1 pub use SyntaxExtension::*;
3 use crate::ast::{self, Attribute, Name, PatKind, MetaItem};
4 use crate::attr::HasAttrs;
5 use crate::source_map::{SourceMap, Spanned, respan};
6 use crate::edition::Edition;
7 use crate::ext::expand::{self, AstFragment, Invocation};
8 use crate::ext::hygiene::{Mark, SyntaxContext, Transparency};
9 use crate::mut_visit::{self, MutVisitor};
10 use crate::parse::{self, parser, DirectoryOwnership};
11 use crate::parse::token;
13 use crate::symbol::{kw, sym, Ident, Symbol};
14 use crate::{ThinVec, MACRO_ARGUMENTS};
15 use crate::tokenstream::{self, TokenStream};
17 use errors::{DiagnosticBuilder, DiagnosticId};
18 use smallvec::{smallvec, SmallVec};
19 use syntax_pos::{Span, MultiSpan, DUMMY_SP};
21 use rustc_data_structures::fx::FxHashMap;
22 use rustc_data_structures::sync::{self, Lrc};
24 use std::path::PathBuf;
26 use std::default::Default;
29 #[derive(Debug,Clone)]
30 pub enum Annotatable {
32 TraitItem(P<ast::TraitItem>),
33 ImplItem(P<ast::ImplItem>),
34 ForeignItem(P<ast::ForeignItem>),
39 impl HasAttrs for Annotatable {
40 fn attrs(&self) -> &[Attribute] {
42 Annotatable::Item(ref item) => &item.attrs,
43 Annotatable::TraitItem(ref trait_item) => &trait_item.attrs,
44 Annotatable::ImplItem(ref impl_item) => &impl_item.attrs,
45 Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs,
46 Annotatable::Stmt(ref stmt) => stmt.attrs(),
47 Annotatable::Expr(ref expr) => &expr.attrs,
51 fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
53 Annotatable::Item(item) => item.visit_attrs(f),
54 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
55 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
56 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
57 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
58 Annotatable::Expr(expr) => expr.visit_attrs(f),
64 pub fn span(&self) -> Span {
66 Annotatable::Item(ref item) => item.span,
67 Annotatable::TraitItem(ref trait_item) => trait_item.span,
68 Annotatable::ImplItem(ref impl_item) => impl_item.span,
69 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
70 Annotatable::Stmt(ref stmt) => stmt.span,
71 Annotatable::Expr(ref expr) => expr.span,
75 pub fn expect_item(self) -> P<ast::Item> {
77 Annotatable::Item(i) => i,
78 _ => panic!("expected Item")
82 pub fn map_item_or<F, G>(self, mut f: F, mut or: G) -> Annotatable
83 where F: FnMut(P<ast::Item>) -> P<ast::Item>,
84 G: FnMut(Annotatable) -> Annotatable
87 Annotatable::Item(i) => Annotatable::Item(f(i)),
92 pub fn expect_trait_item(self) -> ast::TraitItem {
94 Annotatable::TraitItem(i) => i.into_inner(),
95 _ => panic!("expected Item")
99 pub fn expect_impl_item(self) -> ast::ImplItem {
101 Annotatable::ImplItem(i) => i.into_inner(),
102 _ => panic!("expected Item")
106 pub fn expect_foreign_item(self) -> ast::ForeignItem {
108 Annotatable::ForeignItem(i) => i.into_inner(),
109 _ => panic!("expected foreign item")
113 pub fn expect_stmt(self) -> ast::Stmt {
115 Annotatable::Stmt(stmt) => stmt.into_inner(),
116 _ => panic!("expected statement"),
120 pub fn expect_expr(self) -> P<ast::Expr> {
122 Annotatable::Expr(expr) => expr,
123 _ => panic!("expected expression"),
127 pub fn derive_allowed(&self) -> bool {
129 Annotatable::Item(ref item) => match item.node {
130 ast::ItemKind::Struct(..) |
131 ast::ItemKind::Enum(..) |
132 ast::ItemKind::Union(..) => true,
140 // A more flexible ItemDecorator.
141 pub trait MultiItemDecorator {
143 ecx: &mut ExtCtxt<'_>,
145 meta_item: &ast::MetaItem,
147 push: &mut dyn FnMut(Annotatable));
150 impl<F> MultiItemDecorator for F
151 where F : Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, &Annotatable, &mut dyn FnMut(Annotatable))
154 ecx: &mut ExtCtxt<'_>,
156 meta_item: &ast::MetaItem,
158 push: &mut dyn FnMut(Annotatable)) {
159 (*self)(ecx, sp, meta_item, item, push)
163 // `meta_item` is the annotation, and `item` is the item being modified.
164 // FIXME Decorators should follow the same pattern too.
165 pub trait MultiItemModifier {
167 ecx: &mut ExtCtxt<'_>,
169 meta_item: &ast::MetaItem,
174 impl<F, T> MultiItemModifier for F
175 where F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T,
176 T: Into<Vec<Annotatable>>,
179 ecx: &mut ExtCtxt<'_>,
181 meta_item: &ast::MetaItem,
183 -> Vec<Annotatable> {
184 (*self)(ecx, span, meta_item, item).into()
188 impl Into<Vec<Annotatable>> for Annotatable {
189 fn into(self) -> Vec<Annotatable> {
194 pub trait ProcMacro {
195 fn expand<'cx>(&self,
196 ecx: &'cx mut ExtCtxt<'_>,
202 impl<F> ProcMacro for F
203 where F: Fn(TokenStream) -> TokenStream
205 fn expand<'cx>(&self,
206 _ecx: &'cx mut ExtCtxt<'_>,
210 // FIXME setup implicit context in TLS before calling self.
215 pub trait AttrProcMacro {
216 fn expand<'cx>(&self,
217 ecx: &'cx mut ExtCtxt<'_>,
219 annotation: TokenStream,
220 annotated: TokenStream)
224 impl<F> AttrProcMacro for F
225 where F: Fn(TokenStream, TokenStream) -> TokenStream
227 fn expand<'cx>(&self,
228 _ecx: &'cx mut ExtCtxt<'_>,
230 annotation: TokenStream,
231 annotated: TokenStream)
233 // FIXME setup implicit context in TLS before calling self.
234 (*self)(annotation, annotated)
238 /// Represents a thing that maps token trees to Macro Results
239 pub trait TTMacroExpander {
242 ecx: &'cx mut ExtCtxt<'_>,
245 def_span: Option<Span>,
246 ) -> Box<dyn MacResult+'cx>;
249 pub type MacroExpanderFn =
250 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &[tokenstream::TokenTree])
251 -> Box<dyn MacResult+'cx>;
253 impl<F> TTMacroExpander for F
254 where F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, &[tokenstream::TokenTree])
255 -> Box<dyn MacResult+'cx>
259 ecx: &'cx mut ExtCtxt<'_>,
262 _def_span: Option<Span>,
263 ) -> Box<dyn MacResult+'cx> {
264 struct AvoidInterpolatedIdents;
266 impl MutVisitor for AvoidInterpolatedIdents {
267 fn visit_tt(&mut self, tt: &mut tokenstream::TokenTree) {
268 if let tokenstream::TokenTree::Token(token) = tt {
269 if let token::Interpolated(nt) = &token.kind {
270 if let token::NtIdent(ident, is_raw) = **nt {
271 *tt = tokenstream::TokenTree::token(
272 token::Ident(ident.name, is_raw), ident.span
277 mut_visit::noop_visit_tt(tt, self)
280 fn visit_mac(&mut self, mac: &mut ast::Mac) {
281 mut_visit::noop_visit_mac(mac, self)
286 input.trees().map(|mut tt| { AvoidInterpolatedIdents.visit_tt(&mut tt); tt }).collect();
287 (*self)(ecx, span, &input)
291 pub trait IdentMacroExpander {
292 fn expand<'cx>(&self,
293 cx: &'cx mut ExtCtxt<'_>,
296 token_tree: Vec<tokenstream::TokenTree>)
297 -> Box<dyn MacResult+'cx>;
300 pub type IdentMacroExpanderFn =
301 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident, Vec<tokenstream::TokenTree>)
302 -> Box<dyn MacResult+'cx>;
304 impl<F> IdentMacroExpander for F
305 where F : for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident,
306 Vec<tokenstream::TokenTree>) -> Box<dyn MacResult+'cx>
308 fn expand<'cx>(&self,
309 cx: &'cx mut ExtCtxt<'_>,
312 token_tree: Vec<tokenstream::TokenTree>)
313 -> Box<dyn MacResult+'cx>
315 (*self)(cx, sp, ident, token_tree)
319 // Use a macro because forwarding to a simple function has type system issues
320 macro_rules! make_stmts_default {
322 $me.make_expr().map(|e| smallvec![ast::Stmt {
323 id: ast::DUMMY_NODE_ID,
325 node: ast::StmtKind::Expr(e),
330 /// The result of a macro expansion. The return values of the various
331 /// methods are spliced into the AST at the callsite of the macro.
332 pub trait MacResult {
333 /// Creates an expression.
334 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
337 /// Creates zero or more items.
338 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
342 /// Creates zero or more impl items.
343 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
347 /// Creates zero or more trait items.
348 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
352 /// Creates zero or more items in an `extern {}` block
353 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { None }
355 /// Creates a pattern.
356 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
360 /// Creates zero or more statements.
362 /// By default this attempts to create an expression statement,
363 /// returning None if that fails.
364 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
365 make_stmts_default!(self)
368 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
373 macro_rules! make_MacEager {
374 ( $( $fld:ident: $t:ty, )* ) => {
375 /// `MacResult` implementation for the common case where you've already
376 /// built each form of AST that you might return.
378 pub struct MacEager {
380 pub $fld: Option<$t>,
386 pub fn $fld(v: $t) -> Box<dyn MacResult> {
400 items: SmallVec<[P<ast::Item>; 1]>,
401 impl_items: SmallVec<[ast::ImplItem; 1]>,
402 trait_items: SmallVec<[ast::TraitItem; 1]>,
403 foreign_items: SmallVec<[ast::ForeignItem; 1]>,
404 stmts: SmallVec<[ast::Stmt; 1]>,
408 impl MacResult for MacEager {
409 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
413 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
417 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
421 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
425 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
429 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
430 match self.stmts.as_ref().map_or(0, |s| s.len()) {
431 0 => make_stmts_default!(self),
436 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
437 if let Some(p) = self.pat {
440 if let Some(e) = self.expr {
441 if let ast::ExprKind::Lit(_) = e.node {
442 return Some(P(ast::Pat {
443 id: ast::DUMMY_NODE_ID,
445 node: PatKind::Lit(e),
452 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
457 /// Fill-in macro expansion result, to allow compilation to continue
458 /// after hitting errors.
459 #[derive(Copy, Clone)]
460 pub struct DummyResult {
467 /// Creates a default MacResult that can be anything.
469 /// Use this as a return value after hitting any errors and
470 /// calling `span_err`.
471 pub fn any(span: Span) -> Box<dyn MacResult+'static> {
472 Box::new(DummyResult { expr_only: false, is_error: true, span })
475 /// Same as `any`, but must be a valid fragment, not error.
476 pub fn any_valid(span: Span) -> Box<dyn MacResult+'static> {
477 Box::new(DummyResult { expr_only: false, is_error: false, span })
480 /// Creates a default MacResult that can only be an expression.
482 /// Use this for macros that must expand to an expression, so even
483 /// if an error is encountered internally, the user will receive
484 /// an error that they also used it in the wrong place.
485 pub fn expr(span: Span) -> Box<dyn MacResult+'static> {
486 Box::new(DummyResult { expr_only: true, is_error: true, span })
489 /// A plain dummy expression.
490 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
492 id: ast::DUMMY_NODE_ID,
493 node: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
495 attrs: ThinVec::new(),
499 /// A plain dummy pattern.
500 pub fn raw_pat(sp: Span) -> ast::Pat {
502 id: ast::DUMMY_NODE_ID,
508 /// A plain dummy type.
509 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
511 id: ast::DUMMY_NODE_ID,
512 node: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
518 impl MacResult for DummyResult {
519 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
520 Some(DummyResult::raw_expr(self.span, self.is_error))
523 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
524 Some(P(DummyResult::raw_pat(self.span)))
527 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
528 // this code needs a comment... why not always just return the Some() ?
532 Some(SmallVec::new())
536 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
540 Some(SmallVec::new())
544 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
548 Some(SmallVec::new())
552 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
556 Some(SmallVec::new())
560 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
561 Some(smallvec![ast::Stmt {
562 id: ast::DUMMY_NODE_ID,
563 node: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
568 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
569 Some(DummyResult::raw_ty(self.span, self.is_error))
573 pub type BuiltinDeriveFn =
574 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
576 /// Represents different kinds of macro invocations that can be resolved.
577 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
579 /// A bang macro - foo!()
581 /// An attribute macro - #[foo]
583 /// A derive attribute macro - #[derive(Foo)]
585 /// A view of a procedural macro from the same crate that defines it.
590 pub fn descr(self) -> &'static str {
592 MacroKind::Bang => "macro",
593 MacroKind::Attr => "attribute macro",
594 MacroKind::Derive => "derive macro",
595 MacroKind::ProcMacroStub => "crate-local procedural macro",
599 pub fn article(self) -> &'static str {
601 MacroKind::Attr => "an",
607 /// An enum representing the different kinds of syntax extensions.
608 pub enum SyntaxExtension {
609 /// A trivial "extension" that does nothing, only keeps the attribute and marks it as known.
610 NonMacroAttr { mark_used: bool },
612 /// A syntax extension that is attached to an item and creates new items
615 /// `#[derive(...)]` is a `MultiItemDecorator`.
617 /// Prefer ProcMacro or MultiModifier since they are more flexible.
618 MultiDecorator(Box<dyn MultiItemDecorator + sync::Sync + sync::Send>),
620 /// A syntax extension that is attached to an item and modifies it
621 /// in-place. Also allows decoration, i.e., creating new items.
622 MultiModifier(Box<dyn MultiItemModifier + sync::Sync + sync::Send>),
624 /// A function-like procedural macro. TokenStream -> TokenStream.
626 expander: Box<dyn ProcMacro + sync::Sync + sync::Send>,
627 /// Whitelist of unstable features that are treated as stable inside this macro
628 allow_internal_unstable: Option<Lrc<[Symbol]>>,
632 /// An attribute-like procedural macro. TokenStream, TokenStream -> TokenStream.
633 /// The first TokenSteam is the attribute, the second is the annotated item.
634 /// Allows modification of the input items and adding new items, similar to
635 /// MultiModifier, but uses TokenStreams, rather than AST nodes.
636 AttrProcMacro(Box<dyn AttrProcMacro + sync::Sync + sync::Send>, Edition),
638 /// A normal, function-like syntax extension.
640 /// `bytes!` is a `NormalTT`.
642 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
643 def_info: Option<(ast::NodeId, Span)>,
644 /// Whether the contents of the macro can
645 /// directly use `#[unstable]` things.
647 /// Only allows things that require a feature gate in the given whitelist
648 allow_internal_unstable: Option<Lrc<[Symbol]>>,
649 /// Whether the contents of the macro can use `unsafe`
650 /// without triggering the `unsafe_code` lint.
651 allow_internal_unsafe: bool,
652 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`)
653 /// for a given macro.
654 local_inner_macros: bool,
655 /// The macro's feature name if it is unstable, and the stability feature
656 unstable_feature: Option<(Symbol, u32)>,
657 /// Edition of the crate in which the macro is defined
661 /// A function-like syntax extension that has an extra ident before
664 expander: Box<dyn IdentMacroExpander + sync::Sync + sync::Send>,
666 allow_internal_unstable: Option<Lrc<[Symbol]>>,
669 /// An attribute-like procedural macro. TokenStream -> TokenStream.
670 /// The input is the annotated item.
671 /// Allows generating code to implement a Trait for a given struct
673 ProcMacroDerive(Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
674 Vec<Symbol> /* inert attribute names */, Edition),
676 /// An attribute-like procedural macro that derives a builtin trait.
677 BuiltinDerive(BuiltinDeriveFn),
679 /// A declarative macro, e.g., `macro m() {}`.
681 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
682 def_info: Option<(ast::NodeId, Span)>,
683 is_transparent: bool,
688 impl SyntaxExtension {
689 /// Returns which kind of macro calls this syntax extension.
690 pub fn kind(&self) -> MacroKind {
692 SyntaxExtension::DeclMacro { .. } |
693 SyntaxExtension::NormalTT { .. } |
694 SyntaxExtension::IdentTT { .. } |
695 SyntaxExtension::ProcMacro { .. } =>
697 SyntaxExtension::NonMacroAttr { .. } |
698 SyntaxExtension::MultiDecorator(..) |
699 SyntaxExtension::MultiModifier(..) |
700 SyntaxExtension::AttrProcMacro(..) =>
702 SyntaxExtension::ProcMacroDerive(..) |
703 SyntaxExtension::BuiltinDerive(..) =>
708 pub fn default_transparency(&self) -> Transparency {
710 SyntaxExtension::ProcMacro { .. } |
711 SyntaxExtension::AttrProcMacro(..) |
712 SyntaxExtension::ProcMacroDerive(..) |
713 SyntaxExtension::DeclMacro { is_transparent: false, .. } => Transparency::Opaque,
714 SyntaxExtension::DeclMacro { is_transparent: true, .. } => Transparency::Transparent,
715 _ => Transparency::SemiTransparent,
719 pub fn edition(&self, default_edition: Edition) -> Edition {
721 SyntaxExtension::NormalTT { edition, .. } |
722 SyntaxExtension::DeclMacro { edition, .. } |
723 SyntaxExtension::ProcMacro { edition, .. } |
724 SyntaxExtension::AttrProcMacro(.., edition) |
725 SyntaxExtension::ProcMacroDerive(.., edition) => edition,
726 // Unstable legacy stuff
727 SyntaxExtension::NonMacroAttr { .. } |
728 SyntaxExtension::IdentTT { .. } |
729 SyntaxExtension::MultiDecorator(..) |
730 SyntaxExtension::MultiModifier(..) |
731 SyntaxExtension::BuiltinDerive(..) => default_edition,
736 pub type NamedSyntaxExtension = (Name, SyntaxExtension);
739 fn next_node_id(&mut self) -> ast::NodeId;
741 fn get_module_scope(&mut self, id: ast::NodeId) -> Mark;
743 fn resolve_dollar_crates(&mut self, fragment: &AstFragment);
744 fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
746 fn add_builtin(&mut self, ident: ast::Ident, ext: Lrc<SyntaxExtension>);
748 fn resolve_imports(&mut self);
750 fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: Mark, force: bool)
751 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy>;
752 fn resolve_macro_path(&mut self, path: &ast::Path, kind: MacroKind, invoc_id: Mark,
753 derives_in_scope: Vec<ast::Path>, force: bool)
754 -> Result<Lrc<SyntaxExtension>, Determinacy>;
756 fn check_unused_macros(&self);
759 #[derive(Copy, Clone, PartialEq, Debug)]
760 pub enum Determinacy {
766 pub fn determined(determined: bool) -> Determinacy {
767 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
771 pub struct DummyResolver;
773 impl Resolver for DummyResolver {
774 fn next_node_id(&mut self) -> ast::NodeId { ast::DUMMY_NODE_ID }
776 fn get_module_scope(&mut self, _id: ast::NodeId) -> Mark { Mark::root() }
778 fn resolve_dollar_crates(&mut self, _fragment: &AstFragment) {}
779 fn visit_ast_fragment_with_placeholders(&mut self, _invoc: Mark, _fragment: &AstFragment,
780 _derives: &[Mark]) {}
781 fn add_builtin(&mut self, _ident: ast::Ident, _ext: Lrc<SyntaxExtension>) {}
783 fn resolve_imports(&mut self) {}
784 fn resolve_macro_invocation(&mut self, _invoc: &Invocation, _invoc_id: Mark, _force: bool)
785 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy> {
786 Err(Determinacy::Determined)
788 fn resolve_macro_path(&mut self, _path: &ast::Path, _kind: MacroKind, _invoc_id: Mark,
789 _derives_in_scope: Vec<ast::Path>, _force: bool)
790 -> Result<Lrc<SyntaxExtension>, Determinacy> {
791 Err(Determinacy::Determined)
793 fn check_unused_macros(&self) {}
797 pub struct ModuleData {
798 pub mod_path: Vec<ast::Ident>,
799 pub directory: PathBuf,
803 pub struct ExpansionData {
806 pub module: Rc<ModuleData>,
807 pub directory_ownership: DirectoryOwnership,
808 pub crate_span: Option<Span>,
811 /// One of these is made during expansion and incrementally updated as we go;
812 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
813 /// -> expn_info` of their expansion context stored into their span.
814 pub struct ExtCtxt<'a> {
815 pub parse_sess: &'a parse::ParseSess,
816 pub ecfg: expand::ExpansionConfig<'a>,
817 pub root_path: PathBuf,
818 pub resolver: &'a mut dyn Resolver,
819 pub current_expansion: ExpansionData,
820 pub expansions: FxHashMap<Span, Vec<String>>,
823 impl<'a> ExtCtxt<'a> {
824 pub fn new(parse_sess: &'a parse::ParseSess,
825 ecfg: expand::ExpansionConfig<'a>,
826 resolver: &'a mut dyn Resolver)
831 root_path: PathBuf::new(),
833 current_expansion: ExpansionData {
836 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
837 directory_ownership: DirectoryOwnership::Owned { relative: None },
840 expansions: FxHashMap::default(),
844 /// Returns a `Folder` for deeply expanding all macros in an AST node.
845 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
846 expand::MacroExpander::new(self, false)
849 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
850 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
851 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
852 expand::MacroExpander::new(self, true)
855 pub fn new_parser_from_tts(&self, tts: &[tokenstream::TokenTree]) -> parser::Parser<'a> {
856 parse::stream_to_parser(self.parse_sess, tts.iter().cloned().collect(), MACRO_ARGUMENTS)
858 pub fn source_map(&self) -> &'a SourceMap { self.parse_sess.source_map() }
859 pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
860 pub fn cfg(&self) -> &ast::CrateConfig { &self.parse_sess.config }
861 pub fn call_site(&self) -> Span {
862 match self.current_expansion.mark.expn_info() {
863 Some(expn_info) => expn_info.call_site,
867 pub fn backtrace(&self) -> SyntaxContext {
868 SyntaxContext::empty().apply_mark(self.current_expansion.mark)
871 /// Returns span for the macro which originally caused the current expansion to happen.
873 /// Stops backtracing at include! boundary.
874 pub fn expansion_cause(&self) -> Option<Span> {
875 let mut ctxt = self.backtrace();
876 let mut last_macro = None;
878 if ctxt.outer_expn_info().map_or(None, |info| {
879 if info.format.name() == sym::include {
880 // Stop going up the backtrace once include! is encountered
883 ctxt = info.call_site.ctxt();
884 last_macro = Some(info.call_site);
893 pub fn struct_span_warn<S: Into<MultiSpan>>(&self,
896 -> DiagnosticBuilder<'a> {
897 self.parse_sess.span_diagnostic.struct_span_warn(sp, msg)
899 pub fn struct_span_err<S: Into<MultiSpan>>(&self,
902 -> DiagnosticBuilder<'a> {
903 self.parse_sess.span_diagnostic.struct_span_err(sp, msg)
905 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self,
908 -> DiagnosticBuilder<'a> {
909 self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg)
912 /// Emit `msg` attached to `sp`, and stop compilation immediately.
914 /// `span_err` should be strongly preferred where-ever possible:
915 /// this should *only* be used when:
917 /// - continuing has a high risk of flow-on errors (e.g., errors in
918 /// declaring a macro would cause all uses of that macro to
919 /// complain about "undefined macro"), or
920 /// - there is literally nothing else that can be done (however,
921 /// in most cases one can construct a dummy expression/item to
922 /// substitute; we never hit resolve/type-checking so the dummy
923 /// value doesn't have to match anything)
924 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
925 self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise();
928 /// Emit `msg` attached to `sp`, without immediately stopping
931 /// Compilation will be stopped in the near future (at the end of
932 /// the macro expansion phase).
933 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
934 self.parse_sess.span_diagnostic.span_err(sp, msg);
936 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
937 self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code);
939 pub fn mut_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str)
940 -> DiagnosticBuilder<'a> {
941 self.parse_sess.span_diagnostic.mut_span_err(sp, msg)
943 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
944 self.parse_sess.span_diagnostic.span_warn(sp, msg);
946 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
947 self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
949 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
950 self.parse_sess.span_diagnostic.span_bug(sp, msg);
952 pub fn trace_macros_diag(&mut self) {
953 for (sp, notes) in self.expansions.iter() {
954 let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
960 // Fixme: does this result in errors?
961 self.expansions.clear();
963 pub fn bug(&self, msg: &str) -> ! {
964 self.parse_sess.span_diagnostic.bug(msg);
966 pub fn trace_macros(&self) -> bool {
969 pub fn set_trace_macros(&mut self, x: bool) {
970 self.ecfg.trace_mac = x
972 pub fn ident_of(&self, st: &str) -> ast::Ident {
973 ast::Ident::from_str(st)
975 pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
976 let def_site = DUMMY_SP.apply_mark(self.current_expansion.mark);
977 iter::once(Ident::new(kw::DollarCrate, def_site))
978 .chain(components.iter().map(|&s| Ident::with_empty_ctxt(s)))
981 pub fn name_of(&self, st: &str) -> ast::Name {
985 pub fn check_unused_macros(&self) {
986 self.resolver.check_unused_macros();
990 /// Extracts a string literal from the macro expanded version of `expr`,
991 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
992 /// compilation on error, merely emits a non-fatal error and returns `None`.
993 pub fn expr_to_spanned_string<'a>(
994 cx: &'a mut ExtCtxt<'_>,
995 mut expr: P<ast::Expr>,
997 ) -> Result<Spanned<(Symbol, ast::StrStyle)>, Option<DiagnosticBuilder<'a>>> {
998 // Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
999 expr.span = expr.span.apply_mark(cx.current_expansion.mark);
1001 // we want to be able to handle e.g., `concat!("foo", "bar")`
1002 cx.expander().visit_expr(&mut expr);
1003 Err(match expr.node {
1004 ast::ExprKind::Lit(ref l) => match l.node {
1005 ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
1006 ast::LitKind::Err(_) => None,
1007 _ => Some(cx.struct_span_err(l.span, err_msg))
1009 ast::ExprKind::Err => None,
1010 _ => Some(cx.struct_span_err(expr.span, err_msg))
1014 pub fn expr_to_string(cx: &mut ExtCtxt<'_>, expr: P<ast::Expr>, err_msg: &str)
1015 -> Option<(Symbol, ast::StrStyle)> {
1016 expr_to_spanned_string(cx, expr, err_msg)
1017 .map_err(|err| err.map(|mut err| err.emit()))
1022 /// Non-fatally assert that `tts` is empty. Note that this function
1023 /// returns even when `tts` is non-empty, macros that *need* to stop
1024 /// compilation should call
1025 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1026 /// done as rarely as possible).
1027 pub fn check_zero_tts(cx: &ExtCtxt<'_>,
1029 tts: &[tokenstream::TokenTree],
1031 if !tts.is_empty() {
1032 cx.span_err(sp, &format!("{} takes no arguments", name));
1036 /// Interpreting `tts` as a comma-separated sequence of expressions,
1037 /// expect exactly one string literal, or emit an error and return `None`.
1038 pub fn get_single_str_from_tts(cx: &mut ExtCtxt<'_>,
1040 tts: &[tokenstream::TokenTree],
1043 let mut p = cx.new_parser_from_tts(tts);
1044 if p.token == token::Eof {
1045 cx.span_err(sp, &format!("{} takes 1 argument", name));
1048 let ret = panictry!(p.parse_expr());
1049 let _ = p.eat(&token::Comma);
1051 if p.token != token::Eof {
1052 cx.span_err(sp, &format!("{} takes 1 argument", name));
1054 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| {
1059 /// Extracts comma-separated expressions from `tts`. If there is a
1060 /// parsing error, emit a non-fatal error and return `None`.
1061 pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
1063 tts: &[tokenstream::TokenTree]) -> Option<Vec<P<ast::Expr>>> {
1064 let mut p = cx.new_parser_from_tts(tts);
1065 let mut es = Vec::new();
1066 while p.token != token::Eof {
1067 let mut expr = panictry!(p.parse_expr());
1068 cx.expander().visit_expr(&mut expr);
1070 if p.eat(&token::Comma) {
1073 if p.token != token::Eof {
1074 cx.span_err(sp, "expected token: `,`");