Add better error message when == operator is badly used
Part of #40660.
With the following code:
```rust
fn foo<T: PartialEq>(a: &T, b: T) {
a == b;
}
fn main() {
foo(&1, 1);
}
```
It prints:
```
error[E0277]: the trait bound `&T: std::cmp::PartialEq<T>` is not satisfied
--> test.rs:2:5
|
2 | a == b;
| ^^^^^^ can't compare `&T` with `T`
|
= help: the trait `std::cmp::PartialEq<T>` is not implemented for `&T`
= help: consider adding a `where &T: std::cmp::PartialEq<T>` bound
error: aborting due to previous error
```
debuginfo: Generate unique DW_AT_names for compilation units to work around OSX linker bug
This should fix issue #39160 and does not seem to cause any problems.
cc @tromey, @Manishearth
r? @jdm
Remove interior mutability from TraitDef by turning fields into queries
This PR gets rid of anything `std::cell` in `TraitDef` by
- moving the global list of trait impls from `TraitDef` into a query,
- moving the list of trait impls relevent for some self-type from `TraitDef` into a query
- moving the specialization graph of trait impls into a query, and
- moving `TraitDef::object_safety` into a query.
I really like how querifying things not only helps with incremental compilation and on-demand, but also just plain makes the code cleaner `:)`
There are also some smaller fixes in the PR. Commits can be reviewed separately.
r? @eddyb or @nikomatsakis
Fix#35829 (`quote!()` does not handle `br#"…"#`)
Fix issue #35829 (syntax extension's `quote_expr!()` does not handle `b"…"` and proc_macro's `quote!()` does not handle `r#"…"#`)
* Handles `b"…"`, `br#"…"#` and `...` for `quote_expr!()`.
* Refactored the match statement to allow it to complain loudly on any unhandled token.
* Similarly, proc_macro's `quote!()` did not handle `br#"…"#` or `r#"…"#`, so this PR fixes it too.
* #42007 happens because the Session LintStore is emptied when linting.
* The Session LintStore is emptied because the checker (Early/LateContext)
wants ownership.
* The checker wants ownership because it wants to mutate the pass objects
and lint levels.
The ownership of the whole store is not essential, only the lint levels and
pass objects need to be owned. Therefore, these parts are extracted out of
the LintStore into a separate structure `LintSession`. The "check crates"
methods can operate on `&mut LintSession` instead of `&mut LintStore`.
This is a minor BREAKING CHANGE for lint writers since the `LintContext`
trait is changed: the `mut_lints` and `level_stack` methods are removed.
But no one outside of `librustc/lint/context.rs` is using these functions,
so it should be safe.
avoid cycles in mir-dump, take 2
This fixes#41697, for real this time, but I'm not sure how best to add a regression test. I was considering maybe adding some flag so that the MIR dumping doesn't actually get written to files (e.g., overloading the directory flag so you can specify nil or something).
cc @dwrensha @oli-obk
use equality in the coerce-unsized check
This seems both to be a safe, conservative choice, and it sidesteps the cycle in #41849. Note that, before I converted variance into proper queries, we were using a hybrid of subtyping and equality, due to the presence of a flag that forced invariance if variance had not yet been computed. (Also, Coerce Unsized is unstable.)
Fixes#41936.
r? @eddyb
Add lint for unused macros
Addresses parts of #34938, to add a lint for unused macros.
We now output warnings by default when we encounter a macro that we didn't use for expansion.
Issues to be resolved before this PR is ready for merge:
- [x] fix the NodeId issue described above
- [x] remove all unused macros from rustc and the libraries or set `#[allow(unused_macros)]` next to them if they should be kept for some reason. This is needed for successful boostrap and bors to accept the PR. -> #41934
- [x] ~~implement the full extent of #34938, that means the macro match arm checking as well.~~ *let's not do this for now*
rustdoc: Display `extern "C" fn` instead of `extern fn`
It was decided in rust-lang-nursery/fmt-rfcs#52 to be explicit about the ABI so rustdoc should follow suit.
Make unsatisfied trait bounds note multiline
Make diagnostic note for existing method with unsatisfied trait bounds
multiline for cleaner output.
```
= note: the method `count` exists but the following trait bounds were not satisfied:
`[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`
`std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>> [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
```
Before:
```
= note: the method `count` exists but the following trait bounds were not satisfied: `[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`, `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
```
Consequently, session creation can no longer initialize LLVM.
The few places that use the compiler without going through
rustc_driver/CompilerCalls thus need to be careful to manually
initialize LLVM (via rustc_trans!) immediately after session
creation.
This means librustc is not rebuilt when LLVM changes.
Make diagnostic note for existing method with unsatisfied trait bounds
multiline for cleaner output.
```
= note: the method `count` exists but the following trait bounds were not satisfied:
`[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`
`std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>> [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
Before:
```
= note: the method `count` exists but the following trait bounds were not satisfied: `[closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`, `std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@../../src/test/compile-fail/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
```
Move the code for loading metadata from rlibs and dylibs from
rustc_metadata into rustc_trans, and introduce a trait to avoid
introducing a direct dependency on rustc_trans.
This means rustc_metadata is no longer rebuilt when LLVM changes.
Disallow ._ in float literal.
This patch makes lexer stop parsing number literals before `._`, as well as before `.a`. Underscore itself is still allowed like in `4_000_000.000_000_`.
Fixes a half part of #41723. The other is `""_`.
rustc_resolve: don't deny outer type parameters in embedded constants.
This solves a problem noted at https://github.com/rust-lang/rust/issues/29646#issuecomment-300929548, where an associated const default in a trait couldn't refer to `Self` or type parameters, due to inaccuracies in lexical scoping.
I've also allowed "embedded expressions" (`[T; expr]`, `[x; expr]`, `typeof expr`) to refer to type parameters in scope. *However*, the typesystem still doesn't handle #34344.
Fully resolving that issue requires breaking cycles more aggressively (e.g. lazy evaluation), *even* in when the expression doesn't depend on type parameters, to type-check it at all, and then also type-level "constant projections" (in the vein of `{expr}` from const generics).
rustc: simpler ParameterEnvironment and free regions.
The commits describe the slow transformation but the highlights are:
* `ReEarlyBound` is considered free, with a scope based on the item that defined the lifetime parameter, and the root body of the `RegionMaps` in use, removing the need for `free_substs`
* `liberate_late_bound_regions` and `implicit_region_bound` moved to typeck
* `CodeExtent` not interned at all now - ideally it would be 2 `u32` but it's small anyway
Future work building up on this could include:
* `ParameterEnvironment` becoming just the result of `predicates_of`
* interning makes my "parent chain" scheme unnecessary
* `implicit_region_bound` could be retrieved from `RegionMaps`
* renaming `CodeExtent` to `Scope`
* generalizing "call site" to "use site" or something better to include constants
* renaming `RegionMaps` to `ScopeTree` and its API to talk about "parents" explicitly
