This test is failing to verify the generic signature for this bogus
program, because the generic signature isn't minimal. We should
gracefully handle this situation and still have a minimal signature,
despite rejecting this program.
When a no-payload enum is stored inside a multi-payload enum,
the outer enum may be using some of the extra high-order bits.
So when we examine the inner enum, we should just strip those bits.
We don't currently support building resilient relative protocol witness tables.
One might want to build with relative witness tables but not need
resilient protocols. Allow for that scenario.
Add a test configuration to test library-evolution + fragile resilient
protocols + relative protocol witness tables.
With this build-script has a flag --enable-experimental-nonescpable-types=1
to enable this feature in stdlib.
Also we can now add // REQUIRES: nonescapable_types to tests which run only when
the compiler is built with this feature turned on.
and implement it for @isolated(any) function types.
The existing testing was pretty broken: we were diagnosing all sorts
of things that don't require type metadata (like using a tuple with
an extended existential in a value position in an API signature)
and not diagnosing several things that do (like covariant function
conversions that erase types). There's therefore some risk to this
patch, but I'm not too worried because needing metadata like this is
pretty uncommon, and it's likely that programs won't build correctly
anyway --- it'll just get caught by the linker instead of the compiler.
- Pass down the TypeResolution instance so we can get the generic
signature. This ensures we always use the correct signature in
SIL mode.
- Don't diagnose if the type contains error types.
When completing in cases like `bar(arg: foo(|, option: 1)`, we don’t know if `option` belongs to the call to `foo` or `bar`. Be defensive and also suggest the signature.
If we fail to build a generic signature (or requirement signature of a
protocol) because of a request cycle or because Knuth-Bendix completion
failed, we would create a placeholder signature with no requirements.
However in a move-only world, a completely unconstrained generic
parameter might generate spurious diagnostics when used in a copyable
way. For this reason, let's outfit these placeholder signatures with
a default set of conformance requirements to Copyable and Escapable.
Although inference doesn't allow direct bindings to
type variables, they can still get through via `matchTypes`
when type is a partially resolved pack expansion that simplifies
down to a type variable.
These tests are using FileCheck to check the result of diagnostic
formatting in ways that don't match the new formatter. Force the old
formatter or, where possible, generalize so that they match both
formatters.
