rustc_attr_parsing/attributes/
macro_attrs.rs

1use rustc_attr_ir::{CollapseMacroDebuginfo, MacroUseArgs, find_attr};
2use rustc_feature::AttributeStability;
3use rustc_session::lint::builtin::INVALID_MACRO_EXPORT_ARGUMENTS;
4
5use super::prelude::*;
6use crate::diagnostics::MacroOnlyAttribute;
7
8pub(crate) struct MacroEscapeParser;
9impl NoArgsAttributeParser for MacroEscapeParser {
10    const PATH: &[Symbol] = &[sym::macro_escape];
11    const ON_DUPLICATE: OnDuplicate = OnDuplicate::Warn;
12    const ALLOWED_TARGETS: AllowedTargets<'_> = MACRO_USE_ALLOWED_TARGETS;
13    const STABILITY: AttributeStability = AttributeStability::Stable;
14    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::MacroEscape;
15}
16
17/// `#[macro_use]` attributes can either:
18/// - Use all macros from a crate, if provided without arguments
19/// - Use specific macros from a crate, if provided with arguments `#[macro_use(macro1, macro2)]`
20/// A warning should be provided if an use all is combined with specific uses, or if multiple use-alls are used.
21#[derive(#[automatically_derived]
impl ::core::default::Default for MacroUseParser {
    #[inline]
    fn default() -> MacroUseParser {
        MacroUseParser {
            state: ::core::default::Default::default(),
            uses_attr_spans: ::core::default::Default::default(),
            first_span: ::core::default::Default::default(),
        }
    }
}Default)]
22pub(crate) struct MacroUseParser {
23    state: MacroUseArgs,
24
25    /// Spans of all `#[macro_use]` arguments with arguments, used for linting
26    uses_attr_spans: ThinVec<Span>,
27    /// If `state` is `UseSpecific`, stores the span of the first `#[macro_use]` argument, used as the span for this attribute
28    /// If `state` is `UseAll`, stores the span of the first `#[macro_use]` arguments without arguments
29    first_span: Option<Span>,
30}
31
32const MACRO_USE_TEMPLATE: AttributeTemplate = crate::AttributeTemplate {
    word: true,
    list: Some(&["name1, name2, ..."]),
    one_of: &[],
    name_value_str: None,
    docs: Some("https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute"),
}template!(
33    Word, List: &["name1, name2, ..."],
34    "https://doc.rust-lang.org/reference/macros-by-example.html#the-macro_use-attribute"
35);
36const MACRO_USE_ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowListWarnRest(&[
37    Allow(Target::Mod),
38    Allow(Target::ExternCrate),
39    Error(Target::WherePredicate),
40]);
41
42impl AttributeParser for MacroUseParser {
43    const ATTRIBUTES: AcceptMapping<Self> = &[(
44        &[sym::macro_use],
45        MACRO_USE_TEMPLATE,
46        AttributeStability::Stable,
47        |group: &mut Self, cx: &mut AcceptContext<'_, '_>, args| {
48            let span = cx.attr_span;
49            group.first_span.get_or_insert(span);
50            match args {
51                ArgParser::NoArgs => {
52                    match group.state {
53                        MacroUseArgs::UseAll => {
54                            let first_span = group.first_span.expect(
55                                "State is UseAll is some so this is not the first attribute",
56                            );
57                            // Since there is a `#[macro_use]` import already, give a warning
58                            cx.warn_unused_duplicate(first_span, span);
59                        }
60                        MacroUseArgs::UseSpecific(_) => {
61                            group.state = MacroUseArgs::UseAll;
62                            group.first_span = Some(span);
63                            // If there is a `#[macro_use]` attribute, warn on all `#[macro_use(...)]` attributes since everything is already imported
64                            for specific_use in group.uses_attr_spans.drain(..) {
65                                cx.warn_unused_duplicate(span, specific_use);
66                            }
67                        }
68                    }
69                }
70                ArgParser::List(list) => {
71                    if list.is_empty() {
72                        cx.adcx().warn_empty_attribute(list.span);
73                        return;
74                    }
75
76                    match &mut group.state {
77                        MacroUseArgs::UseAll => {
78                            let first_span = group.first_span.expect(
79                                "State is UseAll is some so this is not the first attribute",
80                            );
81                            cx.warn_unused_duplicate(first_span, span);
82                        }
83                        MacroUseArgs::UseSpecific(arguments) => {
84                            // Store here so if we encounter a `UseAll` later we can still lint this attribute
85                            group.uses_attr_spans.push(cx.attr_span);
86
87                            for item in list.mixed() {
88                                let Some(item) = item.meta_item() else {
89                                    cx.adcx().expected_identifier(item.span());
90                                    continue;
91                                };
92                                let Some(()) = cx.expect_no_args(item.args()) else {
93                                    continue;
94                                };
95                                let Some(item) = item.path().word() else {
96                                    cx.adcx().expected_identifier(item.span());
97                                    continue;
98                                };
99                                arguments.push(item);
100                            }
101                        }
102                    }
103                }
104                ArgParser::NameValue(nv) => {
105                    cx.adcx().expected_list_or_no_args(nv.args_span());
106                }
107            }
108        },
109    )];
110    const ALLOWED_TARGETS: AllowedTargets<'_> = MACRO_USE_ALLOWED_TARGETS;
111
112    fn finalize(self, _cx: &FinalizeContext<'_, '_>) -> Option<AttributeKind> {
113        Some(AttributeKind::MacroUse { span: self.first_span?, arguments: self.state })
114    }
115}
116
117/// `#[allow_internal_unsafe]` and `#[allow_internal_unstable]` may only be applied to macros.
118/// Applying them to a function is only allowed if that function is a procedural macro, i.e. it
119/// also carries `#[proc_macro]`, `#[proc_macro_attribute]`, or `#[proc_macro_derive]`.
120pub(crate) fn check_macro_only(cx: &FinalizeCheckContext<'_, '_>, attr_span: Span) {
121    if cx.target == Target::Fn
122        && !{
    {
            'done:
                {
                for i in cx.parsed_attrs {
                    #[allow(unused_imports)]
                    use ::rustc_attr_ir::AttributeKind::*;
                    let i: &::rustc_attr_ir::Attribute = i;
                    match i {
                        ::rustc_attr_ir::Attribute::Parsed(ProcMacro |
                            ProcMacroAttribute | ProcMacroDerive { .. }) => {
                            break 'done Some(());
                        }
                        ::rustc_attr_ir::Attribute::Unparsed(..) =>
                            {}
                            #[deny(unreachable_patterns)]
                            _ => {}
                    }
                }
                None
            }
        }.is_some()
}find_attr!(cx.parsed_attrs, ProcMacro | ProcMacroAttribute | ProcMacroDerive { .. })
123    {
124        cx.emit_err(MacroOnlyAttribute { attr_span, span: cx.target_span });
125    }
126}
127
128pub(crate) struct AllowInternalUnsafeParser;
129
130impl NoArgsAttributeParser for AllowInternalUnsafeParser {
131    const PATH: &[Symbol] = &[sym::allow_internal_unsafe];
132    const ON_DUPLICATE: OnDuplicate = OnDuplicate::Ignore;
133    const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowList(&[
134        Allow(Target::Fn),
135        Allow(Target::MacroDef),
136        Warn(Target::Field),
137        Warn(Target::Arm),
138    ]);
139    const STABILITY: AttributeStability = AttributeStability::Unstable {
    gate_name: rustc_span::sym::allow_internal_unsafe,
    gate_check: rustc_feature::Features::allow_internal_unsafe,
    notes: &[],
}unstable!(allow_internal_unsafe);
140    const CREATE: fn(Span) -> AttributeKind = |span| AttributeKind::AllowInternalUnsafe(span);
141
142    fn finalize_check(cx: &FinalizeCheckContext<'_, '_>, attr_span: Span) {
143        check_macro_only(cx, attr_span);
144    }
145}
146
147pub(crate) struct MacroExportParser;
148
149impl SingleAttributeParser for MacroExportParser {
150    const PATH: &[Symbol] = &[sym::macro_export];
151    const ON_DUPLICATE: OnDuplicate = OnDuplicate::Warn;
152    const TEMPLATE: AttributeTemplate = crate::AttributeTemplate {
    word: true,
    list: Some(&["local_inner_macros"]),
    one_of: &[],
    name_value_str: None,
    docs: None,
}template!(Word, List: &["local_inner_macros"]);
153    const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowListWarnRest(&[
154        Allow(Target::MacroDef),
155        Error(Target::WherePredicate),
156        Error(Target::Crate),
157    ]);
158    const STABILITY: AttributeStability = AttributeStability::Stable;
159
160    fn convert(cx: &mut AcceptContext<'_, '_>, args: &ArgParser) -> Option<AttributeKind> {
161        let local_inner_macros = match args {
162            ArgParser::NoArgs => false,
163            ArgParser::List(list) => {
164                let Some(l) = list.as_single() else {
165                    cx.adcx().warn_ill_formed_attribute_input(INVALID_MACRO_EXPORT_ARGUMENTS);
166                    return None;
167                };
168                if l.meta_item_no_args().is_some_and(|m| m.path().word_is(sym::local_inner_macros))
169                {
170                    true
171                } else {
172                    cx.adcx().warn_ill_formed_attribute_input(INVALID_MACRO_EXPORT_ARGUMENTS);
173                    return None;
174                }
175            }
176            ArgParser::NameValue(nv) => {
177                cx.adcx().expected_list_or_no_args(nv.args_span());
178                return None;
179            }
180        };
181        Some(AttributeKind::MacroExport { span: cx.attr_span, local_inner_macros })
182    }
183}
184
185pub(crate) struct CollapseDebugInfoParser;
186
187impl SingleAttributeParser for CollapseDebugInfoParser {
188    const PATH: &[Symbol] = &[sym::collapse_debuginfo];
189    const TEMPLATE: AttributeTemplate = crate::AttributeTemplate {
    word: false,
    list: Some(&["no", "external", "yes"]),
    one_of: &[],
    name_value_str: None,
    docs: Some("https://doc.rust-lang.org/reference/attributes/debugger.html#the-collapse_debuginfo-attribute"),
}template!(
190        List: &["no", "external", "yes"],
191        "https://doc.rust-lang.org/reference/attributes/debugger.html#the-collapse_debuginfo-attribute"
192    );
193    const ALLOWED_TARGETS: AllowedTargets<'_> =
194        AllowedTargets::AllowList(&[Allow(Target::MacroDef)]);
195    const STABILITY: AttributeStability = AttributeStability::Stable;
196
197    fn convert(cx: &mut AcceptContext<'_, '_>, args: &ArgParser) -> Option<AttributeKind> {
198        let single = cx.expect_single_element_list(args, cx.attr_span)?;
199        let Some(mi) = single.meta_item() else {
200            cx.adcx().expected_not_literal(single.span());
201            return None;
202        };
203        let _ = cx.expect_no_args(mi.args());
204        let path = mi.path().word_sym();
205        let info = match path {
206            Some(sym::yes) => CollapseMacroDebuginfo::Yes,
207            Some(sym::no) => CollapseMacroDebuginfo::No,
208            Some(sym::external) => CollapseMacroDebuginfo::External,
209            _ => {
210                cx.adcx()
211                    .expected_specific_argument(mi.span(), &[sym::yes, sym::no, sym::external]);
212                return None;
213            }
214        };
215
216        Some(AttributeKind::CollapseDebugInfo(info))
217    }
218}
219
220pub(crate) struct RustcProcMacroDeclsParser;
221
222impl NoArgsAttributeParser for RustcProcMacroDeclsParser {
223    const PATH: &[Symbol] = &[sym::rustc_proc_macro_decls];
224    const ALLOWED_TARGETS: AllowedTargets<'_> = AllowedTargets::AllowList(&[Allow(Target::Static)]);
225    const STABILITY: AttributeStability = AttributeStability::Unstable {
    gate_name: rustc_span::sym::rustc_attrs,
    gate_check: rustc_feature::Features::rustc_attrs,
    notes: &[],
}unstable!(rustc_attrs);
226    const CREATE: fn(Span) -> AttributeKind = |_| AttributeKind::RustcProcMacroDecls;
227}
rustc_attr_parsing/attributes/macro_attrs.rs

rustc_attr_parsing/attributes/
macro_attrs.rs
