We'll already suggest the addition of `@_predatesConcurrency` on an import
to downgrade or silence `Sendable`-related diagnostics, so we'll be
adding these to people's code. Over time, this attribute can go stale,
if the imported module's adopt `Sendable`. When the attribute isn't
doing anything, because it didn't suppress any `Sendable`-related
diagnostics, suggest that it be removed.
Unloaded implicit imports (e.g. the `-import-module` flag) will now be processed by import resolution, and will be fully validated and cross-imported. Preloaded imports, like the standard library import, are still not run through full import resolution, but this is a definite improvement over the status quo.
This also folds `-import-underlying-module` and `@_exported import <ParentModule>` into a single code path, slightly changing the diagnostic for a failed overlay-style underlying module import.
Rename ImportedModuleDesc to AttributedImport and make it a template that’s parameterized on the representation of the module. This will allow us to reduce duplicated representations of “abstract” ImportDecls.
To help consolidate our various types describing imports, this commit moves the following types and methods to Import.h:
* ImplicitImports
* ImplicitStdlibKind
* ImplicitImportInfo
* ModuleDecl::ImportedModule
* ModuleDecl::OrderImportedModules (as ImportedModule::Order)
* ModuleDecl::removeDuplicateImports() (as ImportedModule::removeDuplicates())
* SourceFile::ImportFlags
* SourceFile::ImportOptions
* SourceFile::ImportedModuleDesc
This commit is large and intentionally kept mechanical—nothing interesting to see here.
To avoid ambiguity, ImportResolution and a few other things used the term “decl path” instead of “access path”. Switch back to the correct terminology now that the compiler is becoming more consistent about it.
