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(ident.span,
272 token::Ident(ident.name, is_raw));
276 mut_visit::noop_visit_tt(tt, self)
279 fn visit_mac(&mut self, mac: &mut ast::Mac) {
280 mut_visit::noop_visit_mac(mac, self)
285 input.trees().map(|mut tt| { AvoidInterpolatedIdents.visit_tt(&mut tt); tt }).collect();
286 (*self)(ecx, span, &input)
290 pub trait IdentMacroExpander {
291 fn expand<'cx>(&self,
292 cx: &'cx mut ExtCtxt<'_>,
295 token_tree: Vec<tokenstream::TokenTree>)
296 -> Box<dyn MacResult+'cx>;
299 pub type IdentMacroExpanderFn =
300 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident, Vec<tokenstream::TokenTree>)
301 -> Box<dyn MacResult+'cx>;
303 impl<F> IdentMacroExpander for F
304 where F : for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident,
305 Vec<tokenstream::TokenTree>) -> Box<dyn MacResult+'cx>
307 fn expand<'cx>(&self,
308 cx: &'cx mut ExtCtxt<'_>,
311 token_tree: Vec<tokenstream::TokenTree>)
312 -> Box<dyn MacResult+'cx>
314 (*self)(cx, sp, ident, token_tree)
318 // Use a macro because forwarding to a simple function has type system issues
319 macro_rules! make_stmts_default {
321 $me.make_expr().map(|e| smallvec![ast::Stmt {
322 id: ast::DUMMY_NODE_ID,
324 node: ast::StmtKind::Expr(e),
329 /// The result of a macro expansion. The return values of the various
330 /// methods are spliced into the AST at the callsite of the macro.
331 pub trait MacResult {
332 /// Creates an expression.
333 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
336 /// Creates zero or more items.
337 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
341 /// Creates zero or more impl items.
342 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
346 /// Creates zero or more trait items.
347 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
351 /// Creates zero or more items in an `extern {}` block
352 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { None }
354 /// Creates a pattern.
355 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
359 /// Creates zero or more statements.
361 /// By default this attempts to create an expression statement,
362 /// returning None if that fails.
363 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
364 make_stmts_default!(self)
367 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
372 macro_rules! make_MacEager {
373 ( $( $fld:ident: $t:ty, )* ) => {
374 /// `MacResult` implementation for the common case where you've already
375 /// built each form of AST that you might return.
377 pub struct MacEager {
379 pub $fld: Option<$t>,
385 pub fn $fld(v: $t) -> Box<dyn MacResult> {
399 items: SmallVec<[P<ast::Item>; 1]>,
400 impl_items: SmallVec<[ast::ImplItem; 1]>,
401 trait_items: SmallVec<[ast::TraitItem; 1]>,
402 foreign_items: SmallVec<[ast::ForeignItem; 1]>,
403 stmts: SmallVec<[ast::Stmt; 1]>,
407 impl MacResult for MacEager {
408 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
412 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
416 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
420 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
424 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
428 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
429 match self.stmts.as_ref().map_or(0, |s| s.len()) {
430 0 => make_stmts_default!(self),
435 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
436 if let Some(p) = self.pat {
439 if let Some(e) = self.expr {
440 if let ast::ExprKind::Lit(_) = e.node {
441 return Some(P(ast::Pat {
442 id: ast::DUMMY_NODE_ID,
444 node: PatKind::Lit(e),
451 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
456 /// Fill-in macro expansion result, to allow compilation to continue
457 /// after hitting errors.
458 #[derive(Copy, Clone)]
459 pub struct DummyResult {
466 /// Creates a default MacResult that can be anything.
468 /// Use this as a return value after hitting any errors and
469 /// calling `span_err`.
470 pub fn any(span: Span) -> Box<dyn MacResult+'static> {
471 Box::new(DummyResult { expr_only: false, is_error: true, span })
474 /// Same as `any`, but must be a valid fragment, not error.
475 pub fn any_valid(span: Span) -> Box<dyn MacResult+'static> {
476 Box::new(DummyResult { expr_only: false, is_error: false, span })
479 /// Creates a default MacResult that can only be an expression.
481 /// Use this for macros that must expand to an expression, so even
482 /// if an error is encountered internally, the user will receive
483 /// an error that they also used it in the wrong place.
484 pub fn expr(span: Span) -> Box<dyn MacResult+'static> {
485 Box::new(DummyResult { expr_only: true, is_error: true, span })
488 /// A plain dummy expression.
489 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
491 id: ast::DUMMY_NODE_ID,
492 node: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
494 attrs: ThinVec::new(),
498 /// A plain dummy pattern.
499 pub fn raw_pat(sp: Span) -> ast::Pat {
501 id: ast::DUMMY_NODE_ID,
507 /// A plain dummy type.
508 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
510 id: ast::DUMMY_NODE_ID,
511 node: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
517 impl MacResult for DummyResult {
518 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
519 Some(DummyResult::raw_expr(self.span, self.is_error))
522 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
523 Some(P(DummyResult::raw_pat(self.span)))
526 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
527 // this code needs a comment... why not always just return the Some() ?
531 Some(SmallVec::new())
535 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
539 Some(SmallVec::new())
543 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
547 Some(SmallVec::new())
551 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> {
555 Some(SmallVec::new())
559 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
560 Some(smallvec![ast::Stmt {
561 id: ast::DUMMY_NODE_ID,
562 node: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
567 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
568 Some(DummyResult::raw_ty(self.span, self.is_error))
572 pub type BuiltinDeriveFn =
573 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
575 /// Represents different kinds of macro invocations that can be resolved.
576 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
578 /// A bang macro - foo!()
580 /// An attribute macro - #[foo]
582 /// A derive attribute macro - #[derive(Foo)]
584 /// A view of a procedural macro from the same crate that defines it.
589 pub fn descr(self) -> &'static str {
591 MacroKind::Bang => "macro",
592 MacroKind::Attr => "attribute macro",
593 MacroKind::Derive => "derive macro",
594 MacroKind::ProcMacroStub => "crate-local procedural macro",
598 pub fn article(self) -> &'static str {
600 MacroKind::Attr => "an",
606 /// An enum representing the different kinds of syntax extensions.
607 pub enum SyntaxExtension {
608 /// A trivial "extension" that does nothing, only keeps the attribute and marks it as known.
609 NonMacroAttr { mark_used: bool },
611 /// A syntax extension that is attached to an item and creates new items
614 /// `#[derive(...)]` is a `MultiItemDecorator`.
616 /// Prefer ProcMacro or MultiModifier since they are more flexible.
617 MultiDecorator(Box<dyn MultiItemDecorator + sync::Sync + sync::Send>),
619 /// A syntax extension that is attached to an item and modifies it
620 /// in-place. Also allows decoration, i.e., creating new items.
621 MultiModifier(Box<dyn MultiItemModifier + sync::Sync + sync::Send>),
623 /// A function-like procedural macro. TokenStream -> TokenStream.
625 expander: Box<dyn ProcMacro + sync::Sync + sync::Send>,
626 /// Whitelist of unstable features that are treated as stable inside this macro
627 allow_internal_unstable: Option<Lrc<[Symbol]>>,
631 /// An attribute-like procedural macro. TokenStream, TokenStream -> TokenStream.
632 /// The first TokenSteam is the attribute, the second is the annotated item.
633 /// Allows modification of the input items and adding new items, similar to
634 /// MultiModifier, but uses TokenStreams, rather than AST nodes.
635 AttrProcMacro(Box<dyn AttrProcMacro + sync::Sync + sync::Send>, Edition),
637 /// A normal, function-like syntax extension.
639 /// `bytes!` is a `NormalTT`.
641 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
642 def_info: Option<(ast::NodeId, Span)>,
643 /// Whether the contents of the macro can
644 /// directly use `#[unstable]` things.
646 /// Only allows things that require a feature gate in the given whitelist
647 allow_internal_unstable: Option<Lrc<[Symbol]>>,
648 /// Whether the contents of the macro can use `unsafe`
649 /// without triggering the `unsafe_code` lint.
650 allow_internal_unsafe: bool,
651 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`)
652 /// for a given macro.
653 local_inner_macros: bool,
654 /// The macro's feature name if it is unstable, and the stability feature
655 unstable_feature: Option<(Symbol, u32)>,
656 /// Edition of the crate in which the macro is defined
660 /// A function-like syntax extension that has an extra ident before
663 expander: Box<dyn IdentMacroExpander + sync::Sync + sync::Send>,
665 allow_internal_unstable: Option<Lrc<[Symbol]>>,
668 /// An attribute-like procedural macro. TokenStream -> TokenStream.
669 /// The input is the annotated item.
670 /// Allows generating code to implement a Trait for a given struct
672 ProcMacroDerive(Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
673 Vec<Symbol> /* inert attribute names */, Edition),
675 /// An attribute-like procedural macro that derives a builtin trait.
676 BuiltinDerive(BuiltinDeriveFn),
678 /// A declarative macro, e.g., `macro m() {}`.
680 expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
681 def_info: Option<(ast::NodeId, Span)>,
682 is_transparent: bool,
687 impl SyntaxExtension {
688 /// Returns which kind of macro calls this syntax extension.
689 pub fn kind(&self) -> MacroKind {
691 SyntaxExtension::DeclMacro { .. } |
692 SyntaxExtension::NormalTT { .. } |
693 SyntaxExtension::IdentTT { .. } |
694 SyntaxExtension::ProcMacro { .. } =>
696 SyntaxExtension::NonMacroAttr { .. } |
697 SyntaxExtension::MultiDecorator(..) |
698 SyntaxExtension::MultiModifier(..) |
699 SyntaxExtension::AttrProcMacro(..) =>
701 SyntaxExtension::ProcMacroDerive(..) |
702 SyntaxExtension::BuiltinDerive(..) =>
707 pub fn default_transparency(&self) -> Transparency {
709 SyntaxExtension::ProcMacro { .. } |
710 SyntaxExtension::AttrProcMacro(..) |
711 SyntaxExtension::ProcMacroDerive(..) |
712 SyntaxExtension::DeclMacro { is_transparent: false, .. } => Transparency::Opaque,
713 SyntaxExtension::DeclMacro { is_transparent: true, .. } => Transparency::Transparent,
714 _ => Transparency::SemiTransparent,
718 pub fn edition(&self, default_edition: Edition) -> Edition {
720 SyntaxExtension::NormalTT { edition, .. } |
721 SyntaxExtension::DeclMacro { edition, .. } |
722 SyntaxExtension::ProcMacro { edition, .. } |
723 SyntaxExtension::AttrProcMacro(.., edition) |
724 SyntaxExtension::ProcMacroDerive(.., edition) => edition,
725 // Unstable legacy stuff
726 SyntaxExtension::NonMacroAttr { .. } |
727 SyntaxExtension::IdentTT { .. } |
728 SyntaxExtension::MultiDecorator(..) |
729 SyntaxExtension::MultiModifier(..) |
730 SyntaxExtension::BuiltinDerive(..) => default_edition,
735 pub type NamedSyntaxExtension = (Name, SyntaxExtension);
738 fn next_node_id(&mut self) -> ast::NodeId;
740 fn get_module_scope(&mut self, id: ast::NodeId) -> Mark;
742 fn resolve_dollar_crates(&mut self, fragment: &AstFragment);
743 fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
745 fn add_builtin(&mut self, ident: ast::Ident, ext: Lrc<SyntaxExtension>);
747 fn resolve_imports(&mut self);
749 fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: Mark, force: bool)
750 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy>;
751 fn resolve_macro_path(&mut self, path: &ast::Path, kind: MacroKind, invoc_id: Mark,
752 derives_in_scope: Vec<ast::Path>, force: bool)
753 -> Result<Lrc<SyntaxExtension>, Determinacy>;
755 fn check_unused_macros(&self);
758 #[derive(Copy, Clone, PartialEq, Debug)]
759 pub enum Determinacy {
765 pub fn determined(determined: bool) -> Determinacy {
766 if determined { Determinacy::Determined } else { Determinacy::Undetermined }
770 pub struct DummyResolver;
772 impl Resolver for DummyResolver {
773 fn next_node_id(&mut self) -> ast::NodeId { ast::DUMMY_NODE_ID }
775 fn get_module_scope(&mut self, _id: ast::NodeId) -> Mark { Mark::root() }
777 fn resolve_dollar_crates(&mut self, _fragment: &AstFragment) {}
778 fn visit_ast_fragment_with_placeholders(&mut self, _invoc: Mark, _fragment: &AstFragment,
779 _derives: &[Mark]) {}
780 fn add_builtin(&mut self, _ident: ast::Ident, _ext: Lrc<SyntaxExtension>) {}
782 fn resolve_imports(&mut self) {}
783 fn resolve_macro_invocation(&mut self, _invoc: &Invocation, _invoc_id: Mark, _force: bool)
784 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy> {
785 Err(Determinacy::Determined)
787 fn resolve_macro_path(&mut self, _path: &ast::Path, _kind: MacroKind, _invoc_id: Mark,
788 _derives_in_scope: Vec<ast::Path>, _force: bool)
789 -> Result<Lrc<SyntaxExtension>, Determinacy> {
790 Err(Determinacy::Determined)
792 fn check_unused_macros(&self) {}
796 pub struct ModuleData {
797 pub mod_path: Vec<ast::Ident>,
798 pub directory: PathBuf,
802 pub struct ExpansionData {
805 pub module: Rc<ModuleData>,
806 pub directory_ownership: DirectoryOwnership,
807 pub crate_span: Option<Span>,
810 /// One of these is made during expansion and incrementally updated as we go;
811 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
812 /// -> expn_info` of their expansion context stored into their span.
813 pub struct ExtCtxt<'a> {
814 pub parse_sess: &'a parse::ParseSess,
815 pub ecfg: expand::ExpansionConfig<'a>,
816 pub root_path: PathBuf,
817 pub resolver: &'a mut dyn Resolver,
818 pub current_expansion: ExpansionData,
819 pub expansions: FxHashMap<Span, Vec<String>>,
822 impl<'a> ExtCtxt<'a> {
823 pub fn new(parse_sess: &'a parse::ParseSess,
824 ecfg: expand::ExpansionConfig<'a>,
825 resolver: &'a mut dyn Resolver)
830 root_path: PathBuf::new(),
832 current_expansion: ExpansionData {
835 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
836 directory_ownership: DirectoryOwnership::Owned { relative: None },
839 expansions: FxHashMap::default(),
843 /// Returns a `Folder` for deeply expanding all macros in an AST node.
844 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
845 expand::MacroExpander::new(self, false)
848 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
849 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
850 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
851 expand::MacroExpander::new(self, true)
854 pub fn new_parser_from_tts(&self, tts: &[tokenstream::TokenTree]) -> parser::Parser<'a> {
855 parse::stream_to_parser(self.parse_sess, tts.iter().cloned().collect(), MACRO_ARGUMENTS)
857 pub fn source_map(&self) -> &'a SourceMap { self.parse_sess.source_map() }
858 pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
859 pub fn cfg(&self) -> &ast::CrateConfig { &self.parse_sess.config }
860 pub fn call_site(&self) -> Span {
861 match self.current_expansion.mark.expn_info() {
862 Some(expn_info) => expn_info.call_site,
866 pub fn backtrace(&self) -> SyntaxContext {
867 SyntaxContext::empty().apply_mark(self.current_expansion.mark)
870 /// Returns span for the macro which originally caused the current expansion to happen.
872 /// Stops backtracing at include! boundary.
873 pub fn expansion_cause(&self) -> Option<Span> {
874 let mut ctxt = self.backtrace();
875 let mut last_macro = None;
877 if ctxt.outer_expn_info().map_or(None, |info| {
878 if info.format.name() == sym::include {
879 // Stop going up the backtrace once include! is encountered
882 ctxt = info.call_site.ctxt();
883 last_macro = Some(info.call_site);
892 pub fn struct_span_warn<S: Into<MultiSpan>>(&self,
895 -> DiagnosticBuilder<'a> {
896 self.parse_sess.span_diagnostic.struct_span_warn(sp, msg)
898 pub fn struct_span_err<S: Into<MultiSpan>>(&self,
901 -> DiagnosticBuilder<'a> {
902 self.parse_sess.span_diagnostic.struct_span_err(sp, msg)
904 pub fn struct_span_fatal<S: Into<MultiSpan>>(&self,
907 -> DiagnosticBuilder<'a> {
908 self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg)
911 /// Emit `msg` attached to `sp`, and stop compilation immediately.
913 /// `span_err` should be strongly preferred where-ever possible:
914 /// this should *only* be used when:
916 /// - continuing has a high risk of flow-on errors (e.g., errors in
917 /// declaring a macro would cause all uses of that macro to
918 /// complain about "undefined macro"), or
919 /// - there is literally nothing else that can be done (however,
920 /// in most cases one can construct a dummy expression/item to
921 /// substitute; we never hit resolve/type-checking so the dummy
922 /// value doesn't have to match anything)
923 pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
924 self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise();
927 /// Emit `msg` attached to `sp`, without immediately stopping
930 /// Compilation will be stopped in the near future (at the end of
931 /// the macro expansion phase).
932 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
933 self.parse_sess.span_diagnostic.span_err(sp, msg);
935 pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) {
936 self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code);
938 pub fn mut_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str)
939 -> DiagnosticBuilder<'a> {
940 self.parse_sess.span_diagnostic.mut_span_err(sp, msg)
942 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
943 self.parse_sess.span_diagnostic.span_warn(sp, msg);
945 pub fn span_unimpl<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
946 self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
948 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
949 self.parse_sess.span_diagnostic.span_bug(sp, msg);
951 pub fn trace_macros_diag(&mut self) {
952 for (sp, notes) in self.expansions.iter() {
953 let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
959 // Fixme: does this result in errors?
960 self.expansions.clear();
962 pub fn bug(&self, msg: &str) -> ! {
963 self.parse_sess.span_diagnostic.bug(msg);
965 pub fn trace_macros(&self) -> bool {
968 pub fn set_trace_macros(&mut self, x: bool) {
969 self.ecfg.trace_mac = x
971 pub fn ident_of(&self, st: &str) -> ast::Ident {
972 ast::Ident::from_str(st)
974 pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> {
975 let def_site = DUMMY_SP.apply_mark(self.current_expansion.mark);
976 iter::once(Ident::new(kw::DollarCrate, def_site))
977 .chain(components.iter().map(|&s| Ident::with_empty_ctxt(s)))
980 pub fn name_of(&self, st: &str) -> ast::Name {
984 pub fn check_unused_macros(&self) {
985 self.resolver.check_unused_macros();
989 /// Extracts a string literal from the macro expanded version of `expr`,
990 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
991 /// compilation on error, merely emits a non-fatal error and returns `None`.
992 pub fn expr_to_spanned_string<'a>(
993 cx: &'a mut ExtCtxt<'_>,
994 mut expr: P<ast::Expr>,
996 ) -> Result<Spanned<(Symbol, ast::StrStyle)>, Option<DiagnosticBuilder<'a>>> {
997 // Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
998 expr.span = expr.span.apply_mark(cx.current_expansion.mark);
1000 // we want to be able to handle e.g., `concat!("foo", "bar")`
1001 cx.expander().visit_expr(&mut expr);
1002 Err(match expr.node {
1003 ast::ExprKind::Lit(ref l) => match l.node {
1004 ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
1005 ast::LitKind::Err(_) => None,
1006 _ => Some(cx.struct_span_err(l.span, err_msg))
1008 ast::ExprKind::Err => None,
1009 _ => Some(cx.struct_span_err(expr.span, err_msg))
1013 pub fn expr_to_string(cx: &mut ExtCtxt<'_>, expr: P<ast::Expr>, err_msg: &str)
1014 -> Option<(Symbol, ast::StrStyle)> {
1015 expr_to_spanned_string(cx, expr, err_msg)
1016 .map_err(|err| err.map(|mut err| err.emit()))
1021 /// Non-fatally assert that `tts` is empty. Note that this function
1022 /// returns even when `tts` is non-empty, macros that *need* to stop
1023 /// compilation should call
1024 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1025 /// done as rarely as possible).
1026 pub fn check_zero_tts(cx: &ExtCtxt<'_>,
1028 tts: &[tokenstream::TokenTree],
1030 if !tts.is_empty() {
1031 cx.span_err(sp, &format!("{} takes no arguments", name));
1035 /// Interpreting `tts` as a comma-separated sequence of expressions,
1036 /// expect exactly one string literal, or emit an error and return `None`.
1037 pub fn get_single_str_from_tts(cx: &mut ExtCtxt<'_>,
1039 tts: &[tokenstream::TokenTree],
1042 let mut p = cx.new_parser_from_tts(tts);
1043 if p.token == token::Eof {
1044 cx.span_err(sp, &format!("{} takes 1 argument", name));
1047 let ret = panictry!(p.parse_expr());
1048 let _ = p.eat(&token::Comma);
1050 if p.token != token::Eof {
1051 cx.span_err(sp, &format!("{} takes 1 argument", name));
1053 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| {
1058 /// Extracts comma-separated expressions from `tts`. If there is a
1059 /// parsing error, emit a non-fatal error and return `None`.
1060 pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
1062 tts: &[tokenstream::TokenTree]) -> Option<Vec<P<ast::Expr>>> {
1063 let mut p = cx.new_parser_from_tts(tts);
1064 let mut es = Vec::new();
1065 while p.token != token::Eof {
1066 let mut expr = panictry!(p.parse_expr());
1067 cx.expander().visit_expr(&mut expr);
1069 if p.eat(&token::Comma) {
1072 if p.token != token::Eof {
1073 cx.span_err(sp, "expected token: `,`");