This PR removes random remaining `Ident`s outside of libsyntax and performs general cleanup
In particular, interfaces of `Name` and `Ident` are tidied up, `Name`s and `Ident`s being small `Copy` aggregates are always passed to functions by value, and `Ident`s are never used as keys in maps, because `Ident` comparisons are tricky.
Although this PR closes https://github.com/rust-lang/rust/issues/6993 there's still work related to it:
- `Name` can be made `NonZero` to compress numerous `Option<Name>`s and `Option<Ident>`s but it requires const unsafe functions.
- Implementation of `PartialEq` on `Ident` should be eliminated and replaced with explicit hygienic, non-hygienic or member-wise comparisons.
- Finally, large parts of AST can potentially be converted to `Name`s in the same way as HIR to clearly separate identifiers used in hygienic and non-hygienic contexts.
r? @nrc
Make sure Name, SyntaxContext and Ident are passed by value
Make sure Idents don't serve as keys (or parts of keys) in maps, Ident comparison is not well defined
This is a [breaking-change] for syntax extension authors. The fix is to use MultiModifier or MultiDecorator, which have the same functionality but are more flexible. Users of syntax extensions are unaffected.
This is a [breaking-change] for syntax extension authors. The fix is to use MultiModifier or MultiDecorator, which have the same functionality but are more flexible. Users of syntax extensions are unaffected.
This is theoretically a breaking change, but GitHub search turns up no
uses of it, and most non-built-in cfg's are passed via cargo features,
which look like `feature = "..."`, and hence can't overlap.
This pull request implements the functionality for [RFC 873](https://github.com/rust-lang/rfcs/blob/master/text/0873-type-macros.md). This is currently just an update of @freebroccolo's branch from January, the corresponding commits are linked in each commit message.
@nikomatsakis and I had talked about updating the macro language to support a lifetime fragment specifier, and it is possible to do that work on this branch as well. If so we can (collectively) talk about it next week during the pre-RustCamp work week.
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
Fixes#25022
This adapts the deriving mechanism to not repeat bounds for the same type parameter. To give an example: for the following code:
```rust
#[derive(Clone)]
pub struct FlatMap<I, U: IntoIterator, F> {
iter: I,
f: F,
frontiter: Option<U::IntoIter>,
backiter: Option<U::IntoIter>,
}
```
the latest nightly generates the following impl signature:
```rust
impl <I: ::std::clone::Clone,
U: ::std::clone::Clone + IntoIterator,
F: ::std::clone::Clone>
::std::clone::Clone for FlatMap<I, U, F> where
I: ::std::clone::Clone,
F: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone
```
With these changes, the signature changes to this:
```rust
impl <I, U: IntoIterator, F> ::std::clone::Clone for FlatMap<I, U, F> where
I: ::std::clone::Clone,
F: ::std::clone::Clone,
U::IntoIter: ::std::clone::Clone
```
(Nothing in the body of the impl changes)
Note that the second impl is more permissive, as it doesn't have a `Clone` bound on `U` at all. There was a compile-fail test that failed due to this. I don't understand why we would want the old behaviour (and nobody on IRC could tell me either), so please tell me if there is a good reason that I missed.
`LocalSource` indicated wether a let binding originated from for-loop desugaring to enable specialized error messages, but for-loop expansion has changed and this is now achieved through `MatchSource::ForLoopDesugar`.
This introduces a test for #23389 and improves the error behaviour to treat the malformed LHS as an error, not a compiler bug.
The parse phase that precedes the call to `check_lhs_nt_follows` could possibly be enhanced to police the format itself (which the old code suggests was the original intention), but I'm not sure that's any nicer than just parsing the matcher as generic rust code and then policing the specific requirements for being a macro matcher afterwards (as this does).
Fixes#23389
(Over time the stability checking has gotten more finicky; in
particular one must attach the (whole) span of the original `in PLACE
BLOCK` expression to the injected references to unstable paths, as
noted in the comments.)
call `push_compiler_expansion` during the placement-`in` expansion.
Even after expansion, the generated expressions still track depth of
such pushes (i.e. how often you have "pushed" without a corresponding
"pop"), and we add a rule that in a context with a positive
`push_unsafe!` depth, it is effectively an `unsafe` block context.
(This way, we can inject code that uses `unsafe` features, but still
contains within it a sub-expression that should inherit the outer
safety checking setting, outside of the injected code.)
This is a total hack; it not only needs a feature-gate, but probably
should be feature-gated forever (if possible).
ignore-pretty in test/run-pass/pushpop-unsafe-okay.rs
