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
Some spots of constraint simplification logic are too eager to
fail right away without giving repair logic to run in diagnostic
mode and attempt to fix the problem. Failing early in diagnostic
mode means solver wouldn't be able to reach some possible
solutions which leads to subpar diagnostics.
This helps us to better diagnose failures related to generic
requirements like `T == [Int]` as well as protocol compositions,
which require deep equality check.
They weren't always mapped out of context before building the interface type for the opaque
type decl, and we failed to substitute the base class constraint when forming an opaque archetype
with specific substitutions. Fixes rdar://problem/53318811.
