Add ModuleImplicitImportsRequest, which computes
the modules that should be implicitly imported by
each file of a given module. Use this request in
import resolution to add all the necessary
implicit imports.
The request computes the implicit imports by
consulting the ImplicitImportInfo, which ModuleDecl
can now be created with. This allows us to remove
uses of `SourceFile::addImports` in favor of
adding modules needed to be implicitly imported to
the ImplicitImportInfo.
Ensure that lazy parsing of the members of nominal type definitions
and extensions is handled through a request. Most of the effort here
is in establishing a new request zone for parser requests.
Rather than call through the LazyResolver (when available) to satisfy
queries that may require type checking, call into the evaluator
directly: it will make use of the type checker (via the lazy resolver)
when necessary. This change should allow us to use the
request-evaluator’s cache for state rather than mutable AST state,
as well as the ability to see requests that were evaluated after
type checking.
This patch allows Parser to generate a refined token stream to satisfy tooling's need. For syntax coloring, token stream from lexer is insufficient because (1) we have contextual keywords like get and set; (2) we may allow keywords to be used as argument labels and names; and (3) we need to split tokens like "==<". In this patch, these refinements are directly fulfilled through parsing without additional heuristics. The refined token vector is optionally saved in SourceFile instance.
