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
Avoid a re-typecheck in `diagnoseContextualConversionError` if the
expression type is already known and only return `true` if we know
that at least one error diagnostic has been emitted otherwise there
is a risk that type-check is going to return without any and fail
in verifier.
Resolves: rdar://problem/40002266
Avoid a re-typecheck in `diagnoseContextualConversionError` if the
expression type is already known and only return `true` if we know
that at least one error diagnostic has been emitted otherwise there
is a risk that type-check is going to return without any and fail
in verifier.
Resolves: rdar://problem/40002266