Now look through other opaque return types that appear in the
underlying type. This catches various forms of recursion that
otherwise would cause a SILGen or SILOptimizer crash.
- Fixes rdar://82992151.
While the intent behind this functor was noble, it has grown in complexity
considerably over the years, and it seems to be nothing but a source of
crashes in practice. I don't want to deal with it anymore, so I've decided
to just subsume all usages with LookUpConformanceInModule instead.
This check had two problems. First, it would assert upon encountering
a layout requirement, due to an unimplemented code path.
A more fundamental issue is that the logic wasn't fully sound, because
it would miss certain cases, for example:
protocol P {
associatedtype A
func run<B: Equatable>(_: B) where B == Self.A
}
Here, the reduced type of `Self.A` is `B`, and at first glance, the
requirement `B: Equatable` appears to be fine. However, this
is actually a new requirement on `Self`, and the protocol be rejected.
Now that we can change the reduction order by assigning weights to
generic parameters, this check can be implemented in a better way,
by building a new generic signature first, where all generic
parameters introduced by the protocol method, like 'B' above, are
assigned a non-zero weight.
With this reduction order, any type that is equivalent to
a member type of `Self` will have a reduced type rooted in `Self`,
at which point the previous syntactic check becomes sound.
Since this may cause us to reject code we accepted previously,
the type checker now performs the check once: first on the original
signature, which may miss certain cases, and then again on the new
signature built with the weighted reduction order.
If the first check fails, we diagnose an error. If the second
check fails, we only diagnose a warning.
However, this warning will become an error soon, and it really
can cause compiler crashes and miscompiles to have a malformed
protocol like this.
Fixes rdar://116938972.
`TypeSimplifier` may not eliminate type variables from e.g the
pattern types of pattern expansion types since they can remain
unresolved due to e.g having a placeholder count type. Make sure we
eliminate any remaining type variables along with the placeholders.
There's probably a more principled fix here, but this is a quick and
low risk fix we can hopefully take for 6.2.
rdar://154954995
If we fail to resolve the value type for a value generic parameter,
previously we would have returned a null Type, causing crashes
downstream. Instead, return an ErrorType, leaving a null Type for
cases where the generic parameter isn't a value generic at all.
rdar://154856417
Diagnostics can outlive the ConstraintSystem itself if we have a
diagnostic transaction for e.g `typeCheckParameterDefault`, make sure
we don't try to use a solver-allocated type as an argument.
Adjust isolation checking to handle misused `isolated` attribute
and let attribute checker property diagnose it.
Resolves: rdar://148076903
Resolves: https://github.com/swiftlang/swift/issues/80363
Turns out we can also get solver-allocated original ErrorTypes through
type resolution. Given the original type is only used for
printing/debugging, let's just fold away any type variables and
placeholders into UnresolvedType (which print as placeholders). This
matches what `Solution::simplifyType` does.
Escaping solver-allocated types into a nested allocation arena is
problematic since we can e.g lazily compute the `ContextSubMap` for a
`NominalOrBoundGenericNominalType`, which is then destroyed when we
exit the nested arena. Ensure we don't pass any types with type
variables or placeholders to `typesSatisfyConstraint`.
rdar://152763265
This can return ErrorType if the AST is invalid.
A handful of callers handle the ErrorType result, but most don't,
blindly assuming the result is always a nominal type. This resulted
in a crash in at least one test case.
Lift the burden from callers by always returning a nominal type here.
Fixes a crash on invalid. The previous logic was causing a label
mismatch constraint fix to be recorded for an unlabeled trailing closure
argument matching a variadic paramater after a late recovery argument
claim in `matchCallArgumentsImpl`, because the recovery claiming skips
arguments matching defaulted parameters, but not variadic ones. We may
want to reconsider that last part, but currently it regresses the
quality of some diagnostics, and this is a targeted fix.
The previous behavior is fine because the diagnosis routine associate
with the constraint fix (`diagnoseArgumentLabelError`) skips unlabeled
trailing closures when tallying labeling issues — *unless* there are no
other issues and the tally is zero, which we assert it is not.
Fixes rdar://152313388.
