A program like the following one:
```rust
enum E { A, B, C }
fn f(x: E) -> bool {
match x {
A | B => false,
C => true
}
}
```
is rejected by the compiler due to `E` variant paths not being in scope.
In this case `A`, `B` are resolved as pattern bindings and consequently
the pattern is considered invalid as the inner or-patterns do not bind
to the same set of identifiers.
This is expected but the compiler errors that follow could be surprising
or confusing to some users. This commit adds a help note explaining that
if the user desired to match against variants or consts, they should use
a qualified path. The note is restricted to cases where the identifier
starts with an upper-case sequence so as to reduce the false negatives.
Since this happens during resolution, there's no clean way to check what
the patterns match against. The syntactic criterium, however, is in line
with the convention that's assumed by the `non-camel-case-types` lint.
Cleanup some surrounding code.
Support resolution of intra doc links in unnamed block scopes.
(Paths from rustdoc now use early resolution and no longer need results of late resolution like all the built ribs.)
Fix one test hitting file path limits on Windows.
Move methods logically belonging to build-reduced-graph into `impl BuildReducedGraphVisitor` and `build_reduced_graph.rs`
Move types mostly specific to late resolution closer to the late resolution visitor
