Move private bignum module to core::num, because it is not only used in flt2dec.
Extract private 80-bit soft-float into new core::num module for the same reason.
Overflows in integer pow() computations would be missed if they
preceded a 0 bit of the exponent being processed. This made
calls such as 2i32.pow(1024) not trigger an overflow.
This does cause some breakage due to deficiencies in resolve -
`path::Components` is both an `Iterator` and implements `Eq`, `Ord`,
etc. If one calls e.g. `partial_cmp` on a `Components` and passes a
`&Components` intending to target the `PartialOrd` impl, the compiler
will select the `partial_cmp` from `Iterator` and then error out. I
doubt anyone will run into breakage from `Components` specifically, but
we should see if there are third party types that will run into issues.
`iter::order::equals` wasn't moved to `Iterator` since it's exactly the
same as `iter::order::eq` but with an `Eq` instead of `PartialEq` bound,
which doensn't seem very useful.
I also updated `le`, `gt`, etc to use `partial_cmp` which lets us drop
the extra `PartialEq` bound.
cc #27737
These commits move libcore into a state so that it's ready for stabilization, performing some minor cleanup:
* The primitive modules for integers in the standard library were all removed from the source tree as they were just straight reexports of the libcore variants.
* The `core::atomic` module now lives in `core::sync::atomic`. The `core::sync` module is otherwise empty, but ripe for expansion!
* The `core::prelude::v1` module was stabilized after auditing that it is a subset of the standard library's prelude plus some primitive extension traits (char, str, and slice)
* Some unstable-hacks for float parsing errors were shifted around to not use the same unstable hacks (e.g. the `flt2dec` module is now used for "privacy").
After this commit, the remaining large unstable functionality specific to libcore is:
* `raw`, `intrinsics`, `nonzero`, `array`, `panicking`, `simd` -- these modules are all unstable or not reexported in the standard library, so they're just remaining in the same status quo as before
* `num::Float` - this extension trait for floats needs to be audited for functionality (much of that is happening in #27823) and may also want to be renamed to `FloatExt` or `F32Ext`/`F64Ext`.
* Should the extension traits for primitives be stabilized in libcore?
I believe other unstable pieces are not isolated to just libcore but also affect the standard library.
cc #27701
There wasn't any particular reason the functions needed to be there
anyway, so just get rid of them, and adjust libstd to compensate.
With this change, libcore depends on exactly two floating-point functions:
fmod and fmodf. They are implicitly referenced because they are used to
implement "%".
Dependencies of libcore on Linux x86-x64 with this patch:
```
0000000000000000 *UND* 0000000000000000 __powidf2
0000000000000000 *UND* 0000000000000000 __powisf2
0000000000000000 *UND* 0000000000000000 fmod
0000000000000000 *UND* 0000000000000000 fmodf
0000000000000000 *UND* 0000000000000000 memcmp
0000000000000000 *UND* 0000000000000000 memcpy
0000000000000000 *UND* 0000000000000000 memset
0000000000000000 *UND* 0000000000000000 rust_begin_unwind
0000000000000000 *UND* 0000000000000000 rust_eh_personality
```
Stop using stability to hide the implementation details of ParseFloatError and
instead move the error type into the `dec2flt` module. Also move the
implementation blocks of `FromStr for f{32,64}` into `dec2flt` directly.
All of the modules in the standard library were just straight reexports of those
in libcore, so remove all the "macro modules" from the standard library and just
reexport what's in core directly.
There wasn't any particular reason the functions needed to be there
anyway, so just get rid of them, and adjust libstd to compensate.
With this change, libcore depends on exactly two floating-point functions:
fmod and fmodf. They are implicitly referenced because they are
used to implement "%".
This PR implements the majority of RFC 1214. In particular, it implements:
- the new outlives relation
- comprehensive WF checking
For the most part, new code receives warnings, not errors, though 3 regressions were found via a crater run.
There are some deviations from RFC 1214. Most notably:
- we still consider implied bounds from fn ret; this intersects other soundness issues that I intend to address in detail in a follow-up RFC. Fixing this without breaking a lot of code probably requires rewriting compare-method somewhat (which is probably a good thing).
- object types do not check trait bounds for fear of encountering `Self`; this was left as an unresolved question in RFC 1214, but ultimately feels inconsistent.
Both of those two issues are highlighted in the tracking issue, https://github.com/rust-lang/rust/issues/27579. #27579 also includes a testing matrix with new tests that I wrote -- these probably duplicate some existing tests, I tried to check but wasn't quite sure what to look for. I tried to be thorough in testing the WF relation, at least, but would welcome suggestions for missing tests.
r? @nrc (or perhaps someone else?)
This commit removes all unstable and deprecated functions in the standard
library. A release was recently cut (1.3) which makes this a good time for some
spring cleaning of the deprecated functions.
This commit removes all unstable and deprecated functions in the standard
library. A release was recently cut (1.3) which makes this a good time for some
spring cleaning of the deprecated functions.
This commit primarily adds implementations of the algorithms from William
Clinger's paper "How to Read Floating Point Numbers Accurately". It also
includes a lot of infrastructure necessary for those algorithms, and some
unit tests.
Since these algorithms reject a few (extreme) inputs that were previously
accepted, this could be seen as a [breaking-change]
- Exposing digits and individual bits
- Counting the number of bits
- Add small (digit-sized) values
- Multiplication by power of 5
- Division with remainder
All are necessary for decimal to floating point conversions.
All but the most trivial ones come with tests.
This is necessary for decimal-to-float code (in a later commit) to handle
inputs such as 4.9406564584124654e-324 (the smallest subnormal f64).
According to the benchmarks for flt2dec::dragon, this does not
affect performance measurably. It probably uses slightly more stack
space though.
This commit is an implementation of [RFC 1184][rfc] which tweaks the behavior of
the `#![no_std]` attribute and adds a new `#![no_core]` attribute. The
`#![no_std]` attribute now injects `extern crate core` at the top of the crate
as well as the libcore prelude into all modules (in the same manner as the
standard library's prelude). The `#![no_core]` attribute disables both std and
core injection.
[rfc]: https://github.com/rust-lang/rfcs/pull/1184
Having the primitive and module docs derived from the same source
causes problems, primarily that they can't contain hyperlinks
cross-referencing each other.
This crates dedicated private modules in `std` to document the
primitive types, then for all primitives that have a corresponding
module, puts hyperlinks in moth the primitive docs and the module docs
cross-linking each other.
This should help clear up confusion when readers find themselves on
the wrong page.
This resolves#26845.
I'm not entirely satisfied with the placement of the rounding discussion in the docs for the `Div` and `Rem` traits, but I couldn't come up with anywhere better to put it. Suggestions are welcome.
I didn't add any discussion of rounding to the `checked_div` (or rem) or `wrapping_div` documentation because those seem to make it pretty clear that they do the same thing as `Div`.
I noticed in docs, specifically http://doc.rust-lang.org/std/primitive.u8.html#method.is_power_of_two, that it was like this, and it was apparently in multiple places too.
Didn't change any occurrences through the cross-depo things. There's a lot in /src/llvm/ for instance, but I'm not confident on how to go about sending fixes for those, so this is just what's in the base rust depo.
r? @steveklabnik
Fixes#24249
I've tagged all items that were missing docs to allow them to compile for now, the ones in core/num should probably be documented at least.
This is also a breaking change for any crates using `#[deny(missing_docs)]` that have undocumented constants, not sure there is any way to avoid this without making it a separate lint?
It turns out that the 32-bit toolchain for MSVC has many of these functions as
`static inline` functions in header files so there's not actually a symbol for
Rust to call. All of the implementations just cast floats to their 64-bit
variants and then cast back to 32-bit at the end, so the standard library now
takes this strategy.
This commit stabilizes the remaining `wrapping_*` functions on the primitive
integer types as they follow the same conventions as other wrapping methods are
were likely just initially unstable to be conservative.
This commit shards the broad `core` feature of the libcore library into finer
grained features. This split groups together similar APIs and enables tracking
each API separately, giving a better sense of where each feature is within the
stabilization process.
A few minor APIs were deprecated along the way:
* Iterator::reverse_in_place
* marker::NoCopy
