Protocol conformances can be implied by super classes. When collecting the list
of IncludedProtocols, we should traverse the class inheritance chain and collect
all protocols.
Without this change, these implied conformances will be printed again via a synthesized
extension at the end of the Swift interface file, leading to an error of redundant
conformances when building modules.
rdar://58563540
Currently, when a swiftinterface file fails to load, we emit the specific diagnostics for the failures, followed by a generic “failed to load module ‘Foo’” message. This PR improves that final diagnostic, particularly when the cause may be that the interface was emitted by a newer compiler using backwards-incompatible syntax.
This reverts commit e805fe486e, which reverted
the change earlier. The problem was caused due to a simultaneous change to some
code by the PR with parsing and printing for Clang function types (#28737)
and the PR which introduced Located<T> (#28643).
This commit also includes a small change to make sure the intersecting region
is fixed: the change is limited to using the fields of Located<T> in the
`tryParseClangType` lambda.
