`updateNonUserModule` was accidentally copying `SearchPathOptions`. Take
a reference to it instead. Also, since `addFile` is actually called many
times (once for every submodule, of which there are many), change
`isNonUserModule` to a request so that it's only calculated when needed.
Resolves rdar://107155587.
I think that preferring identical over convertible makes sense in e.g. C++ where we have implicit user-defined type conversions but since we don’t have them in Swift, I think the distinction doesn’t make too much sense, because if we have a `func foo(x: Int?)`, want don’t really want to prioritize variables of type `Int?` over `Int` Similarly if we have `func foo(x: View)`, we don’t want to prioritize a variable of type `View` over e.g. `Text`.
rdar://91349364
'available(..., deprecated: <version>)'. If the version is larger than the
current active version, the declaration is "soft deprecated". Emit a
relevant diagnostics for those items. If the version is equal to or
larger than '100000.0', it means the distant future without specifying
the version.
rdar://76122625
* Implement 'getDiagnosticSeverity()' and 'getDiagnosticMessage()' on
'CodeCompletionResult'
* Differentiate 'RedundantImportIndirect' from 'RedundantImport'
* Make non-Sendable check respects '-warn-concurrency'
rdar://76129658