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Feature gate macro attributes in #[derive] output
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@petrochenkov
petrochenkov committed Feb 7, 2021
1 parent dbdbd30 commit f6caae5
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Showing 7 changed files with 124 additions and 29 deletions.
4 changes: 4 additions & 0 deletions compiler/rustc_feature/src/active.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -634,6 +634,10 @@ declare_features! (

/// Lessens the requirements for structs to implement `Unsize`.
(active, relaxed_struct_unsize, "1.51.0", Some(1), None),

/// Allows macro attributes to observe output of `#[derive]`.
(active, macro_attributes_in_derive_output, "1.51.0", Some(81119), None),

// -------------------------------------------------------------------------
// feature-group-end: actual feature gates
// -------------------------------------------------------------------------
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30 changes: 30 additions & 0 deletions compiler/rustc_resolve/src/macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -280,6 +280,36 @@ impl<'a> ResolverExpand for Resolver<'a> {
if let Res::Def(_, _) = res {
let normal_module_def_id = self.macro_def_scope(invoc_id).nearest_parent_mod;
self.definitions.add_parent_module_of_macro_def(invoc_id, normal_module_def_id);

// Gate macro attributes in `#[derive]` output.
if !self.session.features_untracked().macro_attributes_in_derive_output
&& kind == MacroKind::Attr
&& ext.builtin_name != Some(sym::derive)
{
let mut expn_id = parent_scope.expansion;
loop {
// Helper attr table is a quick way to determine whether the attr is `derive`.
if self.helper_attrs.contains_key(&expn_id) {
feature_err(
&self.session.parse_sess,
sym::macro_attributes_in_derive_output,
path.span,
"macro attributes in `#[derive]` output are unstable",
)
.emit();
break;
} else {
let expn_data = expn_id.expn_data();
match expn_data.kind {
ExpnKind::Root
| ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
break;
}
_ => expn_id = expn_data.parent,
}
}
}
}
}

Ok(ext)
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1 change: 1 addition & 0 deletions compiler/rustc_span/src/symbol.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -679,6 +679,7 @@ symbols! {
loop_break_value,
lt,
macro_at_most_once_rep,
macro_attributes_in_derive_output,
macro_escape,
macro_export,
macro_lifetime_matcher,
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28 changes: 28 additions & 0 deletions src/test/ui/proc-macro/attribute-after-derive-feature-gate.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
// gate-test-macro_attributes_in_derive_output
// aux-build: test-macros.rs

#![feature(proc_macro_hygiene)]
#![feature(stmt_expr_attributes)]

#[macro_use]
extern crate test_macros;

#[derive(Empty)]
#[empty_attr] //~ ERROR macro attributes in `#[derive]` output are unstable
struct S1 {
field: [u8; 10],
}

#[derive(Empty)]
#[empty_helper]
#[empty_attr] //~ ERROR macro attributes in `#[derive]` output are unstable
struct S2 {
field: [u8; 10],
}

#[derive(Empty)]
struct S3 {
field: [u8; #[identity_attr] 10], //~ ERROR macro attributes in `#[derive]` output are unstable
}

fn main() {}
30 changes: 30 additions & 0 deletions src/test/ui/proc-macro/attribute-after-derive-feature-gate.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
error[E0658]: macro attributes in `#[derive]` output are unstable
--> $DIR/attribute-after-derive-feature-gate.rs:11:3
|
LL | #[empty_attr]
| ^^^^^^^^^^
|
= note: see issue #81119 <https://github.com/rust-lang/rust/issues/81119> for more information
= help: add `#![feature(macro_attributes_in_derive_output)]` to the crate attributes to enable

error[E0658]: macro attributes in `#[derive]` output are unstable
--> $DIR/attribute-after-derive-feature-gate.rs:18:3
|
LL | #[empty_attr]
| ^^^^^^^^^^
|
= note: see issue #81119 <https://github.com/rust-lang/rust/issues/81119> for more information
= help: add `#![feature(macro_attributes_in_derive_output)]` to the crate attributes to enable

error[E0658]: macro attributes in `#[derive]` output are unstable
--> $DIR/attribute-after-derive-feature-gate.rs:25:19
|
LL | field: [u8; #[identity_attr] 10],
| ^^^^^^^^^^^^^
|
= note: see issue #81119 <https://github.com/rust-lang/rust/issues/81119> for more information
= help: add `#![feature(macro_attributes_in_derive_output)]` to the crate attributes to enable

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0658`.
2 changes: 2 additions & 0 deletions src/test/ui/proc-macro/attribute-after-derive.rs
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Expand Up @@ -5,6 +5,8 @@
// compile-flags: -Z span-debug
// aux-build: test-macros.rs

#![feature(macro_attributes_in_derive_output)]

#![no_std] // Don't load unnecessary hygiene information from std
extern crate std;

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58 changes: 29 additions & 29 deletions src/test/ui/proc-macro/attribute-after-derive.stdout
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Original file line number Diff line number Diff line change
Expand Up @@ -3,146 +3,146 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:15:1: 15:2 (#0),
span: $DIR/attribute-after-derive.rs:17:1: 17:2 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "derive",
span: $DIR/attribute-after-derive.rs:15:3: 15:9 (#0),
span: $DIR/attribute-after-derive.rs:17:3: 17:9 (#0),
},
Group {
delimiter: Parenthesis,
stream: TokenStream [
Ident {
ident: "Print",
span: $DIR/attribute-after-derive.rs:15:10: 15:15 (#0),
span: $DIR/attribute-after-derive.rs:17:10: 17:15 (#0),
},
],
span: $DIR/attribute-after-derive.rs:15:9: 15:16 (#0),
span: $DIR/attribute-after-derive.rs:17:9: 17:16 (#0),
},
],
span: $DIR/attribute-after-derive.rs:15:2: 15:17 (#0),
span: $DIR/attribute-after-derive.rs:17:2: 17:17 (#0),
},
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
span: $DIR/attribute-after-derive.rs:18:1: 18:7 (#0),
},
Ident {
ident: "AttributeDerive",
span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
span: $DIR/attribute-after-derive.rs:18:8: 18:23 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:17:5: 17:6 (#0),
span: $DIR/attribute-after-derive.rs:19:5: 19:6 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "cfg",
span: $DIR/attribute-after-derive.rs:17:7: 17:10 (#0),
span: $DIR/attribute-after-derive.rs:19:7: 19:10 (#0),
},
Group {
delimiter: Parenthesis,
stream: TokenStream [
Ident {
ident: "FALSE",
span: $DIR/attribute-after-derive.rs:17:11: 17:16 (#0),
span: $DIR/attribute-after-derive.rs:19:11: 19:16 (#0),
},
],
span: $DIR/attribute-after-derive.rs:17:10: 17:17 (#0),
span: $DIR/attribute-after-derive.rs:19:10: 19:17 (#0),
},
],
span: $DIR/attribute-after-derive.rs:17:6: 17:18 (#0),
span: $DIR/attribute-after-derive.rs:19:6: 19:18 (#0),
},
Ident {
ident: "field",
span: $DIR/attribute-after-derive.rs:18:5: 18:10 (#0),
span: $DIR/attribute-after-derive.rs:20:5: 20:10 (#0),
},
Punct {
ch: ':',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:18:10: 18:11 (#0),
span: $DIR/attribute-after-derive.rs:20:10: 20:11 (#0),
},
Ident {
ident: "u8",
span: $DIR/attribute-after-derive.rs:18:12: 18:14 (#0),
span: $DIR/attribute-after-derive.rs:20:12: 20:14 (#0),
},
Punct {
ch: ',',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:18:14: 18:15 (#0),
span: $DIR/attribute-after-derive.rs:20:14: 20:15 (#0),
},
],
span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
span: $DIR/attribute-after-derive.rs:18:24: 21:2 (#0),
},
]
PRINT-DERIVE INPUT (DISPLAY): struct AttributeDerive { }
PRINT-DERIVE INPUT (DEBUG): TokenStream [
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
span: $DIR/attribute-after-derive.rs:18:1: 21:2 (#0),
},
Ident {
ident: "AttributeDerive",
span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
span: $DIR/attribute-after-derive.rs:18:1: 21:2 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [],
span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
span: $DIR/attribute-after-derive.rs:18:1: 21:2 (#0),
},
]
PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { }
PRINT-ATTR INPUT (DEBUG): TokenStream [
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Ident {
ident: "DeriveAttribute",
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [],
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
]
PRINT-DERIVE INPUT (DISPLAY): #[print_attr] struct DeriveAttribute { }
PRINT-DERIVE INPUT (DEBUG): TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "print_attr",
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
],
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Ident {
ident: "DeriveAttribute",
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [],
span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
span: $DIR/attribute-after-derive.rs:25:1: 28:2 (#0),
},
]

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