Many unsafe features are now in the unstable section, so this section is
really just about raw pointers now. That also makes sense for its place
in the TOC.
This addresses part of #12905.
Without the `box` keyword, one of these two reasons is not correct, so
let's just eliminate this section and elaborate on the reason for the
legit use case inline.
Fixes#24511
Fixes#24173
These docs could all use examples, so for now, let's just remove the bad one, and when I go over this whole module I'll put in better ones.
When `liballoc` is compiled with `--cfg feature=\"external_features\"`, several `improper_ctypes` warnings are generated. Since these warnings are harmless, I have added a directive to suppress them.
Many unsafe features are now in the unstable section, so this section is
really just about raw pointers now. That also makes sense for its place
in the TOC.
This addresses part of #12905.
Without the `box` keyword, one of these two reasons is not correct, so
let's just eliminate this section and elaborate on the reason for the
legit use case inline.
Fixes#24511
At the moment, when compilation is stopped at a stop point (like `-Z parse-only`), `rustc` does not return an nonzero exit code even if there are errors (expect fatal ones, that cause it to panic immediately). As an example, compiling `src/test/compile-fail/doc-before-semi.rs` with `-Z parse-only` raises an error, but exists with 0.
Note that I could not use `sess.abort_if_errors()` in the macro, because `sess` is passed by value and move at some point.
skolemize_late_bound_regions essentially copies the entire type (most of the times it shouldn't, but it does), and match_impl runs millions of times.
Times compiling rustc, tested with
$ make -j4 rustc-stage1
$ ( time RUSTFLAGS=-Z time-passes make -j4 rustc-stage2 ) # need LLVM time for calibration
Before:
real 21m44.960s
user 29m38.812s
sys 0m14.944s
After:
real 19m31.445s
user 26m47.260s
sys 0m14.952s
Making this is a 10% performance improvement.
LLVM passes took 867 seconds before, 862 seconds after.
This implementation is currently about 3-4 times faster than using the `.to_string()` based approach.
I would also suggest we deprecate `String::from_str` since it's redundant with the stable `String::from` method, but I'll leave that for a future PR.
