The reason why I am making this change is because I want to put a merge
operation on DiagnosticBehavior. This merge operation allows for
DiagnosticBehavior to work like a lattice. When one merges, one moves
potentially from fatal, error to things like note, ignore.
When a retroactive conformance to a protocol that inherits from `Sendable`
introduces an implicit `Sendable` conformance, allow `@preconcurrency`
to suppress the diagnostic about the `Sendable` conformance being
introduced outside of the original source file.
Fixes rdar://125080066.
The "send non-Sendable" pass had a copy of the code for determining
what limit to put on the diagnostic behavior for a given reference to
a nominal type declaration. Rather than update that copy for the
recent changes to the canonical version of this in the type checker,
share the computation.
Instance properties of non-sendable types cannot safely be
accessed within deinitializers. Make sure we respect `@preconcurrency`
when diagnosing these.
This translates the rules for @preconcurrency import from SE-0337 into the
region isolation world. Specifically if a module is compiled without strict
concurrency checking and imported with @preconcurrency:
1. All types from that module that are implicitly non-Sendable have diagnostics
suppressed in swift 5 and swift 6.
2. All types from that module that are explicitly non-Sendable emit warnings in
both swift 5 and swift 6.
rdar://126804052
The reason why I am doing this is that I am going to be adding support for
preconcurrency imports to TransferNonSendable. That implies that we can have
preconcurrency import suppression in the SIL pipeline and thus that emitting the
diagnostic in Sema is too early.
To do this, I introduced a new module pass called
DiagnoseUnnecessaryPreconcurrencyImports that runs after the SILFunction pass
TransferNonSendable. The reason why I use a module pass is to ensure that
TransferNonSendable has run on all functions before we attempt to emit these
diagnostics. Then in that pass, we iterate over all of the modules functions and
construct a uniqued array of SourceFiles for these functions. Then we iterate
over the uniqued SourceFiles and use the already constructed Sema machinery to
emit the diagnostic using the source files.
rdar://126928265
