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Auto merge of #129972 - eholk:stabilize-expr_2021, r=compiler-errors,traviscross
Stabilize expr_2021 fragment specifier in all editions This is part of the `expr`/`expr_2021` fragment specifier for Edition 2024 (#123742). The RFC says we can support expr_2021 in as many editions as is practical, and there's nothing particularly hard about supporting it all the way back to 2015. In editions 2021 and earlier, `expr` and `expr_2021` are synonyms. Their behavior diverges starting in Edition 2024. This is checked by the `expr_2021_inline_const.rs` test. cc `@vincenzopalazzo` `@rust-lang/wg-macros` `@traviscross`
2 parents 07f08ff + c7cd55f commit 21aa500

21 files changed

+44
-95
lines changed

‎compiler/rustc_expand/src/mbe/macro_check.rs

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -119,7 +119,7 @@ use rustc_span::symbol::{MacroRulesNormalizedIdent, kw};
119119
use rustc_span::{ErrorGuaranteed, Span};
120120
use smallvec::SmallVec;
121121

122-
use super::quoted::VALID_FRAGMENT_NAMES_MSG_2021;
122+
use super::quoted::VALID_FRAGMENT_NAMES_MSG;
123123
use crate::errors;
124124
use crate::mbe::{KleeneToken, TokenTree};
125125

@@ -274,7 +274,7 @@ fn check_binders(
274274
psess.dcx().emit_err(errors::MissingFragmentSpecifier {
275275
span,
276276
add_span: span.shrink_to_hi(),
277-
valid: VALID_FRAGMENT_NAMES_MSG_2021,
277+
valid: VALID_FRAGMENT_NAMES_MSG,
278278
});
279279
} else {
280280
psess.buffer_lint(

‎compiler/rustc_expand/src/mbe/quoted.rs

Lines changed: 4 additions & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,3 @@
1-
use rustc_ast::token::NtExprKind::*;
21
use rustc_ast::token::{self, Delimiter, IdentIsRaw, NonterminalKind, Token};
32
use rustc_ast::{NodeId, tokenstream};
43
use rustc_ast_pretty::pprust;
@@ -13,12 +12,9 @@ use crate::errors;
1312
use crate::mbe::macro_parser::count_metavar_decls;
1413
use crate::mbe::{Delimited, KleeneOp, KleeneToken, MetaVarExpr, SequenceRepetition, TokenTree};
1514

16-
const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
17-
`ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, \
18-
`item` and `vis`";
19-
pub(crate) const VALID_FRAGMENT_NAMES_MSG_2021: &str = "valid fragment specifiers are \
20-
`ident`, `block`, `stmt`, `expr`, `expr_2021`, `pat`, `ty`, `lifetime`, `literal`, `path`, \
21-
`meta`, `tt`, `item` and `vis`";
15+
pub(crate) const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
16+
`ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, \
17+
`meta`, `tt`, `item` and `vis`, along with `expr_2021` and `pat_param` for edition compatibility";
2218

2319
/// Takes a `tokenstream::TokenStream` and returns a `Vec<self::TokenTree>`. Specifically, this
2420
/// takes a generic `TokenStream`, such as is used in the rest of the compiler, and returns a
@@ -92,39 +88,13 @@ pub(super) fn parse(
9288
};
9389
let kind = NonterminalKind::from_symbol(fragment.name, edition)
9490
.unwrap_or_else(|| {
95-
let help = match fragment.name {
96-
sym::expr_2021 => {
97-
format!(
98-
"fragment specifier `expr_2021` \
99-
requires Rust 2021 or later\n\
100-
{VALID_FRAGMENT_NAMES_MSG}"
101-
)
102-
}
103-
_ if edition().at_least_rust_2021()
104-
&& features.expr_fragment_specifier_2024 =>
105-
{
106-
VALID_FRAGMENT_NAMES_MSG_2021.into()
107-
}
108-
_ => VALID_FRAGMENT_NAMES_MSG.into(),
109-
};
11091
sess.dcx().emit_err(errors::InvalidFragmentSpecifier {
11192
span,
11293
fragment,
113-
help,
94+
help: VALID_FRAGMENT_NAMES_MSG.into(),
11495
});
11596
NonterminalKind::Ident
11697
});
117-
if kind == NonterminalKind::Expr(Expr2021 { inferred: false })
118-
&& !features.expr_fragment_specifier_2024
119-
{
120-
rustc_session::parse::feature_err(
121-
sess,
122-
sym::expr_fragment_specifier_2024,
123-
span,
124-
"fragment specifier `expr_2021` is unstable",
125-
)
126-
.emit();
127-
}
12898
result.push(TokenTree::MetaVarDecl(span, ident, Some(kind)));
12999
continue;
130100
}

‎compiler/rustc_feature/src/accepted.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -189,6 +189,8 @@ declare_features! (
189189
(accepted, exhaustive_integer_patterns, "1.33.0", Some(50907)),
190190
/// Allows explicit generic arguments specification with `impl Trait` present.
191191
(accepted, explicit_generic_args_with_impl_trait, "1.63.0", Some(83701)),
192+
/// Uses 2024 rules for matching `expr` fragments in macros. Also enables `expr_2021` fragment.
193+
(accepted, expr_fragment_specifier_2024, "CURRENT_RUSTC_VERSION", Some(123742)),
192194
/// Allows arbitrary expressions in key-value attributes at parse time.
193195
(accepted, extended_key_value_attributes, "1.54.0", Some(78835)),
194196
/// Allows resolving absolute paths as paths from other crates.

‎compiler/rustc_feature/src/unstable.rs

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -450,8 +450,6 @@ declare_features! (
450450
(unstable, exhaustive_patterns, "1.13.0", Some(51085)),
451451
/// Allows explicit tail calls via `become` expression.
452452
(incomplete, explicit_tail_calls, "1.72.0", Some(112788)),
453-
/// Uses 2024 rules for matching `expr` fragments in macros. Also enables `expr_2021` fragment.
454-
(incomplete, expr_fragment_specifier_2024, "1.80.0", Some(123742)),
455453
/// Allows using `efiapi`, `sysv64` and `win64` as calling convention
456454
/// for functions with varargs.
457455
(unstable, extended_varargs_abi_support, "1.65.0", Some(100189)),

‎tests/ui/lint/unused/unused-macro-with-bad-frag-spec.stderr

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,7 @@ error: invalid fragment specifier `t_ty`
44
LL | ($wrong:t_ty) => ()
55
| ^^^^^^^^^^^
66
|
7-
= help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis`
7+
= help: valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, `literal`, `path`, `meta`, `tt`, `item` and `vis`, along with `expr_2021` and `pat_param` for edition compatibility
88

99
error: aborting due to 1 previous error
1010

‎tests/ui/macros/expr_2021.rs

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
//@ check-pass
2+
//@ edition: 2015
3+
4+
// Ensures expr_2021 fragment specifier is accepted in old editions
5+
6+
macro_rules! my_macro {
7+
($x:expr_2021) => {
8+
println!("Hello, {}!", $x);
9+
};
10+
}
11+
12+
fn main() {
13+
my_macro!("world");
14+
}

‎tests/ui/macros/expr_2021_cargo_fix_edition.fixed

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,6 @@
11
//@ run-rustfix
22
//@ check-pass
33
//@ compile-flags: --edition=2021
4-
#![allow(incomplete_features)]
5-
#![feature(expr_fragment_specifier_2024)]
64
#![warn(edition_2024_expr_fragment_specifier)]
75

86
macro_rules! m {

‎tests/ui/macros/expr_2021_cargo_fix_edition.rs

Lines changed: 0 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,6 @@
11
//@ run-rustfix
22
//@ check-pass
33
//@ compile-flags: --edition=2021
4-
#![allow(incomplete_features)]
5-
#![feature(expr_fragment_specifier_2024)]
64
#![warn(edition_2024_expr_fragment_specifier)]
75

86
macro_rules! m {

‎tests/ui/macros/expr_2021_cargo_fix_edition.stderr

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,13 +1,13 @@
11
warning: the `expr` fragment specifier will accept more expressions in the 2024 edition
2-
--> $DIR/expr_2021_cargo_fix_edition.rs:9:9
2+
--> $DIR/expr_2021_cargo_fix_edition.rs:7:9
33
|
44
LL | ($e:expr) => {
55
| ^^^^
66
|
77
= warning: this changes meaning in Rust 2024
88
= note: for more information, see Migration Guide <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/macro-fragment-specifiers.html>
99
note: the lint level is defined here
10-
--> $DIR/expr_2021_cargo_fix_edition.rs:6:9
10+
--> $DIR/expr_2021_cargo_fix_edition.rs:4:9
1111
|
1212
LL | #![warn(edition_2024_expr_fragment_specifier)]
1313
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -17,7 +17,7 @@ LL | ($e:expr_2021) => {
1717
| ~~~~~~~~~
1818

1919
warning: the `expr` fragment specifier will accept more expressions in the 2024 edition
20-
--> $DIR/expr_2021_cargo_fix_edition.rs:13:11
20+
--> $DIR/expr_2021_cargo_fix_edition.rs:11:11
2121
|
2222
LL | ($($i:expr)*) => { };
2323
| ^^^^

‎tests/ui/macros/expr_2021_inline_const.edi2021.stderr

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error: no rules expected the token `const`
2-
--> $DIR/expr_2021_inline_const.rs:26:12
2+
--> $DIR/expr_2021_inline_const.rs:23:12
33
|
44
LL | macro_rules! m2021 {
55
| ------------------ when calling this macro
@@ -8,13 +8,13 @@ LL | m2021!(const { 1 });
88
| ^^^^^ no rules expected this token in macro call
99
|
1010
note: while trying to match meta-variable `$e:expr_2021`
11-
--> $DIR/expr_2021_inline_const.rs:10:6
11+
--> $DIR/expr_2021_inline_const.rs:7:6
1212
|
1313
LL | ($e:expr_2021) => {
1414
| ^^^^^^^^^^^^
1515

1616
error: no rules expected the token `const`
17-
--> $DIR/expr_2021_inline_const.rs:27:12
17+
--> $DIR/expr_2021_inline_const.rs:24:12
1818
|
1919
LL | macro_rules! m2024 {
2020
| ------------------ when calling this macro
@@ -23,7 +23,7 @@ LL | m2024!(const { 1 });
2323
| ^^^^^ no rules expected this token in macro call
2424
|
2525
note: while trying to match meta-variable `$e:expr`
26-
--> $DIR/expr_2021_inline_const.rs:16:6
26+
--> $DIR/expr_2021_inline_const.rs:13:6
2727
|
2828
LL | ($e:expr) => {
2929
| ^^^^^^^

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