ForEach support for Borrowing sequence
For testing purposes, this commit includes _BorrowingSequence and _BorrowingIterator protocols, with conformance for Span and InlineArray.
Still record overload choices for `makeIterator` and `next` when
solving a `ForEachElement` constraint. This maintains compatibility
with the previous behavior where we would solve these in the constraint
system, since the choices can affect ranking if e.g Collection's
default `makeIterator` is compared with a concrete `makeIterator`
overload. This is a complete hack though and we ought to rip this out
as soon as we can.
rdar://168840696
If the base captured type still has type variables when we bind the
member function type, form a Sendable dependent function type with
the base type. This will then be eliminated by TypeSimplifier once
all the type variables in the base type have been resolved.
This then allows us to remove the delaying logic from member lookup.
We no longer need to track the `ForEachStmtInfo` in the
`SyntacticElementTarget`, and we can remove the special diagnostic
logic for `next` and `makeIterator` since those are type-checked
separately now.
This helps to propagate types bi-directionally and avoid extraneous
failures related to generic parameter inference when the real issue
is mutability or type erasure.
In #65125 (and beyond) `matchTypes`, has logic to attempt to wrap an
incoming parameter in a tuple under certain conditions that might help
with type expansion.
In the case the incoming type was backed by a `var`, it would be wrapped
by an `LValueType` then be subsequently mis-diagnosed as not-a-tuple.
More details in #85924 , this this is also the cause of (and fix for)
#85837 as well...
Impact for an unknown property access was frequently higher than other options
on ambiguous selections, by 3 to 5 points, causing fix selections that were
farther away and frequently noted to be in accurate. This commit lowers the
impact to be in a similar range to other fixes and this causes property accesses
to be selected more proprotionaly.
In the existing test suite, this changed the diagnostic only in the case of
protocol composition, which was also discovered to be a flawed binding lookup.
Tests added for the property lookup, tests updated for protocol composition
(Including correcting a likely error in a test specification)
If arguments are represented by a single tuple it's possible
that the issue is not about missing parameters but instead
about tuple destructuring. Fix `fixMissingArguments` to check for
overruns after destructuring and stop if that produces more
arguments then parameters because such situations are better
diagnosed as a general conversion failure rather than a missing
argument(s) problem.
Resolves: rdar://159408715
Make sure we don't produce unnecessary diagnostics while still allowing
things like cursor info to work. No test change since it's covered by
the next commit.
We know this is where the issue is so we can immediately bind to a hole,
ensuring we don't produce unnecessary downstream diagnostics from
things we can't infer.
We currently disallow these by deleting them in the `swift` namespace.
This approach has several loopholes, all of which ultimately work
because we happen to define specializations of `simplify_type` for
`swift::Type`:
* `llvm::isa/cast/dyn_cast`. The deleted partial specializations will
not be selected because they are not defined in the `llvm` namespace.
* The argument is a non-const `Type`. The deleted function templates
will not be selected because they all accept a `const Type &`, and
there is a better `Y &Val` partial specialization in LLVM.
* Other casting function templates such as `isa_and_nonull` and
`cast_if_present` are not deleted.
Eliminate these loopholes by instead triggering a static assertion
failure with a helpful message upon instantiation of `CastInfo` for
`swift::Type`.
Missed this in my original patch, handle pack parameters the same as
regular generic parameters, ensuring we don't prefer a pack overload
over a generic overload just because there are pointer conversions
involved. Note this doesn't fix the wider issue of rdar://122011759,
I'm planning on looking into that in a follow-up.
These methods can be simplified a bunch since the returned decl is
always the input decl and we can refactor the lambdas to just return
the auxiliary variable and have the type computation in the caller.
