The only change is that `expect_file` now uses path relative to the
current file (same as `include!`). Before, it used paths relative to
the workspace root, which makes no sense.
It's a unit-test in a sense that it only checks syntax highlighting.
However, the resulting HTML is written to disk and can be easily
inspected in the browser.
To update the test, run with `--bless` argument or set
`UPDATE_EXPEC=1` env var
rustc_lexer is the lossless lexer, which is a better fit for
approximate syntax highlighting.
As a side-effect, we can now syntax-highlight even broken code.
By moving `{known,used}_attrs` from `SessionGlobals` to `Session`. This
means they are accessed via the `Session`, rather than via TLS. A few
`Attr` methods and `librustc_ast` functions are now methods of
`Session`.
All of this required passing a `Session` to lots of functions that didn't
already have one. Some of these functions also had arguments removed, because
those arguments could be accessed directly via the `Session` argument.
`contains_feature_attr()` was dead, and is removed.
Some functions were moved from `librustc_ast` elsewhere because they now need
to access `Session`, which isn't available in that crate.
- `entry_point_type()` --> `librustc_builtin_macros`
- `global_allocator_spans()` --> `librustc_metadata`
- `is_proc_macro_attr()` --> `Session`
