1 use crate::expand::{self, AstFragment, Invocation};
2 use crate::module::DirectoryOwnership;
5 use rustc_ast::token::{self, Nonterminal};
6 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream};
7 use rustc_ast::visit::{AssocCtxt, Visitor};
8 use rustc_ast::{self as ast, Attribute, NodeId, PatKind};
9 use rustc_attr::{self as attr, Deprecation, HasAttrs, Stability};
10 use rustc_data_structures::fx::FxHashMap;
11 use rustc_data_structures::sync::{self, Lrc};
12 use rustc_errors::{DiagnosticBuilder, ErrorReported};
13 use rustc_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS};
14 use rustc_session::{parse::ParseSess, Limit, Session};
15 use rustc_span::def_id::DefId;
16 use rustc_span::edition::Edition;
17 use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
18 use rustc_span::source_map::SourceMap;
19 use rustc_span::symbol::{kw, sym, Ident, Symbol};
20 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
21 use smallvec::{smallvec, SmallVec};
23 use std::default::Default;
25 use std::path::PathBuf;
28 crate use rustc_span::hygiene::MacroKind;
30 #[derive(Debug, Clone)]
31 pub enum Annotatable {
33 TraitItem(P<ast::AssocItem>),
34 ImplItem(P<ast::AssocItem>),
35 ForeignItem(P<ast::ForeignItem>),
40 FieldPat(ast::FieldPat),
41 GenericParam(ast::GenericParam),
43 StructField(ast::StructField),
44 Variant(ast::Variant),
47 impl HasAttrs for Annotatable {
48 fn attrs(&self) -> &[Attribute] {
50 Annotatable::Item(ref item) => &item.attrs,
51 Annotatable::TraitItem(ref trait_item) => &trait_item.attrs,
52 Annotatable::ImplItem(ref impl_item) => &impl_item.attrs,
53 Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs,
54 Annotatable::Stmt(ref stmt) => stmt.attrs(),
55 Annotatable::Expr(ref expr) => &expr.attrs,
56 Annotatable::Arm(ref arm) => &arm.attrs,
57 Annotatable::Field(ref field) => &field.attrs,
58 Annotatable::FieldPat(ref fp) => &fp.attrs,
59 Annotatable::GenericParam(ref gp) => &gp.attrs,
60 Annotatable::Param(ref p) => &p.attrs,
61 Annotatable::StructField(ref sf) => &sf.attrs,
62 Annotatable::Variant(ref v) => &v.attrs(),
66 fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
68 Annotatable::Item(item) => item.visit_attrs(f),
69 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
70 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
71 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
72 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
73 Annotatable::Expr(expr) => expr.visit_attrs(f),
74 Annotatable::Arm(arm) => arm.visit_attrs(f),
75 Annotatable::Field(field) => field.visit_attrs(f),
76 Annotatable::FieldPat(fp) => fp.visit_attrs(f),
77 Annotatable::GenericParam(gp) => gp.visit_attrs(f),
78 Annotatable::Param(p) => p.visit_attrs(f),
79 Annotatable::StructField(sf) => sf.visit_attrs(f),
80 Annotatable::Variant(v) => v.visit_attrs(f),
86 pub fn span(&self) -> Span {
88 Annotatable::Item(ref item) => item.span,
89 Annotatable::TraitItem(ref trait_item) => trait_item.span,
90 Annotatable::ImplItem(ref impl_item) => impl_item.span,
91 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
92 Annotatable::Stmt(ref stmt) => stmt.span,
93 Annotatable::Expr(ref expr) => expr.span,
94 Annotatable::Arm(ref arm) => arm.span,
95 Annotatable::Field(ref field) => field.span,
96 Annotatable::FieldPat(ref fp) => fp.pat.span,
97 Annotatable::GenericParam(ref gp) => gp.ident.span,
98 Annotatable::Param(ref p) => p.span,
99 Annotatable::StructField(ref sf) => sf.span,
100 Annotatable::Variant(ref v) => v.span,
104 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
106 Annotatable::Item(item) => visitor.visit_item(item),
107 Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait),
108 Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl),
109 Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
110 Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
111 Annotatable::Expr(expr) => visitor.visit_expr(expr),
112 Annotatable::Arm(arm) => visitor.visit_arm(arm),
113 Annotatable::Field(field) => visitor.visit_field(field),
114 Annotatable::FieldPat(fp) => visitor.visit_field_pattern(fp),
115 Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
116 Annotatable::Param(p) => visitor.visit_param(p),
117 Annotatable::StructField(sf) => visitor.visit_struct_field(sf),
118 Annotatable::Variant(v) => visitor.visit_variant(v),
122 crate fn into_nonterminal(self) -> Nonterminal {
124 Annotatable::Item(item) => token::NtItem(item),
125 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
126 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
128 Annotatable::ForeignItem(item) => {
129 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
131 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
132 Annotatable::Expr(expr) => token::NtExpr(expr),
134 | Annotatable::Field(..)
135 | Annotatable::FieldPat(..)
136 | Annotatable::GenericParam(..)
137 | Annotatable::Param(..)
138 | Annotatable::StructField(..)
139 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
143 crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
144 nt_to_tokenstream(&self.into_nonterminal(), sess, CanSynthesizeMissingTokens::No)
147 pub fn expect_item(self) -> P<ast::Item> {
149 Annotatable::Item(i) => i,
150 _ => panic!("expected Item"),
154 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
156 Annotatable::TraitItem(i) => i,
157 _ => panic!("expected Item"),
161 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
163 Annotatable::ImplItem(i) => i,
164 _ => panic!("expected Item"),
168 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
170 Annotatable::ForeignItem(i) => i,
171 _ => panic!("expected foreign item"),
175 pub fn expect_stmt(self) -> ast::Stmt {
177 Annotatable::Stmt(stmt) => stmt.into_inner(),
178 _ => panic!("expected statement"),
182 pub fn expect_expr(self) -> P<ast::Expr> {
184 Annotatable::Expr(expr) => expr,
185 _ => panic!("expected expression"),
189 pub fn expect_arm(self) -> ast::Arm {
191 Annotatable::Arm(arm) => arm,
192 _ => panic!("expected match arm"),
196 pub fn expect_field(self) -> ast::Field {
198 Annotatable::Field(field) => field,
199 _ => panic!("expected field"),
203 pub fn expect_field_pattern(self) -> ast::FieldPat {
205 Annotatable::FieldPat(fp) => fp,
206 _ => panic!("expected field pattern"),
210 pub fn expect_generic_param(self) -> ast::GenericParam {
212 Annotatable::GenericParam(gp) => gp,
213 _ => panic!("expected generic parameter"),
217 pub fn expect_param(self) -> ast::Param {
219 Annotatable::Param(param) => param,
220 _ => panic!("expected parameter"),
224 pub fn expect_struct_field(self) -> ast::StructField {
226 Annotatable::StructField(sf) => sf,
227 _ => panic!("expected struct field"),
231 pub fn expect_variant(self) -> ast::Variant {
233 Annotatable::Variant(v) => v,
234 _ => panic!("expected variant"),
238 pub fn derive_allowed(&self) -> bool {
240 Annotatable::Stmt(ref stmt) => match stmt.kind {
241 ast::StmtKind::Item(ref item) => matches!(
243 ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..)
247 Annotatable::Item(ref item) => match item.kind {
248 ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..) => {
258 /// Result of an expansion that may need to be retried.
259 /// Consider using this for non-`MultiItemModifier` expanders as well.
260 pub enum ExpandResult<T, U> {
261 /// Expansion produced a result (possibly dummy).
263 /// Expansion could not produce a result and needs to be retried.
267 // `meta_item` is the attribute, and `item` is the item being modified.
268 pub trait MultiItemModifier {
271 ecx: &mut ExtCtxt<'_>,
273 meta_item: &ast::MetaItem,
275 ) -> ExpandResult<Vec<Annotatable>, Annotatable>;
278 impl<F> MultiItemModifier for F
280 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
284 ecx: &mut ExtCtxt<'_>,
286 meta_item: &ast::MetaItem,
288 ) -> ExpandResult<Vec<Annotatable>, Annotatable> {
289 ExpandResult::Ready(self(ecx, span, meta_item, item))
293 pub trait ProcMacro {
296 ecx: &'cx mut ExtCtxt<'_>,
299 ) -> Result<TokenStream, ErrorReported>;
302 impl<F> ProcMacro for F
304 F: Fn(TokenStream) -> TokenStream,
308 _ecx: &'cx mut ExtCtxt<'_>,
311 ) -> Result<TokenStream, ErrorReported> {
312 // FIXME setup implicit context in TLS before calling self.
317 pub trait AttrProcMacro {
320 ecx: &'cx mut ExtCtxt<'_>,
322 annotation: TokenStream,
323 annotated: TokenStream,
324 ) -> Result<TokenStream, ErrorReported>;
327 impl<F> AttrProcMacro for F
329 F: Fn(TokenStream, TokenStream) -> TokenStream,
333 _ecx: &'cx mut ExtCtxt<'_>,
335 annotation: TokenStream,
336 annotated: TokenStream,
337 ) -> Result<TokenStream, ErrorReported> {
338 // FIXME setup implicit context in TLS before calling self.
339 Ok(self(annotation, annotated))
343 /// Represents a thing that maps token trees to Macro Results
344 pub trait TTMacroExpander {
347 ecx: &'cx mut ExtCtxt<'_>,
350 ) -> Box<dyn MacResult + 'cx>;
353 pub type MacroExpanderFn =
354 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
356 impl<F> TTMacroExpander for F
358 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
362 ecx: &'cx mut ExtCtxt<'_>,
365 ) -> Box<dyn MacResult + 'cx> {
366 self(ecx, span, input)
370 // Use a macro because forwarding to a simple function has type system issues
371 macro_rules! make_stmts_default {
373 $me.make_expr().map(|e| {
374 smallvec![ast::Stmt {
375 id: ast::DUMMY_NODE_ID,
377 kind: ast::StmtKind::Expr(e),
383 /// The result of a macro expansion. The return values of the various
384 /// methods are spliced into the AST at the callsite of the macro.
385 pub trait MacResult {
386 /// Creates an expression.
387 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
390 /// Creates zero or more items.
391 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
395 /// Creates zero or more impl items.
396 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
400 /// Creates zero or more trait items.
401 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
405 /// Creates zero or more items in an `extern {}` block
406 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
410 /// Creates a pattern.
411 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
415 /// Creates zero or more statements.
417 /// By default this attempts to create an expression statement,
418 /// returning None if that fails.
419 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
420 make_stmts_default!(self)
423 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
427 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
431 fn make_fields(self: Box<Self>) -> Option<SmallVec<[ast::Field; 1]>> {
435 fn make_field_patterns(self: Box<Self>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
439 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
443 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
447 fn make_struct_fields(self: Box<Self>) -> Option<SmallVec<[ast::StructField; 1]>> {
451 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
456 macro_rules! make_MacEager {
457 ( $( $fld:ident: $t:ty, )* ) => {
458 /// `MacResult` implementation for the common case where you've already
459 /// built each form of AST that you might return.
461 pub struct MacEager {
463 pub $fld: Option<$t>,
469 pub fn $fld(v: $t) -> Box<dyn MacResult> {
483 items: SmallVec<[P<ast::Item>; 1]>,
484 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
485 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
486 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
487 stmts: SmallVec<[ast::Stmt; 1]>,
491 impl MacResult for MacEager {
492 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
496 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
500 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
504 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
508 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
512 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
513 match self.stmts.as_ref().map_or(0, |s| s.len()) {
514 0 => make_stmts_default!(self),
519 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
520 if let Some(p) = self.pat {
523 if let Some(e) = self.expr {
524 if let ast::ExprKind::Lit(_) = e.kind {
525 return Some(P(ast::Pat {
526 id: ast::DUMMY_NODE_ID,
528 kind: PatKind::Lit(e),
536 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
541 /// Fill-in macro expansion result, to allow compilation to continue
542 /// after hitting errors.
543 #[derive(Copy, Clone)]
544 pub struct DummyResult {
550 /// Creates a default MacResult that can be anything.
552 /// Use this as a return value after hitting any errors and
553 /// calling `span_err`.
554 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
555 Box::new(DummyResult { is_error: true, span })
558 /// Same as `any`, but must be a valid fragment, not error.
559 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
560 Box::new(DummyResult { is_error: false, span })
563 /// A plain dummy expression.
564 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
566 id: ast::DUMMY_NODE_ID,
567 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
569 attrs: ast::AttrVec::new(),
574 /// A plain dummy pattern.
575 pub fn raw_pat(sp: Span) -> ast::Pat {
576 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp, tokens: None }
579 /// A plain dummy type.
580 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
582 id: ast::DUMMY_NODE_ID,
583 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
590 impl MacResult for DummyResult {
591 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
592 Some(DummyResult::raw_expr(self.span, self.is_error))
595 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
596 Some(P(DummyResult::raw_pat(self.span)))
599 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
600 Some(SmallVec::new())
603 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
604 Some(SmallVec::new())
607 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
608 Some(SmallVec::new())
611 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
612 Some(SmallVec::new())
615 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
616 Some(smallvec![ast::Stmt {
617 id: ast::DUMMY_NODE_ID,
618 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
623 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
624 Some(DummyResult::raw_ty(self.span, self.is_error))
627 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
628 Some(SmallVec::new())
631 fn make_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::Field; 1]>> {
632 Some(SmallVec::new())
635 fn make_field_patterns(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
636 Some(SmallVec::new())
639 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
640 Some(SmallVec::new())
643 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
644 Some(SmallVec::new())
647 fn make_struct_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::StructField; 1]>> {
648 Some(SmallVec::new())
651 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
652 Some(SmallVec::new())
656 /// A syntax extension kind.
657 pub enum SyntaxExtensionKind {
658 /// A token-based function-like macro.
660 /// An expander with signature TokenStream -> TokenStream.
661 Box<dyn ProcMacro + sync::Sync + sync::Send>,
664 /// An AST-based function-like macro.
666 /// An expander with signature TokenStream -> AST.
667 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
670 /// A token-based attribute macro.
672 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
673 /// The first TokenSteam is the attribute itself, the second is the annotated item.
674 /// The produced TokenSteam replaces the input TokenSteam.
675 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
678 /// An AST-based attribute macro.
680 /// An expander with signature (AST, AST) -> AST.
681 /// The first AST fragment is the attribute itself, the second is the annotated item.
682 /// The produced AST fragment replaces the input AST fragment.
683 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
686 /// A trivial attribute "macro" that does nothing,
687 /// only keeps the attribute and marks it as inert,
688 /// thus making it ineligible for further expansion.
690 /// Suppresses the `unused_attributes` lint for this attribute.
694 /// A token-based derive macro.
696 /// An expander with signature TokenStream -> TokenStream (not yet).
697 /// The produced TokenSteam is appended to the input TokenSteam.
698 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
701 /// An AST-based derive macro.
703 /// An expander with signature AST -> AST.
704 /// The produced AST fragment is appended to the input AST fragment.
705 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
709 /// A struct representing a macro definition in "lowered" form ready for expansion.
710 pub struct SyntaxExtension {
711 /// A syntax extension kind.
712 pub kind: SyntaxExtensionKind,
713 /// Span of the macro definition.
715 /// List of unstable features that are treated as stable inside this macro.
716 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
717 /// Suppresses the `unsafe_code` lint for code produced by this macro.
718 pub allow_internal_unsafe: bool,
719 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
720 pub local_inner_macros: bool,
721 /// The macro's stability info.
722 pub stability: Option<Stability>,
723 /// The macro's deprecation info.
724 pub deprecation: Option<Deprecation>,
725 /// Names of helper attributes registered by this macro.
726 pub helper_attrs: Vec<Symbol>,
727 /// Edition of the crate in which this macro is defined.
728 pub edition: Edition,
729 /// Built-in macros have a couple of special properties like availability
730 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
731 pub is_builtin: bool,
732 /// We have to identify macros providing a `Copy` impl early for compatibility reasons.
733 pub is_derive_copy: bool,
736 impl SyntaxExtension {
737 /// Returns which kind of macro calls this syntax extension.
738 pub fn macro_kind(&self) -> MacroKind {
740 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
741 SyntaxExtensionKind::Attr(..)
742 | SyntaxExtensionKind::LegacyAttr(..)
743 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
744 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
750 /// Constructs a syntax extension with default properties.
751 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
754 allow_internal_unstable: None,
755 allow_internal_unsafe: false,
756 local_inner_macros: false,
759 helper_attrs: Vec::new(),
762 is_derive_copy: false,
767 /// Constructs a syntax extension with the given properties
768 /// and other properties converted from attributes.
771 kind: SyntaxExtensionKind,
773 helper_attrs: Vec<Symbol>,
776 attrs: &[ast::Attribute],
777 ) -> SyntaxExtension {
778 let allow_internal_unstable = attr::allow_internal_unstable(sess, &attrs)
779 .map(|features| features.collect::<Vec<Symbol>>().into());
781 let mut local_inner_macros = false;
782 if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) {
783 if let Some(l) = macro_export.meta_item_list() {
784 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
788 let is_builtin = sess.contains_name(attrs, sym::rustc_builtin_macro);
789 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
790 if const_stability.is_some() {
793 .span_err(span, "macros cannot have const stability attributes");
799 allow_internal_unstable,
800 allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
803 deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
807 is_derive_copy: is_builtin && name == sym::Copy,
811 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
813 _: &'cx mut ExtCtxt<'_>,
816 ) -> Box<dyn MacResult + 'cx> {
817 DummyResult::any(span)
819 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
822 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
828 ) -> Vec<Annotatable> {
831 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
834 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
835 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
843 macro_def_id: Option<DefId>,
846 ExpnKind::Macro(self.macro_kind(), descr),
850 self.allow_internal_unstable.clone(),
851 self.allow_internal_unsafe,
852 self.local_inner_macros,
859 /// Result of resolving a macro invocation.
860 pub enum InvocationRes {
861 Single(Lrc<SyntaxExtension>),
862 DeriveContainer(Vec<Lrc<SyntaxExtension>>),
865 /// Error type that denotes indeterminacy.
866 pub struct Indeterminate;
868 pub trait ResolverExpand {
869 fn next_node_id(&mut self) -> NodeId;
871 fn resolve_dollar_crates(&mut self);
872 fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
873 fn register_builtin_macro(&mut self, ident: Ident, ext: SyntaxExtension);
875 fn expansion_for_ast_pass(
880 parent_module_id: Option<NodeId>,
883 fn resolve_imports(&mut self);
885 fn resolve_macro_invocation(
888 eager_expansion_root: ExpnId,
890 ) -> Result<InvocationRes, Indeterminate>;
892 fn check_unused_macros(&mut self);
894 /// Some parent node that is close enough to the given macro call.
895 fn lint_node_id(&mut self, expn_id: ExpnId) -> NodeId;
897 // Resolver interfaces for specific built-in macros.
898 /// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
899 fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
900 /// Path resolution logic for `#[cfg_accessible(path)]`.
901 fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result<bool, Indeterminate>;
905 pub struct ModuleData {
906 pub mod_path: Vec<Ident>,
907 pub directory: PathBuf,
911 pub struct ExpansionData {
914 pub module: Rc<ModuleData>,
915 pub directory_ownership: DirectoryOwnership,
916 pub prior_type_ascription: Option<(Span, bool)>,
919 /// One of these is made during expansion and incrementally updated as we go;
920 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
921 /// -> expn_data` of their expansion context stored into their span.
922 pub struct ExtCtxt<'a> {
923 pub sess: &'a Session,
924 pub ecfg: expand::ExpansionConfig<'a>,
925 pub reduced_recursion_limit: Option<Limit>,
926 pub root_path: PathBuf,
927 pub resolver: &'a mut dyn ResolverExpand,
928 pub current_expansion: ExpansionData,
929 /// Error recovery mode entered when expansion is stuck
930 /// (or during eager expansion, but that's a hack).
931 pub force_mode: bool,
932 pub expansions: FxHashMap<Span, Vec<String>>,
933 /// Called directly after having parsed an external `mod foo;` in expansion.
934 pub(super) extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
937 impl<'a> ExtCtxt<'a> {
940 ecfg: expand::ExpansionConfig<'a>,
941 resolver: &'a mut dyn ResolverExpand,
942 extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
947 reduced_recursion_limit: None,
950 root_path: PathBuf::new(),
951 current_expansion: ExpansionData {
954 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
955 directory_ownership: DirectoryOwnership::Owned { relative: None },
956 prior_type_ascription: None,
959 expansions: FxHashMap::default(),
963 /// Returns a `Folder` for deeply expanding all macros in an AST node.
964 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
965 expand::MacroExpander::new(self, false)
968 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
969 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
970 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
971 expand::MacroExpander::new(self, true)
973 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
974 rustc_parse::stream_to_parser(&self.sess.parse_sess, stream, MACRO_ARGUMENTS)
976 pub fn source_map(&self) -> &'a SourceMap {
977 self.sess.parse_sess.source_map()
979 pub fn parse_sess(&self) -> &'a ParseSess {
980 &self.sess.parse_sess
982 pub fn call_site(&self) -> Span {
983 self.current_expansion.id.expn_data().call_site
986 /// Equivalent of `Span::def_site` from the proc macro API,
987 /// except that the location is taken from the span passed as an argument.
988 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
989 span.with_def_site_ctxt(self.current_expansion.id)
992 /// Equivalent of `Span::call_site` from the proc macro API,
993 /// except that the location is taken from the span passed as an argument.
994 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
995 span.with_call_site_ctxt(self.current_expansion.id)
998 /// Equivalent of `Span::mixed_site` from the proc macro API,
999 /// except that the location is taken from the span passed as an argument.
1000 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
1001 span.with_mixed_site_ctxt(self.current_expansion.id)
1004 /// Returns span for the macro which originally caused the current expansion to happen.
1006 /// Stops backtracing at include! boundary.
1007 pub fn expansion_cause(&self) -> Option<Span> {
1008 self.current_expansion.id.expansion_cause()
1011 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1012 self.sess.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1015 /// Emit `msg` attached to `sp`, without immediately stopping
1018 /// Compilation will be stopped in the near future (at the end of
1019 /// the macro expansion phase).
1020 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1021 self.sess.parse_sess.span_diagnostic.span_err(sp, msg);
1023 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1024 self.sess.parse_sess.span_diagnostic.span_warn(sp, msg);
1026 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1027 self.sess.parse_sess.span_diagnostic.span_bug(sp, msg);
1029 pub fn trace_macros_diag(&mut self) {
1030 for (sp, notes) in self.expansions.iter() {
1031 let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1037 // Fixme: does this result in errors?
1038 self.expansions.clear();
1040 pub fn bug(&self, msg: &str) -> ! {
1041 self.sess.parse_sess.span_diagnostic.bug(msg);
1043 pub fn trace_macros(&self) -> bool {
1046 pub fn set_trace_macros(&mut self, x: bool) {
1047 self.ecfg.trace_mac = x
1049 pub fn std_path(&self, components: &[Symbol]) -> Vec<Ident> {
1050 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1051 iter::once(Ident::new(kw::DollarCrate, def_site))
1052 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1056 pub fn check_unused_macros(&mut self) {
1057 self.resolver.check_unused_macros();
1060 /// Resolves a path mentioned inside Rust code.
1062 /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
1064 /// Returns an absolute path to the file that `path` refers to.
1065 pub fn resolve_path(
1067 path: impl Into<PathBuf>,
1069 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1070 let path = path.into();
1072 // Relative paths are resolved relative to the file in which they are found
1073 // after macro expansion (that is, they are unhygienic).
1074 if !path.is_absolute() {
1075 let callsite = span.source_callsite();
1076 let mut result = match self.source_map().span_to_unmapped_path(callsite) {
1077 FileName::Real(name) => name.into_local_path(),
1078 FileName::DocTest(path, _) => path,
1080 return Err(self.struct_span_err(
1082 &format!("cannot resolve relative path in non-file source `{}`", other),
1095 /// Extracts a string literal from the macro expanded version of `expr`,
1096 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1097 /// compilation on error, merely emits a non-fatal error and returns `None`.
1098 pub fn expr_to_spanned_string<'a>(
1099 cx: &'a mut ExtCtxt<'_>,
1102 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1103 // Perform eager expansion on the expression.
1104 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1105 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1107 Err(match expr.kind {
1108 ast::ExprKind::Lit(ref l) => match l.kind {
1109 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1110 ast::LitKind::Err(_) => None,
1111 _ => Some(cx.struct_span_err(l.span, err_msg)),
1113 ast::ExprKind::Err => None,
1114 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1118 pub fn expr_to_string(
1119 cx: &mut ExtCtxt<'_>,
1122 ) -> Option<(Symbol, ast::StrStyle)> {
1123 expr_to_spanned_string(cx, expr, err_msg)
1130 .map(|(symbol, style, _)| (symbol, style))
1133 /// Non-fatally assert that `tts` is empty. Note that this function
1134 /// returns even when `tts` is non-empty, macros that *need* to stop
1135 /// compilation should call
1136 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1137 /// done as rarely as possible).
1138 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1139 if !tts.is_empty() {
1140 cx.span_err(sp, &format!("{} takes no arguments", name));
1144 /// Parse an expression. On error, emit it, advancing to `Eof`, and return `None`.
1145 pub fn parse_expr(p: &mut parser::Parser<'_>) -> Option<P<ast::Expr>> {
1146 match p.parse_expr() {
1147 Ok(e) => return Some(e),
1148 Err(mut err) => err.emit(),
1150 while p.token != token::Eof {
1156 /// Interpreting `tts` as a comma-separated sequence of expressions,
1157 /// expect exactly one string literal, or emit an error and return `None`.
1158 pub fn get_single_str_from_tts(
1159 cx: &mut ExtCtxt<'_>,
1163 ) -> Option<String> {
1164 let mut p = cx.new_parser_from_tts(tts);
1165 if p.token == token::Eof {
1166 cx.span_err(sp, &format!("{} takes 1 argument", name));
1169 let ret = parse_expr(&mut p)?;
1170 let _ = p.eat(&token::Comma);
1172 if p.token != token::Eof {
1173 cx.span_err(sp, &format!("{} takes 1 argument", name));
1175 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1178 /// Extracts comma-separated expressions from `tts`.
1179 /// On error, emit it, and return `None`.
1180 pub fn get_exprs_from_tts(
1181 cx: &mut ExtCtxt<'_>,
1184 ) -> Option<Vec<P<ast::Expr>>> {
1185 let mut p = cx.new_parser_from_tts(tts);
1186 let mut es = Vec::new();
1187 while p.token != token::Eof {
1188 let expr = parse_expr(&mut p)?;
1190 // Perform eager expansion on the expression.
1191 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1192 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1195 if p.eat(&token::Comma) {
1198 if p.token != token::Eof {
1199 cx.span_err(sp, "expected token: `,`");