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::Interpolated(nt)) = tt {
269 if let token::NtIdent(ident, is_raw) = **nt {
270 *tt = tokenstream::TokenTree::Token(ident.span,
271 token::Ident(ident, is_raw));
274 mut_visit::noop_visit_tt(tt, self)
277 fn visit_mac(&mut self, mac: &mut ast::Mac) {
278 mut_visit::noop_visit_mac(mac, self)
283 input.trees().map(|mut tt| { AvoidInterpolatedIdents.visit_tt(&mut tt); tt }).collect();
284 (*self)(ecx, span, &input)
288 pub trait IdentMacroExpander {
289 fn expand<'cx>(&self,
290 cx: &'cx mut ExtCtxt<'_>,
293 token_tree: Vec<tokenstream::TokenTree>)
294 -> Box<dyn MacResult+'cx>;
297 pub type IdentMacroExpanderFn =
298 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident, Vec<tokenstream::TokenTree>)
299 -> Box<dyn MacResult+'cx>;
301 impl<F> IdentMacroExpander for F
302 where F : for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident,
303 Vec<tokenstream::TokenTree>) -> Box<dyn MacResult+'cx>
305 fn expand<'cx>(&self,
306 cx: &'cx mut ExtCtxt<'_>,
309 token_tree: Vec<tokenstream::TokenTree>)
310 -> Box<dyn MacResult+'cx>
312 (*self)(cx, sp, ident, token_tree)
316 // Use a macro because forwarding to a simple function has type system issues
317 macro_rules! make_stmts_default {
319 $me.make_expr().map(|e| smallvec![ast::Stmt {
320 id: ast::DUMMY_NODE_ID,
322 node: ast::StmtKind::Expr(e),
327 /// The result of a macro expansion. The return values of the various
328 /// methods are spliced into the AST at the callsite of the macro.
329 pub trait MacResult {
330 /// Creates an expression.
331 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
334 /// Creates zero or more items.
335 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
339 /// Creates zero or more impl items.
340 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
344 /// Creates zero or more trait items.
345 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
349 /// Creates zero or more items in an `extern {}` block
350 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { None }
352 /// Creates a pattern.
353 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
357 /// Creates zero or more statements.
359 /// By default this attempts to create an expression statement,
360 /// returning None if that fails.
361 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
362 make_stmts_default!(self)
365 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
370 macro_rules! make_MacEager {
371 ( $( $fld:ident: $t:ty, )* ) => {
372 /// `MacResult` implementation for the common case where you've already
373 /// built each form of AST that you might return.
375 pub struct MacEager {
377 pub $fld: Option<$t>,
383 pub fn $fld(v: $t) -> Box<dyn MacResult> {
397 items: SmallVec<[P<ast::Item>; 1]>,
398 impl_items: SmallVec<[ast::ImplItem; 1]>,
399 trait_items: SmallVec<[ast::TraitItem; 1]>,
400 foreign_items: SmallVec<[ast::ForeignItem; 1]>,
401 stmts: SmallVec<[ast::Stmt; 1]>,
405 impl MacResult for MacEager {
406 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
410 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
414 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
418 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
422 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
426 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
427 match self.stmts.as_ref().map_or(0, |s| s.len()) {
428 0 => make_stmts_default!(self),
433 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
434 if let Some(p) = self.pat {
437 if let Some(e) = self.expr {
438 if let ast::ExprKind::Lit(_) = e.node {
439 return Some(P(ast::Pat {
440 id: ast::DUMMY_NODE_ID,
442 node: PatKind::Lit(e),
449 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
454 /// Fill-in macro expansion result, to allow compilation to continue
455 /// after hitting errors.
456 #[derive(Copy, Clone)]
457 pub struct DummyResult {
464 /// Creates a default MacResult that can be anything.
466 /// Use this as a return value after hitting any errors and
467 /// calling `span_err`.
468 pub fn any(span: Span) -> Box<dyn MacResult+'static> {
469 Box::new(DummyResult { expr_only: false, is_error: true, span })
472 /// Same as `any`, but must be a valid fragment, not error.
473 pub fn any_valid(span: Span) -> Box<dyn MacResult+'static> {
474 Box::new(DummyResult { expr_only: false, is_error: false, span })
477 /// Creates a default MacResult that can only be an expression.
479 /// Use this for macros that must expand to an expression, so even
480 /// if an error is encountered internally, the user will receive
481 /// an error that they also used it in the wrong place.
482 pub fn expr(span: Span) -> Box<dyn MacResult+'static> {
483 Box::new(DummyResult { expr_only: true, is_error: true, span })
486 /// A plain dummy expression.
487 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
489 id: ast::DUMMY_NODE_ID,
490 node: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
492 attrs: ThinVec::new(),
496 /// A plain dummy pattern.
497 pub fn raw_pat(sp: Span) -> ast::Pat {
499 id: ast::DUMMY_NODE_ID,
505 /// A plain dummy type.
506 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
508 id: ast::DUMMY_NODE_ID,
509 node: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
515 impl MacResult for DummyResult {
516 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
517 Some(DummyResult::raw_expr(self.span, self.is_error))
520 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
521 Some(P(DummyResult::raw_pat(self.span)))
524 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
525 // this code needs a comment... why not always just return the Some() ?
529 Some(SmallVec::new())
533 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
537 Some(SmallVec::new())
541 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
545 Some(SmallVec::new())
549 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
553 Some(SmallVec::new())
557 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
558 Some(smallvec![ast::Stmt {
559 id: ast::DUMMY_NODE_ID,
560 node: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
565 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
566 Some(DummyResult::raw_ty(self.span, self.is_error))
570 pub type BuiltinDeriveFn =
571 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
573 /// Represents different kinds of macro invocations that can be resolved.
574 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
576 /// A bang macro - foo!()
578 /// An attribute macro - #[foo]
580 /// A derive attribute macro - #[derive(Foo)]
582 /// A view of a procedural macro from the same crate that defines it.
587 pub fn descr(self) -> &'static str {
589 MacroKind::Bang => "macro",
590 MacroKind::Attr => "attribute macro",
591 MacroKind::Derive => "derive macro",
592 MacroKind::ProcMacroStub => "crate-local procedural macro",
596 pub fn article(self) -> &'static str {
598 MacroKind::Attr => "an",
604 /// An enum representing the different kinds of syntax extensions.
605 pub enum SyntaxExtension {
606 /// A trivial "extension" that does nothing, only keeps the attribute and marks it as known.
607 NonMacroAttr { mark_used: bool },
609 /// A syntax extension that is attached to an item and creates new items
612 /// `#[derive(...)]` is a `MultiItemDecorator`.
614 /// Prefer ProcMacro or MultiModifier since they are more flexible.
615 MultiDecorator(Box<dyn MultiItemDecorator + sync::Sync + sync::Send>),
617 /// A syntax extension that is attached to an item and modifies it
618 /// in-place. Also allows decoration, i.e., creating new items.
619 MultiModifier(Box<dyn MultiItemModifier + sync::Sync + sync::Send>),
621 /// A function-like procedural macro. TokenStream -> TokenStream.
623 expander: Box<dyn ProcMacro + sync::Sync + sync::Send>,
624 /// Whitelist of unstable features that are treated as stable inside this macro
625 allow_internal_unstable: Option<Lrc<[Symbol]>>,
629 /// An attribute-like procedural macro. TokenStream, TokenStream -> TokenStream.
630 /// The first TokenSteam is the attribute, the second is the annotated item.
631 /// Allows modification of the input items and adding new items, similar to
632 /// MultiModifier, but uses TokenStreams, rather than AST nodes.
633 AttrProcMacro(Box<dyn AttrProcMacro + sync::Sync + sync::Send>, Edition),
635 /// A normal, function-like syntax extension.
637 /// `bytes!` is a `NormalTT`.
639 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
640 def_info: Option<(ast::NodeId, Span)>,
641 /// Whether the contents of the macro can
642 /// directly use `#[unstable]` things.
644 /// Only allows things that require a feature gate in the given whitelist
645 allow_internal_unstable: Option<Lrc<[Symbol]>>,
646 /// Whether the contents of the macro can use `unsafe`
647 /// without triggering the `unsafe_code` lint.
648 allow_internal_unsafe: bool,
649 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`)
650 /// for a given macro.
651 local_inner_macros: bool,
652 /// The macro's feature name if it is unstable, and the stability feature
653 unstable_feature: Option<(Symbol, u32)>,
654 /// Edition of the crate in which the macro is defined
658 /// A function-like syntax extension that has an extra ident before
661 expander: Box<dyn IdentMacroExpander + sync::Sync + sync::Send>,
663 allow_internal_unstable: Option<Lrc<[Symbol]>>,
666 /// An attribute-like procedural macro. TokenStream -> TokenStream.
667 /// The input is the annotated item.
668 /// Allows generating code to implement a Trait for a given struct
670 ProcMacroDerive(Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
671 Vec<Symbol> /* inert attribute names */, Edition),
673 /// An attribute-like procedural macro that derives a builtin trait.
674 BuiltinDerive(BuiltinDeriveFn),
676 /// A declarative macro, e.g., `macro m() {}`.
678 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
679 def_info: Option<(ast::NodeId, Span)>,
680 is_transparent: bool,
685 impl SyntaxExtension {
686 /// Returns which kind of macro calls this syntax extension.
687 pub fn kind(&self) -> MacroKind {
689 SyntaxExtension::DeclMacro { .. } |
690 SyntaxExtension::NormalTT { .. } |
691 SyntaxExtension::IdentTT { .. } |
692 SyntaxExtension::ProcMacro { .. } =>
694 SyntaxExtension::NonMacroAttr { .. } |
695 SyntaxExtension::MultiDecorator(..) |
696 SyntaxExtension::MultiModifier(..) |
697 SyntaxExtension::AttrProcMacro(..) =>
699 SyntaxExtension::ProcMacroDerive(..) |
700 SyntaxExtension::BuiltinDerive(..) =>
705 pub fn default_transparency(&self) -> Transparency {
707 SyntaxExtension::ProcMacro { .. } |
708 SyntaxExtension::AttrProcMacro(..) |
709 SyntaxExtension::ProcMacroDerive(..) |
710 SyntaxExtension::DeclMacro { is_transparent: false, .. } => Transparency::Opaque,
711 SyntaxExtension::DeclMacro { is_transparent: true, .. } => Transparency::Transparent,
712 _ => Transparency::SemiTransparent,
716 pub fn edition(&self, default_edition: Edition) -> Edition {
718 SyntaxExtension::NormalTT { edition, .. } |
719 SyntaxExtension::DeclMacro { edition, .. } |
720 SyntaxExtension::ProcMacro { edition, .. } |
721 SyntaxExtension::AttrProcMacro(.., edition) |
722 SyntaxExtension::ProcMacroDerive(.., edition) => edition,
723 // Unstable legacy stuff
724 SyntaxExtension::NonMacroAttr { .. } |
725 SyntaxExtension::IdentTT { .. } |
726 SyntaxExtension::MultiDecorator(..) |
727 SyntaxExtension::MultiModifier(..) |
728 SyntaxExtension::BuiltinDerive(..) => default_edition,
733 pub type NamedSyntaxExtension = (Name, SyntaxExtension);
736 fn next_node_id(&mut self) -> ast::NodeId;
738 fn get_module_scope(&mut self, id: ast::NodeId) -> Mark;
740 fn resolve_dollar_crates(&mut self, fragment: &AstFragment);
741 fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
743 fn add_builtin(&mut self, ident: ast::Ident, ext: Lrc<SyntaxExtension>);
745 fn resolve_imports(&mut self);
747 fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: Mark, force: bool)
748 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy>;
749 fn resolve_macro_path(&mut self, path: &ast::Path, kind: MacroKind, invoc_id: Mark,
750 derives_in_scope: Vec<ast::Path>, force: bool)
751 -> Result<Lrc<SyntaxExtension>, Determinacy>;
753 fn check_unused_macros(&self);
756 #[derive(Copy, Clone, PartialEq, Debug)]
757 pub enum Determinacy {
763 pub fn determined(determined: bool) -> Determinacy {
764 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
768 pub struct DummyResolver;
770 impl Resolver for DummyResolver {
771 fn next_node_id(&mut self) -> ast::NodeId { ast::DUMMY_NODE_ID }
773 fn get_module_scope(&mut self, _id: ast::NodeId) -> Mark { Mark::root() }
775 fn resolve_dollar_crates(&mut self, _fragment: &AstFragment) {}
776 fn visit_ast_fragment_with_placeholders(&mut self, _invoc: Mark, _fragment: &AstFragment,
777 _derives: &[Mark]) {}
778 fn add_builtin(&mut self, _ident: ast::Ident, _ext: Lrc<SyntaxExtension>) {}
780 fn resolve_imports(&mut self) {}
781 fn resolve_macro_invocation(&mut self, _invoc: &Invocation, _invoc_id: Mark, _force: bool)
782 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy> {
783 Err(Determinacy::Determined)
785 fn resolve_macro_path(&mut self, _path: &ast::Path, _kind: MacroKind, _invoc_id: Mark,
786 _derives_in_scope: Vec<ast::Path>, _force: bool)
787 -> Result<Lrc<SyntaxExtension>, Determinacy> {
788 Err(Determinacy::Determined)
790 fn check_unused_macros(&self) {}
794 pub struct ModuleData {
795 pub mod_path: Vec<ast::Ident>,
796 pub directory: PathBuf,
800 pub struct ExpansionData {
803 pub module: Rc<ModuleData>,
804 pub directory_ownership: DirectoryOwnership,
805 pub crate_span: Option<Span>,
808 /// One of these is made during expansion and incrementally updated as we go;
809 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
810 /// -> expn_info` of their expansion context stored into their span.
811 pub struct ExtCtxt<'a> {
812 pub parse_sess: &'a parse::ParseSess,
813 pub ecfg: expand::ExpansionConfig<'a>,
814 pub root_path: PathBuf,
815 pub resolver: &'a mut dyn Resolver,
816 pub current_expansion: ExpansionData,
817 pub expansions: FxHashMap<Span, Vec<String>>,
820 impl<'a> ExtCtxt<'a> {
821 pub fn new(parse_sess: &'a parse::ParseSess,
822 ecfg: expand::ExpansionConfig<'a>,
823 resolver: &'a mut dyn Resolver)
828 root_path: PathBuf::new(),
830 current_expansion: ExpansionData {
833 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
834 directory_ownership: DirectoryOwnership::Owned { relative: None },
837 expansions: FxHashMap::default(),
841 /// Returns a `Folder` for deeply expanding all macros in an AST node.
842 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
843 expand::MacroExpander::new(self, false)
846 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
847 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
848 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
849 expand::MacroExpander::new(self, true)
852 pub fn new_parser_from_tts(&self, tts: &[tokenstream::TokenTree]) -> parser::Parser<'a> {
853 parse::stream_to_parser(self.parse_sess, tts.iter().cloned().collect(), MACRO_ARGUMENTS)
855 pub fn source_map(&self) -> &'a SourceMap { self.parse_sess.source_map() }
856 pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
857 pub fn cfg(&self) -> &ast::CrateConfig { &self.parse_sess.config }
858 pub fn call_site(&self) -> Span {
859 match self.current_expansion.mark.expn_info() {
860 Some(expn_info) => expn_info.call_site,
864 pub fn backtrace(&self) -> SyntaxContext {
865 SyntaxContext::empty().apply_mark(self.current_expansion.mark)
868 /// Returns span for the macro which originally caused the current expansion to happen.
870 /// Stops backtracing at include! boundary.
871 pub fn expansion_cause(&self) -> Option<Span> {
872 let mut ctxt = self.backtrace();
873 let mut last_macro = None;
875 if ctxt.outer_expn_info().map_or(None, |info| {
876 if info.format.name() == sym::include {
877 // Stop going up the backtrace once include! is encountered
880 ctxt = info.call_site.ctxt();
881 last_macro = Some(info.call_site);
890 pub fn struct_span_warn<S: Into<MultiSpan>>(&self,
893 -> DiagnosticBuilder<'a> {
894 self.parse_sess.span_diagnostic.struct_span_warn(sp, msg)
896 pub fn struct_span_err<S: Into<MultiSpan>>(&self,
899 -> DiagnosticBuilder<'a> {
900 self.parse_sess.span_diagnostic.struct_span_err(sp, msg)
902 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self,
905 -> DiagnosticBuilder<'a> {
906 self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg)
909 /// Emit `msg` attached to `sp`, and stop compilation immediately.
911 /// `span_err` should be strongly preferred where-ever possible:
912 /// this should *only* be used when:
914 /// - continuing has a high risk of flow-on errors (e.g., errors in
915 /// declaring a macro would cause all uses of that macro to
916 /// complain about "undefined macro"), or
917 /// - there is literally nothing else that can be done (however,
918 /// in most cases one can construct a dummy expression/item to
919 /// substitute; we never hit resolve/type-checking so the dummy
920 /// value doesn't have to match anything)
921 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
922 self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise();
925 /// Emit `msg` attached to `sp`, without immediately stopping
928 /// Compilation will be stopped in the near future (at the end of
929 /// the macro expansion phase).
930 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
931 self.parse_sess.span_diagnostic.span_err(sp, msg);
933 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
934 self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code);
936 pub fn mut_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str)
937 -> DiagnosticBuilder<'a> {
938 self.parse_sess.span_diagnostic.mut_span_err(sp, msg)
940 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
941 self.parse_sess.span_diagnostic.span_warn(sp, msg);
943 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
944 self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
946 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
947 self.parse_sess.span_diagnostic.span_bug(sp, msg);
949 pub fn trace_macros_diag(&mut self) {
950 for (sp, notes) in self.expansions.iter() {
951 let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
957 // Fixme: does this result in errors?
958 self.expansions.clear();
960 pub fn bug(&self, msg: &str) -> ! {
961 self.parse_sess.span_diagnostic.bug(msg);
963 pub fn trace_macros(&self) -> bool {
966 pub fn set_trace_macros(&mut self, x: bool) {
967 self.ecfg.trace_mac = x
969 pub fn ident_of(&self, st: &str) -> ast::Ident {
970 ast::Ident::from_str(st)
972 pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
973 let def_site = DUMMY_SP.apply_mark(self.current_expansion.mark);
974 iter::once(Ident::new(kw::DollarCrate, def_site))
975 .chain(components.iter().map(|&s| Ident::with_empty_ctxt(s)))
978 pub fn name_of(&self, st: &str) -> ast::Name {
982 pub fn check_unused_macros(&self) {
983 self.resolver.check_unused_macros();
987 /// Extracts a string literal from the macro expanded version of `expr`,
988 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
989 /// compilation on error, merely emits a non-fatal error and returns `None`.
990 pub fn expr_to_spanned_string<'a>(
991 cx: &'a mut ExtCtxt<'_>,
992 mut expr: P<ast::Expr>,
994 ) -> Result<Spanned<(Symbol, ast::StrStyle)>, Option<DiagnosticBuilder<'a>>> {
995 // Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
996 expr.span = expr.span.apply_mark(cx.current_expansion.mark);
998 // we want to be able to handle e.g., `concat!("foo", "bar")`
999 cx.expander().visit_expr(&mut expr);
1000 Err(match expr.node {
1001 ast::ExprKind::Lit(ref l) => match l.node {
1002 ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
1003 ast::LitKind::Err(_) => None,
1004 _ => Some(cx.struct_span_err(l.span, err_msg))
1006 ast::ExprKind::Err => None,
1007 _ => Some(cx.struct_span_err(expr.span, err_msg))
1011 pub fn expr_to_string(cx: &mut ExtCtxt<'_>, expr: P<ast::Expr>, err_msg: &str)
1012 -> Option<(Symbol, ast::StrStyle)> {
1013 expr_to_spanned_string(cx, expr, err_msg)
1014 .map_err(|err| err.map(|mut err| err.emit()))
1019 /// Non-fatally assert that `tts` is empty. Note that this function
1020 /// returns even when `tts` is non-empty, macros that *need* to stop
1021 /// compilation should call
1022 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1023 /// done as rarely as possible).
1024 pub fn check_zero_tts(cx: &ExtCtxt<'_>,
1026 tts: &[tokenstream::TokenTree],
1028 if !tts.is_empty() {
1029 cx.span_err(sp, &format!("{} takes no arguments", name));
1033 /// Interpreting `tts` as a comma-separated sequence of expressions,
1034 /// expect exactly one string literal, or emit an error and return `None`.
1035 pub fn get_single_str_from_tts(cx: &mut ExtCtxt<'_>,
1037 tts: &[tokenstream::TokenTree],
1040 let mut p = cx.new_parser_from_tts(tts);
1041 if p.token == token::Eof {
1042 cx.span_err(sp, &format!("{} takes 1 argument", name));
1045 let ret = panictry!(p.parse_expr());
1046 let _ = p.eat(&token::Comma);
1048 if p.token != token::Eof {
1049 cx.span_err(sp, &format!("{} takes 1 argument", name));
1051 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| {
1056 /// Extracts comma-separated expressions from `tts`. If there is a
1057 /// parsing error, emit a non-fatal error and return `None`.
1058 pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
1060 tts: &[tokenstream::TokenTree]) -> Option<Vec<P<ast::Expr>>> {
1061 let mut p = cx.new_parser_from_tts(tts);
1062 let mut es = Vec::new();
1063 while p.token != token::Eof {
1064 let mut expr = panictry!(p.parse_expr());
1065 cx.expander().visit_expr(&mut expr);
1067 if p.eat(&token::Comma) {
1070 if p.token != token::Eof {
1071 cx.span_err(sp, "expected token: `,`");