In Swift 5.3, we only checked the 'where' clause for unsupported
existential types if the declaration was itself generic. If the
declaration was only nested inside of another generic declaration,
the check was skipped.
This was fixed by the following refactoring but I didn't realize it at
the time:
commit c46eb22fcd
Author: Slava Pestov <spestov@apple.com>
Date: Fri Jul 24 23:54:22 2020 -0400
AST: Don't attach trailing where clause requirements to the GenericParamList
The substituted type of the member reference is an OpaqueTypeArchetypeType
whose substitution map sends Self to the opened existential type for the
base value. Sema erases opened existential types to their upper bound, but
this is not a valid transformation in this case, because the 'Self' type
reference is invariant. Calling this member on two different existential
values would produce the same erased type, but this is wrong, because
it actually depends on the concrete type stored in the existential.
Fixes <https://bugs.swift.org/browse/SR-13419>, <rdar://problem/67451810>.
'canParseType()' didn't use to handle 'some'.
Also, use 'isContexttualKeyword("some")' for checking 'some' keyword.
https://bugs.swift.org/browse/SR-10769
Instead of requiring sub-classes of `ContextualMismatch` to implement
`diagnoseForAmbiguity` let's implement it directly on `ContextualMismatch`
itself and check whether all of the aggregated fixes have same types on
both sides and if so, diagnose as-if it was a single fix.
Some protocols, such as protocols marked with 'objc', do not have a Witness Table.
The code before this patch assumes all protocols do have a Witness Table when generating the layout of an OpaqueTypeDescriptor, causing an assert to be triggered for opaque return types that conform to an 'objc' protocol.
Fixes SR-12257 / rdar://problem/59740179
Reverts apple/swift#30006. It caused a regression that we'd like to address before re-landing:
```swift
struct X {
var cgf: CGFloat
}
func test(x: X?) {
let _ = (x?.cgf ?? 0) <= 0.5
}
```
This reverts commit 0a6b444b49.
This reverts commit ed255596a6.
This reverts commit 3e01160a2f.
This reverts commit 96297b7e39.
Resolves: rdar://problem/60185506
This adds the RangeSet and DiscontiguousSlice types, as well as collection
operations for working with discontiguous ranges of elements. This also adds
a COWLoggingArray type to the test suite to verify that mutable collection
algorithms don't perform unexpected copy-on-write operations when mutating
slices mid-operation.
This fixes a recent source break. We need to perform the normal
unqualified lookup before we handle the special case of 'Self',
because there might be a type named Self defined in an outer
context.
Fixes <https://bugs.swift.org/browse/SR-12133> / <rdar://problem/59216636>
It's done by first retrieving all generic parameters from each solution,
filtering boundings into distrinct set and diagnosing any differences.
For example:
```swift
func foo<T>(_: T, _: T) {}
func bar(x: Int, y: Float) {
foo(x, y)
}
```
Delay "fixing" contextual conversion failures until restriction is applied
this helps to tidy up logic for superclass and existential conversions.
Too bad we have to "fix" in `simplifyRestrictedConstraintImpl` now but
we can't really do much about that because diagnostics need both top-level
types to be useful.
Argument-to-Parameter mismatch handles conformance failures
related to arguments, so the logic in `MissingConformanceFailure`
which wasn't entirely correct is now completely obsolete.
Resolves: rdar://problem/56234611
