers and other
contexts that are type checked before conformances.
(currently spelled with an underscore to indicate its WIP state)
Later commits will handle imported enums correctly and implement the
checks for switch cases.
A given Objective-C error enum, which is effectively an NS_ENUM that
specifies its corresponding error domain, will now be mapped to an
ErrorProtocol-conforming struct that wraps an NSError, much like
NSCocoaError does. The actual enum is mapped to a nested "Code"
enum. For example, CoreLocation's CLError becomes:
struct CLError : ErrorProtocol {
let _nsError: NSError
// ...
@objc enum Code : Int {
case ...
}
}
This implements bullet (2) in the proposed solution of SE-0112, so
that Cocoa error types are mapped into structures that maintain the
underlying NSError to allow more information to be extracted from it.
along with recent policy changes:
- For expression types that are not specifically handled, make sure to
produce a general "unused value" warning, catching a bunch of unused
values in the testsuite.
- For unused operator results, diagnose them as uses of the operator
instead of "calls".
- For calls, mutter the type of the result for greater specificity.
- For initializers, mutter the type of the initialized value.
- Look through OpenExistentialExpr's so we can handle protocol member
references propertly.
- Look through several other expressions so we handle @discardableResult
better.
If the mismatched argument is on an archetype param, check to see
whether the argument conforms to all of the protocols on the archetype,
using a specific does-not-conform diagnosis if one or more protocols
fail.
Also added another closeness class
`CC_GenericNonsubstitutableMismatch`, which happens when more than one
argument is a mismatch, but all the failing arguments are of the same
type and mismatch only because of substitutability. This closeness is
farther away than normal `CC_ArgumentMismatch` so that if we note
expected matches, we’ll prefer non-generic matches. But if this is the
result, we can still produce the specific conforms-to-protocol
diagnosis (since, in a sense, it’s only one type of argument that is
wrong even though it is multiple arguments).
- Improve the specific cases of nil and empty collection literals.
- Improve cases of contextual member lookup where the result type of the looked up member disagrees with context.
- Add some fixme's to the testsuite for cases of this diagnostic that should be diagnosed in other ways.
On something like this:
let x = .Tomato(cloud: .None)
we previously emitted a "type of expression is ambiguous without more context" error
while pointing to .None. With a previous fix, we now produce the same error pointing
to the .Tomato. With this fix, we now produce:
error: reference to member 'Tomato' cannot be resolved without a contextual type
to really drive the problem home.
information and use this to improve the UnresolvedMemberExpr errors.
The notable problem remaining is that we don't handle problems involving
argument labels.
Swift SVN r31378
diagnoseGeneralFailure to be named diagnoseConstraintFailure and change how
it works:
Now it ranks unresolved constraints in the system based on kind (e.g. whether
they are favored, member constraints ahead of conversion constraints, etc) and
then tries to emit a diagnostic for each failure kind one after another.
This means that if there are multiple failed conversion constraints, but one
is obviously satisfiable, that we continue on to diagnose the next one. This
clears up a swath of embarassing diagnostics and refixes:
<rdar://problem/19658691> QoI: Incorrect diagnostic for calling nonexistent members on literals
Swift SVN r31046
"unavoidable failure" path, along with Failure::DoesNotHaveNonMutatingMember and
just doing some basic disambiguation in CSDiags.
This provides some benefits:
- Allows us to plug in much more specific diagnostics for the existing "only has
mutating members" diagnostic, including producing notes for why the base expr
isn't mutable (see e.g. test/Sema/immutability.swift diffs).
- Corrects issues where we'd drop full decl name info for selector references.
- Wordsmiths diagnostics to not complain about "values of type Foo.Type" instead
complaining about "type Foo"
- Where before we would diagnose all failures with "has no member named", we now
distinguish between when there is no member, and when you can't use it. When you
can't use it, you get a vauge "cannot use it" diagnostic, but...
- This provides an infrastructure for diagnosing other kinds of problems (e.g.
trying to use a private member or a static member from an instance).
- Improves a number of cases where failed type member constraints would produce uglier
diagnostics than a different constraint failure would.
- Resolves a number of rdars, e.g. (and probably others):
<rdar://problem/20294245> QoI: Error message mentions value rather than key for subscript
Swift SVN r30715
get the same wording, fixing <rdar://problem/21964599> Different diagnostics for the same issue
While I'm in the area, remove some dead code.
Swift SVN r30713
