Make spec_extend use for_each()
`for_each` will use an iterator's own implementation of `try_fold`, which I understand to be generally preferable (because nested iterator adapter's will use each other's `try_fold` and be designed for the specific adaptation in a way that promotes performance and inlining.
Add doc for impl From for Std Error
As part of issue #51430 (cc @skade).
I am not sure if it is going to a correct direction so put up here so that people can comment.
Limit the promotion of const fns to the libstd and the `rustc_promotable` attribute
There are so many questions around promoting const fn calls... it seems saner to try to limit automatic promotion to const fns which were explicitly opted in for promotion.
I added the attribute to all public stable const fns that were already promotable (e.g. not Cell::new) in order to not cause any breakage
r? @eddyb
cc @nikomatsakis
handle outlives predicates in trait evaluation
This handles higher-ranked outlives predicates in trait evaluation the same way they are handled in projection.
Fixes#54302. I think this is a more correct fix than #54401 because it fixes the root case in evaluation instead of making evaluation used in less cases. However, we might want to go to a direction closer to @nikomatsakis's solution with Chalk.
r? @nikomatsakis
suggest `crate::...` for "local" paths in 2018
Fixes#54230.
This commit adds suggestions for unresolved imports in the cases where
there could be a missing `crate::`, `super::`, `self::` or a missing
external crate name before an import.
r? @nikomatsakis
Give a special message when the later use is from a call. Use the span
of the callee instead of the whole expression. For conflicting borrow
messages say that the later use is of the first borrow.
resolve: Disambiguate a subset of conflicts "macro_rules" vs "macro name in module"
Currently if macro name may refer to both a `macro_rules` macro definition and a macro defined/imported into module we conservatively report an ambiguity error.
Unfortunately, these errors became a source of regressions when macro modularization was enabled - see issue https://github.com/rust-lang/rust/issues/54472.
This PR disambiguates such conflicts in favor of `macro_rules` if both the `macro_rules` item and in-module macro name are defined in the same normal (named) module and `macro_rules` is closer in scope to the point of use (see the tests for examples).
This is a subset of more general approach described in https://github.com/rust-lang/rust/issues/54472#issuecomment-424666659.
The subset is enough to fix all the regressions from https://github.com/rust-lang/rust/issues/54472, but it can be extended to apply to all "macro_rules" vs "macro name in module" conflicts in the future.
To give an analogy, this is equivalent to scoping rules for `let` variables and items defined in blocks (`macro_rules` behaves like "`let` at module level" in general).
```rust
{ // beginning of the block
use xxx::m; // (1)
// Starting from the beginning of the block and until here m!() refers to (1)
macro_rules! m { ... } // (2)
// Starting from here and until the end of the block m!() refers to (2)
} // end of the block
```
More complex examples with `use` and `macro_rules` from different modules still report ambiguity errors, even if equivalent examples with `let` are legal.
Fixes https://github.com/rust-lang/rust/issues/54472 (stable-to-beta regression)
This commit ensures that the external crate suggestion is deterministic
by using a `BTreeMap` rather than a `FxHashMap`. This is particularly
useful as `std` and `core` will often contain the same items and
therefore the suggestion would previously suggest either for any given
error - in this case, the suggestion will always prefer `std` now.
Previously, `meta` crate was hardcoded as attempting to resolve a path
with it would ICE. Now, we attempt to load each extern crate first so
that resolving a path involving that crate doesn't error.
This commit adds suggestions for unresolved imports in the cases where
there could be a missing `crate::`, `super::`, `self::` or a missing
external crate name before an import.
NLL fails to suggest "try removing `&mut` here"
Fixes#51191.
This PR adds ``try removing `&mut` here`` suggestions to functions where a mutable borrow is being taken of a `&mut self` or a `self: &mut Self`. This PR also enables the suggestion for adding a `mut` pattern to by-value implicit self arguments without `mut` patterns already.
r? @nikomatsakis
Joshua Netterfield reported an ICE when the unused-parentheses lint
triggered around an async block (#54752). In order to compose an
autofixable suggestion, the lint invokes the pretty-printer on the
unnecessarily-parenthesized expression. (One wonders why the lint
doesn't just use `SourceMap::span_to_snippet` instead, to preserve the
formatting of the original source?—but for that, you'd have to ask the
author of 5c9f806d.)
But then the pretty-printer panics when trying to call `<pprust::State
as PrintState>::end` when `State.boxes` is empty. Empirically, the
problem would seem to be solved if we start some "boxes" beforehand in
the `ast::ExprKind::Async` arm of the big match in
`print_expr_outer_attr_style`, exactly like we do in the
immediately-preceding match arm for `ast::ExprKind::Block`—it would
seem pretty ("pretty") reasonable for the pretty-printing of async
blocks to work a lot like the pretty-printing of ordinary non-async
blocks, right??
Of course, it would be shamefully cargo-culty to commit code on the
basis of this kind of mere reasoning-by-analogy (in contrast to
understanding the design of the pretty-printer in such detail that the
correctness of the patch is comprehended with all the lucid certainty
of mathematical proof, rather than being merely surmised by
intuition). But maybe we care more about fixing the bug with high
probability today, than with certainty in some indefinite hypothetical
future? Maybe the effort is worth a fifth of a shirt??
Humbly resolves#54752.
In #51833, I improved the performance of `copy_undef_mask()`. As such, the old FIXME wasn't appropriate anymore. The main remaining thing left to do is to implement a fast path for non-overlapping copies (per @oli-obk).
Renumber `proc_macro` tracking issues
Lots of issue links in the compiler still point to https://github.com/rust-lang/rust/issues/38356 which is a bit of a monster issue that isn't serving much purpose any more. I've split the issue into a number of more fine-grained tracking issues to track stabilizations.
do not promote comparing function pointers
This *could* break existing code that relied on fn ptr comparison getting promoted to `'static` lifetime.
Fixes https://github.com/rust-lang/rust/issues/54696
Re-export `getopts` so custom drivers can reference it.
Otherwise, custom drivers will have to use their own copy of `getopts`, which won't match the types used in `CompilerCalls`.
Use impl_header_lifetime_elision in libcore
The feature is approved for stabilization, so let's use it to remove about 300 `'a`s.
Tracking issue for the feature: https://github.com/rust-lang/rust/issues/15872
make run-pass tests with empty main just compile-pass tests
Many run-pass tests have an empty main, so there is not actually any point in running them. This makes them `compile-pass` tests instead, saving some time (generating the binary and then running it).
For now I did this only for `run-pass/issues`; if there is interest I can also do it for the other directories. I used `^\s*fn\s+main\(\s*\)\s*\{\s*\}` as regexp to identify these files.
Add `crate::` to trait suggestions in Rust 2018.
Fixes#54559.
In the 2018 edition, when suggesting traits to import that implement a
given method that is being invoked, suggestions will now include the
`crate::` prefix if the suggested trait is local to the current crate.
r? @nikomatsakis
Allow both explicit and elided lifetimes in the same impl header
While still prohibiting explicit and in-band in the same header.
Fixes#54456
As usual, I don't know the broader context of the code I'm changing, so please let me know whatever I can do better.
Pre-existing test that mixing explicit and in-band remains an error: https://github.com/rust-lang/rust/blob/master/src/test/ui/in-band-lifetimes/E0688.rs
#53840: Consolidate pattern check errors
#53840 on this PR we are aggregating `cannot bind by-move and by-ref in the same pattern` message present on the different lines into one diagnostic message. Here we are first gathering those `spans` on `vector` then we are throwing them with the help of `MultiSpan`
r? @estebank
Addresses: #53480
