Add functions for reversing the bit pattern in an integer
I'm reviving PR #32798 now that the LLVM issues have been resolved.
> This adds the bitreverse intrinsic and adds a reverse_bits function to all integer types.
Suggest type for overflowing bin/hex-literals
Fixes#48073
For hexadecimal and binary literals, which overflow, it gives an additional note to the warning message, like in this [comment](https://github.com/rust-lang/rust/issues/48073#issuecomment-365370113).
Additionally it will suggest a type (`X < Y`):
- `iX`: if literal fits in `uX` => `uX`, else => `iY`
- `-iX` => `iY`
- `uX` => `uY`
Exceptions: `isize`, `usize`. I don't think you can make a good suggestion here. The programmer has to figure it out on it's own in this case.
r? @oli-obk
Slight modification to the as_ref example of std::option::Option
A user in a reddit thread was confused by the name of the variable
"num_as_int"; they thought the example was trying to convert the
string "10" as if it were binary 2 by calling str::len(). In reality,
the example is simply demonstrating how to take an immutable reference
to the value of an Option. The confusion comes from the coincidence
that the length of the string "10" is also its binary representation,
and the implication from the variable names that a conversion was
occuring ("num_as_str" to "num_as_int").
This PR changes the example number to 12 instead of 10, and changes
the variable name from "num_as_int" to "num_length" to better
communicate what the example is doing.
The reddit thread:
https://www.reddit.com/r/rust/comments/7zpvev/notyetawesome_rust_what_use_cases_would_you_like/dur39xw/
Users coming from other languages (namely C and C++) often expect
to use a -Wall flag. Rustc doesn't support that, and previously it
simply printed that it didn't recognize the "all" lint.
This change makes rustc print out a help message, explaining:
- Why there is no -Wall flag
- How to view all the available warnings
- Point out that the most commonly used warning is -Wunused
- Instead of using a command-line flag, the user should consider
a !#[warn(unused)] directive in the root of their crate.
This Python script converts documentation comments from the
`#[doc = "..."]` attribute to the `///` syntax. It was added six
years ago, presumably to help with the transition when `///` was
implemented and hasn't really been touched since. I don't think there's
much value in keeping it around at this point.
Turn feature-gate table into a query so it is covered by dependency tracking.
Turn access to feature gates into a query so we handle them correctly during incremental compilation.
Features are still available via `Session` through `features_untracked()`. I wish we had a better way of hiding untracked information. It would be great if we could remove the `sess` field from `TyCtxt`.
Fixes#47003.
The ExplicitSelf::determine function expects to be able to compare regions.
However, when the compare_self_type error reporting code runs we haven't
resolved bound regions yet. Thus we replace them with free regions first.
