Code like that is usually indicative of programmer error, and does not
round-trip through module interface files since there is no source
syntax to refer to an outer generic parameter.
For source compatibility this is a warning, but becomes an error with
-swift-version 6.
Fixes rdar://problem/108385980 and https://github.com/apple/swift/issues/62767.
Inject `buildBlock` call into `return`, `buildFinalResult`, and
`build{Optional, Either}` to take advantage of contextual information
and maintain compatibility with current inference behavior.
