This commit adds explicit imp blocks to ensure that all publicly exported types
(except simple enums) are not `Send` nor `Sync` in the `proc_macro` crate.
cc #38356
proc_macro: Generalize `FromIterator` impl
While never intended to be stable we forgot that trait impls are insta-stable!
This construction of `FromIterator` wasn't our first choice of how to stabilize
the impl but our hands are tied at this point, so revert back to the original
definition of `FromIterator` before #49597Closes#49725
A span covering a single byte, such as for an operator `+` token, should
print as e.g. `80..81` rather than `80...81`. The lo end of the range is
inclusive and the hi end is exclusive.
This commit improves the `fmt::Debug` output of `proc_macro` data structures by
primarily focusing on the representation exposed by `proc_macro` rather than the
compiler's own internal representation. This cuts down quite a bit on assorted
wrapper types and ensure a relatively clean output.
Closes#49720
While never intended to be stable we forgot that trait impls are insta-stable!
This construction of `FromIterator` wasn't our first choice of how to stabilize
the impl but our hands are tied at this point, so revert back to the original
definition of `FromIterator` before #49597Closes#49725
* Expand `!` tokens for inner doc comments
* Trim leading doc comment decoration in the string literal
Both of these should help bring the expansion inline with what `macro_rules!`
already does.
Closes#49655Closes#49656
This commit is a reorganization of the `proc_macro` crate's public user-facing
API. This is the result of a number of discussions at the recent Rust All-Hands
where we're hoping to get the `proc_macro` crate into ship shape for
stabilization of a subset of its functionality in the Rust 2018 release.
The reorganization here is motivated by experiences from the `proc-macro2`,
`quote`, and `syn` crates on crates.io (and other crates which depend on them).
The main focus is future flexibility along with making a few more operations
consistent and/or fixing bugs. A summary of the changes made from today's
`proc_macro` API is:
* The `TokenNode` enum has been removed and the public fields of `TokenTree`
have also been removed. Instead the `TokenTree` type is now a public enum
(what `TokenNode` was) and each variant is an opaque struct which internally
contains `Span` information. This makes the various tokens a bit more
consistent, require fewer wrappers, and otherwise provides good
future-compatibility as opaque structs are easy to modify later on.
* `Literal` integer constructors have been expanded to be unambiguous as to what
they're doing and also allow for more future flexibility. Previously
constructors like `Literal::float` and `Literal::integer` were used to create
unsuffixed literals and the concrete methods like `Literal::i32` would create
a suffixed token. This wasn't immediately clear to all users (the
suffixed/unsuffixed aspect) and having *one* constructor for unsuffixed
literals required us to pick a largest type which may not always be true. To
fix these issues all constructors are now of the form
`Literal::i32_unsuffixed` or `Literal::i32_suffixed` (for all integral types).
This should allow future compatibility as well as being immediately clear
what's suffixed and what isn't.
* Each variant of `TokenTree` internally contains a `Span` which can also be
configured via `set_span`. For example `Literal` and `Term` now both
internally contain a `Span` rather than having it stored in an auxiliary
location.
* Constructors of all tokens are called `new` now (aka `Term::intern` is gone)
and most do not take spans. Manufactured tokens typically don't have a fresh
span to go with them and the span is purely used for error-reporting
**except** the span for `Term`, which currently affects hygiene. The default
spans for all these constructed tokens is `Span::call_site()` for now.
The `Term` type's constructor explicitly requires passing in a `Span` to
provide future-proofing against possible hygiene changes. It's intended that a
first pass of stabilization will likely only stabilize `Span::call_site()`
which is an explicit opt-in for "I would like no hygiene here please". The
intention here is to make this explicit in procedural macros to be
forwards-compatible with a hygiene-specifying solution.
* Some of the conversions for `TokenStream` have been simplified a little.
* The `TokenTreeIter` iterator was renamed to `token_stream::IntoIter`.
Overall the hope is that this is the "final pass" at the API of `TokenStream`
and most of `TokenTree` before stabilization. Explicitly left out here is any
changes to `Span`'s API which will likely need to be re-evaluated before
stabilization.
All changes in this PR have already been reflected to the [`proc-macro2`],
`quote`, and `syn` crates. New versions of all these crates have also been
published to crates.io.
Once this lands in nightly I plan on making an internals post again summarizing
the changes made here and also calling on all macro authors to give the APIs a
spin and see how they work. Hopefully pending no major issues we can then have
an FCP to stabilize later this cycle!
[`proc-macro2`]: https://docs.rs/proc-macro2/0.3.1/proc_macro2/
This commit tweaks the tokenization of a doc comment to use `#[doc = "..."]`
like `macro_rules!` does (instead of treating it as a `Literal` token).
Additionally it fixes treatment of negative literals in the compiler, for
exapmle `Literal::i32(-1)`. The current fix is a bit of a hack around the
current compiler implementation, providing a fix at the proc-macro layer rather
than the libsyntax layer.
Remove experimental -Zremap-path-prefix-from/to, and replace it with
the stabilized --remap-path-prefix=from=to variant.
This is an implementation for issue of #41555.
macros: improve 1.0/2.0 interaction
This PR supports using unhygienic macros from hygienic macros without breaking the latter's hygiene.
```rust
// crate A:
#[macro_export]
macro_rules! m1 { () => {
f(); // unhygienic: this macro needs `f` in its environment
fn g() {} // (1) unhygienic: `g` is usable outside the macro definition
} }
// crate B:
#![feature(decl_macro)]
extern crate A;
use A::m1;
macro m2() {
fn f() {} // (2)
m1!(); // After this PR, `f()` in the expansion resolves to (2), not (3)
g(); // After this PR, this resolves to `fn g() {}` from the above expansion.
// Today, it is a resolution error.
}
fn test() {
fn f() {} // (3)
m2!(); // Today, `m2!()` can see (3) even though it should be hygienic.
fn g() {} // Today, this conflicts with `fn g() {}` from the expansion, even though it should be hygienic.
}
```
Once this PR lands, you can make an existing unhygienic macro hygienic by wrapping it in a hygienic macro. There is an [example](b766fa887d) of this in the tests.
r? @nrc
Proc macro spans serve two mostly unrelated purposes: controlling name
resolution and controlling error messages. It can be useful to mix the
name resolution behavior of one span with the line/column error message
locations of a different span.
In particular, consider the case of a trait brought into scope within
the def_site of a custom derive. I want to invoke trait methods on the
fields of the user's struct. If the field type does not implement the
right trait, I want the error message to underline the corresponding
struct field.
Generating the method call with the def_site span is not ideal -- it
compiles and runs but error messages sadly always point to the derive
attribute like we saw with Macros 1.1.
```
|
4 | #[derive(HeapSize)]
| ^^^^^^^^
```
Generating the method call with the same span as the struct field's
ident or type is not correct -- it shows the right underlines but fails
to resolve to the trait in scope at the def_site.
```
|
7 | bad: std:🧵:Thread,
| ^^^^^^^^^^^^^^^^^^^^^^^^
```
The correct span for the method call is one that combines the def_site's
name resolution with the struct field's line/column.
```
field.span.resolved_at(Span::def_site())
// equivalently
Span::def_site().located_at(field.span)
```
Adding both because which one is more natural will depend on context.
Expose the line and column fields from the proc_macro::LineColumn struct
Right now the `LineColumn` struct is pretty useless because the fields are private.
This patch just marks the fields as public, which seems like the easiest solution.
Add ..= to the parser
Add ..= to libproc_macro
Add ..= to ICH
Highlight ..= in rustdoc
Update impl Debug for RangeInclusive to ..=
Replace `...` to `..=` in range docs
Make the dotdoteq warning point to the ...
Add warning for ... in expressions
Updated more tests to the ..= syntax
Updated even more tests to the ..= syntax
Updated the inclusive_range entry in unstable book
Right now the HIR contains raw `syntax::ast::Attribute` structure but nowadays
these can contain arbitrary tokens. One variant of the `Token` enum is an
"interpolated" token which basically means to shove all the tokens for a
nonterminal in this position. A "nonterminal" in this case is roughly analagous
to a macro argument:
macro_rules! foo {
($a:expr) => {
// $a is a nonterminal as an expression
}
}
Currently nonterminals contain namely items and expressions, and this poses a
problem for incremental compilation! With incremental we want a stable hash of
all HIR items, but this means we may transitively need a stable hash *of the
entire AST*, which is certainly not stable w/ node ids and whatnot. Hence today
there's a "bug" where the "stable hash" of an AST is just the raw hash value of
the AST, and this only arises with interpolated nonterminals. The downside of
this approach, however, is that a bunch of errors get spewed out during
compilation about how this isn't a great idea.
This PR is focused at fixing these warnings, basically deleting them from the
compiler. The implementation here is to alter attributes as they're lowered from
the AST to HIR, expanding all nonterminals in-place as we see them. This code
for expanding a nonterminal to a token stream already exists for the
`proc_macro` crate, so we basically just reuse the same implementation there.
After this PR it's considered a bug to have an `Interpolated` token and hence
the stable hash implementation simply uses `bug!` in this location.
Closes#40946
Initial diagnostic API for proc-macros.
This commit introduces the ability to create and emit `Diagnostic` structures from proc-macros, allowing for proc-macro authors to emit warning, error, note, and help messages just like the compiler does.
The API is somewhat based on the diagnostic API already present in `rustc` with several changes that improve usability. The entry point into the diagnostic API is a new `Diagnostic` type which is primarily created through new `error`, `warning`, `help`, and `note` methods on `Span`. The `Diagnostic` type records the diagnostic level, message, and optional `Span` for the top-level diagnostic and contains a `Vec` of all of the child diagnostics. Child diagnostics can be added through builder methods on `Diagnostic`.
A typical use of the API may look like:
```rust
let token = parse_token();
let val = parse_val();
val.span
.error(format!("expected A but found {}", val))
.span_note(token.span, "because of this token")
.help("consider using a different token")
.emit();
```
cc @jseyfried @nrc @dtolnay @alexcrichton
This commit introduces the ability to create and emit `Diagnostic`
structures from proc-macros, allowing for proc-macro authors to emit
warning, error, note, and help messages just like the compiler does.
