Auto merge of #143843 - JonathanBrouwer:macro-use-parser, r=oli-obk

Ports `#[macro_use]` and `#[macro_escape]` to the new attribute parsing infrastructure

Ports `#[macro_use]` and `#[macro_escape]` to the new attribute parsing infrastructure for #131229 (comment)

r? `@jdonszelmann` `@oli-obk`

Author: bors

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -157,6 +157,19 @@ pub enum UsedBy {
     Linker,
 }
 
+#[derive(Encodable, Decodable, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic, PrintAttribute)]
+pub enum MacroUseArgs {
+    UseAll,
+    UseSpecific(ThinVec<Ident>),
+}
+
+impl Default for MacroUseArgs {
+    fn default() -> Self {
+        Self::UseSpecific(ThinVec::new())
+    }
+}
+
 #[derive(Debug, Clone, Encodable, Decodable, HashStable_Generic)]
 pub struct StrippedCfgItem<ModId = DefId> {
     pub parent_module: ModId,
@@ -351,9 +364,15 @@ pub enum AttributeKind {
     /// Represents `#[loop_match]`.
     LoopMatch(Span),
 
+    /// Represents `#[macro_escape]`.
+    MacroEscape(Span),
+
     /// Represents `#[rustc_macro_transparency]`.
     MacroTransparency(Transparency),
 
+    /// Represents `#[macro_use]`.
+    MacroUse { span: Span, arguments: MacroUseArgs },
+
     /// Represents `#[marker]`.
     Marker(Span),
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -45,7 +45,9 @@ impl AttributeKind {
             LinkOrdinal { .. } => No,
             LinkSection { .. } => Yes, // Needed for rustdoc
             LoopMatch(..) => No,
+            MacroEscape(..) => No,
             MacroTransparency(..) => Yes,
+            MacroUse { .. } => No,
             Marker(..) => No,
             MayDangle(..) => No,
             MustUse { .. } => Yes,

compiler/rustc_attr_data_structures/src/lib.rs

@@ -24,7 +24,7 @@ use rustc_ast::token::CommentKind;
 use rustc_ast::{AttrStyle, IntTy, UintTy};
 use rustc_ast_pretty::pp::Printer;
 use rustc_span::hygiene::Transparency;
-use rustc_span::{ErrorGuaranteed, Span, Symbol};
+use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol};
 pub use stability::*;
 use thin_vec::ThinVec;
 pub use version::*;
@@ -172,7 +172,7 @@ macro_rules! print_tup {
 print_tup!(A B C D E F G H);
 print_skip!(Span, (), ErrorGuaranteed);
 print_disp!(u16, bool, NonZero<u32>);
-print_debug!(Symbol, UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
+print_debug!(Symbol, Ident, UintTy, IntTy, Align, AttrStyle, CommentKind, Transparency);
 
 /// Finds attributes in sequences of attributes by pattern matching.
 ///

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -0,0 +1,115 @@
+use rustc_attr_data_structures::{AttributeKind, MacroUseArgs};
+use rustc_errors::DiagArgValue;
+use rustc_feature::{AttributeTemplate, template};
+use rustc_span::{Span, Symbol, sym};
+use thin_vec::ThinVec;
+
+use crate::attributes::{AcceptMapping, AttributeParser, NoArgsAttributeParser, OnDuplicate};
+use crate::context::{AcceptContext, FinalizeContext, Stage};
+use crate::parser::ArgParser;
+use crate::session_diagnostics;
+
+pub(crate) struct MacroEscapeParser;
+impl<S: Stage> NoArgsAttributeParser<S> for MacroEscapeParser {
+    const PATH: &[Symbol] = &[sym::macro_escape];
+    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::Warn;
+    const CREATE: fn(Span) -> AttributeKind = AttributeKind::MacroEscape;
+}
+
+/// `#[macro_use]` attributes can either:
+/// - Use all macros from a crate, if provided without arguments
+/// - Use specific macros from a crate, if provided with arguments `#[macro_use(macro1, macro2)]`
+/// A warning should be provided if an use all is combined with specific uses, or if multiple use-alls are used.
+#[derive(Default)]
+pub(crate) struct MacroUseParser {
+    state: MacroUseArgs,
+
+    /// Spans of all `#[macro_use]` arguments with arguments, used for linting
+    uses_attr_spans: ThinVec<Span>,
+    /// If `state` is `UseSpecific`, stores the span of the first `#[macro_use]` argument, used as the span for this attribute
+    /// If `state` is `UseAll`, stores the span of the first `#[macro_use]` arguments without arguments
+    first_span: Option<Span>,
+}
+
+const MACRO_USE_TEMPLATE: AttributeTemplate = template!(Word, List: "name1, name2, ...");
+
+impl<S: Stage> AttributeParser<S> for MacroUseParser {
+    const ATTRIBUTES: AcceptMapping<Self, S> = &[(
+        &[sym::macro_use],
+        MACRO_USE_TEMPLATE,
+        |group: &mut Self, cx: &mut AcceptContext<'_, '_, S>, args| {
+            let span = cx.attr_span;
+            group.first_span.get_or_insert(span);
+            match args {
+                ArgParser::NoArgs => {
+                    match group.state {
+                        MacroUseArgs::UseAll => {
+                            let first_span = group.first_span.expect(
+                                "State is UseAll is some so this is not the first attribute",
+                            );
+                            // Since there is a `#[macro_use]` import already, give a warning
+                            cx.warn_unused_duplicate(first_span, span);
+                        }
+                        MacroUseArgs::UseSpecific(_) => {
+                            group.state = MacroUseArgs::UseAll;
+                            group.first_span = Some(span);
+                            // If there is a `#[macro_use]` attribute, warn on all `#[macro_use(...)]` attributes since everything is already imported
+                            for specific_use in group.uses_attr_spans.drain(..) {
+                                cx.warn_unused_duplicate(span, specific_use);
+                            }
+                        }
+                    }
+                }
+                ArgParser::List(list) => {
+                    if list.is_empty() {
+                        cx.warn_empty_attribute(list.span);
+                        return;
+                    }
+
+                    match &mut group.state {
+                        MacroUseArgs::UseAll => {
+                            let first_span = group.first_span.expect(
+                                "State is UseAll is some so this is not the first attribute",
+                            );
+                            cx.warn_unused_duplicate(first_span, span);
+                        }
+                        MacroUseArgs::UseSpecific(arguments) => {
+                            // Store here so if we encounter a `UseAll` later we can still lint this attribute
+                            group.uses_attr_spans.push(cx.attr_span);
+
+                            for item in list.mixed() {
+                                let Some(item) = item.meta_item() else {
+                                    cx.expected_identifier(item.span());
+                                    continue;
+                                };
+                                if let Err(err_span) = item.args().no_args() {
+                                    cx.expected_no_args(err_span);
+                                    continue;
+                                }
+                                let Some(item) = item.path().word() else {
+                                    cx.expected_identifier(item.span());
+                                    continue;
+                                };
+                                arguments.push(item);
+                            }
+                        }
+                    }
+                }
+                ArgParser::NameValue(_) => {
+                    let suggestions = MACRO_USE_TEMPLATE.suggestions(false, sym::macro_use);
+                    cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
+                        num_suggestions: suggestions.len(),
+                        suggestions: DiagArgValue::StrListSepByAnd(
+                            suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
+                        ),
+                        span,
+                    });
+                }
+            }
+        },
+    )];
+
+    fn finalize(self, _cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
+        Some(AttributeKind::MacroUse { span: self.first_span?, arguments: self.state })
+    }
+}

compiler/rustc_attr_parsing/src/attributes/mod.rs

@@ -36,6 +36,7 @@ pub(crate) mod inline;
 pub(crate) mod link_attrs;
 pub(crate) mod lint_helpers;
 pub(crate) mod loop_match;
+pub(crate) mod macro_attrs;
 pub(crate) mod must_use;
 pub(crate) mod no_implicit_prelude;
 pub(crate) mod non_exhaustive;

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -34,7 +34,7 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
                 ArgParser::List(_) => {
                     let suggestions =
                         <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "must_use");
-                    cx.emit_err(session_diagnostics::MustUseIllFormedAttributeInput {
+                    cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
                         num_suggestions: suggestions.len(),
                         suggestions: DiagArgValue::StrListSepByAnd(
                             suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),

compiler/rustc_attr_parsing/src/context.rs

@@ -33,6 +33,7 @@ use crate::attributes::lint_helpers::{
     AsPtrParser, AutomaticallyDerivedParser, PassByValueParser, PubTransparentParser,
 };
 use crate::attributes::loop_match::{ConstContinueParser, LoopMatchParser};
+use crate::attributes::macro_attrs::{MacroEscapeParser, MacroUseParser};
 use crate::attributes::must_use::MustUseParser;
 use crate::attributes::no_implicit_prelude::NoImplicitPreludeParser;
 use crate::attributes::non_exhaustive::NonExhaustiveParser;
@@ -126,6 +127,7 @@ attribute_parsers!(
         BodyStabilityParser,
         ConfusablesParser,
         ConstStabilityParser,
+        MacroUseParser,
         NakedParser,
         StabilityParser,
         UsedParser,
@@ -174,6 +176,7 @@ attribute_parsers!(
         Single<WithoutArgs<FfiPureParser>>,
         Single<WithoutArgs<FundamentalParser>>,
         Single<WithoutArgs<LoopMatchParser>>,
+        Single<WithoutArgs<MacroEscapeParser>>,
         Single<WithoutArgs<MarkerParser>>,
         Single<WithoutArgs<MayDangleParser>>,
         Single<WithoutArgs<NoImplicitPreludeParser>>,
@@ -386,6 +389,17 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
         })
     }
 
+    /// emit an error that a `name` was expected here
+    pub(crate) fn expected_identifier(&self, span: Span) -> ErrorGuaranteed {
+        self.emit_err(AttributeParseError {
+            span,
+            attr_span: self.attr_span,
+            template: self.template.clone(),
+            attribute: self.attr_path.clone(),
+            reason: AttributeParseErrorReason::ExpectedIdentifier,
+        })
+    }
+
     /// emit an error that a `name = value` pair was expected at this span. The symbol can be given for
     /// a nicer error message talking about the specific name that was found lacking a value.
     pub(crate) fn expected_name_value(&self, span: Span, name: Option<Symbol>) -> ErrorGuaranteed {

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -438,7 +438,7 @@ pub(crate) struct IllFormedAttributeInput {
 
 #[derive(Diagnostic)]
 #[diag(attr_parsing_ill_formed_attribute_input)]
-pub(crate) struct MustUseIllFormedAttributeInput {
+pub(crate) struct IllFormedAttributeInputLint {
     #[primary_span]
     pub span: Span,
     pub num_suggestions: usize,
@@ -549,6 +549,7 @@ pub(crate) enum AttributeParseErrorReason {
         /// Should we tell the user to write a list when they didn't?
         list: bool,
     },
+    ExpectedIdentifier,
 }
 
 pub(crate) struct AttributeParseError {
@@ -600,11 +601,11 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                 diag.code(E0538);
             }
             AttributeParseErrorReason::UnexpectedLiteral => {
-                diag.span_label(self.span, format!("didn't expect a literal here"));
+                diag.span_label(self.span, "didn't expect a literal here");
                 diag.code(E0565);
             }
             AttributeParseErrorReason::ExpectedNoArgs => {
-                diag.span_label(self.span, format!("didn't expect any arguments here"));
+                diag.span_label(self.span, "didn't expect any arguments here");
                 diag.code(E0565);
             }
             AttributeParseErrorReason::ExpectedNameValue(None) => {
@@ -684,6 +685,9 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
                     }
                 }
             }
+            AttributeParseErrorReason::ExpectedIdentifier => {
+                diag.span_label(self.span, "expected a valid identifier here");
+            }
         }
 
         let suggestions = self.template.suggestions(false, &name);

compiler/rustc_error_codes/src/error_codes/E0466.md

@@ -1,8 +1,10 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 Macro import declaration was malformed.
 
 Erroneous code examples:
 
-```compile_fail,E0466
+```compile_fail
 #[macro_use(a_macro(another_macro))] // error: invalid import declaration
 extern crate core as some_crate;
 

compiler/rustc_hir/src/hir.rs

@@ -1302,6 +1302,7 @@ impl AttributeExt for Attribute {
             // FIXME: should not be needed anymore when all attrs are parsed
             Attribute::Parsed(AttributeKind::Deprecation { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::DocComment { span, .. }) => *span,
+            Attribute::Parsed(AttributeKind::MacroUse { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::MayDangle(span)) => *span,
             Attribute::Parsed(AttributeKind::Ignore { span, .. }) => *span,
             Attribute::Parsed(AttributeKind::AutomaticallyDerived(span)) => *span,