We no longer require `use` and `extern crate` items to precede other items in modules thanks to [RFC #385](https://github.com/rust-lang/rfcs/pull/385), but we still require `use` and `extern crate` items to precede statements in blocks (other items can appear anywhere in a block).
I think that this is a needless distinction between imports and other items that contradicts the intent of the RFC.
This commit removes the `-D warnings` flag being passed through the makefiles to
all crates to instead be a crate attribute. We want these attributes always
applied for all our standard builds, and this is more amenable to Cargo-based
builds as well.
Note that all `deny(warnings)` attributes are gated with a `cfg(stage0)`
attribute currently to match the same semantics we have today
This fixes#23880, a scoping bug in which items in a block are shadowed by local variables and type parameters that are in scope.
After this PR, an item in a block will shadow any local variables or type parameters above the item in the scope hierarchy. Items in a block will continue to be shadowed by local variables in the same block (even if the item is defined after the local variable).
This is a [breaking-change]. For example, the following code breaks:
```rust
fn foo() {
let mut f = 1;
{
fn f() {}
f += 1; // This will resolve to the function instead of the local variable
}
}
This fixes a bug in which items in a block are shadowed by local variables and type parameters that are in scope.
It is a [breaking-change]. For example, the following code breaks:
```rust
fn foo() {
let mut f = 1;
{
fn f() {}
f += 1; // This will now resolve to the function instead of the local variable
}
}
```
Any breakage can be fixed by renaming the item that is no longer shadowed.
This commit removes the `-D warnings` flag being passed through the makefiles to
all crates to instead be a crate attribute. We want these attributes always
applied for all our standard builds, and this is more amenable to Cargo-based
builds as well.
Note that all `deny(warnings)` attributes are gated with a `cfg(stage0)`
attribute currently to match the same semantics we have today
Fix a bug allowing an item and an external crate to collide so long as the external crate is declared after the item. For example,
```rust
mod core { pub fn f() {} } // This would be an error if it followed the `extern crate`
extern crate core; // This declaration is shadowed by the preceding module
fn main() { core::f(); }
```
This is a [breaking-change], but it looks unlikely to cause breakage in practice, and any breakage can be fixed by removing colliding `extern crate` declarations, which are shadowed and hence unused.
Add note when item accessed from module via `m.i` rather than `m::i`.
(I tried to make this somewhat future-proofed, in that the `UnresolvedNameContext` could be expanded in the future with other cases besides paths that are known to be modules.)
This supersedes PR #30356 ; since I'm responsible for a bunch of new code here, someone else should review it. :)
Instead of `ast::Ident`, bindings, paths and labels in HIR now keep a new structure called `hir::Ident` containing mtwt-renamed `name` and the original not-renamed `unhygienic_name`. `name` is supposed to be used by default, `unhygienic_name` is rarely used.
This is not ideal, but better than the status quo for two reasons:
- MTWT tables can be cleared immediately after lowering to HIR
- This is less bug-prone, because it is impossible now to forget applying `mtwt::resolve` to a name. It is still possible to use `name` instead of `unhygienic_name` by mistake, but `unhygienic_name`s are used only in few very special circumstances, so it shouldn't be a problem.
Besides name resolution `unhygienic_name` is used in some lints and debuginfo. `unhygienic_name` can be very well approximated by "reverse renaming" `token::intern(name.as_str())` or even plain string `name.as_str()`, except that it would break gensyms like `iter` in desugared `for` loops. This approximation is likely good enough for lints and debuginfo, but not for name resolution, unfortunately (see https://github.com/rust-lang/rust/issues/27639), so `unhygienic_name` has to be kept.
cc https://github.com/rust-lang/rust/issues/29782
r? @nrc
Fixes https://github.com/rust-lang/rust/issues/28692
Fixes https://github.com/rust-lang/rust/issues/28992
Fixes some other similar issues (see the tests)
[breaking-change], needs crater run (cc @brson or @alexcrichton )
The pattern with parens `UnitVariant(..)` for unit variants seems to be popular in rustc (see the second commit), but mostly used by one person (@nikomatsakis), according to git blame. If it causes breakage on crates.io I'll add an exceptional case for it.
Fixes#13677
This does the same sort of suggestion for misspelt macros that we already do for misspelt identifiers.
Example. Compiling this program:
```rust
macro_rules! foo {
($e:expr) => ( $e )
}
fn main() {
fob!("hello!");
}
```
gives the following error message:
```
/Users/mcp/temp/test.rs:7:5: 7:8 error: macro undefined: 'fob!'
/Users/mcp/temp/test.rs:7 fob!("hello!");
^~~
/Users/mcp/temp/test.rs:7:5: 7:8 help: did you mean `foo`?
/Users/mcp/temp/test.rs:7 fob!("hello!");
```
I had to move the levenshtein distance function into libsyntax for this. Maybe this should live somewhere else (some utility crate?), but I couldn't find a crate to put it in that is imported by libsyntax and the other rustc crates.
Replace `TypeNsDef` and `ValueNsDef` with a more general type `NsDef`.
Define a newtype `NameBinding` for `Rc<RefCell<Option<NsDef>>>` and refactor `NameBindings` to be a `NameBinding` for each namespace.
Replace uses of `NameBindings` with `NameBinding` where only one binding is being used (in `NamespaceResult`, `Target,` etc).
Refactor away `resolve_definition_of_name_in_module` and `NameDefinition`, fixing issue #4952.
