1 use crate::expand::{self, AstFragment, Invocation};
2 use crate::module::DirOwnership;
4 use rustc_ast::attr::MarkedAttrs;
6 use rustc_ast::token::{self, Nonterminal};
7 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream};
8 use rustc_ast::visit::{AssocCtxt, Visitor};
9 use rustc_ast::{self as ast, AstLike, Attribute, Item, NodeId, PatKind};
10 use rustc_attr::{self as attr, Deprecation, Stability};
11 use rustc_data_structures::fx::FxHashMap;
12 use rustc_data_structures::sync::{self, Lrc};
13 use rustc_errors::{DiagnosticBuilder, ErrorReported};
14 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
15 use rustc_lint_defs::BuiltinLintDiagnostics;
16 use rustc_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS};
17 use rustc_session::{parse::ParseSess, Limit, Session};
18 use rustc_span::def_id::{CrateNum, DefId};
19 use rustc_span::edition::Edition;
20 use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
21 use rustc_span::source_map::SourceMap;
22 use rustc_span::symbol::{kw, sym, Ident, Symbol};
23 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
24 use smallvec::{smallvec, SmallVec};
26 use std::default::Default;
28 use std::path::PathBuf;
31 crate use rustc_span::hygiene::MacroKind;
33 // When adding new variants, make sure to
34 // adjust the `visit_*` / `flat_map_*` calls in `InvocationCollector`
35 // to use `assign_id!`
36 #[derive(Debug, Clone)]
37 pub enum Annotatable {
39 TraitItem(P<ast::AssocItem>),
40 ImplItem(P<ast::AssocItem>),
41 ForeignItem(P<ast::ForeignItem>),
45 ExprField(ast::ExprField),
46 PatField(ast::PatField),
47 GenericParam(ast::GenericParam),
49 FieldDef(ast::FieldDef),
50 Variant(ast::Variant),
54 pub fn span(&self) -> Span {
56 Annotatable::Item(ref item) => item.span,
57 Annotatable::TraitItem(ref trait_item) => trait_item.span,
58 Annotatable::ImplItem(ref impl_item) => impl_item.span,
59 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
60 Annotatable::Stmt(ref stmt) => stmt.span,
61 Annotatable::Expr(ref expr) => expr.span,
62 Annotatable::Arm(ref arm) => arm.span,
63 Annotatable::ExprField(ref field) => field.span,
64 Annotatable::PatField(ref fp) => fp.pat.span,
65 Annotatable::GenericParam(ref gp) => gp.ident.span,
66 Annotatable::Param(ref p) => p.span,
67 Annotatable::FieldDef(ref sf) => sf.span,
68 Annotatable::Variant(ref v) => v.span,
72 pub fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
74 Annotatable::Item(item) => item.visit_attrs(f),
75 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
76 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
77 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
78 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
79 Annotatable::Expr(expr) => expr.visit_attrs(f),
80 Annotatable::Arm(arm) => arm.visit_attrs(f),
81 Annotatable::ExprField(field) => field.visit_attrs(f),
82 Annotatable::PatField(fp) => fp.visit_attrs(f),
83 Annotatable::GenericParam(gp) => gp.visit_attrs(f),
84 Annotatable::Param(p) => p.visit_attrs(f),
85 Annotatable::FieldDef(sf) => sf.visit_attrs(f),
86 Annotatable::Variant(v) => v.visit_attrs(f),
90 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
92 Annotatable::Item(item) => visitor.visit_item(item),
93 Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait),
94 Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl),
95 Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
96 Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
97 Annotatable::Expr(expr) => visitor.visit_expr(expr),
98 Annotatable::Arm(arm) => visitor.visit_arm(arm),
99 Annotatable::ExprField(field) => visitor.visit_expr_field(field),
100 Annotatable::PatField(fp) => visitor.visit_pat_field(fp),
101 Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
102 Annotatable::Param(p) => visitor.visit_param(p),
103 Annotatable::FieldDef(sf) => visitor.visit_field_def(sf),
104 Annotatable::Variant(v) => visitor.visit_variant(v),
108 pub fn into_nonterminal(self) -> Nonterminal {
110 Annotatable::Item(item) => token::NtItem(item),
111 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
112 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
114 Annotatable::ForeignItem(item) => {
115 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
117 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
118 Annotatable::Expr(expr) => token::NtExpr(expr),
120 | Annotatable::ExprField(..)
121 | Annotatable::PatField(..)
122 | Annotatable::GenericParam(..)
123 | Annotatable::Param(..)
124 | Annotatable::FieldDef(..)
125 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
129 crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
130 nt_to_tokenstream(&self.into_nonterminal(), sess, CanSynthesizeMissingTokens::No)
133 pub fn expect_item(self) -> P<ast::Item> {
135 Annotatable::Item(i) => i,
136 _ => panic!("expected Item"),
140 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
142 Annotatable::TraitItem(i) => i,
143 _ => panic!("expected Item"),
147 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
149 Annotatable::ImplItem(i) => i,
150 _ => panic!("expected Item"),
154 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
156 Annotatable::ForeignItem(i) => i,
157 _ => panic!("expected foreign item"),
161 pub fn expect_stmt(self) -> ast::Stmt {
163 Annotatable::Stmt(stmt) => stmt.into_inner(),
164 _ => panic!("expected statement"),
168 pub fn expect_expr(self) -> P<ast::Expr> {
170 Annotatable::Expr(expr) => expr,
171 _ => panic!("expected expression"),
175 pub fn expect_arm(self) -> ast::Arm {
177 Annotatable::Arm(arm) => arm,
178 _ => panic!("expected match arm"),
182 pub fn expect_expr_field(self) -> ast::ExprField {
184 Annotatable::ExprField(field) => field,
185 _ => panic!("expected field"),
189 pub fn expect_pat_field(self) -> ast::PatField {
191 Annotatable::PatField(fp) => fp,
192 _ => panic!("expected field pattern"),
196 pub fn expect_generic_param(self) -> ast::GenericParam {
198 Annotatable::GenericParam(gp) => gp,
199 _ => panic!("expected generic parameter"),
203 pub fn expect_param(self) -> ast::Param {
205 Annotatable::Param(param) => param,
206 _ => panic!("expected parameter"),
210 pub fn expect_field_def(self) -> ast::FieldDef {
212 Annotatable::FieldDef(sf) => sf,
213 _ => panic!("expected struct field"),
217 pub fn expect_variant(self) -> ast::Variant {
219 Annotatable::Variant(v) => v,
220 _ => panic!("expected variant"),
225 /// Result of an expansion that may need to be retried.
226 /// Consider using this for non-`MultiItemModifier` expanders as well.
227 pub enum ExpandResult<T, U> {
228 /// Expansion produced a result (possibly dummy).
230 /// Expansion could not produce a result and needs to be retried.
234 // `meta_item` is the attribute, and `item` is the item being modified.
235 pub trait MultiItemModifier {
238 ecx: &mut ExtCtxt<'_>,
240 meta_item: &ast::MetaItem,
242 ) -> ExpandResult<Vec<Annotatable>, Annotatable>;
245 impl<F> MultiItemModifier for F
247 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
251 ecx: &mut ExtCtxt<'_>,
253 meta_item: &ast::MetaItem,
255 ) -> ExpandResult<Vec<Annotatable>, Annotatable> {
256 ExpandResult::Ready(self(ecx, span, meta_item, item))
260 pub trait ProcMacro {
263 ecx: &'cx mut ExtCtxt<'_>,
266 ) -> Result<TokenStream, ErrorReported>;
269 impl<F> ProcMacro for F
271 F: Fn(TokenStream) -> TokenStream,
275 _ecx: &'cx mut ExtCtxt<'_>,
278 ) -> Result<TokenStream, ErrorReported> {
279 // FIXME setup implicit context in TLS before calling self.
284 pub trait AttrProcMacro {
287 ecx: &'cx mut ExtCtxt<'_>,
289 annotation: TokenStream,
290 annotated: TokenStream,
291 ) -> Result<TokenStream, ErrorReported>;
294 impl<F> AttrProcMacro for F
296 F: Fn(TokenStream, TokenStream) -> TokenStream,
300 _ecx: &'cx mut ExtCtxt<'_>,
302 annotation: TokenStream,
303 annotated: TokenStream,
304 ) -> Result<TokenStream, ErrorReported> {
305 // FIXME setup implicit context in TLS before calling self.
306 Ok(self(annotation, annotated))
310 /// Represents a thing that maps token trees to Macro Results
311 pub trait TTMacroExpander {
314 ecx: &'cx mut ExtCtxt<'_>,
317 ) -> Box<dyn MacResult + 'cx>;
320 pub type MacroExpanderFn =
321 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
323 impl<F> TTMacroExpander for F
325 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
329 ecx: &'cx mut ExtCtxt<'_>,
332 ) -> Box<dyn MacResult + 'cx> {
333 self(ecx, span, input)
337 // Use a macro because forwarding to a simple function has type system issues
338 macro_rules! make_stmts_default {
340 $me.make_expr().map(|e| {
341 smallvec![ast::Stmt {
342 id: ast::DUMMY_NODE_ID,
344 kind: ast::StmtKind::Expr(e),
350 /// The result of a macro expansion. The return values of the various
351 /// methods are spliced into the AST at the callsite of the macro.
352 pub trait MacResult {
353 /// Creates an expression.
354 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
357 /// Creates zero or more items.
358 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
362 /// Creates zero or more impl items.
363 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
367 /// Creates zero or more trait items.
368 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
372 /// Creates zero or more items in an `extern {}` block
373 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
377 /// Creates a pattern.
378 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
382 /// Creates zero or more statements.
384 /// By default this attempts to create an expression statement,
385 /// returning None if that fails.
386 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
387 make_stmts_default!(self)
390 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
394 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
398 fn make_expr_fields(self: Box<Self>) -> Option<SmallVec<[ast::ExprField; 1]>> {
402 fn make_pat_fields(self: Box<Self>) -> Option<SmallVec<[ast::PatField; 1]>> {
406 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
410 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
414 fn make_field_defs(self: Box<Self>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
418 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
423 macro_rules! make_MacEager {
424 ( $( $fld:ident: $t:ty, )* ) => {
425 /// `MacResult` implementation for the common case where you've already
426 /// built each form of AST that you might return.
428 pub struct MacEager {
430 pub $fld: Option<$t>,
436 pub fn $fld(v: $t) -> Box<dyn MacResult> {
450 items: SmallVec<[P<ast::Item>; 1]>,
451 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
452 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
453 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
454 stmts: SmallVec<[ast::Stmt; 1]>,
458 impl MacResult for MacEager {
459 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
463 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
467 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
471 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
475 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
479 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
480 match self.stmts.as_ref().map_or(0, |s| s.len()) {
481 0 => make_stmts_default!(self),
486 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
487 if let Some(p) = self.pat {
490 if let Some(e) = self.expr {
491 if let ast::ExprKind::Lit(_) = e.kind {
492 return Some(P(ast::Pat {
493 id: ast::DUMMY_NODE_ID,
495 kind: PatKind::Lit(e),
503 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
508 /// Fill-in macro expansion result, to allow compilation to continue
509 /// after hitting errors.
510 #[derive(Copy, Clone)]
511 pub struct DummyResult {
517 /// Creates a default MacResult that can be anything.
519 /// Use this as a return value after hitting any errors and
520 /// calling `span_err`.
521 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
522 Box::new(DummyResult { is_error: true, span })
525 /// Same as `any`, but must be a valid fragment, not error.
526 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
527 Box::new(DummyResult { is_error: false, span })
530 /// A plain dummy expression.
531 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
533 id: ast::DUMMY_NODE_ID,
534 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
536 attrs: ast::AttrVec::new(),
541 /// A plain dummy pattern.
542 pub fn raw_pat(sp: Span) -> ast::Pat {
543 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp, tokens: None }
546 /// A plain dummy type.
547 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
549 id: ast::DUMMY_NODE_ID,
550 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
557 impl MacResult for DummyResult {
558 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
559 Some(DummyResult::raw_expr(self.span, self.is_error))
562 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
563 Some(P(DummyResult::raw_pat(self.span)))
566 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
567 Some(SmallVec::new())
570 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
571 Some(SmallVec::new())
574 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
575 Some(SmallVec::new())
578 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
579 Some(SmallVec::new())
582 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
583 Some(smallvec![ast::Stmt {
584 id: ast::DUMMY_NODE_ID,
585 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
590 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
591 Some(DummyResult::raw_ty(self.span, self.is_error))
594 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
595 Some(SmallVec::new())
598 fn make_expr_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::ExprField; 1]>> {
599 Some(SmallVec::new())
602 fn make_pat_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::PatField; 1]>> {
603 Some(SmallVec::new())
606 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
607 Some(SmallVec::new())
610 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
611 Some(SmallVec::new())
614 fn make_field_defs(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
615 Some(SmallVec::new())
618 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
619 Some(SmallVec::new())
623 /// A syntax extension kind.
624 pub enum SyntaxExtensionKind {
625 /// A token-based function-like macro.
627 /// An expander with signature TokenStream -> TokenStream.
628 Box<dyn ProcMacro + sync::Sync + sync::Send>,
631 /// An AST-based function-like macro.
633 /// An expander with signature TokenStream -> AST.
634 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
637 /// A token-based attribute macro.
639 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
640 /// The first TokenSteam is the attribute itself, the second is the annotated item.
641 /// The produced TokenSteam replaces the input TokenSteam.
642 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
645 /// An AST-based attribute macro.
647 /// An expander with signature (AST, AST) -> AST.
648 /// The first AST fragment is the attribute itself, the second is the annotated item.
649 /// The produced AST fragment replaces the input AST fragment.
650 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
653 /// A trivial attribute "macro" that does nothing,
654 /// only keeps the attribute and marks it as inert,
655 /// thus making it ineligible for further expansion.
657 /// Suppresses the `unused_attributes` lint for this attribute.
661 /// A token-based derive macro.
663 /// An expander with signature TokenStream -> TokenStream (not yet).
664 /// The produced TokenSteam is appended to the input TokenSteam.
665 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
668 /// An AST-based derive macro.
670 /// An expander with signature AST -> AST.
671 /// The produced AST fragment is appended to the input AST fragment.
672 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
676 /// A struct representing a macro definition in "lowered" form ready for expansion.
677 pub struct SyntaxExtension {
678 /// A syntax extension kind.
679 pub kind: SyntaxExtensionKind,
680 /// Span of the macro definition.
682 /// List of unstable features that are treated as stable inside this macro.
683 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
684 /// Suppresses the `unsafe_code` lint for code produced by this macro.
685 pub allow_internal_unsafe: bool,
686 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
687 pub local_inner_macros: bool,
688 /// The macro's stability info.
689 pub stability: Option<Stability>,
690 /// The macro's deprecation info.
691 pub deprecation: Option<Deprecation>,
692 /// Names of helper attributes registered by this macro.
693 pub helper_attrs: Vec<Symbol>,
694 /// Edition of the crate in which this macro is defined.
695 pub edition: Edition,
696 /// Built-in macros have a couple of special properties like availability
697 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
698 pub builtin_name: Option<Symbol>,
701 impl SyntaxExtension {
702 /// Returns which kind of macro calls this syntax extension.
703 pub fn macro_kind(&self) -> MacroKind {
705 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
706 SyntaxExtensionKind::Attr(..)
707 | SyntaxExtensionKind::LegacyAttr(..)
708 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
709 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
715 /// Constructs a syntax extension with default properties.
716 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
719 allow_internal_unstable: None,
720 allow_internal_unsafe: false,
721 local_inner_macros: false,
724 helper_attrs: Vec::new(),
731 /// Constructs a syntax extension with the given properties
732 /// and other properties converted from attributes.
735 kind: SyntaxExtensionKind,
737 helper_attrs: Vec<Symbol>,
740 attrs: &[ast::Attribute],
741 ) -> SyntaxExtension {
742 let allow_internal_unstable =
743 attr::allow_internal_unstable(sess, &attrs).collect::<Vec<Symbol>>();
745 let mut local_inner_macros = false;
746 if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) {
747 if let Some(l) = macro_export.meta_item_list() {
748 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
752 let (builtin_name, helper_attrs) = sess
753 .find_by_name(attrs, sym::rustc_builtin_macro)
755 // Override `helper_attrs` passed above if it's a built-in macro,
756 // marking `proc_macro_derive` macros as built-in is not a realistic use case.
757 parse_macro_name_and_helper_attrs(sess.diagnostic(), attr, "built-in").map_or_else(
758 || (Some(name), Vec::new()),
759 |(name, helper_attrs)| (Some(name), helper_attrs),
762 .unwrap_or_else(|| (None, helper_attrs));
763 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
764 if let Some((_, sp)) = const_stability {
767 .struct_span_err(sp, "macros cannot have const stability attributes")
768 .span_label(sp, "invalid const stability attribute")
770 sess.source_map().guess_head_span(span),
771 "const stability attribute affects this macro",
779 allow_internal_unstable: (!allow_internal_unstable.is_empty())
780 .then(|| allow_internal_unstable.into()),
781 allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
783 stability: stability.map(|(s, _)| s),
784 deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
791 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
793 _: &'cx mut ExtCtxt<'_>,
796 ) -> Box<dyn MacResult + 'cx> {
797 DummyResult::any(span)
799 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
802 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
808 ) -> Vec<Annotatable> {
811 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
814 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
815 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
823 macro_def_id: Option<DefId>,
824 parent_module: Option<DefId>,
827 ExpnKind::Macro(self.macro_kind(), descr),
831 self.allow_internal_unstable.clone(),
832 self.allow_internal_unsafe,
833 self.local_inner_macros,
841 /// Error type that denotes indeterminacy.
842 pub struct Indeterminate;
844 pub type DeriveResolutions = Vec<(ast::Path, Annotatable, Option<Lrc<SyntaxExtension>>)>;
846 pub trait ResolverExpand {
847 fn next_node_id(&mut self) -> NodeId;
849 fn resolve_dollar_crates(&mut self);
850 fn visit_ast_fragment_with_placeholders(
852 expn_id: LocalExpnId,
853 fragment: &AstFragment,
855 fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind);
857 fn expansion_for_ast_pass(
862 parent_module_id: Option<NodeId>,
865 fn resolve_imports(&mut self);
867 fn resolve_macro_invocation(
870 eager_expansion_root: LocalExpnId,
872 ) -> Result<Lrc<SyntaxExtension>, Indeterminate>;
874 fn check_unused_macros(&mut self);
876 // Resolver interfaces for specific built-in macros.
877 /// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
878 fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool;
879 /// Resolve paths inside the `#[derive(...)]` attribute with the given `ExpnId`.
882 expn_id: LocalExpnId,
884 derive_paths: &dyn Fn() -> DeriveResolutions,
885 ) -> Result<(), Indeterminate>;
886 /// Take resolutions for paths inside the `#[derive(...)]` attribute with the given `ExpnId`
887 /// back from resolver.
888 fn take_derive_resolutions(&mut self, expn_id: LocalExpnId) -> Option<DeriveResolutions>;
889 /// Path resolution logic for `#[cfg_accessible(path)]`.
892 expn_id: LocalExpnId,
894 ) -> Result<bool, Indeterminate>;
896 /// Decodes the proc-macro quoted span in the specified crate, with the specified id.
897 /// No caching is performed.
898 fn get_proc_macro_quoted_span(&self, krate: CrateNum, id: usize) -> Span;
901 #[derive(Clone, Default)]
902 pub struct ModuleData {
903 /// Path to the module starting from the crate name, like `my_crate::foo::bar`.
904 pub mod_path: Vec<Ident>,
905 /// Stack of paths to files loaded by out-of-line module items,
906 /// used to detect and report recursive module inclusions.
907 pub file_path_stack: Vec<PathBuf>,
908 /// Directory to search child module files in,
909 /// often (but not necessarily) the parent of the top file path on the `file_path_stack`.
910 pub dir_path: PathBuf,
914 pub fn with_dir_path(&self, dir_path: PathBuf) -> ModuleData {
916 mod_path: self.mod_path.clone(),
917 file_path_stack: self.file_path_stack.clone(),
924 pub struct ExpansionData {
927 pub module: Rc<ModuleData>,
928 pub dir_ownership: DirOwnership,
929 pub prior_type_ascription: Option<(Span, bool)>,
930 /// Some parent node that is close to this macro call
931 pub lint_node_id: NodeId,
932 pub is_trailing_mac: bool,
935 type OnExternModLoaded<'a> =
936 Option<&'a dyn Fn(Ident, Vec<Attribute>, Vec<P<Item>>, Span) -> (Vec<Attribute>, Vec<P<Item>>)>;
938 /// One of these is made during expansion and incrementally updated as we go;
939 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
940 /// -> expn_data` of their expansion context stored into their span.
941 pub struct ExtCtxt<'a> {
942 pub sess: &'a Session,
943 pub ecfg: expand::ExpansionConfig<'a>,
944 pub reduced_recursion_limit: Option<Limit>,
945 pub root_path: PathBuf,
946 pub resolver: &'a mut dyn ResolverExpand,
947 pub current_expansion: ExpansionData,
948 /// Error recovery mode entered when expansion is stuck
949 /// (or during eager expansion, but that's a hack).
950 pub force_mode: bool,
951 pub expansions: FxHashMap<Span, Vec<String>>,
952 /// Called directly after having parsed an external `mod foo;` in expansion.
954 /// `Ident` is the module name.
955 pub(super) extern_mod_loaded: OnExternModLoaded<'a>,
956 /// When we 'expand' an inert attribute, we leave it
957 /// in the AST, but insert it here so that we know
958 /// not to expand it again.
959 pub(super) expanded_inert_attrs: MarkedAttrs,
962 impl<'a> ExtCtxt<'a> {
965 ecfg: expand::ExpansionConfig<'a>,
966 resolver: &'a mut dyn ResolverExpand,
967 extern_mod_loaded: OnExternModLoaded<'a>,
972 reduced_recursion_limit: None,
975 root_path: PathBuf::new(),
976 current_expansion: ExpansionData {
977 id: LocalExpnId::ROOT,
979 module: Default::default(),
980 dir_ownership: DirOwnership::Owned { relative: None },
981 prior_type_ascription: None,
982 lint_node_id: ast::CRATE_NODE_ID,
983 is_trailing_mac: false,
986 expansions: FxHashMap::default(),
987 expanded_inert_attrs: MarkedAttrs::new(),
991 /// Returns a `Folder` for deeply expanding all macros in an AST node.
992 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
993 expand::MacroExpander::new(self, false)
996 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
997 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
998 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
999 expand::MacroExpander::new(self, true)
1001 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
1002 rustc_parse::stream_to_parser(&self.sess.parse_sess, stream, MACRO_ARGUMENTS)
1004 pub fn source_map(&self) -> &'a SourceMap {
1005 self.sess.parse_sess.source_map()
1007 pub fn parse_sess(&self) -> &'a ParseSess {
1008 &self.sess.parse_sess
1010 pub fn call_site(&self) -> Span {
1011 self.current_expansion.id.expn_data().call_site
1014 /// Equivalent of `Span::def_site` from the proc macro API,
1015 /// except that the location is taken from the span passed as an argument.
1016 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
1017 span.with_def_site_ctxt(self.current_expansion.id.to_expn_id())
1020 /// Equivalent of `Span::call_site` from the proc macro API,
1021 /// except that the location is taken from the span passed as an argument.
1022 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
1023 span.with_call_site_ctxt(self.current_expansion.id.to_expn_id())
1026 /// Equivalent of `Span::mixed_site` from the proc macro API,
1027 /// except that the location is taken from the span passed as an argument.
1028 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
1029 span.with_mixed_site_ctxt(self.current_expansion.id.to_expn_id())
1032 /// Returns span for the macro which originally caused the current expansion to happen.
1034 /// Stops backtracing at include! boundary.
1035 pub fn expansion_cause(&self) -> Option<Span> {
1036 self.current_expansion.id.expansion_cause()
1039 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1040 self.sess.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1043 /// Emit `msg` attached to `sp`, without immediately stopping
1046 /// Compilation will be stopped in the near future (at the end of
1047 /// the macro expansion phase).
1048 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1049 self.sess.parse_sess.span_diagnostic.span_err(sp, msg);
1051 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1052 self.sess.parse_sess.span_diagnostic.span_warn(sp, msg);
1054 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1055 self.sess.parse_sess.span_diagnostic.span_bug(sp, msg);
1057 pub fn trace_macros_diag(&mut self) {
1058 for (sp, notes) in self.expansions.iter() {
1059 let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1065 // Fixme: does this result in errors?
1066 self.expansions.clear();
1068 pub fn bug(&self, msg: &str) -> ! {
1069 self.sess.parse_sess.span_diagnostic.bug(msg);
1071 pub fn trace_macros(&self) -> bool {
1074 pub fn set_trace_macros(&mut self, x: bool) {
1075 self.ecfg.trace_mac = x
1077 pub fn std_path(&self, components: &[Symbol]) -> Vec<Ident> {
1078 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1079 iter::once(Ident::new(kw::DollarCrate, def_site))
1080 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1083 pub fn def_site_path(&self, components: &[Symbol]) -> Vec<Ident> {
1084 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1085 components.iter().map(|&s| Ident::new(s, def_site)).collect()
1088 pub fn check_unused_macros(&mut self) {
1089 self.resolver.check_unused_macros();
1092 /// Resolves a `path` mentioned inside Rust code, returning an absolute path.
1094 /// This unifies the logic used for resolving `include_X!`.
1096 /// FIXME: move this to `rustc_builtin_macros` and make it private.
1097 pub fn resolve_path(
1099 path: impl Into<PathBuf>,
1101 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1102 let path = path.into();
1104 // Relative paths are resolved relative to the file in which they are found
1105 // after macro expansion (that is, they are unhygienic).
1106 if !path.is_absolute() {
1107 let callsite = span.source_callsite();
1108 let mut result = match self.source_map().span_to_filename(callsite) {
1109 FileName::Real(name) => name
1111 .expect("attempting to resolve a file path in an external file"),
1112 FileName::DocTest(path, _) => path,
1114 return Err(self.struct_span_err(
1117 "cannot resolve relative path in non-file source `{}`",
1118 other.prefer_local()
1132 /// Extracts a string literal from the macro expanded version of `expr`,
1133 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1134 /// compilation on error, merely emits a non-fatal error and returns `None`.
1135 pub fn expr_to_spanned_string<'a>(
1136 cx: &'a mut ExtCtxt<'_>,
1139 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1140 // Perform eager expansion on the expression.
1141 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1142 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1144 Err(match expr.kind {
1145 ast::ExprKind::Lit(ref l) => match l.kind {
1146 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1147 ast::LitKind::Err(_) => None,
1148 _ => Some(cx.struct_span_err(l.span, err_msg)),
1150 ast::ExprKind::Err => None,
1151 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1155 pub fn expr_to_string(
1156 cx: &mut ExtCtxt<'_>,
1159 ) -> Option<(Symbol, ast::StrStyle)> {
1160 expr_to_spanned_string(cx, expr, err_msg)
1167 .map(|(symbol, style, _)| (symbol, style))
1170 /// Non-fatally assert that `tts` is empty. Note that this function
1171 /// returns even when `tts` is non-empty, macros that *need* to stop
1172 /// compilation should call
1173 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1174 /// done as rarely as possible).
1175 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1176 if !tts.is_empty() {
1177 cx.span_err(sp, &format!("{} takes no arguments", name));
1181 /// Parse an expression. On error, emit it, advancing to `Eof`, and return `None`.
1182 pub fn parse_expr(p: &mut parser::Parser<'_>) -> Option<P<ast::Expr>> {
1183 match p.parse_expr() {
1184 Ok(e) => return Some(e),
1185 Err(mut err) => err.emit(),
1187 while p.token != token::Eof {
1193 /// Interpreting `tts` as a comma-separated sequence of expressions,
1194 /// expect exactly one string literal, or emit an error and return `None`.
1195 pub fn get_single_str_from_tts(
1196 cx: &mut ExtCtxt<'_>,
1200 ) -> Option<String> {
1201 let mut p = cx.new_parser_from_tts(tts);
1202 if p.token == token::Eof {
1203 cx.span_err(sp, &format!("{} takes 1 argument", name));
1206 let ret = parse_expr(&mut p)?;
1207 let _ = p.eat(&token::Comma);
1209 if p.token != token::Eof {
1210 cx.span_err(sp, &format!("{} takes 1 argument", name));
1212 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1215 /// Extracts comma-separated expressions from `tts`.
1216 /// On error, emit it, and return `None`.
1217 pub fn get_exprs_from_tts(
1218 cx: &mut ExtCtxt<'_>,
1221 ) -> Option<Vec<P<ast::Expr>>> {
1222 let mut p = cx.new_parser_from_tts(tts);
1223 let mut es = Vec::new();
1224 while p.token != token::Eof {
1225 let expr = parse_expr(&mut p)?;
1227 // Perform eager expansion on the expression.
1228 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1229 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1232 if p.eat(&token::Comma) {
1235 if p.token != token::Eof {
1236 cx.span_err(sp, "expected token: `,`");
1243 pub fn parse_macro_name_and_helper_attrs(
1244 diag: &rustc_errors::Handler,
1247 ) -> Option<(Symbol, Vec<Symbol>)> {
1248 // Once we've located the `#[proc_macro_derive]` attribute, verify
1249 // that it's of the form `#[proc_macro_derive(Foo)]` or
1250 // `#[proc_macro_derive(Foo, attributes(A, ..))]`
1251 let list = match attr.meta_item_list() {
1253 None => return None,
1255 if list.len() != 1 && list.len() != 2 {
1256 diag.span_err(attr.span, "attribute must have either one or two arguments");
1259 let trait_attr = match list[0].meta_item() {
1260 Some(meta_item) => meta_item,
1262 diag.span_err(list[0].span(), "not a meta item");
1266 let trait_ident = match trait_attr.ident() {
1267 Some(trait_ident) if trait_attr.is_word() => trait_ident,
1269 diag.span_err(trait_attr.span, "must only be one word");
1274 if !trait_ident.name.can_be_raw() {
1277 &format!("`{}` cannot be a name of {} macro", trait_ident, descr),
1281 let attributes_attr = list.get(1);
1282 let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
1283 if !attr.has_name(sym::attributes) {
1284 diag.span_err(attr.span(), "second argument must be `attributes`")
1286 attr.meta_item_list()
1287 .unwrap_or_else(|| {
1288 diag.span_err(attr.span(), "attribute must be of form: `attributes(foo, bar)`");
1292 .filter_map(|attr| {
1293 let attr = match attr.meta_item() {
1294 Some(meta_item) => meta_item,
1296 diag.span_err(attr.span(), "not a meta item");
1301 let ident = match attr.ident() {
1302 Some(ident) if attr.is_word() => ident,
1304 diag.span_err(attr.span, "must only be one word");
1308 if !ident.name.can_be_raw() {
1311 &format!("`{}` cannot be a name of derive helper attribute", ident),
1322 Some((trait_ident.name, proc_attrs))
1325 /// This nonterminal looks like some specific enums from
1326 /// `proc-macro-hack` and `procedural-masquerade` crates.
1327 /// We need to maintain some special pretty-printing behavior for them due to incorrect
1328 /// asserts in old versions of those crates and their wide use in the ecosystem.
1329 /// See issue #73345 for more details.
1330 /// FIXME(#73933): Remove this eventually.
1331 pub(crate) fn pretty_printing_compatibility_hack(nt: &Nonterminal, sess: &ParseSess) -> bool {
1332 let item = match nt {
1333 Nonterminal::NtItem(item) => item,
1334 Nonterminal::NtStmt(stmt) => match &stmt.kind {
1335 ast::StmtKind::Item(item) => item,
1341 let name = item.ident.name;
1342 if name == sym::ProceduralMasqueradeDummyType {
1343 if let ast::ItemKind::Enum(enum_def, _) = &item.kind {
1344 if let [variant] = &*enum_def.variants {
1345 if variant.ident.name == sym::Input {
1346 sess.buffer_lint_with_diagnostic(
1347 &PROC_MACRO_BACK_COMPAT,
1350 "using `procedural-masquerade` crate",
1351 BuiltinLintDiagnostics::ProcMacroBackCompat(
1352 "The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. \
1353 Versions of this crate below 0.1.7 will eventually stop compiling.".to_string())