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Allow passing expr metavariable to cfg #146961

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2 changes: 1 addition & 1 deletion compiler/rustc_ast/src/attr/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -424,7 +424,7 @@ impl MetaItem {
_span,
_spacing,
Delimiter::Invisible(InvisibleOrigin::MetaVar(
MetaVarKind::Meta { .. } | MetaVarKind::Path,
MetaVarKind::Meta | MetaVarKind::Path,
)),
_stream,
)) => {
Expand Down
9 changes: 3 additions & 6 deletions compiler/rustc_ast/src/token.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -64,10 +64,7 @@ pub enum MetaVarKind {
Ident,
Lifetime,
Literal,
Meta {
/// Will `AttrItem::meta` succeed on this, if reparsed?
has_meta_form: bool,
},
Meta,
Path,
Vis,
TT,
Expand All @@ -87,7 +84,7 @@ impl fmt::Display for MetaVarKind {
MetaVarKind::Ident => sym::ident,
MetaVarKind::Lifetime => sym::lifetime,
MetaVarKind::Literal => sym::literal,
MetaVarKind::Meta { .. } => sym::meta,
MetaVarKind::Meta => sym::meta,
MetaVarKind::Path => sym::path,
MetaVarKind::Vis => sym::vis,
MetaVarKind::TT => sym::tt,
Expand Down Expand Up @@ -693,7 +690,7 @@ impl Token {
OpenInvisible(InvisibleOrigin::MetaVar(
MetaVarKind::Expr { .. } |
MetaVarKind::Literal |
MetaVarKind::Meta { .. } |
MetaVarKind::Meta |
MetaVarKind::Pat(_) |
MetaVarKind::Path |
MetaVarKind::Ty { .. }
Expand Down
25 changes: 12 additions & 13 deletions compiler/rustc_attr_parsing/src/parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -410,19 +410,18 @@ impl<'a, 'sess> MetaItemListParserContext<'a, 'sess> {
}

fn parse_attr_item(&mut self) -> PResult<'sess, MetaItemParser<'static>> {
if let Some(MetaVarKind::Meta { has_meta_form }) = self.parser.token.is_metavar_seq() {
return if has_meta_form {
let attr_item = self
.parser
.eat_metavar_seq(MetaVarKind::Meta { has_meta_form: true }, |this| {
MetaItemListParserContext { parser: this, should_emit: self.should_emit }
.parse_attr_item()
})
.unwrap();
Ok(attr_item)
} else {
self.parser.unexpected_any()
};
if let Some(mv_kind @ (MetaVarKind::Meta | MetaVarKind::Expr { .. })) =
self.parser.token.is_metavar_seq()
{
return self
.parser
.eat_metavar_seq(mv_kind, |this| {
MetaItemListParserContext { parser: this, should_emit: self.should_emit }
.parse_attr_item()
})
.ok_or_else(|| {
self.parser.unexpected_any::<core::convert::Infallible>().unwrap_err()
});
}

let path = self.parser.parse_path(PathStyle::Mod)?;
Expand Down
7 changes: 1 addition & 6 deletions compiler/rustc_expand/src/mbe/transcribe.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -481,12 +481,7 @@ fn transcribe_pnr<'tx>(
mk_delimited(ty.span, MetaVarKind::Ty { is_path }, TokenStream::from_ast(ty))
}
ParseNtResult::Meta(attr_item) => {
let has_meta_form = attr_item.meta_kind().is_some();
mk_delimited(
attr_item.span(),
MetaVarKind::Meta { has_meta_form },
TokenStream::from_ast(attr_item),
)
mk_delimited(attr_item.span(), MetaVarKind::Meta, TokenStream::from_ast(attr_item))
}
ParseNtResult::Path(path) => {
mk_delimited(path.span, MetaVarKind::Path, TokenStream::from_ast(path))
Expand Down
20 changes: 8 additions & 12 deletions compiler/rustc_parse/src/parser/attr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -290,7 +290,7 @@ impl<'a> Parser<'a> {
/// The delimiters or `=` are still put into the resulting token stream.
pub fn parse_attr_item(&mut self, force_collect: ForceCollect) -> PResult<'a, ast::AttrItem> {
if let Some(item) = self.eat_metavar_seq_with_matcher(
|mv_kind| matches!(mv_kind, MetaVarKind::Meta { .. }),
|mv_kind| matches!(mv_kind, MetaVarKind::Meta),
|this| this.parse_attr_item(force_collect),
) {
return Ok(item);
Expand Down Expand Up @@ -421,17 +421,13 @@ impl<'a> Parser<'a> {
&mut self,
unsafe_allowed: AllowLeadingUnsafe,
) -> PResult<'a, ast::MetaItem> {
if let Some(MetaVarKind::Meta { has_meta_form }) = self.token.is_metavar_seq() {
return if has_meta_form {
let attr_item = self
.eat_metavar_seq(MetaVarKind::Meta { has_meta_form: true }, |this| {
this.parse_attr_item(ForceCollect::No)
})
.unwrap();
Ok(attr_item.meta(attr_item.path.span).unwrap())
} else {
self.unexpected_any()
};
if let Some(mv_kind @ (MetaVarKind::Meta | MetaVarKind::Expr { .. })) =
self.token.is_metavar_seq()
{
return self
.eat_metavar_seq(mv_kind, |this| this.parse_attr_item(ForceCollect::No))
.map(|attr_item| attr_item.meta(attr_item.path.span).unwrap())
.ok_or_else(|| self.unexpected_any::<core::convert::Infallible>().unwrap_err());
}

let lo = self.token.span;
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_parse/src/parser/nonterminal.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ impl<'a> Parser<'a> {
| MetaVarKind::Expr { .. }
| MetaVarKind::Ty { .. }
| MetaVarKind::Literal // `true`, `false`
| MetaVarKind::Meta { .. }
| MetaVarKind::Meta
| MetaVarKind::Path => true,

MetaVarKind::Item
Expand Down Expand Up @@ -82,7 +82,7 @@ impl<'a> Parser<'a> {
MetaVarKind::Item
| MetaVarKind::Pat(_)
| MetaVarKind::Ty { .. }
| MetaVarKind::Meta { .. }
| MetaVarKind::Meta
| MetaVarKind::Path
| MetaVarKind::Vis => false,
MetaVarKind::Lifetime | MetaVarKind::Ident | MetaVarKind::TT => {
Expand Down
4 changes: 2 additions & 2 deletions tests/ui/attributes/nonterminal-expansion.rs
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Expand Up @@ -5,8 +5,7 @@
macro_rules! pass_nonterminal {
($n:expr) => {
#[repr(align($n))]
//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `expr` metavariable
struct S;
fn foo() {}
};
}

Expand All @@ -15,5 +14,6 @@ macro_rules! n {
}

pass_nonterminal!(n!());
//~^ ERROR expected one of `(`, `::`, or `=`, found `!`
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This error is surprisingly different from what you get when "inlining" the macro?

error: expected unsuffixed literal, found `!`
 --> src/main.rs:6:15
  |
6 | #[repr(align(n!()))]
  |               ^

https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=979f349ee4be2e88b300d4f97f5e1db9

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$expr effectively has parentheses around it, so the "inlined" version would look more like #[repr(align((n!())))].


fn main() {}
11 changes: 3 additions & 8 deletions tests/ui/attributes/nonterminal-expansion.stderr
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@@ -1,13 +1,8 @@
error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `expr` metavariable
--> $DIR/nonterminal-expansion.rs:7:22
error: expected one of `(`, `::`, or `=`, found `!`
--> $DIR/nonterminal-expansion.rs:16:20
|
LL | #[repr(align($n))]
| ^^
...
LL | pass_nonterminal!(n!());
| ----------------------- in this macro invocation
|
= note: this error originates in the macro `pass_nonterminal` (in Nightly builds, run with -Z macro-backtrace for more info)
| ^ expected one of `(`, `::`, or `=`

error: aborting due to 1 previous error

11 changes: 11 additions & 0 deletions tests/ui/macros/attr-expr.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
macro_rules! foo {
($e:expr) => {
#[$e]
//~^ ERROR expected identifier, found metavariable
fn foo() {}
}
}

foo!(inline);

fn main() {}
13 changes: 13 additions & 0 deletions tests/ui/macros/attr-expr.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
error: expected identifier, found metavariable
--> $DIR/attr-expr.rs:3:11
|
LL | #[$e]
| ^^ expected identifier, found metavariable
...
LL | foo!(inline);
| ------------ in this macro invocation
|
= note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

11 changes: 11 additions & 0 deletions tests/ui/macros/cfg_attr-expr.rs
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@@ -0,0 +1,11 @@
macro_rules! foo {
($e:expr) => {
#[cfg_attr(true, $e)]
//~^ ERROR expected identifier, found metavariable
fn foo() {}
}
}

foo!(inline);

fn main() {}
15 changes: 15 additions & 0 deletions tests/ui/macros/cfg_attr-expr.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
error: expected identifier, found metavariable
--> $DIR/cfg_attr-expr.rs:3:26
|
LL | #[cfg_attr(true, $e)]
| ^^ expected identifier, found metavariable
...
LL | foo!(inline);
| ------------ in this macro invocation
|
= help: the valid syntax is `#[cfg_attr(condition, attribute, other_attribute, ...)]`
= note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
= note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

26 changes: 26 additions & 0 deletions tests/ui/macros/cfg_expr.rs
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@@ -0,0 +1,26 @@
//@ run-pass

macro_rules! foo {
($e:expr, $n:ident) => {
#[cfg_attr($e, allow(non_snake_case))]
#[cfg($e)]
fn $n() {}

#[cfg_attr(not($e), allow(unused))]
#[cfg(not($e))]
fn $n() {
panic!()
}
}
}

foo!(true, BAR);
foo!(any(true, unix, target_pointer_width = "64"), baz);
foo!(target_pointer_width = "64", quux);

fn main() {
BAR();
baz();
#[cfg(target_pointer_width = "64")]
quux();
}
4 changes: 3 additions & 1 deletion tests/ui/parser/attribute/attr-bad-meta-4.rs
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Original file line number Diff line number Diff line change
@@ -1,12 +1,14 @@
macro_rules! mac {
($attr_item: meta) => {
#[cfg($attr_item)]
//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `meta` metavariable
struct S;
}
}

mac!(an(arbitrary token stream));
//~^ ERROR expected one of `(`, `)`, `,`, `::`, or `=`, found `token`
//~| ERROR expected one of `(`, `)`, `,`, `::`, or `=`, found `stream`
//~| ERROR [E0537]

#[cfg(feature = -1)]
//~^ ERROR expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
Expand Down
30 changes: 21 additions & 9 deletions tests/ui/parser/attribute/attr-bad-meta-4.stderr
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `-`
--> $DIR/attr-bad-meta-4.rs:11:17
--> $DIR/attr-bad-meta-4.rs:13:17
|
LL | #[cfg(feature = -1)]
| ^
Expand All @@ -10,16 +10,28 @@ LL - #[cfg(feature = -1)]
LL + #[cfg(feature = 1)]
|

error: expected a literal (`1u8`, `1.0f32`, `"string"`, etc.) here, found `meta` metavariable
--> $DIR/attr-bad-meta-4.rs:3:15
error: expected one of `(`, `)`, `,`, `::`, or `=`, found `token`
--> $DIR/attr-bad-meta-4.rs:8:19
|
LL | #[cfg($attr_item)]
| ^^^^^^^^^^
...
LL | mac!(an(arbitrary token stream));
| -------------------------------- in this macro invocation
| -^^^^^ expected one of `(`, `)`, `,`, `::`, or `=`
| |
| help: missing `,`

error: expected one of `(`, `)`, `,`, `::`, or `=`, found `stream`
--> $DIR/attr-bad-meta-4.rs:8:25
|
= note: this error originates in the macro `mac` (in Nightly builds, run with -Z macro-backtrace for more info)
LL | mac!(an(arbitrary token stream));
| -^^^^^^ expected one of `(`, `)`, `,`, `::`, or `=`
| |
| help: missing `,`

error[E0537]: invalid predicate `an`
--> $DIR/attr-bad-meta-4.rs:8:6
|
LL | mac!(an(arbitrary token stream));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors
error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0537`.
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