1 use crate::expand::{self, AstFragment, Invocation};
2 use crate::module::DirectoryOwnership;
4 use rustc_ast::ast::{self, Attribute, Name, NodeId, PatKind};
5 use rustc_ast::mut_visit::{self, MutVisitor};
8 use rustc_ast::tokenstream::{self, TokenStream, TokenTree};
9 use rustc_ast::visit::{AssocCtxt, Visitor};
10 use rustc_attr::{self as attr, Deprecation, HasAttrs, Stability};
11 use rustc_data_structures::fx::FxHashMap;
12 use rustc_data_structures::sync::{self, Lrc};
13 use rustc_errors::{DiagnosticBuilder, DiagnosticId};
14 use rustc_parse::{self, parser, MACRO_ARGUMENTS};
15 use rustc_session::parse::ParseSess;
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_tokens(self) -> TokenStream {
123 // `Annotatable` can be converted into tokens directly, but we
124 // are packing it into a nonterminal as a piece of AST to make
125 // the produced token stream look nicer in pretty-printed form.
126 let nt = match self {
127 Annotatable::Item(item) => token::NtItem(item),
128 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
129 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
131 Annotatable::ForeignItem(item) => {
132 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
134 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
135 Annotatable::Expr(expr) => token::NtExpr(expr),
137 | Annotatable::Field(..)
138 | Annotatable::FieldPat(..)
139 | Annotatable::GenericParam(..)
140 | Annotatable::Param(..)
141 | Annotatable::StructField(..)
142 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
144 TokenTree::token(token::Interpolated(Lrc::new(nt)), DUMMY_SP).into()
147 pub fn expect_item(self) -> P<ast::Item> {
149 Annotatable::Item(i) => i,
150 _ => panic!("expected Item"),
154 pub fn map_item_or<F, G>(self, mut f: F, mut or: G) -> Annotatable
156 F: FnMut(P<ast::Item>) -> P<ast::Item>,
157 G: FnMut(Annotatable) -> Annotatable,
160 Annotatable::Item(i) => Annotatable::Item(f(i)),
165 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
167 Annotatable::TraitItem(i) => i,
168 _ => panic!("expected Item"),
172 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
174 Annotatable::ImplItem(i) => i,
175 _ => panic!("expected Item"),
179 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
181 Annotatable::ForeignItem(i) => i,
182 _ => panic!("expected foreign item"),
186 pub fn expect_stmt(self) -> ast::Stmt {
188 Annotatable::Stmt(stmt) => stmt.into_inner(),
189 _ => panic!("expected statement"),
193 pub fn expect_expr(self) -> P<ast::Expr> {
195 Annotatable::Expr(expr) => expr,
196 _ => panic!("expected expression"),
200 pub fn expect_arm(self) -> ast::Arm {
202 Annotatable::Arm(arm) => arm,
203 _ => panic!("expected match arm"),
207 pub fn expect_field(self) -> ast::Field {
209 Annotatable::Field(field) => field,
210 _ => panic!("expected field"),
214 pub fn expect_field_pattern(self) -> ast::FieldPat {
216 Annotatable::FieldPat(fp) => fp,
217 _ => panic!("expected field pattern"),
221 pub fn expect_generic_param(self) -> ast::GenericParam {
223 Annotatable::GenericParam(gp) => gp,
224 _ => panic!("expected generic parameter"),
228 pub fn expect_param(self) -> ast::Param {
230 Annotatable::Param(param) => param,
231 _ => panic!("expected parameter"),
235 pub fn expect_struct_field(self) -> ast::StructField {
237 Annotatable::StructField(sf) => sf,
238 _ => panic!("expected struct field"),
242 pub fn expect_variant(self) -> ast::Variant {
244 Annotatable::Variant(v) => v,
245 _ => panic!("expected variant"),
249 pub fn derive_allowed(&self) -> bool {
251 Annotatable::Item(ref item) => match item.kind {
252 ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..) => {
262 /// Result of an expansion that may need to be retried.
263 /// Consider using this for non-`MultiItemModifier` expanders as well.
264 pub enum ExpandResult<T, U> {
265 /// Expansion produced a result (possibly dummy).
267 /// Expansion could not produce a result and needs to be retried.
268 /// The string is an explanation that will be printed if we are stuck in an infinite retry loop.
272 // `meta_item` is the attribute, and `item` is the item being modified.
273 pub trait MultiItemModifier {
276 ecx: &mut ExtCtxt<'_>,
278 meta_item: &ast::MetaItem,
280 ) -> ExpandResult<Vec<Annotatable>, Annotatable>;
283 impl<F> MultiItemModifier for F
285 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
289 ecx: &mut ExtCtxt<'_>,
291 meta_item: &ast::MetaItem,
293 ) -> ExpandResult<Vec<Annotatable>, Annotatable> {
294 ExpandResult::Ready(self(ecx, span, meta_item, item))
298 pub trait ProcMacro {
299 fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt<'_>, span: Span, ts: TokenStream) -> TokenStream;
302 impl<F> ProcMacro for F
304 F: Fn(TokenStream) -> TokenStream,
306 fn expand<'cx>(&self, _ecx: &'cx mut ExtCtxt<'_>, _span: Span, ts: TokenStream) -> TokenStream {
307 // FIXME setup implicit context in TLS before calling self.
312 pub trait AttrProcMacro {
315 ecx: &'cx mut ExtCtxt<'_>,
317 annotation: TokenStream,
318 annotated: TokenStream,
322 impl<F> AttrProcMacro for F
324 F: Fn(TokenStream, TokenStream) -> TokenStream,
328 _ecx: &'cx mut ExtCtxt<'_>,
330 annotation: TokenStream,
331 annotated: TokenStream,
333 // FIXME setup implicit context in TLS before calling self.
334 (*self)(annotation, annotated)
338 /// Represents a thing that maps token trees to Macro Results
339 pub trait TTMacroExpander {
342 ecx: &'cx mut ExtCtxt<'_>,
345 ) -> Box<dyn MacResult + 'cx>;
348 pub type MacroExpanderFn =
349 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
351 impl<F> TTMacroExpander for F
353 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
357 ecx: &'cx mut ExtCtxt<'_>,
359 mut input: TokenStream,
360 ) -> Box<dyn MacResult + 'cx> {
361 struct AvoidInterpolatedIdents;
363 impl MutVisitor for AvoidInterpolatedIdents {
364 fn visit_tt(&mut self, tt: &mut tokenstream::TokenTree) {
365 if let tokenstream::TokenTree::Token(token) = tt {
366 if let token::Interpolated(nt) = &token.kind {
367 if let token::NtIdent(ident, is_raw) = **nt {
368 *tt = tokenstream::TokenTree::token(
369 token::Ident(ident.name, is_raw),
375 mut_visit::noop_visit_tt(tt, self)
378 fn visit_mac(&mut self, mac: &mut ast::MacCall) {
379 mut_visit::noop_visit_mac(mac, self)
382 AvoidInterpolatedIdents.visit_tts(&mut input);
383 (*self)(ecx, span, input)
387 // Use a macro because forwarding to a simple function has type system issues
388 macro_rules! make_stmts_default {
390 $me.make_expr().map(|e| {
391 smallvec![ast::Stmt {
392 id: ast::DUMMY_NODE_ID,
394 kind: ast::StmtKind::Expr(e),
400 /// The result of a macro expansion. The return values of the various
401 /// methods are spliced into the AST at the callsite of the macro.
402 pub trait MacResult {
403 /// Creates an expression.
404 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
407 /// Creates zero or more items.
408 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
412 /// Creates zero or more impl items.
413 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
417 /// Creates zero or more trait items.
418 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
422 /// Creates zero or more items in an `extern {}` block
423 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
427 /// Creates a pattern.
428 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
432 /// Creates zero or more statements.
434 /// By default this attempts to create an expression statement,
435 /// returning None if that fails.
436 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
437 make_stmts_default!(self)
440 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
444 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
448 fn make_fields(self: Box<Self>) -> Option<SmallVec<[ast::Field; 1]>> {
452 fn make_field_patterns(self: Box<Self>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
456 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
460 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
464 fn make_struct_fields(self: Box<Self>) -> Option<SmallVec<[ast::StructField; 1]>> {
468 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
473 macro_rules! make_MacEager {
474 ( $( $fld:ident: $t:ty, )* ) => {
475 /// `MacResult` implementation for the common case where you've already
476 /// built each form of AST that you might return.
478 pub struct MacEager {
480 pub $fld: Option<$t>,
486 pub fn $fld(v: $t) -> Box<dyn MacResult> {
500 items: SmallVec<[P<ast::Item>; 1]>,
501 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
502 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
503 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
504 stmts: SmallVec<[ast::Stmt; 1]>,
508 impl MacResult for MacEager {
509 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
513 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
517 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
521 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
525 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
529 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
530 match self.stmts.as_ref().map_or(0, |s| s.len()) {
531 0 => make_stmts_default!(self),
536 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
537 if let Some(p) = self.pat {
540 if let Some(e) = self.expr {
541 if let ast::ExprKind::Lit(_) = e.kind {
542 return Some(P(ast::Pat {
543 id: ast::DUMMY_NODE_ID,
545 kind: PatKind::Lit(e),
552 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
557 /// Fill-in macro expansion result, to allow compilation to continue
558 /// after hitting errors.
559 #[derive(Copy, Clone)]
560 pub struct DummyResult {
566 /// Creates a default MacResult that can be anything.
568 /// Use this as a return value after hitting any errors and
569 /// calling `span_err`.
570 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
571 Box::new(DummyResult { is_error: true, span })
574 /// Same as `any`, but must be a valid fragment, not error.
575 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
576 Box::new(DummyResult { is_error: false, span })
579 /// A plain dummy expression.
580 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
582 id: ast::DUMMY_NODE_ID,
583 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
585 attrs: ast::AttrVec::new(),
589 /// A plain dummy pattern.
590 pub fn raw_pat(sp: Span) -> ast::Pat {
591 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp }
594 /// A plain dummy type.
595 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
597 id: ast::DUMMY_NODE_ID,
598 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
604 impl MacResult for DummyResult {
605 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
606 Some(DummyResult::raw_expr(self.span, self.is_error))
609 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
610 Some(P(DummyResult::raw_pat(self.span)))
613 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
614 Some(SmallVec::new())
617 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
618 Some(SmallVec::new())
621 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
622 Some(SmallVec::new())
625 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
626 Some(SmallVec::new())
629 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
630 Some(smallvec![ast::Stmt {
631 id: ast::DUMMY_NODE_ID,
632 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
637 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
638 Some(DummyResult::raw_ty(self.span, self.is_error))
641 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
642 Some(SmallVec::new())
645 fn make_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::Field; 1]>> {
646 Some(SmallVec::new())
649 fn make_field_patterns(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
650 Some(SmallVec::new())
653 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
654 Some(SmallVec::new())
657 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
658 Some(SmallVec::new())
661 fn make_struct_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::StructField; 1]>> {
662 Some(SmallVec::new())
665 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
666 Some(SmallVec::new())
670 /// A syntax extension kind.
671 pub enum SyntaxExtensionKind {
672 /// A token-based function-like macro.
674 /// An expander with signature TokenStream -> TokenStream.
675 Box<dyn ProcMacro + sync::Sync + sync::Send>,
678 /// An AST-based function-like macro.
680 /// An expander with signature TokenStream -> AST.
681 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
684 /// A token-based attribute macro.
686 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
687 /// The first TokenSteam is the attribute itself, the second is the annotated item.
688 /// The produced TokenSteam replaces the input TokenSteam.
689 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
692 /// An AST-based attribute macro.
694 /// An expander with signature (AST, AST) -> AST.
695 /// The first AST fragment is the attribute itself, the second is the annotated item.
696 /// The produced AST fragment replaces the input AST fragment.
697 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
700 /// A trivial attribute "macro" that does nothing,
701 /// only keeps the attribute and marks it as inert,
702 /// thus making it ineligible for further expansion.
704 /// Suppresses the `unused_attributes` lint for this attribute.
708 /// A token-based derive macro.
710 /// An expander with signature TokenStream -> TokenStream (not yet).
711 /// The produced TokenSteam is appended to the input TokenSteam.
712 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
715 /// An AST-based derive macro.
717 /// An expander with signature AST -> AST.
718 /// The produced AST fragment is appended to the input AST fragment.
719 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
723 /// A struct representing a macro definition in "lowered" form ready for expansion.
724 pub struct SyntaxExtension {
725 /// A syntax extension kind.
726 pub kind: SyntaxExtensionKind,
727 /// Span of the macro definition.
729 /// Whitelist of unstable features that are treated as stable inside this macro.
730 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
731 /// Suppresses the `unsafe_code` lint for code produced by this macro.
732 pub allow_internal_unsafe: bool,
733 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
734 pub local_inner_macros: bool,
735 /// The macro's stability info.
736 pub stability: Option<Stability>,
737 /// The macro's deprecation info.
738 pub deprecation: Option<Deprecation>,
739 /// Names of helper attributes registered by this macro.
740 pub helper_attrs: Vec<Symbol>,
741 /// Edition of the crate in which this macro is defined.
742 pub edition: Edition,
743 /// Built-in macros have a couple of special properties like availability
744 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
745 pub is_builtin: bool,
746 /// We have to identify macros providing a `Copy` impl early for compatibility reasons.
747 pub is_derive_copy: bool,
750 impl SyntaxExtension {
751 /// Returns which kind of macro calls this syntax extension.
752 pub fn macro_kind(&self) -> MacroKind {
754 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
755 SyntaxExtensionKind::Attr(..)
756 | SyntaxExtensionKind::LegacyAttr(..)
757 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
758 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
764 /// Constructs a syntax extension with default properties.
765 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
768 allow_internal_unstable: None,
769 allow_internal_unsafe: false,
770 local_inner_macros: false,
773 helper_attrs: Vec::new(),
776 is_derive_copy: false,
781 /// Constructs a syntax extension with the given properties
782 /// and other properties converted from attributes.
785 kind: SyntaxExtensionKind,
787 helper_attrs: Vec<Symbol>,
790 attrs: &[ast::Attribute],
791 ) -> SyntaxExtension {
792 let allow_internal_unstable = attr::allow_internal_unstable(&attrs, &sess.span_diagnostic)
793 .map(|features| features.collect::<Vec<Symbol>>().into());
795 let mut local_inner_macros = false;
796 if let Some(macro_export) = attr::find_by_name(attrs, sym::macro_export) {
797 if let Some(l) = macro_export.meta_item_list() {
798 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
802 let is_builtin = attr::contains_name(attrs, sym::rustc_builtin_macro);
803 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
804 if const_stability.is_some() {
805 sess.span_diagnostic.span_err(span, "macros cannot have const stability attributes");
811 allow_internal_unstable,
812 allow_internal_unsafe: attr::contains_name(attrs, sym::allow_internal_unsafe),
815 deprecation: attr::find_deprecation(&sess, attrs, span),
819 is_derive_copy: is_builtin && name == sym::Copy,
823 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
825 _: &'cx mut ExtCtxt<'_>,
828 ) -> Box<dyn MacResult + 'cx> {
829 DummyResult::any(span)
831 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
834 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
840 ) -> Vec<Annotatable> {
843 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
846 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
847 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
850 pub fn expn_data(&self, parent: ExpnId, call_site: Span, descr: Symbol) -> ExpnData {
852 kind: ExpnKind::Macro(self.macro_kind(), descr),
856 allow_internal_unstable: self.allow_internal_unstable.clone(),
857 allow_internal_unsafe: self.allow_internal_unsafe,
858 local_inner_macros: self.local_inner_macros,
859 edition: self.edition,
864 /// Result of resolving a macro invocation.
865 pub enum InvocationRes {
866 Single(Lrc<SyntaxExtension>),
867 DeriveContainer(Vec<Lrc<SyntaxExtension>>),
870 /// Error type that denotes indeterminacy.
871 pub struct Indeterminate;
874 fn next_node_id(&mut self) -> NodeId;
876 fn resolve_dollar_crates(&mut self);
877 fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
878 fn register_builtin_macro(&mut self, ident: ast::Ident, ext: SyntaxExtension);
880 fn expansion_for_ast_pass(
885 parent_module_id: Option<NodeId>,
888 fn resolve_imports(&mut self);
890 fn resolve_macro_invocation(
893 eager_expansion_root: ExpnId,
895 ) -> Result<InvocationRes, Indeterminate>;
897 fn check_unused_macros(&mut self);
899 fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
900 fn add_derive_copy(&mut self, expn_id: ExpnId);
901 fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result<bool, Indeterminate>;
905 pub struct ModuleData {
906 pub mod_path: Vec<ast::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 parse_sess: &'a ParseSess,
924 pub ecfg: expand::ExpansionConfig<'a>,
925 pub root_path: PathBuf,
926 pub resolver: &'a mut dyn Resolver,
927 pub current_expansion: ExpansionData,
928 pub expansions: FxHashMap<Span, Vec<String>>,
929 /// Called directly after having parsed an external `mod foo;` in expansion.
930 pub(super) extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
933 impl<'a> ExtCtxt<'a> {
935 parse_sess: &'a ParseSess,
936 ecfg: expand::ExpansionConfig<'a>,
937 resolver: &'a mut dyn Resolver,
938 extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
945 root_path: PathBuf::new(),
946 current_expansion: ExpansionData {
949 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
950 directory_ownership: DirectoryOwnership::Owned { relative: None },
951 prior_type_ascription: None,
953 expansions: FxHashMap::default(),
957 /// Returns a `Folder` for deeply expanding all macros in an AST node.
958 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
959 expand::MacroExpander::new(self, false)
962 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
963 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
964 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
965 expand::MacroExpander::new(self, true)
967 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
968 rustc_parse::stream_to_parser(self.parse_sess, stream, MACRO_ARGUMENTS)
970 pub fn source_map(&self) -> &'a SourceMap {
971 self.parse_sess.source_map()
973 pub fn parse_sess(&self) -> &'a ParseSess {
976 pub fn call_site(&self) -> Span {
977 self.current_expansion.id.expn_data().call_site
980 /// Equivalent of `Span::def_site` from the proc macro API,
981 /// except that the location is taken from the span passed as an argument.
982 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
983 span.with_def_site_ctxt(self.current_expansion.id)
986 /// Equivalent of `Span::call_site` from the proc macro API,
987 /// except that the location is taken from the span passed as an argument.
988 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
989 span.with_call_site_ctxt(self.current_expansion.id)
992 /// Equivalent of `Span::mixed_site` from the proc macro API,
993 /// except that the location is taken from the span passed as an argument.
994 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
995 span.with_mixed_site_ctxt(self.current_expansion.id)
998 /// Returns span for the macro which originally caused the current expansion to happen.
1000 /// Stops backtracing at include! boundary.
1001 pub fn expansion_cause(&self) -> Option<Span> {
1002 self.current_expansion.id.expansion_cause()
1005 pub fn struct_span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1006 self.parse_sess.span_diagnostic.struct_span_warn(sp, msg)
1008 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1009 self.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1011 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1012 self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg)
1015 /// Emit `msg` attached to `sp`, and stop compilation immediately.
1017 /// `span_err` should be strongly preferred where-ever possible:
1018 /// this should *only* be used when:
1020 /// - continuing has a high risk of flow-on errors (e.g., errors in
1021 /// declaring a macro would cause all uses of that macro to
1022 /// complain about "undefined macro"), or
1023 /// - there is literally nothing else that can be done (however,
1024 /// in most cases one can construct a dummy expression/item to
1025 /// substitute; we never hit resolve/type-checking so the dummy
1026 /// value doesn't have to match anything)
1027 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1028 self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise();
1031 /// Emit `msg` attached to `sp`, without immediately stopping
1034 /// Compilation will be stopped in the near future (at the end of
1035 /// the macro expansion phase).
1036 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1037 self.parse_sess.span_diagnostic.span_err(sp, msg);
1039 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
1040 self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code);
1042 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1043 self.parse_sess.span_diagnostic.span_warn(sp, msg);
1045 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1046 self.parse_sess.span_diagnostic.span_bug(sp, msg);
1048 pub fn trace_macros_diag(&mut self) {
1049 for (sp, notes) in self.expansions.iter() {
1050 let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1056 // Fixme: does this result in errors?
1057 self.expansions.clear();
1059 pub fn bug(&self, msg: &str) -> ! {
1060 self.parse_sess.span_diagnostic.bug(msg);
1062 pub fn trace_macros(&self) -> bool {
1065 pub fn set_trace_macros(&mut self, x: bool) {
1066 self.ecfg.trace_mac = x
1068 pub fn ident_of(&self, st: &str, sp: Span) -> ast::Ident {
1069 ast::Ident::from_str_and_span(st, sp)
1071 pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
1072 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1073 iter::once(Ident::new(kw::DollarCrate, def_site))
1074 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1077 pub fn name_of(&self, st: &str) -> ast::Name {
1081 pub fn check_unused_macros(&mut self) {
1082 self.resolver.check_unused_macros();
1085 /// Resolves a path mentioned inside Rust code.
1087 /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
1089 /// Returns an absolute path to the file that `path` refers to.
1090 pub fn resolve_path(
1092 path: impl Into<PathBuf>,
1094 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1095 let path = path.into();
1097 // Relative paths are resolved relative to the file in which they are found
1098 // after macro expansion (that is, they are unhygienic).
1099 if !path.is_absolute() {
1100 let callsite = span.source_callsite();
1101 let mut result = match self.source_map().span_to_unmapped_path(callsite) {
1102 FileName::Real(path) => path,
1103 FileName::DocTest(path, _) => path,
1105 return Err(self.struct_span_err(
1107 &format!("cannot resolve relative path in non-file source `{}`", other),
1120 /// Extracts a string literal from the macro expanded version of `expr`,
1121 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1122 /// compilation on error, merely emits a non-fatal error and returns `None`.
1123 pub fn expr_to_spanned_string<'a>(
1124 cx: &'a mut ExtCtxt<'_>,
1127 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1128 // Perform eager expansion on the expression.
1129 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1130 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1132 Err(match expr.kind {
1133 ast::ExprKind::Lit(ref l) => match l.kind {
1134 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1135 ast::LitKind::Err(_) => None,
1136 _ => Some(cx.struct_span_err(l.span, err_msg)),
1138 ast::ExprKind::Err => None,
1139 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1143 pub fn expr_to_string(
1144 cx: &mut ExtCtxt<'_>,
1147 ) -> Option<(Symbol, ast::StrStyle)> {
1148 expr_to_spanned_string(cx, expr, err_msg)
1155 .map(|(symbol, style, _)| (symbol, style))
1158 /// Non-fatally assert that `tts` is empty. Note that this function
1159 /// returns even when `tts` is non-empty, macros that *need* to stop
1160 /// compilation should call
1161 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1162 /// done as rarely as possible).
1163 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1164 if !tts.is_empty() {
1165 cx.span_err(sp, &format!("{} takes no arguments", name));
1169 /// Interpreting `tts` as a comma-separated sequence of expressions,
1170 /// expect exactly one string literal, or emit an error and return `None`.
1171 pub fn get_single_str_from_tts(
1172 cx: &mut ExtCtxt<'_>,
1176 ) -> Option<String> {
1177 let mut p = cx.new_parser_from_tts(tts);
1178 if p.token == token::Eof {
1179 cx.span_err(sp, &format!("{} takes 1 argument", name));
1182 let ret = panictry!(p.parse_expr());
1183 let _ = p.eat(&token::Comma);
1185 if p.token != token::Eof {
1186 cx.span_err(sp, &format!("{} takes 1 argument", name));
1188 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1191 /// Extracts comma-separated expressions from `tts`. If there is a
1192 /// parsing error, emit a non-fatal error and return `None`.
1193 pub fn get_exprs_from_tts(
1194 cx: &mut ExtCtxt<'_>,
1197 ) -> Option<Vec<P<ast::Expr>>> {
1198 let mut p = cx.new_parser_from_tts(tts);
1199 let mut es = Vec::new();
1200 while p.token != token::Eof {
1201 let expr = panictry!(p.parse_expr());
1203 // Perform eager expansion on the expression.
1204 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1205 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1208 if p.eat(&token::Comma) {
1211 if p.token != token::Eof {
1212 cx.span_err(sp, "expected token: `,`");