We have the technology: no longer do you need to write closures to use `format_args!`.
This is a `[breaking-change]`, as it forces you to clean up old hacks - if you had code like this:
```rust
format_args!(fmt::format, "{} {} {}", a, b, c)
format_args!(|args| { w.write_fmt(args) }, "{} {} {}", x, y, z)
```
change it to this:
```rust
fmt::format(format_args!("{} {} {}", a, b, c))
w.write_fmt(format_args!("{} {} {}", x, y, z))
```
To allow them to be called with `format_args!(...)` directly, several functions were modified to
take `fmt::Arguments` by value instead of by reference. Also, `fmt::Arguments` derives `Copy`
now in order to preserve all usecases that were previously possible.
Implements [RFC 486](https://github.com/rust-lang/rfcs/pull/486). Fixes#19908.
* Rename `to_ascii_{lower,upper}` to `to_ascii_{lower,upper}case`, per #14401
* Remove the `Ascii` type and associated traits: `AsciiCast`, `OwnedAsciiCast`, `AsciiStr`, `IntoBytes`, and `IntoString`.
* As a replacement, add `.is_ascii()` to `AsciiExt`, and implement `AsciiExt` for `u8` and `char`.
[breaking-change]
closes#19141closes#20193closes#20228
---
Currently whenever we encounter `let f = || {/* */}`, we *always* type check the RHS as a *boxed* closure. This is wrong when the RHS is `move || {/* */}` (because boxed closures can't capture by value) and generates all sort of badness during trans (see issues above). What we *should* do is always type check `move || {/* */}` as an *unboxed* closure, but ~~I *think* (haven't tried)~~ (2) this is not feasible right now because we have a limited form of kind (`Fn` vs `FnMut` vs `FnOnce`) inference that only works when there is an expected type (1).
In this PR, I've chosen to generate a type error whenever `let f = move || {/* */}` is encountered. The error asks the user to annotate the kind of the unboxed closure (e.g. `move |:| {/* */}`). Once annotated, the compiler will type check the RHS as an unboxed closure which is what the user wants.
r? @nikomatsakis
(1) AIUI it only triggers in this scenario:
``` rust
fn is_uc<F>(_: F) where F: FnOnce() {}
fn main() {
is_uc(|| {}); // type checked as unboxed closure with kind `FnOnce`
}
```
(2) I checked, and it's not possible because `check_unboxed_closure` expects a `kind` argument, but we can't supply that argument in this case (i.e. `let f = || {}`, what's the kind?). We could force the `FnOnce` kind in that case, but that's ad hoc. We should try to infer the kind depending on how the closure is used afterwards, but there is no inference mechanism to do that (at least, not right now).
... really this time `:)`
I went for the simpler fix after all since it turned out to become a bit too complicated to extract the current iteration value from its containing `Option` with the different memory layouts it can have. It's also what we already do for match bindings.
I also extended the new test case to include the "simple identifier" case.
Fixes#20127, fixes#19732
According to [RFC 344][], methods that return `&[u8]` should have names ending in `bytes`. Though `include_bin!` is a macro not a method, it seems reasonable to follow the convention anyway.
We keep the old name around for now, but trigger a deprecation warning when it is used.
[RFC 344]: https://github.com/rust-lang/rfcs/blob/master/text/0344-conventions-galore.md
[breaking-change]
`check::autoderef()` returns a `ty_err` when it fails to infer the type. `probe::probe()` should respect this failure and fail together to prevent further corruption.
Fixes#19692.
Fixes#19583.
Fixes#19297.
The previous behaviour of using the smallest type possible caused LLVM
to treat padding too conservatively, causing poor codegen. This commit
changes the behaviour to use an alignment-sized integer as the
discriminant. This keeps types the same size, but helps LLVM understand
the data structure a little better, resulting in better codegen.
According to [RFC 344][], methods that return `&[u8]` should have names
ending in `bytes`. Though `include_bin!` is a macro not a method, it
seems reasonable to follow the convention anyway.
We keep the old name around for now, but trigger a deprecation warning
when it is used.
[RFC 344]: https://github.com/rust-lang/rfcs/blob/master/text/0344-conventions-galore.md
[breaking-change]
The previous behaviour of using the smallest type possible caused LLVM
to treat padding too conservatively, causing poor codegen. This commit
changes the behaviour to use an type-alignment-sized integer as the
discriminant. This keeps types the same size, but helps LLVM understand
the data structure a little better, resulting in better codegen.
This commit starts out by consolidating all `str` extension traits into one
`StrExt` trait to be included in the prelude. This means that
`UnicodeStrPrelude`, `StrPrelude`, and `StrAllocating` have all been merged into
one `StrExt` exported by the standard library. Some functionality is currently
duplicated with the `StrExt` present in libcore.
This commit also currently avoids any methods which require any form of pattern
to operate. These functions will be stabilized via a separate RFC.
Next, stability of methods and structures are as follows:
Stable
* from_utf8_unchecked
* CowString - after moving to std::string
* StrExt::as_bytes
* StrExt::as_ptr
* StrExt::bytes/Bytes - also made a struct instead of a typedef
* StrExt::char_indices/CharIndices - CharOffsets was renamed
* StrExt::chars/Chars
* StrExt::is_empty
* StrExt::len
* StrExt::lines/Lines
* StrExt::lines_any/LinesAny
* StrExt::slice_unchecked
* StrExt::trim
* StrExt::trim_left
* StrExt::trim_right
* StrExt::words/Words - also made a struct instead of a typedef
Unstable
* from_utf8 - the error type was changed to a `Result`, but the error type has
yet to prove itself
* from_c_str - this function will be handled by the c_str RFC
* FromStr - this trait will have an associated error type eventually
* StrExt::escape_default - needs iterators at least, unsure if it should make
the cut
* StrExt::escape_unicode - needs iterators at least, unsure if it should make
the cut
* StrExt::slice_chars - this function has yet to prove itself
* StrExt::slice_shift_char - awaiting conventions about slicing and shifting
* StrExt::graphemes/Graphemes - this functionality may only be in libunicode
* StrExt::grapheme_indices/GraphemeIndices - this functionality may only be in
libunicode
* StrExt::width - this functionality may only be in libunicode
* StrExt::utf16_units - this functionality may only be in libunicode
* StrExt::nfd_chars - this functionality may only be in libunicode
* StrExt::nfkd_chars - this functionality may only be in libunicode
* StrExt::nfc_chars - this functionality may only be in libunicode
* StrExt::nfkc_chars - this functionality may only be in libunicode
* StrExt::is_char_boundary - naming is uncertain with container conventions
* StrExt::char_range_at - naming is uncertain with container conventions
* StrExt::char_range_at_reverse - naming is uncertain with container conventions
* StrExt::char_at - naming is uncertain with container conventions
* StrExt::char_at_reverse - naming is uncertain with container conventions
* StrVector::concat - this functionality may be replaced with iterators, but
it's not certain at this time
* StrVector::connect - as with concat, may be deprecated in favor of iterators
Deprecated
* StrAllocating and UnicodeStrPrelude have been merged into StrExit
* eq_slice - compiler implementation detail
* from_str - use the inherent parse() method
* is_utf8 - call from_utf8 instead
* replace - call the method instead
* truncate_utf16_at_nul - this is an implementation detail of windows and does
not need to be exposed.
* utf8_char_width - moved to libunicode
* utf16_items - moved to libunicode
* is_utf16 - moved to libunicode
* Utf16Items - moved to libunicode
* Utf16Item - moved to libunicode
* Utf16Encoder - moved to libunicode
* AnyLines - renamed to LinesAny and made a struct
* SendStr - use CowString<'static> instead
* str::raw - all functionality is deprecated
* StrExt::into_string - call to_string() instead
* StrExt::repeat - use iterators instead
* StrExt::char_len - use .chars().count() instead
* StrExt::is_alphanumeric - use .chars().all(..)
* StrExt::is_whitespace - use .chars().all(..)
Pending deprecation -- while slicing syntax is being worked out, these methods
are all #[unstable]
* Str - while currently used for generic programming, this trait will be
replaced with one of [], deref coercions, or a generic conversion trait.
* StrExt::slice - use slicing syntax instead
* StrExt::slice_to - use slicing syntax instead
* StrExt::slice_from - use slicing syntax instead
* StrExt::lev_distance - deprecated with no replacement
Awaiting stabilization due to patterns and/or matching
* StrExt::contains
* StrExt::contains_char
* StrExt::split
* StrExt::splitn
* StrExt::split_terminator
* StrExt::rsplitn
* StrExt::match_indices
* StrExt::split_str
* StrExt::starts_with
* StrExt::ends_with
* StrExt::trim_chars
* StrExt::trim_left_chars
* StrExt::trim_right_chars
* StrExt::find
* StrExt::rfind
* StrExt::find_str
* StrExt::subslice_offset
Part of #18424
This commit changes the semantics of `reserve` and `capacity` for Bitv and BitvSet to match conventions. It also introduces the notion of `reserve_index` and `reserve_index_exact` for collections with maximum-index-based capacity semantics.
Deprecates free function constructors in favour of functions on Bitv itself.
Changes `Bitv::pop` to return an Option rather than panicking.
Deprecates and renames several methods in favour of conventions.
Marks several blessed methods as unstable.
This commit also substantially refactors Bitv and BitvSet's implementations. The new implementation is simpler, cleaner, better documented, and more robust against overflows. It also reduces coupling between Bitv and BitvSet. Tests have been seperated into seperate submodules.
Fixes#16958
[breaking-change]
cannot use an `as` expression to coerce, so I used a one-off function
instead (this is a no-op in stage0, but in stage1+ it triggers
coercion from the fn pointer to the fn item type).
