This commit clarifies some of the unstable features in the `str` module by
moving them out of the blanket `core` and `collections` features.
The following methods were moved to the `str_char` feature which generally
encompasses decoding specific characters from a `str` and dealing with the
result. It is unclear if any of these methods need to be stabilized for 1.0 and
the most conservative route for now is to continue providing them but to leave
them as unstable under a more specific name.
* `is_char_boundary`
* `char_at`
* `char_range_at`
* `char_at_reverse`
* `char_range_at_reverse`
* `slice_shift_char`
The following methods were moved into the generic `unicode` feature as they are
specifically enabled by the `unicode` crate itself.
* `nfd_chars`
* `nfkd_chars`
* `nfc_chars`
* `graphemes`
* `grapheme_indices`
* `width`
This commit performs another pass over the `std::char` module for stabilization.
Some minor cleanup is performed such as migrating documentation from libcore to
libunicode (where the `std`-facing trait resides) as well as a slight
reorganiation in libunicode itself. Otherwise, the stability modifications made
are:
* `char::from_digit` is now stable
* `CharExt::is_digit` is now stable
* `CharExt::to_digit` is now stable
* `CharExt::to_{lower,upper}case` are now stable after being modified to return
an iterator over characters. While the implementation today has not changed
this should allow us to implement the full set of case conversions in unicode
where some characters can map to multiple when doing an upper or lower case
mapping.
* `StrExt::to_{lower,upper}case` was added as unstable for a convenience of not
having to worry about characters expanding to more characters when you just
want the whole string to get into upper or lower case.
This is a breaking change due to the change in the signatures of the
`CharExt::to_{upper,lower}case` methods. Code can be updated to use functions
like `flat_map` or `collect` to handle the difference.
[breaking-change]
This pulls out the implementations of most built-in lints into a
separate crate, to reduce edit-compile-test iteration times with
librustc_lint and increase parallelism. This should enable lints to be
refactored, added and deleted much more easily as it slashes the
edit-compile cycle to get a minimal working compiler to test with (`make
rustc-stage1`) from
librustc -> librustc_typeck -> ... -> librustc_driver ->
libcore -> ... -> libstd
to
librustc_lint -> librustc_driver -> libcore -> ... libstd
which is significantly faster, mainly due to avoiding the librustc build
itself.
The intention would be to move as much as possible of the infrastructure
into the crate too, but the plumbing is deeply intertwined with librustc
itself at the moment. Also, there are lints for which diagnostics are
registered directly in the compiler code, not in their own crate
traversal, and their definitions have to remain in librustc.
This is a [breaking-change] for direct users of the compiler APIs:
callers of `rustc::session::build_session` or
`rustc::session::build_session_` need to manually call
`rustc_lint::register_builtins` on their return value.
This should make #22206 easier.
