The rationale is that BOM stripping is needed for lazy source loading
for external crates, and duplication can be avoided by moving the
corresponding functionality to libsyntax_pos.
We can use these to perform lazy loading of source files belonging to
external crates. That way we will be able to show the source code of
external spans that have been translated.
Disallow underscore suffix for string-like literals.
This patch turns string/bytestring/char/byte literals followed by an underscore, like `"Foo"_`, to an error.
`scan_optional_raw_name` will parse `_` as a valid raw name, but it will be rejected by the parser. I also considered just stopping parsing when the suffix is `_`, but in that case `"Foo"_` will be lexed as two valid tokens.
Fixes the latter half of #41723.
Use callsite's span for macro calls on suggestion
When suggesting an appropriate mutability for a macro call, use the call
span instead of the expanded macro's span.
```
error[E0308]: mismatched types
--> $DIR/coerce-suggestions.rs:48:9
|
48 | s = format!("foo");
| ^^^^^^^^^^^^^^ expected mutable reference, found struct `std::string::String`
|
= note: expected type `&mut std::string::String`
found type `std::string::String`
= help: try with `&mut format!("foo")`
= note: this error originates in a macro outside of the current crate
```
Fix#41858.
incr.comp.: Track expanded spans instead of FileMaps.
This PR removes explicit tracking of FileMaps in response to #42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map:
1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates).
2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`.
3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash.
One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented).
r? @nikomatsakis
trace_macro: Show both the macro call and its expansion. #42072.
See #42072 for the initial motivation behind this.
The change is not the minimal fix, but I want this behavior almost every time I use `trace_macros`.
add thiscall calling convention support
This support is needed for bindgen to work well on 32-bit Windows, and also enables people to begin experimenting with C++ FFI support on that platform.
Fixes#42044.
Initial implementation of declarative macros 2.0
Implement declarative macros 2.0 (rust-lang/rfcs#1584) behind `#![feature(decl_macro)]`.
Differences from `macro_rules!` include:
- new syntax: `macro m(..) { .. }` instead of `macro_rules! m { (..) => { .. } }`
- declarative macros are items:
```rust
// crate A:
pub mod foo {
m!(); // use before definition; declaration order is irrelevant
pub macro m() {} // `pub`, `pub(super)`, etc. work
}
fn main() {
foo::m!(); // named like other items
{ use foo::m as n; n!(); } // imported like other items
}
pub use foo::m; // re-exported like other items
// crate B:
extern crate A; // no need for `#[macro_use]`
A::foo::m!(); A::m!();
```
- Racket-like hygiene for items, imports, methods, fields, type parameters, privacy, etc.
- Intuitively, names in a macro definition are resolved in the macro definition's scope, not the scope in which the macro is used.
- This [explaination](http://beautifulracket.com/explainer/hygiene.html) of hygiene for Racket applies here (except for the "Breaking Hygiene" section). I wrote a similar [explanation](https://github.com/jseyfried/rfcs/blob/hygiene/text/0000-hygiene.md) for Rust.
- Generally speaking, if `fn f() { <body> }` resolves, `pub macro m() { <body> } ... m!()` also resolves, even if `m!()` is in a separate crate.
- `::foo::bar` in a `macro` behaves like `$crate::foo::bar` in a `macro_rules!`, except it can access everything visible from the `macro` (thus more permissive).
- See [`src/test/{run-pass, compile-fail}/hygiene`](https://github.com/rust-lang/rust/pull/40847/commits/afe7d89858fd72b983e24727d6f4058293153c19) for examples. Small example:
```rust
mod foo {
fn f() { println!("hello world"); }
pub macro m() { f(); }
}
fn main() { foo::m!(); }
```
Limitations:
- This does not address planned changes to matchers (`expr`,`ty`, etc.), c.f. #26361.
- Lints (including stability and deprecation) and `unsafe` are not hygienic.
- adding hygiene here will be mostly or entirely backwards compatible
- Nested macro definitions (a `macro` inside another `macro`) don't always work correctly when invoked from external crates.
- pending improvements in how we encode macro definitions in crate metadata
- There is no way to "escape" hygiene without using a procedural macro.
r? @nrc
Add an option to the parser to avoid parsing out of line modules
This is useful if parsing from stdin or a String and don't want to try and read in a module from another file. Instead we just leave a stub in the AST.
This support is needed for bindgen to work well on 32-bit Windows, and
also enables people to begin experimenting with C++ FFI support on that
platform.
Fixes#42044.
Correct some stability versions
These were found by running tidy on stable versions of rust and finding
features stabilised with the wrong version numbers.
This is useful if parsing from stdin or a String and don't want to try and read in a module from another file. Instead we just leave a stub in the AST.
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.
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*
Inokentiy Babushkin