rustdoc: collect trait impls as an early pass
Fixes https://github.com/rust-lang/rust/issues/52545, fixes https://github.com/rust-lang/rust/issues/41480, fixes https://github.com/rust-lang/rust/issues/36922
Right now, rustdoc pulls all its impl information by scanning a crate's HIR for any items it finds. However, it doesn't recurse into anything other than modules, preventing it from seeing trait impls that may be inside things like functions or consts. Thanks to https://github.com/rust-lang/rust/pull/53002, now these items actually *exist* for rustdoc to see, but they still weren't getting collected for display.
But there was a secret. Whenever we pull in an item from another crate, we don't have any of its impls in the local HIR, so instead we ask the compiler for *everything* and filter out after the fact. This process is only triggered if there's a cross-crate re-export in the crate being documented, which can sometimes leave this info out of the docs. This PR instead moves this collection into an early pass, which occurs immediately after crate cleaning, so that that collection occurs regardless. In addition, by including the HIR's own `trait_impls` in addition to the existing `all_trait_implementations` calls, we can collect all these tricky trait impls without having to scan for them!
Update to a new pinning API.
~~Blocked on #53843 because of method resolution problems with new pin type.~~
@r? @cramertj
cc @RalfJung @pythonesque anyone interested in #49150
By introducing a new map that tracks the errors reported and the
`Place`s that spawned those errors against the move out that the error
was referring to, we are able to silence duplicate errors by emitting
only the error which corresponds to the most specific `Place` (that which
other `Place`s which reported errors are prefixes of).
This generally is an improvement, however there is a case -
`liveness-move-in-while` - where the output regresses.
Issue 54246
I added the option of providing a help message for deprecated features, that takes precedence over the default `help: remove this attribute` message, along with messages for the features that mention replacements in the reason for deprecation.
Fixes#54246.
Regression test for rust-lang/rust#53675.
(Includes a couple variations on the theme. I confirmed that the ones
in `in_expression_position` and `what_if_we_use_panic_directly_in_expr`
both failed back on "rustc 1.30.0-nightly (0f063aef6 2018-09-03)".)
Fix#53675
Temporarily prohibit proc macro attributes placed after derives
... and also proc macro attributes used together with `#[test]`/`#[bench]`.
Addresses item 6 from https://github.com/rust-lang/rust/pull/50911#issuecomment-411605393.
The end goal is straightforward predictable left-to-right expansion order for attributes.
Right now derives are expanded last regardless of their relative ordering with macro attributes and right now it's simpler to temporarily prohibit macro attributes placed after derives than changing the expansion order.
I'm not sure whether the new beta is already released or not, but if it's released, then this patch needs to be backported, so the solution needs to be minimal.
How to fix broken code (derives):
- Move macro attributes above derives. This won't change expansion order, they are expanded before derives anyway.
Using attribute macros on same items with `#[test]` and `#[bench]` is prohibited for similar expansion order reasons, but this one is going to be reverted much sooner than restrictions on derives.
How to fix broken code (test/bench):
- Enable `#![feature(plugin)]` (don't ask why).
r? @ghost
use structured suggestion for "missing mut" label
Fixes#54133 for both NLL and non-NLL.
r? @estebank
I'm not super happy with the existing wording here, since it's now a suggestion. I wonder if the message would work better as something like "help: make binding mutable: `mut foo`"?
Also, are the `HELP` and `SUGGESTION` comments necessary?
(Includes a couple variations on the theme. I confirmed that the ones
in `in_expression_position` and `what_if_we_use_panic_directly_in_expr`
both failed back on "rustc 1.30.0-nightly (0f063aef6 2018-09-03)".)
resolve: Introduce two sub-namespaces in macro namespace
Two sub-namespaces are introduced in the macro namespace - one for bang macros and one for attribute-like macros (attributes, derives).
"Sub-namespace" means this is not a newly introduced full namespace, the single macro namespace is still in place.
I.e. you still can't define/import two macros with the same name in a single module, `use` imports still import only one name in macro namespace (from any sub-namespace) and not possibly two.
However, when we are searching for a name used in a `!` macro call context (`my_macro!()`) we skip attribute names in scope, and when we are searching for a name used in attribute context (`#[my_macro]`/`#[derive(my_macro)]`) we are skipping bang macro names in scope.
In other words, bang macros cannot shadow attribute macros and vice versa.
For a non-macro analogy, we could e.g. skip non-traits when searching for `MyTrait` in `impl MyTrait for Type { ... }`.
However we do not do it in non-macro namespaces because we don't have practical issues with e.g. non-traits shadowing traits with the same name, but with macros we do, especially after macro modularization.
For `#[test]` and `#[bench]` we have a hack in the compiler right now preventing their shadowing by `macro_rules! test` and similar things. This hack was introduced after making `#[test]`/`#[bench]` built-in macros instead of built-in attributes (https://github.com/rust-lang/rust/pull/53410), something that needed to be done from the start since they are "active" attributes transforming their inputs.
Now they are passed through normal name resolution and can be shadowed, but that's a breaking change, so we have a special hack basically applying this PR for `#[test]` and `#[bench]` only.
Soon all potentially built-in attributes will be passed through normal name resolution (https://github.com/rust-lang/rust/pull/53913) and that uncovers even more cases where the strict "macro namespace is a single namespace" rule needs to be broken.
For example, with strict rules, built-in macro `cfg!(...)` would shadow built-in attribute `#[cfg]` (they are different things), standard library macro `thread_local!(...)` would shadow built-in attribute `#[thread_local]` - both of these cases are covered by special hacks in https://github.com/rust-lang/rust/pull/53913 as well.
Crater run uncovered more cases of attributes being shadowed by user-defined macros (`warn`, `doc`, `main`, even `deprecated`), we cannot add exceptions in the compiler for all of them.
Regressions with user-defined attributes like https://github.com/rust-lang/rust/issues/53583 and https://github.com/rust-lang/rust/issues/53898 also appeared after enabling macro modularization.
People are also usually confused (https://github.com/rust-lang/rust/issues/53205#issuecomment-411552763, https://github.com/rust-lang/rust/issues/53583#issuecomment-415447800) when they see conflicts between attributes and non-attribute macros for the first time.
So my proposed solution is to solve this issue by introducing two sub-namespaces and thus skipping resolutions of the wrong kind and preventing more error-causing cases of shadowing.
Fixes https://github.com/rust-lang/rust/issues/53583
rustc_resolve: don't treat uniform_paths canaries as ambiguities unless they resolve to distinct Def's.
In particular, this allows this pattern that @cramertj mentioned in https://github.com/rust-lang/rust/issues/53130#issuecomment-420848814:
```rust
use log::{debug, log};
fn main() {
use log::{debug, log};
debug!(...);
}
```
The canaries for the inner `use log::...;`, *in the macro namespace*, see the `log` macro imported at the module scope, and the (same) `log` macro, imported in the block scope inside `main`.
Previously, these two possible (macro namspace) `log` resolutions would be considered ambiguous (from a forwards-compat standpoint, where we might make imports aware of block scopes).
With this PR, such a case is allowed *if and only if* all the possible resolutions refer to the same definition (more specifically, because the *same* `log` macro is being imported twice).
This condition subsumes previous (weaker) checks like #54005 and the second commit of #54011.
Only the last commit is the main change, the other two are cleanups.
r? @petrochenkov cc @Centril @joshtriplett
[NLL] Suggest let binding
Closes#49821
Also adds an alternative to `explain_why_borrow_contains_point` that allows changing error messages based on the reason that will be given. This will also be useful for #51026, #51169 and maybe further changes to does not live long enough messages.
