Add a nicer error message for missing in for loop, fixes#40782.
As suggested by @estebank in issue #40782, this works in the same way as #42578: if the in keyword is missing, we continue parsing the expression and if this works correctly an adapted error message is produced. Otherwise we return the old error.
A specific test case has also been added.
This is my first PR on rust-lang/rust so any feedback is very welcome.
add TerminatorKind::FalseEdges and use it in matches
impl #45184 and fixes#45043 right way.
False edges unexpectedly affects uninitialized variables analysis in MIR borrowck.
[Syntax] Implement auto trait syntax
Implements `auto trait Send {}` as a substitute for `trait Send {} impl Send for .. {}`.
See the [internals thread](https://internals.rust-lang.org/t/pre-rfc-renaming-oibits-and-changing-their-declaration-syntax/3086) for motivation. Part of #13231.
The first commit is just a rename moving from "default trait" to "auto trait". The rest is parser->AST->HIR work and making it the same as the current syntax for everything below HIR. It's under the `optin_builtin_traits` feature gate.
When can we remove the old syntax? Do we need to wait for a new `stage0`? We also need to formally decide for the new form (even if the keyword is not settled yet).
Observations:
- If you `auto trait Auto {}` and then `impl Auto for .. {}` that's accepted even if it's redundant.
- The new syntax is simpler internally which will allow for a net removal of code, for example well-formedness checks are effectively moved to the parser.
- Rustfmt and clippy are broken, need to fix those.
- Rustdoc just ignores it for now.
ping @petrochenkov @nikomatsakis
DefaultImpl is a highly confusing name for what we now call auto impls,
as in `impl Send for ..`. The name auto impl is not formally decided
but for sanity anything is better than `DefaultImpl` which refers
neither to `default impl` nor to `impl Default`.
`unreachable-pub` lint (as authorized by RFC 2126)
To whom it may concern:
RFC 2126 commissions the creation of a lint for `pub` items that are not visible from crate root (#45521). We understand (but seek confirmation from more knowledgable compiler elders) that this can be implemented by linting HIR items that are _not_ ~~`cx.access_levels.is_exported`~~ `cx.access_levels.is_reachable` but have a `vis` (-ibility) field of `hir::Visibility::Public`.
The lint, tentatively called ~~`unexported-pub`~~ `unreachable-pub` (with the understanding that much could be written on the merits of various names, as it is said of the colors of bicycle-sheds), suggests `crate` as a replacement for `pub` if the `crate_visibility_modifier` feature is enabled (see #45388), and `pub(crate)` otherwise. We also use help messaging to suggest the other potential fix of exporting the item; feedback is desired as to whether this may be confusing or could be worded better.
As a preview of what respecting the proposed lint would look like (and to generate confirmatory evidence that this implementation doesn't issue false positives), ~~we take its suggestions for `libcore`~~ (save one, which is deferred to another pull request because it brings up an unrelated technical matter). I remain your obedient servant.
r? @petrochenkov
typeck: suggest use of match_default_bindings feature
Fixes#45383.
Updates #42640.
r? @nikomatsakis
cc @tschottdorf
This needs a UI test, but thought I'd get some early feedback.
Improve display of error E0308
Ref. Forgetting to call a variant constructor causes a confusing error message #35241.
This PR modifies [`note_type_err`](b7041bfab3/src/librustc/infer/error_reporting/mod.rs (L669-L674)) to display a `help` message when a `TyFnPtr` or `TyFnDef` are found and the return type, of the function or function pointer, is the same as the type that is expected.
The output of compiling
```rust
struct Foo(u32);
fn test() -> Foo { Foo }
fn main() {}
```
is now
```bash
$ rustc src/test/ui/issue-35241.rs
error[E0308]: mismatched types
--> src/test/ui/issue-35241.rs:13:20
|
13 | fn test() -> Foo { Foo }
| --- ^^^ expected struct `Foo`, found fn item
| |
| expected `Foo` because of return type
|
= help: did you mean `Foo { /* fields */ }`?
= note: expected type `Foo`
found type `fn(u32) -> Foo {Foo::{{constructor}}}`
error: aborting due to previous error
```
enable non-lexical lifetimes in the MIR borrow checker
This PR, joint work with @spastorino, fills out the NLL infrastructure and integrates it with the borrow checker. **Don't get too excited:** it includes still a number of hacks (the subtyping code is particularly hacky). However, it *does* kinda' work. =)
The final commit demonstrates this by including a test that -- with both the AST borrowck and MIR borrowck -- reports an error by default. But if you pass `-Znll`, you only get an error from the AST borrowck, demonstrating that the integration succeeds:
```
struct MyStruct {
field: String
}
fn main() {
let mut my_struct = MyStruct { field: format!("Hello") };
let value = &my_struct.field;
if value.is_empty() {
my_struct.field.push_str("Hello, world!");
//~^ ERROR cannot borrow (Ast)
}
}
```
incr.comp.: Implement compiler diagnostic persistence.
This PR implements storing and loading diagnostics that the compiler generates and thus allows for emitting warnings during incremental compilation without actually re-evaluating the thing the warning originally came from. It also lays some groundwork for storing and loading type information and MIR in the incr. comp. cache.
~~It is still work in progress:~~
- ~~There's still some documentation to be added.~~
- ~~The way anonymous queries are handled might lead to duplicated emissions of warnings. Not sure if there is a better way or how frequent such duplication would be in practice.~~
Diagnostic message duplication is addressed separately in #45519.
r? @nikomatsakis
Suggest renaming import if names clash
Closes https://github.com/rust-lang/rust/issues/32354.
The output for the example in the issue looks like this:
```
~/p/local-rust-dev-testing ❯❯❯ cargo +local-s1 build
Compiling local-rust-dev-testing v0.1.0 (file:///home/cldfire/programming_projects/local-rust-dev-testing)
error[E0252]: the name `ConstructorExtension` is defined multiple times
--> src/main.rs:49:5
|
48 | use extension1::ConstructorExtension;
| -------------------------------- previous import of the trait `ConstructorExtension` here
49 | use extension2::ConstructorExtension;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `ConstructorExtension` reimported here
|
= note: `ConstructorExtension` must be defined only once in the type namespace of this module
help: You can use `as` to change the binding name of the import
|
49 | use extension2::ConstructorExtension as OtherConstructorExtension;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
```
This is my first PR that touches the compiler in any way, so if there's something else I need to do here (e.g. add a test), please let me know :).
edit and fix bad spacing of inner-attribute-not-allowed note
This multiline string literal was missing a backslash, leaving an awkward
newline and 35 spaces in the middle of the message.
But while we're here, the existing message seems kind of long in comparison to
similar notes: to cut it down, we excise the mentions of doc comments, which
seems sensible because we know that this erroneous attribute is not a doc
comment (notice the `is_sugared_doc: false` at the end of the function; if it
had been a doc comment, that error would get set in the `token::DocComment`
match branch of `parse_outer_attributes`).
The macro now takes a format string. It no longer defaults to using the
type name. Didn't seem worth going through contortions to maintain. I
also changed most of the debug formats to be `foo[N]` instead of `fooN`.
