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.
