This commit built upon the work of Pull Request 3895. Apart from the
work to make the following work
```swift
let f: (Int, Int) -> Void = { x in } // this is now an error
```
This patch also implement the part 2 mentioned in the #3895
```swift
let g: ((Int, Int)) -> Void = { y in } // y should have type (Int, Int)
```
...not just those where the functions match otherwise. This allows the
fix-it to be provided in cases where the closure being passed is a
subtype, or when there are generics involved. Yes, the '@escaping'
might not be the only issue, but it will need to get fixed, and
probably independently of anything else that's going on (except
perhaps calling the wrong function).
rdar://problem/27729540
Suppose you have this protocol:
protocol P {
typealias A = Int
typealias B = Self
}
Clearly, 'P.B' does not make sense, because then the type parameter
would "leak out" of the existential container. However, 'P.A' is totally
fine, it just means 'Int'.
Previously, we would allow 'P.A' in type context, and diagnose on 'P.B'.
However, due to an oversight, neither one was allowed in expression
context, so for example you could not write 'P.A.self', even though
that should just mean 'Int.self'.
Fix this by generalizing performMemberLookup(), and fix up some
diagnostics to be more specific when something is wrong -- we want
to avoid talking about typealiases as 'static members', since that
doesn't really make much sense.
Fixes <https://bugs.swift.org/browse/SR-2314>.
* [FixCode] Add a fixit to help users migrate to Swift 3 name convention of enum cases. rdar://26887735
When users' referring to a enum case with a wrong name and we can find a correct enum case whose name
differs from the wrong name only in capitalization, we replace the wrong name with the correct one.
* Addressing Argyrios' code review comments. NFC
* [test] Update existing test.
* Grammatical polish suggested by @CodaFi.
Suggest a fix-it for unqualified references to all static members
from instance context, not just enum elements.
Also, fix a small problem with the fix-it for replacing protocol
names with 'Self' inside extension bodies -- we didn't handle nested
functions properly.
This fixit is migration-critical to help users call functions now take 'Any' or 'NSHashble' while used to take 'AnyObject'. We insert coercion to the original call sites.
Extends the more useful diagnostics for non-escaping function
parameters used in @escaping contexts to apply to all functions that
are equivalent modulo ExtInfo.
Attempting to throw an error code value, e.g.,
throw CocoaError.fileNoSuchFileError
is now ill-formed, although it was well-formed prior to the
introduction of NSError bridging (SE-0112). Provide a specialized
diagnostic with a Fix-It to add the appropriate parentheses:
throw CocoaError(.fileNoSuchFileError)
Fixes rdar://problem/27543121.
Issue better diagnostics, along with notes and fixits, for the common
case of using an implicitly non-escaping parameter of function type in
a context expecting an @escaping closure. Provides even more specific
diagnostics for common scenarios such as passing to another function
or assignment.
Implements part of SE-0110. Single argument in closures will not be accepted if
there exists explicit type with a number of arguments that's not 1.
```swift
let f: (Int, Int) -> Void = { x in } // this is now an error
```
Note there's a second part of SE-0110 which could be considered additive,
which says one must add an extra pair of parens to specify a single arugment
type that is a tuple:
```swift
let g ((Int, Int)) -> Void = { y in } // y should have type (Int, Int)
```
This patch does not implement that part.
We previously said:
x.method = 1 // error: cannot assign to property: 'x' is immutable
we now say:
error: cannot assign to property: 'method' is a method
almost always the case that the user didn't know what the rules are between
single expression and multistatement closures, and they often don't know how to
fix the problem.
Address this by doing some heroics when we detect this situation. We now go dive
into the closure body, type check the explicit returns within it, and can usually
divine the right answer. When we do that, generate a fixit hint that generates a
modification to the existing signature, or synthesizes the entire signature from
scratch. This addresses:
<rdar://problem/22123191> QoI: multi-line closure with failure to infer result type should add a fixit
We previously produced the unhelpful error message:
x.swift:11:7: error: type of expression is ambiguous without more context
we now produce:
error: unable to infer closure return type in current context
which is going in the right direction.
Previously:
error: generic parameter 'T' could not be inferred
now:
error: unable to infer closure return type in current context
There is still more to do, but this fixes:
<rdar://problem/23570873> QoI: Poor error calling map without being able to infer "U" (closure result inference)
We previously produced the error message:
rdar25271859.swift:14:11: error: value of tuple type '(Float, Int)' has no member '0'
a.map { $0.0 }
^~ ~
We now produce:
rdar25271859.swift:15:5: error: generic parameter 'U' could not be inferred
.andThen { dataResult in
^
which is at least is correct, if not yet helpful.
Extend the handling of function reference kinds to member references
(e.g., x.f), and therefore the logic for stripping argument labels. We
appear to be stripping argument labels from all of the places where it
is required.
We were crashing attempting to diagnose the case where we cannot assign
an array literal to a type conforming to _ArrayProtocol because we don't
know the element types of the conforming type.
We still don't give a great diagnostic for this, so I've
opened (rdar://problem/27594154) to track improving it.
Resolves rdar://problem/25563498.
What I've implemented here deviates from the current proposal text
in the following ways:
- I had to introduce a FunctionArrowPrecedence to capture the parsing
of -> in expression contexts.
- I found it convenient to continue to model the assignment property
explicitly.
- The comparison and casting operators have historically been
non-associative; I have chosen to preserve that, since I don't
think this proposal intended to change it.
- This uses the precedence group names and higherThan/lowerThan
as agreed in discussion.
Factor out the trailing storage of call arguments, since we'll need it
for a few different kinds of expression nodes. Use it for both
CallExpr (which already had this storage, albeit with a specialized
implementation) and now SubscriptExpr.
