1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use ast::{self, Block, Ident, NodeId, PatKind, Path};
12 use ast::{MacStmtStyle, StmtKind, ItemKind};
13 use attr::{self, HasAttrs};
14 use source_map::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
15 use config::StripUnconfigured;
16 use errors::{Applicability, FatalError};
18 use ext::derive::{add_derived_markers, collect_derives};
19 use ext::hygiene::{self, Mark, SyntaxContext};
20 use ext::placeholders::{placeholder, PlaceholderExpander};
21 use feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
24 use parse::{DirectoryOwnership, PResult, ParseSess};
25 use parse::token::{self, Token};
26 use parse::parser::Parser;
28 use smallvec::SmallVec;
31 use syntax_pos::{Span, DUMMY_SP, FileName};
32 use syntax_pos::hygiene::ExpnFormat;
33 use tokenstream::{TokenStream, TokenTree};
34 use visit::{self, Visitor};
36 use rustc_data_structures::fx::FxHashMap;
41 use std::path::PathBuf;
43 macro_rules! ast_fragments {
45 $($Kind:ident($AstTy:ty) {
47 // FIXME: HACK: this should be `$(one ...)?` and `$(many ...)?` but `?` macro
48 // repetition was removed from 2015 edition in #51587 because of ambiguities.
49 $(one fn $fold_ast:ident; fn $visit_ast:ident;)*
50 $(many fn $fold_ast_elt:ident; fn $visit_ast_elt:ident;)*
54 /// A fragment of AST that can be produced by a single macro expansion.
55 /// Can also serve as an input and intermediate result for macro expansion operations.
56 pub enum AstFragment {
57 OptExpr(Option<P<ast::Expr>>),
61 /// "Discriminant" of an AST fragment.
62 #[derive(Copy, Clone, PartialEq, Eq)]
63 pub enum AstFragmentKind {
68 impl AstFragmentKind {
69 pub fn name(self) -> &'static str {
71 AstFragmentKind::OptExpr => "expression",
72 $(AstFragmentKind::$Kind => $kind_name,)*
76 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
78 AstFragmentKind::OptExpr =>
79 result.make_expr().map(Some).map(AstFragment::OptExpr),
80 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
86 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
88 AstFragment::OptExpr(expr) => expr,
89 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
93 $(pub fn $make_ast(self) -> $AstTy {
95 AstFragment::$Kind(ast) => ast,
96 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
100 pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
102 AstFragment::OptExpr(expr) =>
103 AstFragment::OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
104 $($(AstFragment::$Kind(ast) =>
105 AstFragment::$Kind(folder.$fold_ast(ast)),)*)*
106 $($(AstFragment::$Kind(ast) =>
107 AstFragment::$Kind(ast.into_iter()
108 .flat_map(|ast| folder.$fold_ast_elt(ast))
113 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
115 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
116 AstFragment::OptExpr(None) => {}
117 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)*)*
118 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
119 visitor.$visit_ast_elt(ast_elt);
125 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
126 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
127 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
129 $($(fn $fold_ast(&mut self, ast: $AstTy) -> $AstTy {
130 self.expand_fragment(AstFragment::$Kind(ast)).$make_ast()
132 $($(fn $fold_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
133 self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
137 impl<'a> MacResult for ::ext::tt::macro_rules::ParserAnyMacro<'a> {
138 $(fn $make_ast(self: Box<::ext::tt::macro_rules::ParserAnyMacro<'a>>)
140 Some(self.make(AstFragmentKind::$Kind).$make_ast())
147 Expr(P<ast::Expr>) { "expression"; one fn fold_expr; fn visit_expr; fn make_expr; }
148 Pat(P<ast::Pat>) { "pattern"; one fn fold_pat; fn visit_pat; fn make_pat; }
149 Ty(P<ast::Ty>) { "type"; one fn fold_ty; fn visit_ty; fn make_ty; }
150 Stmts(SmallVec<[ast::Stmt; 1]>) {
151 "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts;
153 Items(SmallVec<[P<ast::Item>; 1]>) {
154 "item"; many fn fold_item; fn visit_item; fn make_items;
156 TraitItems(SmallVec<[ast::TraitItem; 1]>) {
157 "trait item"; many fn fold_trait_item; fn visit_trait_item; fn make_trait_items;
159 ImplItems(SmallVec<[ast::ImplItem; 1]>) {
160 "impl item"; many fn fold_impl_item; fn visit_impl_item; fn make_impl_items;
162 ForeignItems(SmallVec<[ast::ForeignItem; 1]>) {
163 "foreign item"; many fn fold_foreign_item; fn visit_foreign_item; fn make_foreign_items;
167 impl AstFragmentKind {
168 fn dummy(self, span: Span) -> Option<AstFragment> {
169 self.make_from(DummyResult::any(span))
172 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
174 let mut items = items.into_iter();
176 AstFragmentKind::Items =>
177 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
178 AstFragmentKind::ImplItems =>
179 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
180 AstFragmentKind::TraitItems =>
181 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
182 AstFragmentKind::ForeignItems =>
183 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
184 AstFragmentKind::Stmts =>
185 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
186 AstFragmentKind::Expr => AstFragment::Expr(
187 items.next().expect("expected exactly one expression").expect_expr()
189 AstFragmentKind::OptExpr =>
190 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
191 AstFragmentKind::Pat | AstFragmentKind::Ty =>
192 panic!("patterns and types aren't annotatable"),
197 fn macro_bang_format(path: &ast::Path) -> ExpnFormat {
198 // We don't want to format a path using pretty-printing,
199 // `format!("{}", path)`, because that tries to insert
200 // line-breaks and is slow.
201 let mut path_str = String::with_capacity(64);
202 for (i, segment) in path.segments.iter().enumerate() {
204 path_str.push_str("::");
207 if segment.ident.name != keywords::CrateRoot.name() &&
208 segment.ident.name != keywords::DollarCrate.name()
210 path_str.push_str(&segment.ident.as_str())
214 MacroBang(Symbol::intern(&path_str))
217 pub struct Invocation {
218 pub kind: InvocationKind,
219 fragment_kind: AstFragmentKind,
220 pub expansion_data: ExpansionData,
223 pub enum InvocationKind {
226 ident: Option<Ident>,
230 attr: Option<ast::Attribute>,
233 // We temporarily report errors for attribute macros placed after derives
243 pub fn span(&self) -> Span {
245 InvocationKind::Bang { span, .. } => span,
246 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.span,
247 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
248 InvocationKind::Derive { ref path, .. } => path.span,
253 pub struct MacroExpander<'a, 'b:'a> {
254 pub cx: &'a mut ExtCtxt<'b>,
255 monotonic: bool, // c.f. `cx.monotonic_expander()`
258 impl<'a, 'b> MacroExpander<'a, 'b> {
259 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
260 MacroExpander { cx: cx, monotonic: monotonic }
263 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
264 let mut module = ModuleData {
265 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
266 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
267 FileName::Real(path) => path,
268 other => PathBuf::from(other.to_string()),
271 module.directory.pop();
272 self.cx.root_path = module.directory.clone();
273 self.cx.current_expansion.module = Rc::new(module);
274 self.cx.current_expansion.crate_span = Some(krate.span);
276 let orig_mod_span = krate.module.inner;
278 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
281 node: ast::ItemKind::Mod(krate.module),
282 ident: keywords::Invalid.ident(),
283 id: ast::DUMMY_NODE_ID,
284 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
288 match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
289 Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
291 krate.module = module;
294 // Resolution failed so we return an empty expansion
295 krate.attrs = vec![];
296 krate.module = ast::Mod {
297 inner: orig_mod_span,
304 self.cx.trace_macros_diag();
308 // Fully expand all macro invocations in this AST fragment.
309 fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
310 let orig_expansion_data = self.cx.current_expansion.clone();
311 self.cx.current_expansion.depth = 0;
313 // Collect all macro invocations and replace them with placeholders.
314 let (fragment_with_placeholders, mut invocations)
315 = self.collect_invocations(input_fragment, &[]);
317 // Optimization: if we resolve all imports now,
318 // we'll be able to immediately resolve most of imported macros.
319 self.resolve_imports();
321 // Resolve paths in all invocations and produce output expanded fragments for them, but
322 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
323 // The output fragments also go through expansion recursively until no invocations are left.
324 // Unresolved macros produce dummy outputs as a recovery measure.
325 invocations.reverse();
326 let mut expanded_fragments = Vec::new();
327 let mut derives: FxHashMap<Mark, Vec<_>> = FxHashMap::default();
328 let mut undetermined_invocations = Vec::new();
329 let (mut progress, mut force) = (false, !self.monotonic);
331 let invoc = if let Some(invoc) = invocations.pop() {
334 self.resolve_imports();
335 if undetermined_invocations.is_empty() { break }
336 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
337 force = !mem::replace(&mut progress, false);
342 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
343 let ext = match self.cx.resolver.resolve_macro_invocation(&invoc, scope, force) {
344 Ok(ext) => Some(ext),
345 Err(Determinacy::Determined) => None,
346 Err(Determinacy::Undetermined) => {
347 undetermined_invocations.push(invoc);
353 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
354 self.cx.current_expansion = invoc.expansion_data.clone();
356 self.cx.current_expansion.mark = scope;
357 // FIXME(jseyfried): Refactor out the following logic
358 let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
359 if let Some(ext) = ext {
360 let dummy = invoc.fragment_kind.dummy(invoc.span()).unwrap();
361 let fragment = self.expand_invoc(invoc, &*ext).unwrap_or(dummy);
362 self.collect_invocations(fragment, &[])
363 } else if let InvocationKind::Attr { attr: None, traits, item, .. } = invoc.kind {
364 if !item.derive_allowed() {
365 let attr = attr::find_by_name(item.attrs(), "derive")
366 .expect("`derive` attribute should exist");
367 let span = attr.span;
368 let mut err = self.cx.mut_span_err(span,
369 "`derive` may only be applied to \
370 structs, enums and unions");
371 if let ast::AttrStyle::Inner = attr.style {
372 let trait_list = traits.iter()
373 .map(|t| t.to_string()).collect::<Vec<_>>();
374 let suggestion = format!("#[derive({})]", trait_list.join(", "));
375 err.span_suggestion_with_applicability(
376 span, "try an outer attribute", suggestion,
377 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
378 Applicability::MaybeIncorrect
384 let item = self.fully_configure(item)
385 .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
386 let item_with_markers =
387 add_derived_markers(&mut self.cx, item.span(), &traits, item.clone());
388 let derives = derives.entry(invoc.expansion_data.mark).or_default();
390 for path in &traits {
391 let mark = Mark::fresh(self.cx.current_expansion.mark);
393 let item = match self.cx.resolver.resolve_macro_path(
394 path, MacroKind::Derive, Mark::root(), Vec::new(), false) {
395 Ok(ext) => match *ext {
396 BuiltinDerive(..) => item_with_markers.clone(),
401 invocations.push(Invocation {
402 kind: InvocationKind::Derive { path: path.clone(), item: item },
403 fragment_kind: invoc.fragment_kind,
404 expansion_data: ExpansionData {
406 ..invoc.expansion_data.clone()
410 let fragment = invoc.fragment_kind
411 .expect_from_annotatables(::std::iter::once(item_with_markers));
412 self.collect_invocations(fragment, derives)
417 self.collect_invocations(invoc.fragment_kind.dummy(invoc.span()).unwrap(), &[])
420 if expanded_fragments.len() < depth {
421 expanded_fragments.push(Vec::new());
423 expanded_fragments[depth - 1].push((mark, expanded_fragment));
424 if !self.cx.ecfg.single_step {
425 invocations.extend(new_invocations.into_iter().rev());
429 self.cx.current_expansion = orig_expansion_data;
431 // Finally incorporate all the expanded macros into the input AST fragment.
432 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
433 while let Some(expanded_fragments) = expanded_fragments.pop() {
434 for (mark, expanded_fragment) in expanded_fragments.into_iter().rev() {
435 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
436 placeholder_expander.add(NodeId::placeholder_from_mark(mark),
437 expanded_fragment, derives);
440 fragment_with_placeholders.fold_with(&mut placeholder_expander)
443 fn resolve_imports(&mut self) {
445 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
446 self.cx.resolver.resolve_imports();
447 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
451 /// Collect all macro invocations reachable at this time in this AST fragment, and replace
452 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
453 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
454 /// prepares data for resolving paths of macro invocations.
455 fn collect_invocations(&mut self, fragment: AstFragment, derives: &[Mark])
456 -> (AstFragment, Vec<Invocation>) {
457 let (fragment_with_placeholders, invocations) = {
458 let mut collector = InvocationCollector {
459 cfg: StripUnconfigured {
460 sess: self.cx.parse_sess,
461 features: self.cx.ecfg.features,
464 invocations: Vec::new(),
465 monotonic: self.monotonic,
467 (fragment.fold_with(&mut collector), collector.invocations)
471 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
472 let mark = self.cx.current_expansion.mark;
473 self.cx.resolver.visit_ast_fragment_with_placeholders(mark, &fragment_with_placeholders,
475 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
478 (fragment_with_placeholders, invocations)
481 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
482 let mut cfg = StripUnconfigured {
483 sess: self.cx.parse_sess,
484 features: self.cx.ecfg.features,
486 // Since the item itself has already been configured by the InvocationCollector,
487 // we know that fold result vector will contain exactly one element
489 Annotatable::Item(item) => {
490 Annotatable::Item(cfg.fold_item(item).pop().unwrap())
492 Annotatable::TraitItem(item) => {
493 Annotatable::TraitItem(item.map(|item| cfg.fold_trait_item(item).pop().unwrap()))
495 Annotatable::ImplItem(item) => {
496 Annotatable::ImplItem(item.map(|item| cfg.fold_impl_item(item).pop().unwrap()))
498 Annotatable::ForeignItem(item) => {
499 Annotatable::ForeignItem(
500 item.map(|item| cfg.fold_foreign_item(item).pop().unwrap())
503 Annotatable::Stmt(stmt) => {
504 Annotatable::Stmt(stmt.map(|stmt| cfg.fold_stmt(stmt).pop().unwrap()))
506 Annotatable::Expr(expr) => {
507 Annotatable::Expr(cfg.fold_expr(expr))
512 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtension) -> Option<AstFragment> {
513 if invoc.fragment_kind == AstFragmentKind::ForeignItems &&
514 !self.cx.ecfg.macros_in_extern_enabled() {
515 if let SyntaxExtension::NonMacroAttr { .. } = *ext {} else {
516 emit_feature_err(&self.cx.parse_sess, "macros_in_extern",
517 invoc.span(), GateIssue::Language,
518 "macro invocations in `extern {}` blocks are experimental");
522 let result = match invoc.kind {
523 InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext)?,
524 InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext)?,
525 InvocationKind::Derive { .. } => self.expand_derive_invoc(invoc, ext)?,
528 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
529 let info = self.cx.current_expansion.mark.expn_info().unwrap();
530 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
531 let mut err = self.cx.struct_span_err(info.call_site,
532 &format!("recursion limit reached while expanding the macro `{}`",
533 info.format.name()));
535 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
538 self.cx.trace_macros_diag();
545 fn expand_attr_invoc(&mut self,
547 ext: &SyntaxExtension)
548 -> Option<AstFragment> {
549 let (attr, item) = match invoc.kind {
550 InvocationKind::Attr { attr, item, .. } => (attr?, item),
554 if let NonMacroAttr { mark_used: false } = *ext {} else {
555 // Macro attrs are always used when expanded,
556 // non-macro attrs are considered used when the field says so.
557 attr::mark_used(&attr);
559 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
560 call_site: attr.span,
562 format: MacroAttribute(Symbol::intern(&attr.path.to_string())),
563 allow_internal_unstable: false,
564 allow_internal_unsafe: false,
565 local_inner_macros: false,
566 edition: ext.edition(),
570 NonMacroAttr { .. } => {
571 attr::mark_known(&attr);
572 let item = item.map_attrs(|mut attrs| { attrs.push(attr); attrs });
573 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
575 MultiModifier(ref mac) => {
576 let meta = attr.parse_meta(self.cx.parse_sess)
577 .map_err(|mut e| { e.emit(); }).ok()?;
578 let item = mac.expand(self.cx, attr.span, &meta, item);
579 Some(invoc.fragment_kind.expect_from_annotatables(item))
581 MultiDecorator(ref mac) => {
582 let mut items = Vec::new();
583 let meta = attr.parse_meta(self.cx.parse_sess)
584 .expect("derive meta should already have been parsed");
585 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
587 Some(invoc.fragment_kind.expect_from_annotatables(items))
589 AttrProcMacro(ref mac, ..) => {
590 self.gate_proc_macro_attr_item(attr.span, &item);
591 let item_tok = TokenTree::Token(DUMMY_SP, Token::interpolated(match item {
592 Annotatable::Item(item) => token::NtItem(item),
593 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
594 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
595 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
596 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
597 Annotatable::Expr(expr) => token::NtExpr(expr),
599 let input = self.extract_proc_macro_attr_input(attr.tokens, attr.span);
600 let tok_result = mac.expand(self.cx, attr.span, input, item_tok);
601 let res = self.parse_ast_fragment(tok_result, invoc.fragment_kind,
602 &attr.path, attr.span);
603 self.gate_proc_macro_expansion(attr.span, &res);
606 ProcMacroDerive(..) | BuiltinDerive(..) => {
607 self.cx.span_err(attr.span, &format!("`{}` is a derive mode", attr.path));
608 self.cx.trace_macros_diag();
609 invoc.fragment_kind.dummy(attr.span)
612 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
613 self.cx.span_err(attr.span, msg);
614 self.cx.trace_macros_diag();
615 invoc.fragment_kind.dummy(attr.span)
620 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
621 let mut trees = tokens.trees();
623 Some(TokenTree::Delimited(_, delim)) => {
624 if trees.next().is_none() {
625 return delim.tts.into()
628 Some(TokenTree::Token(..)) => {}
629 None => return TokenStream::empty(),
631 self.cx.span_err(span, "custom attribute invocations must be \
632 of the form #[foo] or #[foo(..)], the macro name must only be \
633 followed by a delimiter token");
637 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
638 let (kind, gate) = match *item {
639 Annotatable::Item(ref item) => {
641 ItemKind::Mod(_) if self.cx.ecfg.proc_macro_hygiene() => return,
642 ItemKind::Mod(_) => ("modules", "proc_macro_hygiene"),
646 Annotatable::TraitItem(_) => return,
647 Annotatable::ImplItem(_) => return,
648 Annotatable::ForeignItem(_) => return,
649 Annotatable::Stmt(_) |
650 Annotatable::Expr(_) if self.cx.ecfg.proc_macro_hygiene() => return,
651 Annotatable::Stmt(_) => ("statements", "proc_macro_hygiene"),
652 Annotatable::Expr(_) => ("expressions", "proc_macro_hygiene"),
659 &format!("custom attributes cannot be applied to {}", kind),
663 fn gate_proc_macro_expansion(&self, span: Span, fragment: &Option<AstFragment>) {
664 if self.cx.ecfg.proc_macro_hygiene() {
667 let fragment = match fragment {
668 Some(fragment) => fragment,
672 fragment.visit_with(&mut DisallowMacros {
674 parse_sess: self.cx.parse_sess,
677 struct DisallowMacros<'a> {
679 parse_sess: &'a ParseSess,
682 impl<'ast, 'a> Visitor<'ast> for DisallowMacros<'a> {
683 fn visit_item(&mut self, i: &'ast ast::Item) {
684 if let ast::ItemKind::MacroDef(_) = i.node {
687 "proc_macro_hygiene",
690 &format!("procedural macros cannot expand to macro definitions"),
693 visit::walk_item(self, i);
696 fn visit_mac(&mut self, _mac: &'ast ast::Mac) {
702 /// Expand a macro invocation. Returns the resulting expanded AST fragment.
703 fn expand_bang_invoc(&mut self,
705 ext: &SyntaxExtension)
706 -> Option<AstFragment> {
707 let (mark, kind) = (invoc.expansion_data.mark, invoc.fragment_kind);
708 let (mac, ident, span) = match invoc.kind {
709 InvocationKind::Bang { mac, ident, span } => (mac, ident, span),
712 let path = &mac.node.path;
714 let ident = ident.unwrap_or_else(|| keywords::Invalid.ident());
715 let validate_and_set_expn_info = |this: &mut Self, // arg instead of capture
716 def_site_span: Option<Span>,
717 allow_internal_unstable,
718 allow_internal_unsafe,
720 // can't infer this type
721 unstable_feature: Option<(Symbol, u32)>,
724 // feature-gate the macro invocation
725 if let Some((feature, issue)) = unstable_feature {
726 let crate_span = this.cx.current_expansion.crate_span.unwrap();
727 // don't stability-check macros in the same crate
728 // (the only time this is null is for syntax extensions registered as macros)
729 if def_site_span.map_or(false, |def_span| !crate_span.contains(def_span))
730 && !span.allows_unstable() && this.cx.ecfg.features.map_or(true, |feats| {
731 // macro features will count as lib features
732 !feats.declared_lib_features.iter().any(|&(feat, _)| feat == feature)
734 let explain = format!("macro {}! is unstable", path);
735 emit_feature_err(this.cx.parse_sess, &*feature.as_str(), span,
736 GateIssue::Library(Some(issue)), &explain);
737 this.cx.trace_macros_diag();
738 return Err(kind.dummy(span));
742 if ident.name != keywords::Invalid.name() {
743 let msg = format!("macro {}! expects no ident argument, given '{}'", path, ident);
744 this.cx.span_err(path.span, &msg);
745 this.cx.trace_macros_diag();
746 return Err(kind.dummy(span));
748 mark.set_expn_info(ExpnInfo {
750 def_site: def_site_span,
751 format: macro_bang_format(path),
752 allow_internal_unstable,
753 allow_internal_unsafe,
760 let opt_expanded = match *ext {
761 DeclMacro { ref expander, def_info, edition, .. } => {
762 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
763 false, false, false, None,
767 kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
774 allow_internal_unstable,
775 allow_internal_unsafe,
780 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
781 allow_internal_unstable,
782 allow_internal_unsafe,
788 kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
792 IdentTT(ref expander, tt_span, allow_internal_unstable) => {
793 if ident.name == keywords::Invalid.name() {
794 self.cx.span_err(path.span,
795 &format!("macro {}! expects an ident argument", path));
796 self.cx.trace_macros_diag();
799 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
802 format: macro_bang_format(path),
803 allow_internal_unstable,
804 allow_internal_unsafe: false,
805 local_inner_macros: false,
806 edition: hygiene::default_edition(),
809 let input: Vec<_> = mac.node.stream().into_trees().collect();
810 kind.make_from(expander.expand(self.cx, span, ident, input))
814 MultiDecorator(..) | MultiModifier(..) |
815 AttrProcMacro(..) | SyntaxExtension::NonMacroAttr { .. } => {
816 self.cx.span_err(path.span,
817 &format!("`{}` can only be used in attributes", path));
818 self.cx.trace_macros_diag();
822 ProcMacroDerive(..) | BuiltinDerive(..) => {
823 self.cx.span_err(path.span, &format!("`{}` is a derive mode", path));
824 self.cx.trace_macros_diag();
828 SyntaxExtension::ProcMacro { ref expander, allow_internal_unstable, edition } => {
829 if ident.name != keywords::Invalid.name() {
831 format!("macro {}! expects no ident argument, given '{}'", path, ident);
832 self.cx.span_err(path.span, &msg);
833 self.cx.trace_macros_diag();
836 self.gate_proc_macro_expansion_kind(span, kind);
837 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
839 // FIXME procedural macros do not have proper span info
840 // yet, when they do, we should use it here.
842 format: macro_bang_format(path),
843 // FIXME probably want to follow macro_rules macros here.
844 allow_internal_unstable,
845 allow_internal_unsafe: false,
846 local_inner_macros: false,
850 let tok_result = expander.expand(self.cx, span, mac.node.stream());
851 let result = self.parse_ast_fragment(tok_result, kind, path, span);
852 self.gate_proc_macro_expansion(span, &result);
858 if opt_expanded.is_some() {
861 let msg = format!("non-{kind} macro in {kind} position: {name}",
862 name = path.segments[0].ident.name, kind = kind.name());
863 self.cx.span_err(path.span, &msg);
864 self.cx.trace_macros_diag();
869 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
870 let kind = match kind {
871 AstFragmentKind::Expr => "expressions",
872 AstFragmentKind::OptExpr => "expressions",
873 AstFragmentKind::Pat => "patterns",
874 AstFragmentKind::Ty => "types",
875 AstFragmentKind::Stmts => "statements",
876 AstFragmentKind::Items => return,
877 AstFragmentKind::TraitItems => return,
878 AstFragmentKind::ImplItems => return,
879 AstFragmentKind::ForeignItems => return,
881 if self.cx.ecfg.proc_macro_hygiene() {
886 "proc_macro_hygiene",
889 &format!("procedural macros cannot be expanded to {}", kind),
893 /// Expand a derive invocation. Returns the resulting expanded AST fragment.
894 fn expand_derive_invoc(&mut self,
896 ext: &SyntaxExtension)
897 -> Option<AstFragment> {
898 let (path, item) = match invoc.kind {
899 InvocationKind::Derive { path, item } => (path, item),
902 if !item.derive_allowed() {
906 let pretty_name = Symbol::intern(&format!("derive({})", path));
907 let span = path.span;
908 let attr = ast::Attribute {
910 tokens: TokenStream::empty(),
912 id: ast::AttrId(0), style: ast::AttrStyle::Outer, is_sugared_doc: false,
915 let mut expn_info = ExpnInfo {
918 format: MacroAttribute(pretty_name),
919 allow_internal_unstable: false,
920 allow_internal_unsafe: false,
921 local_inner_macros: false,
922 edition: ext.edition(),
926 ProcMacroDerive(ref ext, ..) => {
927 invoc.expansion_data.mark.set_expn_info(expn_info);
928 let span = span.with_ctxt(self.cx.backtrace());
929 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
930 ident: Path::from_ident(keywords::Invalid.ident()),
932 node: ast::MetaItemKind::Word,
934 let items = ext.expand(self.cx, span, &dummy, item);
935 Some(invoc.fragment_kind.expect_from_annotatables(items))
937 BuiltinDerive(func) => {
938 expn_info.allow_internal_unstable = true;
939 invoc.expansion_data.mark.set_expn_info(expn_info);
940 let span = span.with_ctxt(self.cx.backtrace());
941 let mut items = Vec::new();
942 func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
943 Some(invoc.fragment_kind.expect_from_annotatables(items))
946 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
947 self.cx.span_err(span, msg);
948 self.cx.trace_macros_diag();
949 invoc.fragment_kind.dummy(span)
954 fn parse_ast_fragment(&mut self,
956 kind: AstFragmentKind,
959 -> Option<AstFragment> {
960 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
961 match parser.parse_ast_fragment(kind, false) {
963 parser.ensure_complete_parse(path, kind.name(), span);
969 self.cx.trace_macros_diag();
976 impl<'a> Parser<'a> {
977 pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warnings: bool)
978 -> PResult<'a, AstFragment> {
980 AstFragmentKind::Items => {
981 let mut items = SmallVec::new();
982 while let Some(item) = self.parse_item()? {
985 AstFragment::Items(items)
987 AstFragmentKind::TraitItems => {
988 let mut items = SmallVec::new();
989 while self.token != token::Eof {
990 items.push(self.parse_trait_item(&mut false)?);
992 AstFragment::TraitItems(items)
994 AstFragmentKind::ImplItems => {
995 let mut items = SmallVec::new();
996 while self.token != token::Eof {
997 items.push(self.parse_impl_item(&mut false)?);
999 AstFragment::ImplItems(items)
1001 AstFragmentKind::ForeignItems => {
1002 let mut items = SmallVec::new();
1003 while self.token != token::Eof {
1004 items.push(self.parse_foreign_item()?);
1006 AstFragment::ForeignItems(items)
1008 AstFragmentKind::Stmts => {
1009 let mut stmts = SmallVec::new();
1010 while self.token != token::Eof &&
1011 // won't make progress on a `}`
1012 self.token != token::CloseDelim(token::Brace) {
1013 if let Some(stmt) = self.parse_full_stmt(macro_legacy_warnings)? {
1017 AstFragment::Stmts(stmts)
1019 AstFragmentKind::Expr => AstFragment::Expr(self.parse_expr()?),
1020 AstFragmentKind::OptExpr => {
1021 if self.token != token::Eof {
1022 AstFragment::OptExpr(Some(self.parse_expr()?))
1024 AstFragment::OptExpr(None)
1027 AstFragmentKind::Ty => AstFragment::Ty(self.parse_ty()?),
1028 AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat()?),
1032 pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span: Span) {
1033 if self.token != token::Eof {
1034 let msg = format!("macro expansion ignores token `{}` and any following",
1035 self.this_token_to_string());
1036 // Avoid emitting backtrace info twice.
1037 let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
1038 let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
1039 let msg = format!("caused by the macro expansion here; the usage \
1040 of `{}!` is likely invalid in {} context",
1041 macro_path, kind_name);
1042 err.span_note(span, &msg).emit();
1047 struct InvocationCollector<'a, 'b: 'a> {
1048 cx: &'a mut ExtCtxt<'b>,
1049 cfg: StripUnconfigured<'a>,
1050 invocations: Vec<Invocation>,
1054 impl<'a, 'b> InvocationCollector<'a, 'b> {
1055 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1056 let mark = Mark::fresh(self.cx.current_expansion.mark);
1057 self.invocations.push(Invocation {
1060 expansion_data: ExpansionData {
1062 depth: self.cx.current_expansion.depth + 1,
1063 ..self.cx.current_expansion.clone()
1066 placeholder(fragment_kind, NodeId::placeholder_from_mark(mark))
1069 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
1070 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
1073 fn collect_attr(&mut self,
1074 attr: Option<ast::Attribute>,
1077 kind: AstFragmentKind,
1080 self.collect(kind, InvocationKind::Attr { attr, traits, item, after_derive })
1083 fn find_attr_invoc(&self, attrs: &mut Vec<ast::Attribute>, after_derive: &mut bool)
1084 -> Option<ast::Attribute> {
1085 let attr = attrs.iter()
1087 if a.path == "derive" {
1088 *after_derive = true;
1090 !attr::is_known(a) && !is_builtin_attr(a)
1092 .map(|i| attrs.remove(i));
1093 if let Some(attr) = &attr {
1094 if !self.cx.ecfg.enable_custom_inner_attributes() &&
1095 attr.style == ast::AttrStyle::Inner && attr.path != "test" {
1096 emit_feature_err(&self.cx.parse_sess, "custom_inner_attributes",
1097 attr.span, GateIssue::Language,
1098 "non-builtin inner attributes are unstable");
1104 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1105 fn classify_item<T>(&mut self, mut item: T)
1106 -> (Option<ast::Attribute>, Vec<Path>, T, /* after_derive */ bool)
1109 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1111 item = item.map_attrs(|mut attrs| {
1112 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1114 attr = Some(legacy_attr_invoc);
1118 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1119 traits = collect_derives(&mut self.cx, &mut attrs);
1123 (attr, traits, item, after_derive)
1126 /// Alternative of `classify_item()` that ignores `#[derive]` so invocations fallthrough
1127 /// to the unused-attributes lint (making it an error on statements and expressions
1128 /// is a breaking change)
1129 fn classify_nonitem<T: HasAttrs>(&mut self, mut item: T)
1130 -> (Option<ast::Attribute>, T, /* after_derive */ bool) {
1131 let (mut attr, mut after_derive) = (None, false);
1133 item = item.map_attrs(|mut attrs| {
1134 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1136 attr = Some(legacy_attr_invoc);
1140 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1144 (attr, item, after_derive)
1147 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1148 self.cfg.configure(node)
1151 // Detect use of feature-gated or invalid attributes on macro invocations
1152 // since they will not be detected after macro expansion.
1153 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1154 let features = self.cx.ecfg.features.unwrap();
1155 for attr in attrs.iter() {
1156 self.check_attribute_inner(attr, features);
1158 // macros are expanded before any lint passes so this warning has to be hardcoded
1159 if attr.path == "derive" {
1160 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1161 .note("this may become a hard error in a future release")
1167 fn check_attribute(&mut self, at: &ast::Attribute) {
1168 let features = self.cx.ecfg.features.unwrap();
1169 self.check_attribute_inner(at, features);
1172 fn check_attribute_inner(&mut self, at: &ast::Attribute, features: &Features) {
1173 feature_gate::check_attribute(at, self.cx.parse_sess, features);
1177 impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
1178 fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
1179 let mut expr = self.cfg.configure_expr(expr).into_inner();
1180 expr.node = self.cfg.configure_expr_kind(expr.node);
1182 // ignore derives so they remain unused
1183 let (attr, expr, after_derive) = self.classify_nonitem(expr);
1186 // collect the invoc regardless of whether or not attributes are permitted here
1187 // expansion will eat the attribute so it won't error later
1188 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1190 // AstFragmentKind::Expr requires the macro to emit an expression
1191 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1192 AstFragmentKind::Expr, after_derive).make_expr();
1195 if let ast::ExprKind::Mac(mac) = expr.node {
1196 self.check_attributes(&expr.attrs);
1197 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr()
1199 P(noop_fold_expr(expr, self))
1203 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1204 let mut expr = configure!(self, expr).into_inner();
1205 expr.node = self.cfg.configure_expr_kind(expr.node);
1207 // ignore derives so they remain unused
1208 let (attr, expr, after_derive) = self.classify_nonitem(expr);
1211 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1213 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1214 AstFragmentKind::OptExpr, after_derive).make_opt_expr();
1217 if let ast::ExprKind::Mac(mac) = expr.node {
1218 self.check_attributes(&expr.attrs);
1219 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr).make_opt_expr()
1221 Some(P(noop_fold_expr(expr, self)))
1225 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
1226 let pat = self.cfg.configure_pat(pat);
1228 PatKind::Mac(_) => {}
1229 _ => return noop_fold_pat(pat, self),
1232 pat.and_then(|pat| match pat.node {
1233 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1234 _ => unreachable!(),
1238 fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1239 let mut stmt = match self.cfg.configure_stmt(stmt) {
1241 None => return SmallVec::new(),
1244 // we'll expand attributes on expressions separately
1245 if !stmt.is_expr() {
1246 let (attr, derives, stmt_, after_derive) = if stmt.is_item() {
1247 self.classify_item(stmt)
1249 // ignore derives on non-item statements so it falls through
1250 // to the unused-attributes lint
1251 let (attr, stmt, after_derive) = self.classify_nonitem(stmt);
1252 (attr, vec![], stmt, after_derive)
1255 if attr.is_some() || !derives.is_empty() {
1256 return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt_)),
1257 AstFragmentKind::Stmts, after_derive).make_stmts();
1263 if let StmtKind::Mac(mac) = stmt.node {
1264 let (mac, style, attrs) = mac.into_inner();
1265 self.check_attributes(&attrs);
1266 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1269 // If this is a macro invocation with a semicolon, then apply that
1270 // semicolon to the final statement produced by expansion.
1271 if style == MacStmtStyle::Semicolon {
1272 if let Some(stmt) = placeholder.pop() {
1273 placeholder.push(stmt.add_trailing_semicolon());
1280 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1281 let ast::Stmt { id, node, span } = stmt;
1282 noop_fold_stmt_kind(node, self).into_iter().map(|node| {
1283 ast::Stmt { id, node, span }
1288 fn fold_block(&mut self, block: P<Block>) -> P<Block> {
1289 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1290 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1291 let result = noop_fold_block(block, self);
1292 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1296 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1297 let item = configure!(self, item);
1299 let (attr, traits, item, after_derive) = self.classify_item(item);
1300 if attr.is_some() || !traits.is_empty() {
1301 return self.collect_attr(attr, traits, Annotatable::Item(item),
1302 AstFragmentKind::Items, after_derive).make_items();
1306 ast::ItemKind::Mac(..) => {
1307 self.check_attributes(&item.attrs);
1308 item.and_then(|item| match item.node {
1309 ItemKind::Mac(mac) => {
1310 self.collect(AstFragmentKind::Items, InvocationKind::Bang {
1312 ident: Some(item.ident),
1316 _ => unreachable!(),
1319 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1320 if item.ident == keywords::Invalid.ident() {
1321 return noop_fold_item(item, self);
1324 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1325 let mut module = (*self.cx.current_expansion.module).clone();
1326 module.mod_path.push(item.ident);
1328 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1329 // In the non-inline case, `inner` is never the dummy span (c.f. `parse_item_mod`).
1330 // Thus, if `inner` is the dummy span, we know the module is inline.
1331 let inline_module = item.span.contains(inner) || inner.is_dummy();
1334 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, "path") {
1335 self.cx.current_expansion.directory_ownership =
1336 DirectoryOwnership::Owned { relative: None };
1337 module.directory.push(&*path.as_str());
1339 module.directory.push(&*item.ident.as_str());
1342 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1343 let mut path = match path {
1344 FileName::Real(path) => path,
1345 other => PathBuf::from(other.to_string()),
1347 let directory_ownership = match path.file_name().unwrap().to_str() {
1348 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1349 Some(_) => DirectoryOwnership::Owned {
1350 relative: Some(item.ident),
1352 None => DirectoryOwnership::UnownedViaMod(false),
1355 module.directory = path;
1356 self.cx.current_expansion.directory_ownership = directory_ownership;
1360 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1361 let result = noop_fold_item(item, self);
1362 self.cx.current_expansion.module = orig_module;
1363 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1367 _ => noop_fold_item(item, self),
1371 fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
1372 let item = configure!(self, item);
1374 let (attr, traits, item, after_derive) = self.classify_item(item);
1375 if attr.is_some() || !traits.is_empty() {
1376 return self.collect_attr(attr, traits, Annotatable::TraitItem(P(item)),
1377 AstFragmentKind::TraitItems, after_derive).make_trait_items()
1381 ast::TraitItemKind::Macro(mac) => {
1382 let ast::TraitItem { attrs, span, .. } = item;
1383 self.check_attributes(&attrs);
1384 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1386 _ => fold::noop_fold_trait_item(item, self),
1390 fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
1391 let item = configure!(self, item);
1393 let (attr, traits, item, after_derive) = self.classify_item(item);
1394 if attr.is_some() || !traits.is_empty() {
1395 return self.collect_attr(attr, traits, Annotatable::ImplItem(P(item)),
1396 AstFragmentKind::ImplItems, after_derive).make_impl_items();
1400 ast::ImplItemKind::Macro(mac) => {
1401 let ast::ImplItem { attrs, span, .. } = item;
1402 self.check_attributes(&attrs);
1403 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1405 _ => fold::noop_fold_impl_item(item, self),
1409 fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
1410 let ty = match ty.node {
1411 ast::TyKind::Mac(_) => ty.into_inner(),
1412 _ => return fold::noop_fold_ty(ty, self),
1416 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1417 _ => unreachable!(),
1421 fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
1422 noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
1425 fn fold_foreign_item(&mut self, foreign_item: ast::ForeignItem)
1426 -> SmallVec<[ast::ForeignItem; 1]>
1428 let (attr, traits, foreign_item, after_derive) = self.classify_item(foreign_item);
1430 if attr.is_some() || !traits.is_empty() {
1431 return self.collect_attr(attr, traits, Annotatable::ForeignItem(P(foreign_item)),
1432 AstFragmentKind::ForeignItems, after_derive)
1433 .make_foreign_items();
1436 if let ast::ForeignItemKind::Macro(mac) = foreign_item.node {
1437 self.check_attributes(&foreign_item.attrs);
1438 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1439 .make_foreign_items();
1442 noop_fold_foreign_item(foreign_item, self)
1445 fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
1447 ast::ItemKind::MacroDef(..) => item,
1448 _ => noop_fold_item_kind(self.cfg.configure_item_kind(item), self),
1452 fn fold_generic_param(&mut self, param: ast::GenericParam) -> ast::GenericParam {
1453 self.cfg.disallow_cfg_on_generic_param(¶m);
1454 noop_fold_generic_param(param, self)
1457 fn fold_attribute(&mut self, at: ast::Attribute) -> Option<ast::Attribute> {
1458 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1459 // contents="file contents")]` attributes
1460 if !at.check_name("doc") {
1461 return noop_fold_attribute(at, self);
1464 if let Some(list) = at.meta_item_list() {
1465 if !list.iter().any(|it| it.check_name("include")) {
1466 return noop_fold_attribute(at, self);
1469 let mut items = vec![];
1472 if !it.check_name("include") {
1473 items.push(noop_fold_meta_list_item(it, self));
1477 if let Some(file) = it.value_str() {
1478 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1479 self.check_attribute(&at);
1480 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1481 // avoid loading the file if they haven't enabled the feature
1482 return noop_fold_attribute(at, self);
1485 let mut buf = vec![];
1486 let filename = self.cx.root_path.join(file.to_string());
1488 match File::open(&filename).and_then(|mut f| f.read_to_end(&mut buf)) {
1491 self.cx.span_err(at.span,
1492 &format!("couldn't read {}: {}",
1498 match String::from_utf8(buf) {
1500 let src_interned = Symbol::intern(&src);
1502 // Add this input file to the code map to make it available as
1503 // dependency information
1504 self.cx.source_map().new_source_file(filename.into(), src);
1506 let include_info = vec![
1507 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1508 attr::mk_name_value_item_str(Ident::from_str("file"),
1509 dummy_spanned(file)))),
1510 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1511 attr::mk_name_value_item_str(Ident::from_str("contents"),
1512 dummy_spanned(src_interned)))),
1515 let include_ident = Ident::from_str("include");
1516 let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
1517 items.push(dummy_spanned(ast::NestedMetaItemKind::MetaItem(item)));
1520 self.cx.span_err(at.span,
1521 &format!("{} wasn't a utf-8 file",
1522 filename.display()));
1526 items.push(noop_fold_meta_list_item(it, self));
1530 let meta = attr::mk_list_item(DUMMY_SP, Ident::from_str("doc"), items);
1532 ast::AttrStyle::Inner =>
1533 Some(attr::mk_spanned_attr_inner(at.span, at.id, meta)),
1534 ast::AttrStyle::Outer =>
1535 Some(attr::mk_spanned_attr_outer(at.span, at.id, meta)),
1538 noop_fold_attribute(at, self)
1542 fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
1544 assert_eq!(id, ast::DUMMY_NODE_ID);
1545 self.cx.resolver.next_node_id()
1552 pub struct ExpansionConfig<'feat> {
1553 pub crate_name: String,
1554 pub features: Option<&'feat Features>,
1555 pub recursion_limit: usize,
1556 pub trace_mac: bool,
1557 pub should_test: bool, // If false, strip `#[test]` nodes
1558 pub single_step: bool,
1559 pub keep_macs: bool,
1562 macro_rules! feature_tests {
1563 ($( fn $getter:ident = $field:ident, )*) => {
1565 pub fn $getter(&self) -> bool {
1566 match self.features {
1567 Some(&Features { $field: true, .. }) => true,
1575 impl<'feat> ExpansionConfig<'feat> {
1576 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1580 recursion_limit: 1024,
1589 fn enable_quotes = quote,
1590 fn enable_asm = asm,
1591 fn enable_custom_test_frameworks = custom_test_frameworks,
1592 fn enable_global_asm = global_asm,
1593 fn enable_log_syntax = log_syntax,
1594 fn enable_concat_idents = concat_idents,
1595 fn enable_trace_macros = trace_macros,
1596 fn enable_allow_internal_unstable = allow_internal_unstable,
1597 fn enable_custom_derive = custom_derive,
1598 fn enable_format_args_nl = format_args_nl,
1599 fn macros_in_extern_enabled = macros_in_extern,
1600 fn proc_macro_hygiene = proc_macro_hygiene,
1603 fn enable_custom_inner_attributes(&self) -> bool {
1604 self.features.map_or(false, |features| {
1605 features.custom_inner_attributes || features.custom_attribute || features.rustc_attrs
1610 // A Marker adds the given mark to the syntax context.
1612 pub struct Marker(pub Mark);
1614 impl Folder for Marker {
1615 fn new_span(&mut self, span: Span) -> Span {
1616 span.apply_mark(self.0)
1619 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1620 noop_fold_mac(mac, self)