1 use crate::expand::{self, AstFragment, Invocation};
3 use rustc_ast::ast::{self, Attribute, Name, NodeId, PatKind};
4 use rustc_ast::mut_visit::{self, MutVisitor};
7 use rustc_ast::tokenstream::{self, TokenStream, TokenTree};
8 use rustc_ast::visit::{AssocCtxt, Visitor};
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, DiagnosticId};
13 use rustc_parse::{self, parser, DirectoryOwnership, MACRO_ARGUMENTS};
14 use rustc_session::parse::ParseSess;
15 use rustc_span::edition::Edition;
16 use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
17 use rustc_span::source_map::SourceMap;
18 use rustc_span::symbol::{kw, sym, Ident, Symbol};
19 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
20 use smallvec::{smallvec, SmallVec};
22 use std::default::Default;
24 use std::path::PathBuf;
27 crate use rustc_span::hygiene::MacroKind;
29 #[derive(Debug, Clone)]
30 pub enum Annotatable {
32 TraitItem(P<ast::AssocItem>),
33 ImplItem(P<ast::AssocItem>),
34 ForeignItem(P<ast::ForeignItem>),
39 FieldPat(ast::FieldPat),
40 GenericParam(ast::GenericParam),
42 StructField(ast::StructField),
43 Variant(ast::Variant),
46 impl HasAttrs for Annotatable {
47 fn attrs(&self) -> &[Attribute] {
49 Annotatable::Item(ref item) => &item.attrs,
50 Annotatable::TraitItem(ref trait_item) => &trait_item.attrs,
51 Annotatable::ImplItem(ref impl_item) => &impl_item.attrs,
52 Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs,
53 Annotatable::Stmt(ref stmt) => stmt.attrs(),
54 Annotatable::Expr(ref expr) => &expr.attrs,
55 Annotatable::Arm(ref arm) => &arm.attrs,
56 Annotatable::Field(ref field) => &field.attrs,
57 Annotatable::FieldPat(ref fp) => &fp.attrs,
58 Annotatable::GenericParam(ref gp) => &gp.attrs,
59 Annotatable::Param(ref p) => &p.attrs,
60 Annotatable::StructField(ref sf) => &sf.attrs,
61 Annotatable::Variant(ref v) => &v.attrs(),
65 fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
67 Annotatable::Item(item) => item.visit_attrs(f),
68 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
69 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
70 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
71 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
72 Annotatable::Expr(expr) => expr.visit_attrs(f),
73 Annotatable::Arm(arm) => arm.visit_attrs(f),
74 Annotatable::Field(field) => field.visit_attrs(f),
75 Annotatable::FieldPat(fp) => fp.visit_attrs(f),
76 Annotatable::GenericParam(gp) => gp.visit_attrs(f),
77 Annotatable::Param(p) => p.visit_attrs(f),
78 Annotatable::StructField(sf) => sf.visit_attrs(f),
79 Annotatable::Variant(v) => v.visit_attrs(f),
85 pub fn span(&self) -> Span {
87 Annotatable::Item(ref item) => item.span,
88 Annotatable::TraitItem(ref trait_item) => trait_item.span,
89 Annotatable::ImplItem(ref impl_item) => impl_item.span,
90 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
91 Annotatable::Stmt(ref stmt) => stmt.span,
92 Annotatable::Expr(ref expr) => expr.span,
93 Annotatable::Arm(ref arm) => arm.span,
94 Annotatable::Field(ref field) => field.span,
95 Annotatable::FieldPat(ref fp) => fp.pat.span,
96 Annotatable::GenericParam(ref gp) => gp.ident.span,
97 Annotatable::Param(ref p) => p.span,
98 Annotatable::StructField(ref sf) => sf.span,
99 Annotatable::Variant(ref v) => v.span,
103 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
105 Annotatable::Item(item) => visitor.visit_item(item),
106 Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait),
107 Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl),
108 Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
109 Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
110 Annotatable::Expr(expr) => visitor.visit_expr(expr),
111 Annotatable::Arm(arm) => visitor.visit_arm(arm),
112 Annotatable::Field(field) => visitor.visit_field(field),
113 Annotatable::FieldPat(fp) => visitor.visit_field_pattern(fp),
114 Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
115 Annotatable::Param(p) => visitor.visit_param(p),
116 Annotatable::StructField(sf) => visitor.visit_struct_field(sf),
117 Annotatable::Variant(v) => visitor.visit_variant(v),
121 crate fn into_tokens(self) -> TokenStream {
122 // `Annotatable` can be converted into tokens directly, but we
123 // are packing it into a nonterminal as a piece of AST to make
124 // the produced token stream look nicer in pretty-printed form.
125 let nt = match self {
126 Annotatable::Item(item) => token::NtItem(item),
127 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
128 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
130 Annotatable::ForeignItem(item) => {
131 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
133 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
134 Annotatable::Expr(expr) => token::NtExpr(expr),
136 | Annotatable::Field(..)
137 | Annotatable::FieldPat(..)
138 | Annotatable::GenericParam(..)
139 | Annotatable::Param(..)
140 | Annotatable::StructField(..)
141 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
143 TokenTree::token(token::Interpolated(Lrc::new(nt)), DUMMY_SP).into()
146 pub fn expect_item(self) -> P<ast::Item> {
148 Annotatable::Item(i) => i,
149 _ => panic!("expected Item"),
153 pub fn map_item_or<F, G>(self, mut f: F, mut or: G) -> Annotatable
155 F: FnMut(P<ast::Item>) -> P<ast::Item>,
156 G: FnMut(Annotatable) -> Annotatable,
159 Annotatable::Item(i) => Annotatable::Item(f(i)),
164 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
166 Annotatable::TraitItem(i) => i,
167 _ => panic!("expected Item"),
171 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
173 Annotatable::ImplItem(i) => i,
174 _ => panic!("expected Item"),
178 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
180 Annotatable::ForeignItem(i) => i,
181 _ => panic!("expected foreign item"),
185 pub fn expect_stmt(self) -> ast::Stmt {
187 Annotatable::Stmt(stmt) => stmt.into_inner(),
188 _ => panic!("expected statement"),
192 pub fn expect_expr(self) -> P<ast::Expr> {
194 Annotatable::Expr(expr) => expr,
195 _ => panic!("expected expression"),
199 pub fn expect_arm(self) -> ast::Arm {
201 Annotatable::Arm(arm) => arm,
202 _ => panic!("expected match arm"),
206 pub fn expect_field(self) -> ast::Field {
208 Annotatable::Field(field) => field,
209 _ => panic!("expected field"),
213 pub fn expect_field_pattern(self) -> ast::FieldPat {
215 Annotatable::FieldPat(fp) => fp,
216 _ => panic!("expected field pattern"),
220 pub fn expect_generic_param(self) -> ast::GenericParam {
222 Annotatable::GenericParam(gp) => gp,
223 _ => panic!("expected generic parameter"),
227 pub fn expect_param(self) -> ast::Param {
229 Annotatable::Param(param) => param,
230 _ => panic!("expected parameter"),
234 pub fn expect_struct_field(self) -> ast::StructField {
236 Annotatable::StructField(sf) => sf,
237 _ => panic!("expected struct field"),
241 pub fn expect_variant(self) -> ast::Variant {
243 Annotatable::Variant(v) => v,
244 _ => panic!("expected variant"),
248 pub fn derive_allowed(&self) -> bool {
250 Annotatable::Item(ref item) => match item.kind {
251 ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..) => {
261 // `meta_item` is the annotation, and `item` is the item being modified.
262 // FIXME Decorators should follow the same pattern too.
263 pub trait MultiItemModifier {
266 ecx: &mut ExtCtxt<'_>,
268 meta_item: &ast::MetaItem,
270 ) -> Vec<Annotatable>;
273 impl<F, T> MultiItemModifier for F
275 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T,
276 T: Into<Vec<Annotatable>>,
280 ecx: &mut ExtCtxt<'_>,
282 meta_item: &ast::MetaItem,
284 ) -> Vec<Annotatable> {
285 (*self)(ecx, span, meta_item, item).into()
289 impl Into<Vec<Annotatable>> for Annotatable {
290 fn into(self) -> Vec<Annotatable> {
295 pub trait ProcMacro {
296 fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt<'_>, span: Span, ts: TokenStream) -> TokenStream;
299 impl<F> ProcMacro for F
301 F: Fn(TokenStream) -> TokenStream,
303 fn expand<'cx>(&self, _ecx: &'cx mut ExtCtxt<'_>, _span: Span, ts: TokenStream) -> TokenStream {
304 // FIXME setup implicit context in TLS before calling self.
309 pub trait AttrProcMacro {
312 ecx: &'cx mut ExtCtxt<'_>,
314 annotation: TokenStream,
315 annotated: TokenStream,
319 impl<F> AttrProcMacro for F
321 F: Fn(TokenStream, TokenStream) -> TokenStream,
325 _ecx: &'cx mut ExtCtxt<'_>,
327 annotation: TokenStream,
328 annotated: TokenStream,
330 // FIXME setup implicit context in TLS before calling self.
331 (*self)(annotation, annotated)
335 /// Represents a thing that maps token trees to Macro Results
336 pub trait TTMacroExpander {
339 ecx: &'cx mut ExtCtxt<'_>,
342 ) -> Box<dyn MacResult + 'cx>;
345 pub type MacroExpanderFn =
346 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
348 impl<F> TTMacroExpander for F
350 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
354 ecx: &'cx mut ExtCtxt<'_>,
356 mut input: TokenStream,
357 ) -> Box<dyn MacResult + 'cx> {
358 struct AvoidInterpolatedIdents;
360 impl MutVisitor for AvoidInterpolatedIdents {
361 fn visit_tt(&mut self, tt: &mut tokenstream::TokenTree) {
362 if let tokenstream::TokenTree::Token(token) = tt {
363 if let token::Interpolated(nt) = &token.kind {
364 if let token::NtIdent(ident, is_raw) = **nt {
365 *tt = tokenstream::TokenTree::token(
366 token::Ident(ident.name, is_raw),
372 mut_visit::noop_visit_tt(tt, self)
375 fn visit_mac(&mut self, mac: &mut ast::Mac) {
376 mut_visit::noop_visit_mac(mac, self)
379 AvoidInterpolatedIdents.visit_tts(&mut input);
380 (*self)(ecx, span, input)
384 // Use a macro because forwarding to a simple function has type system issues
385 macro_rules! make_stmts_default {
387 $me.make_expr().map(|e| {
388 smallvec![ast::Stmt {
389 id: ast::DUMMY_NODE_ID,
391 kind: ast::StmtKind::Expr(e),
397 /// The result of a macro expansion. The return values of the various
398 /// methods are spliced into the AST at the callsite of the macro.
399 pub trait MacResult {
400 /// Creates an expression.
401 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
404 /// Creates zero or more items.
405 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
409 /// Creates zero or more impl items.
410 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
414 /// Creates zero or more trait items.
415 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
419 /// Creates zero or more items in an `extern {}` block
420 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
424 /// Creates a pattern.
425 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
429 /// Creates zero or more statements.
431 /// By default this attempts to create an expression statement,
432 /// returning None if that fails.
433 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
434 make_stmts_default!(self)
437 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
441 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
445 fn make_fields(self: Box<Self>) -> Option<SmallVec<[ast::Field; 1]>> {
449 fn make_field_patterns(self: Box<Self>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
453 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
457 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
461 fn make_struct_fields(self: Box<Self>) -> Option<SmallVec<[ast::StructField; 1]>> {
465 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
470 macro_rules! make_MacEager {
471 ( $( $fld:ident: $t:ty, )* ) => {
472 /// `MacResult` implementation for the common case where you've already
473 /// built each form of AST that you might return.
475 pub struct MacEager {
477 pub $fld: Option<$t>,
483 pub fn $fld(v: $t) -> Box<dyn MacResult> {
497 items: SmallVec<[P<ast::Item>; 1]>,
498 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
499 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
500 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
501 stmts: SmallVec<[ast::Stmt; 1]>,
505 impl MacResult for MacEager {
506 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
510 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
514 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
518 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
522 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
526 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
527 match self.stmts.as_ref().map_or(0, |s| s.len()) {
528 0 => make_stmts_default!(self),
533 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
534 if let Some(p) = self.pat {
537 if let Some(e) = self.expr {
538 if let ast::ExprKind::Lit(_) = e.kind {
539 return Some(P(ast::Pat {
540 id: ast::DUMMY_NODE_ID,
542 kind: PatKind::Lit(e),
549 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
554 /// Fill-in macro expansion result, to allow compilation to continue
555 /// after hitting errors.
556 #[derive(Copy, Clone)]
557 pub struct DummyResult {
563 /// Creates a default MacResult that can be anything.
565 /// Use this as a return value after hitting any errors and
566 /// calling `span_err`.
567 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
568 Box::new(DummyResult { is_error: true, span })
571 /// Same as `any`, but must be a valid fragment, not error.
572 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
573 Box::new(DummyResult { is_error: false, span })
576 /// A plain dummy expression.
577 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
579 id: ast::DUMMY_NODE_ID,
580 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
582 attrs: ast::AttrVec::new(),
586 /// A plain dummy pattern.
587 pub fn raw_pat(sp: Span) -> ast::Pat {
588 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp }
591 /// A plain dummy type.
592 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
594 id: ast::DUMMY_NODE_ID,
595 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
601 impl MacResult for DummyResult {
602 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
603 Some(DummyResult::raw_expr(self.span, self.is_error))
606 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
607 Some(P(DummyResult::raw_pat(self.span)))
610 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
611 Some(SmallVec::new())
614 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
615 Some(SmallVec::new())
618 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
619 Some(SmallVec::new())
622 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
623 Some(SmallVec::new())
626 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
627 Some(smallvec![ast::Stmt {
628 id: ast::DUMMY_NODE_ID,
629 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
634 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
635 Some(DummyResult::raw_ty(self.span, self.is_error))
638 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
639 Some(SmallVec::new())
642 fn make_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::Field; 1]>> {
643 Some(SmallVec::new())
646 fn make_field_patterns(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
647 Some(SmallVec::new())
650 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
651 Some(SmallVec::new())
654 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
655 Some(SmallVec::new())
658 fn make_struct_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::StructField; 1]>> {
659 Some(SmallVec::new())
662 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
663 Some(SmallVec::new())
667 /// A syntax extension kind.
668 pub enum SyntaxExtensionKind {
669 /// A token-based function-like macro.
671 /// An expander with signature TokenStream -> TokenStream.
672 Box<dyn ProcMacro + sync::Sync + sync::Send>,
675 /// An AST-based function-like macro.
677 /// An expander with signature TokenStream -> AST.
678 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
681 /// A token-based attribute macro.
683 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
684 /// The first TokenSteam is the attribute itself, the second is the annotated item.
685 /// The produced TokenSteam replaces the input TokenSteam.
686 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
689 /// An AST-based attribute macro.
691 /// An expander with signature (AST, AST) -> AST.
692 /// The first AST fragment is the attribute itself, the second is the annotated item.
693 /// The produced AST fragment replaces the input AST fragment.
694 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
697 /// A trivial attribute "macro" that does nothing,
698 /// only keeps the attribute and marks it as inert,
699 /// thus making it ineligible for further expansion.
701 /// Suppresses the `unused_attributes` lint for this attribute.
705 /// A token-based derive macro.
707 /// An expander with signature TokenStream -> TokenStream (not yet).
708 /// The produced TokenSteam is appended to the input TokenSteam.
709 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
712 /// An AST-based derive macro.
714 /// An expander with signature AST -> AST.
715 /// The produced AST fragment is appended to the input AST fragment.
716 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
720 /// A struct representing a macro definition in "lowered" form ready for expansion.
721 pub struct SyntaxExtension {
722 /// A syntax extension kind.
723 pub kind: SyntaxExtensionKind,
724 /// Span of the macro definition.
726 /// Whitelist of unstable features that are treated as stable inside this macro.
727 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
728 /// Suppresses the `unsafe_code` lint for code produced by this macro.
729 pub allow_internal_unsafe: bool,
730 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
731 pub local_inner_macros: bool,
732 /// The macro's stability info.
733 pub stability: Option<Stability>,
734 /// The macro's deprecation info.
735 pub deprecation: Option<Deprecation>,
736 /// Names of helper attributes registered by this macro.
737 pub helper_attrs: Vec<Symbol>,
738 /// Edition of the crate in which this macro is defined.
739 pub edition: Edition,
740 /// Built-in macros have a couple of special properties like availability
741 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
742 pub is_builtin: bool,
743 /// We have to identify macros providing a `Copy` impl early for compatibility reasons.
744 pub is_derive_copy: bool,
747 impl SyntaxExtension {
748 /// Returns which kind of macro calls this syntax extension.
749 pub fn macro_kind(&self) -> MacroKind {
751 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
752 SyntaxExtensionKind::Attr(..)
753 | SyntaxExtensionKind::LegacyAttr(..)
754 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
755 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
761 /// Constructs a syntax extension with default properties.
762 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
765 allow_internal_unstable: None,
766 allow_internal_unsafe: false,
767 local_inner_macros: false,
770 helper_attrs: Vec::new(),
773 is_derive_copy: false,
778 /// Constructs a syntax extension with the given properties
779 /// and other properties converted from attributes.
782 kind: SyntaxExtensionKind,
784 helper_attrs: Vec<Symbol>,
787 attrs: &[ast::Attribute],
788 ) -> SyntaxExtension {
789 let allow_internal_unstable = attr::allow_internal_unstable(&attrs, &sess.span_diagnostic)
790 .map(|features| features.collect::<Vec<Symbol>>().into());
792 let mut local_inner_macros = false;
793 if let Some(macro_export) = attr::find_by_name(attrs, sym::macro_export) {
794 if let Some(l) = macro_export.meta_item_list() {
795 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
799 let is_builtin = attr::contains_name(attrs, sym::rustc_builtin_macro);
800 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
801 if const_stability.is_some() {
802 sess.span_diagnostic.span_err(span, "macros cannot have const stability attributes");
808 allow_internal_unstable,
809 allow_internal_unsafe: attr::contains_name(attrs, sym::allow_internal_unsafe),
812 deprecation: attr::find_deprecation(&sess, attrs, span),
816 is_derive_copy: is_builtin && name == sym::Copy,
820 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
822 _: &'cx mut ExtCtxt<'_>,
825 ) -> Box<dyn MacResult + 'cx> {
826 DummyResult::any(span)
828 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
831 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
837 ) -> Vec<Annotatable> {
840 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
843 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
844 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
847 pub fn expn_data(&self, parent: ExpnId, call_site: Span, descr: Symbol) -> ExpnData {
849 kind: ExpnKind::Macro(self.macro_kind(), descr),
853 allow_internal_unstable: self.allow_internal_unstable.clone(),
854 allow_internal_unsafe: self.allow_internal_unsafe,
855 local_inner_macros: self.local_inner_macros,
856 edition: self.edition,
861 /// Result of resolving a macro invocation.
862 pub enum InvocationRes {
863 Single(Lrc<SyntaxExtension>),
864 DeriveContainer(Vec<Lrc<SyntaxExtension>>),
867 /// Error type that denotes indeterminacy.
868 pub struct Indeterminate;
871 fn next_node_id(&mut self) -> NodeId;
873 fn resolve_dollar_crates(&mut self);
874 fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
875 fn register_builtin_macro(&mut self, ident: ast::Ident, ext: SyntaxExtension);
877 fn expansion_for_ast_pass(
882 parent_module_id: Option<NodeId>,
885 fn resolve_imports(&mut self);
887 fn resolve_macro_invocation(
890 eager_expansion_root: ExpnId,
892 ) -> Result<InvocationRes, Indeterminate>;
894 fn check_unused_macros(&mut self);
896 fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
897 fn add_derive_copy(&mut self, expn_id: ExpnId);
901 pub struct ModuleData {
902 pub mod_path: Vec<ast::Ident>,
903 pub directory: PathBuf,
907 pub struct ExpansionData {
910 pub module: Rc<ModuleData>,
911 pub directory_ownership: DirectoryOwnership,
912 pub prior_type_ascription: Option<(Span, bool)>,
915 /// One of these is made during expansion and incrementally updated as we go;
916 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
917 /// -> expn_data` of their expansion context stored into their span.
918 pub struct ExtCtxt<'a> {
919 pub parse_sess: &'a ParseSess,
920 pub ecfg: expand::ExpansionConfig<'a>,
921 pub root_path: PathBuf,
922 pub resolver: &'a mut dyn Resolver,
923 pub current_expansion: ExpansionData,
924 pub expansions: FxHashMap<Span, Vec<String>>,
927 impl<'a> ExtCtxt<'a> {
929 parse_sess: &'a ParseSess,
930 ecfg: expand::ExpansionConfig<'a>,
931 resolver: &'a mut dyn Resolver,
936 root_path: PathBuf::new(),
938 current_expansion: ExpansionData {
941 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
942 directory_ownership: DirectoryOwnership::Owned { relative: None },
943 prior_type_ascription: None,
945 expansions: FxHashMap::default(),
949 /// Returns a `Folder` for deeply expanding all macros in an AST node.
950 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
951 expand::MacroExpander::new(self, false)
954 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
955 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
956 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
957 expand::MacroExpander::new(self, true)
959 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
960 rustc_parse::stream_to_parser(self.parse_sess, stream, MACRO_ARGUMENTS)
962 pub fn source_map(&self) -> &'a SourceMap {
963 self.parse_sess.source_map()
965 pub fn parse_sess(&self) -> &'a ParseSess {
968 pub fn call_site(&self) -> Span {
969 self.current_expansion.id.expn_data().call_site
972 /// Equivalent of `Span::def_site` from the proc macro API,
973 /// except that the location is taken from the span passed as an argument.
974 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
975 span.with_def_site_ctxt(self.current_expansion.id)
978 /// Equivalent of `Span::call_site` from the proc macro API,
979 /// except that the location is taken from the span passed as an argument.
980 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
981 span.with_call_site_ctxt(self.current_expansion.id)
984 /// Equivalent of `Span::mixed_site` from the proc macro API,
985 /// except that the location is taken from the span passed as an argument.
986 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
987 span.with_mixed_site_ctxt(self.current_expansion.id)
990 /// Returns span for the macro which originally caused the current expansion to happen.
992 /// Stops backtracing at include! boundary.
993 pub fn expansion_cause(&self) -> Option<Span> {
994 self.current_expansion.id.expansion_cause()
997 pub fn struct_span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
998 self.parse_sess.span_diagnostic.struct_span_warn(sp, msg)
1000 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1001 self.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1003 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1004 self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg)
1007 /// Emit `msg` attached to `sp`, and stop compilation immediately.
1009 /// `span_err` should be strongly preferred where-ever possible:
1010 /// this should *only* be used when:
1012 /// - continuing has a high risk of flow-on errors (e.g., errors in
1013 /// declaring a macro would cause all uses of that macro to
1014 /// complain about "undefined macro"), or
1015 /// - there is literally nothing else that can be done (however,
1016 /// in most cases one can construct a dummy expression/item to
1017 /// substitute; we never hit resolve/type-checking so the dummy
1018 /// value doesn't have to match anything)
1019 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1020 self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise();
1023 /// Emit `msg` attached to `sp`, without immediately stopping
1026 /// Compilation will be stopped in the near future (at the end of
1027 /// the macro expansion phase).
1028 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1029 self.parse_sess.span_diagnostic.span_err(sp, msg);
1031 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
1032 self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code);
1034 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1035 self.parse_sess.span_diagnostic.span_warn(sp, msg);
1037 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1038 self.parse_sess.span_diagnostic.span_bug(sp, msg);
1040 pub fn trace_macros_diag(&mut self) {
1041 for (sp, notes) in self.expansions.iter() {
1042 let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1048 // Fixme: does this result in errors?
1049 self.expansions.clear();
1051 pub fn bug(&self, msg: &str) -> ! {
1052 self.parse_sess.span_diagnostic.bug(msg);
1054 pub fn trace_macros(&self) -> bool {
1057 pub fn set_trace_macros(&mut self, x: bool) {
1058 self.ecfg.trace_mac = x
1060 pub fn ident_of(&self, st: &str, sp: Span) -> ast::Ident {
1061 ast::Ident::from_str_and_span(st, sp)
1063 pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
1064 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1065 iter::once(Ident::new(kw::DollarCrate, def_site))
1066 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1069 pub fn name_of(&self, st: &str) -> ast::Name {
1073 pub fn check_unused_macros(&mut self) {
1074 self.resolver.check_unused_macros();
1077 /// Resolves a path mentioned inside Rust code.
1079 /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
1081 /// Returns an absolute path to the file that `path` refers to.
1082 pub fn resolve_path(
1084 path: impl Into<PathBuf>,
1086 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1087 let path = path.into();
1089 // Relative paths are resolved relative to the file in which they are found
1090 // after macro expansion (that is, they are unhygienic).
1091 if !path.is_absolute() {
1092 let callsite = span.source_callsite();
1093 let mut result = match self.source_map().span_to_unmapped_path(callsite) {
1094 FileName::Real(path) => path,
1095 FileName::DocTest(path, _) => path,
1097 return Err(self.struct_span_err(
1099 &format!("cannot resolve relative path in non-file source `{}`", other),
1112 /// Extracts a string literal from the macro expanded version of `expr`,
1113 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1114 /// compilation on error, merely emits a non-fatal error and returns `None`.
1115 pub fn expr_to_spanned_string<'a>(
1116 cx: &'a mut ExtCtxt<'_>,
1119 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1120 // Perform eager expansion on the expression.
1121 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1122 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1124 Err(match expr.kind {
1125 ast::ExprKind::Lit(ref l) => match l.kind {
1126 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1127 ast::LitKind::Err(_) => None,
1128 _ => Some(cx.struct_span_err(l.span, err_msg)),
1130 ast::ExprKind::Err => None,
1131 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1135 pub fn expr_to_string(
1136 cx: &mut ExtCtxt<'_>,
1139 ) -> Option<(Symbol, ast::StrStyle)> {
1140 expr_to_spanned_string(cx, expr, err_msg)
1147 .map(|(symbol, style, _)| (symbol, style))
1150 /// Non-fatally assert that `tts` is empty. Note that this function
1151 /// returns even when `tts` is non-empty, macros that *need* to stop
1152 /// compilation should call
1153 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1154 /// done as rarely as possible).
1155 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1156 if !tts.is_empty() {
1157 cx.span_err(sp, &format!("{} takes no arguments", name));
1161 /// Interpreting `tts` as a comma-separated sequence of expressions,
1162 /// expect exactly one string literal, or emit an error and return `None`.
1163 pub fn get_single_str_from_tts(
1164 cx: &mut ExtCtxt<'_>,
1168 ) -> Option<String> {
1169 let mut p = cx.new_parser_from_tts(tts);
1170 if p.token == token::Eof {
1171 cx.span_err(sp, &format!("{} takes 1 argument", name));
1174 let ret = panictry!(p.parse_expr());
1175 let _ = p.eat(&token::Comma);
1177 if p.token != token::Eof {
1178 cx.span_err(sp, &format!("{} takes 1 argument", name));
1180 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1183 /// Extracts comma-separated expressions from `tts`. If there is a
1184 /// parsing error, emit a non-fatal error and return `None`.
1185 pub fn get_exprs_from_tts(
1186 cx: &mut ExtCtxt<'_>,
1189 ) -> Option<Vec<P<ast::Expr>>> {
1190 let mut p = cx.new_parser_from_tts(tts);
1191 let mut es = Vec::new();
1192 while p.token != token::Eof {
1193 let expr = panictry!(p.parse_expr());
1195 // Perform eager expansion on the expression.
1196 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1197 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1200 if p.eat(&token::Comma) {
1203 if p.token != token::Eof {
1204 cx.span_err(sp, "expected token: `,`");