- Tests that depend on emitted interfaces should generally use flags that are typical for modules that have textual interfaces (e.g. `-enable-library-evolution`).
- If a test is intended to produce a valid `swiftinterface` then it should verify that interface. This will help prevent interface printing regressions caused by compiler changes.
- Having commonly used substitutions for tests that emit interfaces makes it easy to experiment with compiler flags that might effect interface printing.
Resolves rdar://91634358
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.
