Idiomatic improvements to IP method
Since match ergonomics and slice patterns are stable this might be more idiomatic modern Rust implementations of these methods? Or well, slice patterns with `..` are not stabilized yet, so maybe we want to specify all fields but with `_`?
A few cleanups
- change `skip(1).next()` to `nth(1)`
- collapse some `if-else` expressions
- remove a few explicit `return`s
- remove an unnecessary field name
- dereference once instead of matching on multiple references
- prefer `iter().enumerate()` to indexing with `for`
- remove some unnecessary lifetime annotations
- use `writeln!()` instead of `write!()`+`\n`
- remove redundant parentheses
- shorten some enum variant names
- a few other cleanups suggested by `clippy`
rustc_codegen_llvm: Restore the closure env alloca hack for LLVM 5.
This hack was removed in #50949, but without it I found that building
`std` with full debuginfo would print many LLVM `DW_OP_LLVM_fragment`
errors, then die `LLVM ERROR: Failed to strip malformed debug info`.
It doesn't seem to be a problem for LLVM 6, so we can re-enable the hack
just for older LLVM.
This reverts commit da579ef75e.
Fixes#53204.
r? @eddyb
Make sure rlimit is only ever increased
`libc::setrlimit` will fail if we try to set the rlimit to a value lower than it is currently, so make sure we're never trying to do this. Fixes#52801.
driver: set the syntax edition in phase 1
Fixes https://github.com/rust-lang/rust/issues/53203
It seems the way libsyntax handles the desired edition is to use a global, set via `syntax_pos::hygiene::set_default_edition`. Right now, this is set in the driver in `run_compiler`, which is the entry point for running the compiler all the way through to emitting files. Since rustdoc doesn't use this function, it wasn't properly setting this global. (When initially setting up editions in rustdoc, i'd assumed that setting `sessopts.edition` would have done this... `>_>`) This was "fixed" for doctests in https://github.com/rust-lang/rust/pull/52385, but rather than patching in a call to `set_default_edition` in all the places rustdoc sets up the compiler, i've instead moved the call in the driver to be farther in the process. This means that any use of `phase_1_parse_input` with the right session options will have the edition properly set without having to also remember to set libsyntax up separately.
r? @rust-lang/compiler
Don't panic on std::env::vars() when env is null.
Fixes#53200.
Reviewer(s):
* Do I need to do any `#[cfg()]` here?
* Is this use of libc ok for a dev-dependency?
pretty print BTreeSet
I want pretty printing for BTreeSet.
```rust
use std::collections::*;
fn main() {
let mut s = BTreeSet::new();
s.insert(5);
s.insert(3);
s.insert(7);
s.remove(&3);
println!("{:?}", s);
}
```
```
(gdb) b 9
(gdb) p s
$1 = BTreeSet<i32> with 2 elements = {[0] = 5, [1] = 7}
```
This is analogy of pretty printing for C++ std::set.
Move SmallVector and ThinVec out of libsyntax
- move `libsyntax::util::SmallVector` tests to `librustc_data_structures::small_vec`
- remove `libsyntax::util::SmallVector`
- move `libsyntax::util::thin_vec` to `librustc_data_structures::thin_vec`
Other than moving these data structures where they belong it allows modules using `SmallVector<T>` (`SmallVec<[T; 1]>`) to specify their own length (e.g. 8 or 32) independently from `libsyntax`.
rustc_resolve: crates only exist in the type namespace.
Fixes#53333 by resolving `::crate_name` in `TypeNS` alone, which was overlooked in #52923 and didn't break tests, since having `use crate_name;` and a `crate_name` value in the same scope is rare.
Previously, even if no expected errors were supplied, if a test execution failed
then supplied error patterns would not be checked. This commit modifies the
conditional that determines whether error patterns or expected errors are checked
to remedy this.
Further, this commit modifies the error pattern checking logic so that each pattern
is checked against all lines of the string. This is required for UI tests as the
stderr is in JSON format - all on one line - so in the previous implementation when the
first pattern was found on the first line (which was actually the entire error) then
no other patterns would be found on subsequent lines (as there weren't any).
unsized ManuallyDrop
I think this matches what @eddyb had in https://github.com/rust-lang/rust/pull/52711 originally.
~~However, I have never added a `CoerceUnsized` before so I am not sure if I did this right. I copied the `unstable` attribute on the `impl` from elsewhere, but AFAIK it is useless because `impl`'s are insta-stable... so shouldn't this rather say "stable since 1.30"?~~
This is insta-stable and hence requires FCP, at least.
Fixes https://github.com/rust-lang/rust/issues/47034
#[feature(uniform_paths)]: allow `use x::y;` to resolve through `self::x`, not just `::x`.
_Branch originally by @cramertj, based on @petrochenkov's [description on the internals forum](https://internals.rust-lang.org/t/relative-paths-in-rust-2018/7883/30?u=petrochenkov)._
_(note, however, that the approach has significantly changed since)_
Implements `#[feature(uniform_paths)]` from #53130, by treating unqualified `use` paths as maybe-relative. That is, `use x::y;`, where `x` is a plain identifier (not a keyword), is no longer the same as `use :❌:y;`, and before picking an external crate named `x`, it first looks for an item named `x` in the same module (i.e. `self::x`) and prefers that local item instead.
Such a "maybe-relative" `x` can only resolve to an external crate if it's listed in "`extern_prelude`" (i.e. `core` / `std` and all the crates passed to `--extern`; the latter includes Cargo dependencies) - this is the same condition as being able to refer to the external crate from an unqualified, non-`use` path.
All other crates must be explicitly imported with an absolute path, e.g. `use :❌:y;`
To detect an ambiguity between the external crate and the local item with the same name, a "canary" import (e.g. `use self::x as _;`), tagged with the `is_uniform_paths_canary` flag, is injected. As the initial implementation is not sophisticated enough to handle all possible ways in which `self::x` could appear (e.g. from macro expansion), this also guards against accidentally picking the external crate, when it might actually get "shadowed" later.
Also, more canaries are injected for each block scope around the `use`, as `self::x` cannot resolve to any items named `x` in those scopes, but non-`use` paths can, and that could be confusing or even backwards-incompatible.
Errors are emitted only if the main "canary" import succeeds while an external crate exists (or if any of the block-scoped ones succeed at all), and ambiguities have custom error reporting, e.g.:
```rust
#![feature(uniform_paths)]
pub mod foo {
use std::io;
pub mod std { pub mod io {} }
}
```
```rust
error: import from `std` is ambiguous
--> test.rs:3:9
|
3 | use std::io;
| ^^^ could refer to external crate `::std`
4 | pub mod std { pub mod io {} }
| ----------------------------- could also refer to `self::std`
|
= help: write `::std` or `self::std` explicitly instead
= note: relative `use` paths enabled by `#![feature(uniform_paths)]`
```
Another example, this time with a block-scoped item shadowing a module-scoped one:
```rust
#![feature(uniform_paths)]
enum Foo { A, B }
fn main() {
enum Foo {}
use Foo::*;
}
```
```rust
error: import from `Foo` is ambiguous
--> test.rs:5:9
|
4 | enum Foo {}
| ----------- shadowed by block-scoped `Foo`
5 | use Foo::*;
| ^^^
|
= help: write `::Foo` or `self::Foo` explicitly instead
= note: relative `use` paths enabled by `#![feature(uniform_paths)]`
```
Additionally, this PR, because replacing "the `finalize_import` hack" was a blocker:
* fixes#52140
* fixes#52141
* fixes#52705
cc @aturon @joshtriplett
