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 codemap::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
15 use config::{is_test_or_bench, 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;
30 use syntax_pos::{Span, DUMMY_SP, FileName};
31 use syntax_pos::hygiene::ExpnFormat;
32 use tokenstream::{TokenStream, TokenTree};
33 use util::small_vector::SmallVector;
34 use visit::{self, Visitor};
36 use std::collections::HashMap;
41 use std::path::PathBuf;
43 macro_rules! ast_fragments {
45 $($Kind:ident($AstTy:ty) {
47 $(one fn $fold_ast:ident; fn $visit_ast:ident;)?
48 $(many fn $fold_ast_elt:ident; fn $visit_ast_elt:ident;)?
52 /// A fragment of AST that can be produced by a single macro expansion.
53 /// Can also serve as an input and intermediate result for macro expansion operations.
54 pub enum AstFragment {
55 OptExpr(Option<P<ast::Expr>>),
59 /// "Discriminant" of an AST fragment.
60 #[derive(Copy, Clone, PartialEq, Eq)]
61 pub enum AstFragmentKind {
66 impl AstFragmentKind {
67 pub fn name(self) -> &'static str {
69 AstFragmentKind::OptExpr => "expression",
70 $(AstFragmentKind::$Kind => $kind_name,)*
74 fn make_from<'a>(self, result: Box<MacResult + 'a>) -> Option<AstFragment> {
76 AstFragmentKind::OptExpr =>
77 result.make_expr().map(Some).map(AstFragment::OptExpr),
78 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
84 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
86 AstFragment::OptExpr(expr) => expr,
87 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
91 $(pub fn $make_ast(self) -> $AstTy {
93 AstFragment::$Kind(ast) => ast,
94 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
98 pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
100 AstFragment::OptExpr(expr) =>
101 AstFragment::OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
102 $($(AstFragment::$Kind(ast) =>
103 AstFragment::$Kind(folder.$fold_ast(ast)),)?)*
104 $($(AstFragment::$Kind(ast) =>
105 AstFragment::$Kind(ast.into_iter()
106 .flat_map(|ast| folder.$fold_ast_elt(ast))
111 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
113 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
114 AstFragment::OptExpr(None) => {}
115 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
116 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
117 visitor.$visit_ast_elt(ast_elt);
123 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
124 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
125 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
127 $($(fn $fold_ast(&mut self, ast: $AstTy) -> $AstTy {
128 self.expand_fragment(AstFragment::$Kind(ast)).$make_ast()
130 $($(fn $fold_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
131 self.expand_fragment(AstFragment::$Kind(SmallVector::one(ast_elt))).$make_ast()
135 impl<'a> MacResult for ::ext::tt::macro_rules::ParserAnyMacro<'a> {
136 $(fn $make_ast(self: Box<::ext::tt::macro_rules::ParserAnyMacro<'a>>)
138 Some(self.make(AstFragmentKind::$Kind).$make_ast())
145 Expr(P<ast::Expr>) { "expression"; one fn fold_expr; fn visit_expr; fn make_expr; }
146 Pat(P<ast::Pat>) { "pattern"; one fn fold_pat; fn visit_pat; fn make_pat; }
147 Ty(P<ast::Ty>) { "type"; one fn fold_ty; fn visit_ty; fn make_ty; }
148 Stmts(SmallVector<ast::Stmt>) { "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts; }
149 Items(SmallVector<P<ast::Item>>) { "item"; many fn fold_item; fn visit_item; fn make_items; }
150 TraitItems(SmallVector<ast::TraitItem>) {
151 "trait item"; many fn fold_trait_item; fn visit_trait_item; fn make_trait_items;
153 ImplItems(SmallVector<ast::ImplItem>) {
154 "impl item"; many fn fold_impl_item; fn visit_impl_item; fn make_impl_items;
156 ForeignItems(SmallVector<ast::ForeignItem>) {
157 "foreign item"; many fn fold_foreign_item; fn visit_foreign_item; fn make_foreign_items;
161 impl AstFragmentKind {
162 fn dummy(self, span: Span) -> Option<AstFragment> {
163 self.make_from(DummyResult::any(span))
166 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
168 let mut items = items.into_iter();
170 AstFragmentKind::Items =>
171 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
172 AstFragmentKind::ImplItems =>
173 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
174 AstFragmentKind::TraitItems =>
175 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
176 AstFragmentKind::ForeignItems =>
177 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
178 AstFragmentKind::Stmts =>
179 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
180 AstFragmentKind::Expr => AstFragment::Expr(
181 items.next().expect("expected exactly one expression").expect_expr()
183 AstFragmentKind::OptExpr =>
184 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
185 AstFragmentKind::Pat | AstFragmentKind::Ty =>
186 panic!("patterns and types aren't annotatable"),
191 fn macro_bang_format(path: &ast::Path) -> ExpnFormat {
192 // We don't want to format a path using pretty-printing,
193 // `format!("{}", path)`, because that tries to insert
194 // line-breaks and is slow.
195 let mut path_str = String::with_capacity(64);
196 for (i, segment) in path.segments.iter().enumerate() {
198 path_str.push_str("::");
201 if segment.ident.name != keywords::CrateRoot.name() &&
202 segment.ident.name != keywords::DollarCrate.name()
204 path_str.push_str(&segment.ident.as_str())
208 MacroBang(Symbol::intern(&path_str))
211 pub struct Invocation {
212 pub kind: InvocationKind,
213 fragment_kind: AstFragmentKind,
214 pub expansion_data: ExpansionData,
217 pub enum InvocationKind {
220 ident: Option<Ident>,
224 attr: Option<ast::Attribute>,
235 fn span(&self) -> Span {
237 InvocationKind::Bang { span, .. } => span,
238 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.span,
239 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
240 InvocationKind::Derive { ref path, .. } => path.span,
245 pub struct MacroExpander<'a, 'b:'a> {
246 pub cx: &'a mut ExtCtxt<'b>,
247 monotonic: bool, // c.f. `cx.monotonic_expander()`
250 impl<'a, 'b> MacroExpander<'a, 'b> {
251 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
252 MacroExpander { cx: cx, monotonic: monotonic }
255 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
256 let mut module = ModuleData {
257 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
258 directory: match self.cx.codemap().span_to_unmapped_path(krate.span) {
259 FileName::Real(path) => path,
260 other => PathBuf::from(other.to_string()),
263 module.directory.pop();
264 self.cx.root_path = module.directory.clone();
265 self.cx.current_expansion.module = Rc::new(module);
266 self.cx.current_expansion.crate_span = Some(krate.span);
268 let orig_mod_span = krate.module.inner;
270 let krate_item = AstFragment::Items(SmallVector::one(P(ast::Item {
273 node: ast::ItemKind::Mod(krate.module),
274 ident: keywords::Invalid.ident(),
275 id: ast::DUMMY_NODE_ID,
276 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
280 match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
281 Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
283 krate.module = module;
286 // Resolution failed so we return an empty expansion
287 krate.attrs = vec![];
288 krate.module = ast::Mod {
289 inner: orig_mod_span,
295 self.cx.trace_macros_diag();
299 // Fully expand all macro invocations in this AST fragment.
300 fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
301 let orig_expansion_data = self.cx.current_expansion.clone();
302 self.cx.current_expansion.depth = 0;
304 // Collect all macro invocations and replace them with placeholders.
305 let (fragment_with_placeholders, mut invocations)
306 = self.collect_invocations(input_fragment, &[]);
308 // Optimization: if we resolve all imports now,
309 // we'll be able to immediately resolve most of imported macros.
310 self.resolve_imports();
312 // Resolve paths in all invocations and produce ouput expanded fragments for them, but
313 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
314 // The output fragments also go through expansion recursively until no invocations are left.
315 // Unresolved macros produce dummy outputs as a recovery measure.
316 invocations.reverse();
317 let mut expanded_fragments = Vec::new();
318 let mut derives = HashMap::new();
319 let mut undetermined_invocations = Vec::new();
320 let (mut progress, mut force) = (false, !self.monotonic);
322 let mut invoc = if let Some(invoc) = invocations.pop() {
325 self.resolve_imports();
326 if undetermined_invocations.is_empty() { break }
327 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
328 force = !mem::replace(&mut progress, false);
333 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
334 let ext = match self.cx.resolver.resolve_invoc(&mut invoc, scope, force) {
335 Ok(ext) => Some(ext),
336 Err(Determinacy::Determined) => None,
337 Err(Determinacy::Undetermined) => {
338 undetermined_invocations.push(invoc);
344 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
345 self.cx.current_expansion = invoc.expansion_data.clone();
347 self.cx.current_expansion.mark = scope;
348 // FIXME(jseyfried): Refactor out the following logic
349 let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
350 if let Some(ext) = ext {
351 let dummy = invoc.fragment_kind.dummy(invoc.span()).unwrap();
352 let fragment = self.expand_invoc(invoc, &*ext).unwrap_or(dummy);
353 self.collect_invocations(fragment, &[])
354 } else if let InvocationKind::Attr { attr: None, traits, item } = invoc.kind {
355 if !item.derive_allowed() {
356 let attr = attr::find_by_name(item.attrs(), "derive")
357 .expect("`derive` attribute should exist");
358 let span = attr.span;
359 let mut err = self.cx.mut_span_err(span,
360 "`derive` may only be applied to \
361 structs, enums and unions");
362 if let ast::AttrStyle::Inner = attr.style {
363 let trait_list = traits.iter()
364 .map(|t| format!("{}", t)).collect::<Vec<_>>();
365 let suggestion = format!("#[derive({})]", trait_list.join(", "));
366 err.span_suggestion_with_applicability(
367 span, "try an outer attribute", suggestion,
368 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
369 Applicability::MaybeIncorrect
375 let item = self.fully_configure(item)
376 .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
377 let item_with_markers =
378 add_derived_markers(&mut self.cx, item.span(), &traits, item.clone());
379 let derives = derives.entry(invoc.expansion_data.mark).or_insert_with(Vec::new);
381 for path in &traits {
382 let mark = Mark::fresh(self.cx.current_expansion.mark);
384 let item = match self.cx.resolver.resolve_macro(
385 Mark::root(), path, MacroKind::Derive, false) {
386 Ok(ext) => match *ext {
387 BuiltinDerive(..) => item_with_markers.clone(),
392 invocations.push(Invocation {
393 kind: InvocationKind::Derive { path: path.clone(), item: item },
394 fragment_kind: invoc.fragment_kind,
395 expansion_data: ExpansionData {
397 ..invoc.expansion_data.clone()
401 let fragment = invoc.fragment_kind
402 .expect_from_annotatables(::std::iter::once(item_with_markers));
403 self.collect_invocations(fragment, derives)
408 self.collect_invocations(invoc.fragment_kind.dummy(invoc.span()).unwrap(), &[])
411 if expanded_fragments.len() < depth {
412 expanded_fragments.push(Vec::new());
414 expanded_fragments[depth - 1].push((mark, expanded_fragment));
415 if !self.cx.ecfg.single_step {
416 invocations.extend(new_invocations.into_iter().rev());
420 self.cx.current_expansion = orig_expansion_data;
422 // Finally incorporate all the expanded macros into the input AST fragment.
423 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
424 while let Some(expanded_fragments) = expanded_fragments.pop() {
425 for (mark, expanded_fragment) in expanded_fragments.into_iter().rev() {
426 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
427 placeholder_expander.add(NodeId::placeholder_from_mark(mark),
428 expanded_fragment, derives);
431 fragment_with_placeholders.fold_with(&mut placeholder_expander)
434 fn resolve_imports(&mut self) {
436 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
437 self.cx.resolver.resolve_imports();
438 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
442 /// Collect all macro invocations reachable at this time in this AST fragment, and replace
443 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
444 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
445 /// prepares data for resolving paths of macro invocations.
446 fn collect_invocations(&mut self, fragment: AstFragment, derives: &[Mark])
447 -> (AstFragment, Vec<Invocation>) {
448 let (fragment_with_placeholders, invocations) = {
449 let mut collector = InvocationCollector {
450 cfg: StripUnconfigured {
451 should_test: self.cx.ecfg.should_test,
452 sess: self.cx.parse_sess,
453 features: self.cx.ecfg.features,
456 invocations: Vec::new(),
457 monotonic: self.monotonic,
459 (fragment.fold_with(&mut collector), collector.invocations)
463 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
464 let mark = self.cx.current_expansion.mark;
465 self.cx.resolver.visit_ast_fragment_with_placeholders(mark, &fragment_with_placeholders,
467 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
470 (fragment_with_placeholders, invocations)
473 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
474 let mut cfg = StripUnconfigured {
475 should_test: self.cx.ecfg.should_test,
476 sess: self.cx.parse_sess,
477 features: self.cx.ecfg.features,
479 // Since the item itself has already been configured by the InvocationCollector,
480 // we know that fold result vector will contain exactly one element
482 Annotatable::Item(item) => {
483 Annotatable::Item(cfg.fold_item(item).pop().unwrap())
485 Annotatable::TraitItem(item) => {
486 Annotatable::TraitItem(item.map(|item| cfg.fold_trait_item(item).pop().unwrap()))
488 Annotatable::ImplItem(item) => {
489 Annotatable::ImplItem(item.map(|item| cfg.fold_impl_item(item).pop().unwrap()))
491 Annotatable::ForeignItem(item) => {
492 Annotatable::ForeignItem(
493 item.map(|item| cfg.fold_foreign_item(item).pop().unwrap())
496 Annotatable::Stmt(stmt) => {
497 Annotatable::Stmt(stmt.map(|stmt| cfg.fold_stmt(stmt).pop().unwrap()))
499 Annotatable::Expr(expr) => {
500 Annotatable::Expr(cfg.fold_expr(expr))
505 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtension) -> Option<AstFragment> {
506 let result = match invoc.kind {
507 InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext)?,
508 InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext)?,
509 InvocationKind::Derive { .. } => self.expand_derive_invoc(invoc, ext)?,
512 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
513 let info = self.cx.current_expansion.mark.expn_info().unwrap();
514 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
515 let mut err = self.cx.struct_span_err(info.call_site,
516 &format!("recursion limit reached while expanding the macro `{}`",
517 info.format.name()));
519 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
522 self.cx.trace_macros_diag();
529 fn expand_attr_invoc(&mut self,
531 ext: &SyntaxExtension)
532 -> Option<AstFragment> {
533 let (attr, item) = match invoc.kind {
534 InvocationKind::Attr { attr, item, .. } => (attr?, item),
538 attr::mark_used(&attr);
539 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
540 call_site: attr.span,
542 format: MacroAttribute(Symbol::intern(&format!("{}", attr.path))),
543 allow_internal_unstable: false,
544 allow_internal_unsafe: false,
545 edition: ext.edition(),
549 MultiModifier(ref mac) => {
550 let meta = attr.parse_meta(self.cx.parse_sess)
551 .map_err(|mut e| { e.emit(); }).ok()?;
552 let item = mac.expand(self.cx, attr.span, &meta, item);
553 Some(invoc.fragment_kind.expect_from_annotatables(item))
555 MultiDecorator(ref mac) => {
556 let mut items = Vec::new();
557 let meta = attr.parse_meta(self.cx.parse_sess)
558 .expect("derive meta should already have been parsed");
559 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
561 Some(invoc.fragment_kind.expect_from_annotatables(items))
563 AttrProcMacro(ref mac, ..) => {
564 self.gate_proc_macro_attr_item(attr.span, &item);
565 let item_tok = TokenTree::Token(DUMMY_SP, Token::interpolated(match item {
566 Annotatable::Item(item) => token::NtItem(item),
567 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
568 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
569 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
570 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
571 Annotatable::Expr(expr) => token::NtExpr(expr),
573 let input = self.extract_proc_macro_attr_input(attr.tokens, attr.span);
574 let tok_result = mac.expand(self.cx, attr.span, input, item_tok);
575 let res = self.parse_ast_fragment(tok_result, invoc.fragment_kind,
576 &attr.path, attr.span);
577 self.gate_proc_macro_expansion(attr.span, &res);
580 ProcMacroDerive(..) | BuiltinDerive(..) => {
581 self.cx.span_err(attr.span, &format!("`{}` is a derive mode", attr.path));
582 self.cx.trace_macros_diag();
583 invoc.fragment_kind.dummy(attr.span)
586 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
587 self.cx.span_err(attr.span, msg);
588 self.cx.trace_macros_diag();
589 invoc.fragment_kind.dummy(attr.span)
594 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
595 let mut trees = tokens.trees();
597 Some(TokenTree::Delimited(_, delim)) => {
598 if trees.next().is_none() {
599 return delim.tts.into()
602 Some(TokenTree::Token(..)) => {}
603 None => return TokenStream::empty(),
605 self.cx.span_err(span, "custom attribute invocations must be \
606 of the form #[foo] or #[foo(..)], the macro name must only be \
607 followed by a delimiter token");
611 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
612 let (kind, gate) = match *item {
613 Annotatable::Item(ref item) => {
615 ItemKind::Mod(_) if self.cx.ecfg.proc_macro_mod() => return,
616 ItemKind::Mod(_) => ("modules", "proc_macro_mod"),
620 Annotatable::TraitItem(_) => return,
621 Annotatable::ImplItem(_) => return,
622 Annotatable::ForeignItem(_) => return,
623 Annotatable::Stmt(_) |
624 Annotatable::Expr(_) if self.cx.ecfg.proc_macro_expr() => return,
625 Annotatable::Stmt(_) => ("statements", "proc_macro_expr"),
626 Annotatable::Expr(_) => ("expressions", "proc_macro_expr"),
633 &format!("custom attributes cannot be applied to {}", kind),
637 fn gate_proc_macro_expansion(&self, span: Span, fragment: &Option<AstFragment>) {
638 if self.cx.ecfg.proc_macro_gen() {
641 let fragment = match fragment {
642 Some(fragment) => fragment,
646 fragment.visit_with(&mut DisallowModules {
648 parse_sess: self.cx.parse_sess,
651 struct DisallowModules<'a> {
653 parse_sess: &'a ParseSess,
656 impl<'ast, 'a> Visitor<'ast> for DisallowModules<'a> {
657 fn visit_item(&mut self, i: &'ast ast::Item) {
658 let name = match i.node {
659 ast::ItemKind::Mod(_) => Some("modules"),
660 ast::ItemKind::MacroDef(_) => Some("macro definitions"),
663 if let Some(name) = name {
669 &format!("procedural macros cannot expand to {}", name),
672 visit::walk_item(self, i);
675 fn visit_mac(&mut self, _mac: &'ast ast::Mac) {
681 /// Expand a macro invocation. Returns the resulting expanded AST fragment.
682 fn expand_bang_invoc(&mut self,
684 ext: &SyntaxExtension)
685 -> Option<AstFragment> {
686 let (mark, kind) = (invoc.expansion_data.mark, invoc.fragment_kind);
687 let (mac, ident, span) = match invoc.kind {
688 InvocationKind::Bang { mac, ident, span } => (mac, ident, span),
691 let path = &mac.node.path;
693 let ident = ident.unwrap_or_else(|| keywords::Invalid.ident());
694 let validate_and_set_expn_info = |this: &mut Self, // arg instead of capture
695 def_site_span: Option<Span>,
696 allow_internal_unstable,
697 allow_internal_unsafe,
698 // can't infer this type
699 unstable_feature: Option<(Symbol, u32)>,
702 // feature-gate the macro invocation
703 if let Some((feature, issue)) = unstable_feature {
704 let crate_span = this.cx.current_expansion.crate_span.unwrap();
705 // don't stability-check macros in the same crate
706 // (the only time this is null is for syntax extensions registered as macros)
707 if def_site_span.map_or(false, |def_span| !crate_span.contains(def_span))
708 && !span.allows_unstable() && this.cx.ecfg.features.map_or(true, |feats| {
709 // macro features will count as lib features
710 !feats.declared_lib_features.iter().any(|&(feat, _)| feat == feature)
712 let explain = format!("macro {}! is unstable", path);
713 emit_feature_err(this.cx.parse_sess, &*feature.as_str(), span,
714 GateIssue::Library(Some(issue)), &explain);
715 this.cx.trace_macros_diag();
716 return Err(kind.dummy(span));
720 if ident.name != keywords::Invalid.name() {
721 let msg = format!("macro {}! expects no ident argument, given '{}'", path, ident);
722 this.cx.span_err(path.span, &msg);
723 this.cx.trace_macros_diag();
724 return Err(kind.dummy(span));
726 mark.set_expn_info(ExpnInfo {
728 def_site: def_site_span,
729 format: macro_bang_format(path),
730 allow_internal_unstable,
731 allow_internal_unsafe,
737 let opt_expanded = match *ext {
738 DeclMacro(ref expand, def_span, edition) => {
739 if let Err(dummy_span) = validate_and_set_expn_info(self, def_span.map(|(_, s)| s),
744 kind.make_from(expand.expand(self.cx, span, mac.node.stream()))
751 allow_internal_unstable,
752 allow_internal_unsafe,
756 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
757 allow_internal_unstable,
758 allow_internal_unsafe,
763 kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
767 IdentTT(ref expander, tt_span, allow_internal_unstable) => {
768 if ident.name == keywords::Invalid.name() {
769 self.cx.span_err(path.span,
770 &format!("macro {}! expects an ident argument", path));
771 self.cx.trace_macros_diag();
774 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
777 format: macro_bang_format(path),
778 allow_internal_unstable,
779 allow_internal_unsafe: false,
780 edition: hygiene::default_edition(),
783 let input: Vec<_> = mac.node.stream().into_trees().collect();
784 kind.make_from(expander.expand(self.cx, span, ident, input))
788 MultiDecorator(..) | MultiModifier(..) | AttrProcMacro(..) => {
789 self.cx.span_err(path.span,
790 &format!("`{}` can only be used in attributes", path));
791 self.cx.trace_macros_diag();
795 ProcMacroDerive(..) | BuiltinDerive(..) => {
796 self.cx.span_err(path.span, &format!("`{}` is a derive mode", path));
797 self.cx.trace_macros_diag();
801 ProcMacro(ref expandfun, allow_internal_unstable, edition) => {
802 if ident.name != keywords::Invalid.name() {
804 format!("macro {}! expects no ident argument, given '{}'", path, ident);
805 self.cx.span_err(path.span, &msg);
806 self.cx.trace_macros_diag();
809 self.gate_proc_macro_expansion_kind(span, kind);
810 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
812 // FIXME procedural macros do not have proper span info
813 // yet, when they do, we should use it here.
815 format: macro_bang_format(path),
816 // FIXME probably want to follow macro_rules macros here.
817 allow_internal_unstable,
818 allow_internal_unsafe: false,
822 let tok_result = expandfun.expand(self.cx, span, mac.node.stream());
823 let result = self.parse_ast_fragment(tok_result, kind, path, span);
824 self.gate_proc_macro_expansion(span, &result);
830 if opt_expanded.is_some() {
833 let msg = format!("non-{kind} macro in {kind} position: {name}",
834 name = path.segments[0].ident.name, kind = kind.name());
835 self.cx.span_err(path.span, &msg);
836 self.cx.trace_macros_diag();
841 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
842 let kind = match kind {
843 AstFragmentKind::Expr => "expressions",
844 AstFragmentKind::OptExpr => "expressions",
845 AstFragmentKind::Pat => "patterns",
846 AstFragmentKind::Ty => "types",
847 AstFragmentKind::Stmts => "statements",
848 AstFragmentKind::Items => return,
849 AstFragmentKind::TraitItems => return,
850 AstFragmentKind::ImplItems => return,
851 AstFragmentKind::ForeignItems => return,
853 if self.cx.ecfg.proc_macro_non_items() {
858 "proc_macro_non_items",
861 &format!("procedural macros cannot be expanded to {}", kind),
865 /// Expand a derive invocation. Returns the resulting expanded AST fragment.
866 fn expand_derive_invoc(&mut self,
868 ext: &SyntaxExtension)
869 -> Option<AstFragment> {
870 let (path, item) = match invoc.kind {
871 InvocationKind::Derive { path, item } => (path, item),
874 if !item.derive_allowed() {
878 let pretty_name = Symbol::intern(&format!("derive({})", path));
879 let span = path.span;
880 let attr = ast::Attribute {
882 tokens: TokenStream::empty(),
884 id: ast::AttrId(0), style: ast::AttrStyle::Outer, is_sugared_doc: false,
887 let mut expn_info = ExpnInfo {
890 format: MacroAttribute(pretty_name),
891 allow_internal_unstable: false,
892 allow_internal_unsafe: false,
893 edition: ext.edition(),
897 ProcMacroDerive(ref ext, ..) => {
898 invoc.expansion_data.mark.set_expn_info(expn_info);
899 let span = span.with_ctxt(self.cx.backtrace());
900 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
901 ident: Path::from_ident(keywords::Invalid.ident()),
903 node: ast::MetaItemKind::Word,
905 let items = ext.expand(self.cx, span, &dummy, item);
906 Some(invoc.fragment_kind.expect_from_annotatables(items))
908 BuiltinDerive(func) => {
909 expn_info.allow_internal_unstable = true;
910 invoc.expansion_data.mark.set_expn_info(expn_info);
911 let span = span.with_ctxt(self.cx.backtrace());
912 let mut items = Vec::new();
913 func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
914 Some(invoc.fragment_kind.expect_from_annotatables(items))
917 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
918 self.cx.span_err(span, msg);
919 self.cx.trace_macros_diag();
920 invoc.fragment_kind.dummy(span)
925 fn parse_ast_fragment(&mut self,
927 kind: AstFragmentKind,
930 -> Option<AstFragment> {
931 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
932 match parser.parse_ast_fragment(kind, false) {
934 parser.ensure_complete_parse(path, kind.name(), span);
940 self.cx.trace_macros_diag();
947 impl<'a> Parser<'a> {
948 pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warnings: bool)
949 -> PResult<'a, AstFragment> {
951 AstFragmentKind::Items => {
952 let mut items = SmallVector::new();
953 while let Some(item) = self.parse_item()? {
956 AstFragment::Items(items)
958 AstFragmentKind::TraitItems => {
959 let mut items = SmallVector::new();
960 while self.token != token::Eof {
961 items.push(self.parse_trait_item(&mut false)?);
963 AstFragment::TraitItems(items)
965 AstFragmentKind::ImplItems => {
966 let mut items = SmallVector::new();
967 while self.token != token::Eof {
968 items.push(self.parse_impl_item(&mut false)?);
970 AstFragment::ImplItems(items)
972 AstFragmentKind::ForeignItems => {
973 let mut items = SmallVector::new();
974 while self.token != token::Eof {
975 if let Some(item) = self.parse_foreign_item()? {
979 AstFragment::ForeignItems(items)
981 AstFragmentKind::Stmts => {
982 let mut stmts = SmallVector::new();
983 while self.token != token::Eof &&
984 // won't make progress on a `}`
985 self.token != token::CloseDelim(token::Brace) {
986 if let Some(stmt) = self.parse_full_stmt(macro_legacy_warnings)? {
990 AstFragment::Stmts(stmts)
992 AstFragmentKind::Expr => AstFragment::Expr(self.parse_expr()?),
993 AstFragmentKind::OptExpr => {
994 if self.token != token::Eof {
995 AstFragment::OptExpr(Some(self.parse_expr()?))
997 AstFragment::OptExpr(None)
1000 AstFragmentKind::Ty => AstFragment::Ty(self.parse_ty()?),
1001 AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat()?),
1005 pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span: Span) {
1006 if self.token != token::Eof {
1007 let msg = format!("macro expansion ignores token `{}` and any following",
1008 self.this_token_to_string());
1009 // Avoid emitting backtrace info twice.
1010 let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
1011 let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
1012 let msg = format!("caused by the macro expansion here; the usage \
1013 of `{}!` is likely invalid in {} context",
1014 macro_path, kind_name);
1015 err.span_note(span, &msg).emit();
1020 struct InvocationCollector<'a, 'b: 'a> {
1021 cx: &'a mut ExtCtxt<'b>,
1022 cfg: StripUnconfigured<'a>,
1023 invocations: Vec<Invocation>,
1027 impl<'a, 'b> InvocationCollector<'a, 'b> {
1028 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1029 let mark = Mark::fresh(self.cx.current_expansion.mark);
1030 self.invocations.push(Invocation {
1033 expansion_data: ExpansionData {
1035 depth: self.cx.current_expansion.depth + 1,
1036 ..self.cx.current_expansion.clone()
1039 placeholder(fragment_kind, NodeId::placeholder_from_mark(mark))
1042 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
1043 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
1046 fn collect_attr(&mut self,
1047 attr: Option<ast::Attribute>,
1050 kind: AstFragmentKind)
1052 self.collect(kind, InvocationKind::Attr { attr, traits, item })
1055 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1056 fn classify_item<T>(&mut self, mut item: T) -> (Option<ast::Attribute>, Vec<Path>, T)
1059 let (mut attr, mut traits) = (None, Vec::new());
1061 item = item.map_attrs(|mut attrs| {
1062 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1064 attr = Some(legacy_attr_invoc);
1068 if self.cx.ecfg.proc_macro_enabled() {
1069 attr = find_attr_invoc(&mut attrs);
1071 traits = collect_derives(&mut self.cx, &mut attrs);
1075 (attr, traits, item)
1078 /// Alternative of `classify_item()` that ignores `#[derive]` so invocations fallthrough
1079 /// to the unused-attributes lint (making it an error on statements and expressions
1080 /// is a breaking change)
1081 fn classify_nonitem<T: HasAttrs>(&mut self, mut item: T) -> (Option<ast::Attribute>, T) {
1082 let mut attr = None;
1084 item = item.map_attrs(|mut attrs| {
1085 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1087 attr = Some(legacy_attr_invoc);
1091 if self.cx.ecfg.proc_macro_enabled() {
1092 attr = find_attr_invoc(&mut attrs);
1100 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1101 self.cfg.configure(node)
1104 // Detect use of feature-gated or invalid attributes on macro invocations
1105 // since they will not be detected after macro expansion.
1106 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1107 let features = self.cx.ecfg.features.unwrap();
1108 for attr in attrs.iter() {
1109 self.check_attribute_inner(attr, features);
1111 // macros are expanded before any lint passes so this warning has to be hardcoded
1112 if attr.path == "derive" {
1113 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1114 .note("this may become a hard error in a future release")
1120 fn check_attribute(&mut self, at: &ast::Attribute) {
1121 let features = self.cx.ecfg.features.unwrap();
1122 self.check_attribute_inner(at, features);
1125 fn check_attribute_inner(&mut self, at: &ast::Attribute, features: &Features) {
1126 feature_gate::check_attribute(at, self.cx.parse_sess, features);
1130 pub fn find_attr_invoc(attrs: &mut Vec<ast::Attribute>) -> Option<ast::Attribute> {
1132 .position(|a| !attr::is_known(a) && !is_builtin_attr(a))
1133 .map(|i| attrs.remove(i))
1136 impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
1137 fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
1138 let mut expr = self.cfg.configure_expr(expr).into_inner();
1139 expr.node = self.cfg.configure_expr_kind(expr.node);
1141 // ignore derives so they remain unused
1142 let (attr, expr) = self.classify_nonitem(expr);
1145 // collect the invoc regardless of whether or not attributes are permitted here
1146 // expansion will eat the attribute so it won't error later
1147 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1149 // AstFragmentKind::Expr requires the macro to emit an expression
1150 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1151 AstFragmentKind::Expr).make_expr();
1154 if let ast::ExprKind::Mac(mac) = expr.node {
1155 self.check_attributes(&expr.attrs);
1156 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr()
1158 P(noop_fold_expr(expr, self))
1162 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1163 let mut expr = configure!(self, expr).into_inner();
1164 expr.node = self.cfg.configure_expr_kind(expr.node);
1166 // ignore derives so they remain unused
1167 let (attr, expr) = self.classify_nonitem(expr);
1170 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1172 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1173 AstFragmentKind::OptExpr)
1177 if let ast::ExprKind::Mac(mac) = expr.node {
1178 self.check_attributes(&expr.attrs);
1179 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr).make_opt_expr()
1181 Some(P(noop_fold_expr(expr, self)))
1185 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
1186 let pat = self.cfg.configure_pat(pat);
1188 PatKind::Mac(_) => {}
1189 _ => return noop_fold_pat(pat, self),
1192 pat.and_then(|pat| match pat.node {
1193 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1194 _ => unreachable!(),
1198 fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
1199 let mut stmt = match self.cfg.configure_stmt(stmt) {
1201 None => return SmallVector::new(),
1204 // we'll expand attributes on expressions separately
1205 if !stmt.is_expr() {
1206 let (attr, derives, stmt_) = if stmt.is_item() {
1207 self.classify_item(stmt)
1209 // ignore derives on non-item statements so it falls through
1210 // to the unused-attributes lint
1211 let (attr, stmt) = self.classify_nonitem(stmt);
1212 (attr, vec![], stmt)
1215 if attr.is_some() || !derives.is_empty() {
1216 return self.collect_attr(attr, derives,
1217 Annotatable::Stmt(P(stmt_)), AstFragmentKind::Stmts)
1224 if let StmtKind::Mac(mac) = stmt.node {
1225 let (mac, style, attrs) = mac.into_inner();
1226 self.check_attributes(&attrs);
1227 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1230 // If this is a macro invocation with a semicolon, then apply that
1231 // semicolon to the final statement produced by expansion.
1232 if style == MacStmtStyle::Semicolon {
1233 if let Some(stmt) = placeholder.pop() {
1234 placeholder.push(stmt.add_trailing_semicolon());
1241 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1242 let ast::Stmt { id, node, span } = stmt;
1243 noop_fold_stmt_kind(node, self).into_iter().map(|node| {
1244 ast::Stmt { id, node, span }
1249 fn fold_block(&mut self, block: P<Block>) -> P<Block> {
1250 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1251 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1252 let result = noop_fold_block(block, self);
1253 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1257 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
1258 let item = configure!(self, item);
1260 let (attr, traits, mut item) = self.classify_item(item);
1261 if attr.is_some() || !traits.is_empty() {
1262 let item = Annotatable::Item(item);
1263 return self.collect_attr(attr, traits, item, AstFragmentKind::Items).make_items();
1267 ast::ItemKind::Mac(..) => {
1268 self.check_attributes(&item.attrs);
1269 item.and_then(|item| match item.node {
1270 ItemKind::Mac(mac) => {
1271 self.collect(AstFragmentKind::Items, InvocationKind::Bang {
1273 ident: Some(item.ident),
1277 _ => unreachable!(),
1280 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1281 if item.ident == keywords::Invalid.ident() {
1282 return noop_fold_item(item, self);
1285 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1286 let mut module = (*self.cx.current_expansion.module).clone();
1287 module.mod_path.push(item.ident);
1289 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1290 // In the non-inline case, `inner` is never the dummy span (c.f. `parse_item_mod`).
1291 // Thus, if `inner` is the dummy span, we know the module is inline.
1292 let inline_module = item.span.contains(inner) || inner == DUMMY_SP;
1295 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, "path") {
1296 self.cx.current_expansion.directory_ownership =
1297 DirectoryOwnership::Owned { relative: None };
1298 module.directory.push(&*path.as_str());
1300 module.directory.push(&*item.ident.as_str());
1303 let path = self.cx.parse_sess.codemap().span_to_unmapped_path(inner);
1304 let mut path = match path {
1305 FileName::Real(path) => path,
1306 other => PathBuf::from(other.to_string()),
1308 let directory_ownership = match path.file_name().unwrap().to_str() {
1309 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1310 Some(_) => DirectoryOwnership::Owned {
1311 relative: Some(item.ident),
1313 None => DirectoryOwnership::UnownedViaMod(false),
1316 module.directory = path;
1317 self.cx.current_expansion.directory_ownership = directory_ownership;
1321 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1322 let result = noop_fold_item(item, self);
1323 self.cx.current_expansion.module = orig_module;
1324 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1327 // Ensure that test functions are accessible from the test harness.
1328 ast::ItemKind::Fn(..) if self.cx.ecfg.should_test => {
1329 if item.attrs.iter().any(|attr| is_test_or_bench(attr)) {
1330 item = item.map(|mut item| {
1331 item.vis = respan(item.vis.span, ast::VisibilityKind::Public);
1335 noop_fold_item(item, self)
1337 _ => noop_fold_item(item, self),
1341 fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
1342 let item = configure!(self, item);
1344 let (attr, traits, item) = self.classify_item(item);
1345 if attr.is_some() || !traits.is_empty() {
1346 let item = Annotatable::TraitItem(P(item));
1347 return self.collect_attr(attr, traits, item, AstFragmentKind::TraitItems)
1352 ast::TraitItemKind::Macro(mac) => {
1353 let ast::TraitItem { attrs, span, .. } = item;
1354 self.check_attributes(&attrs);
1355 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1357 _ => fold::noop_fold_trait_item(item, self),
1361 fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
1362 let item = configure!(self, item);
1364 let (attr, traits, item) = self.classify_item(item);
1365 if attr.is_some() || !traits.is_empty() {
1366 let item = Annotatable::ImplItem(P(item));
1367 return self.collect_attr(attr, traits, item, AstFragmentKind::ImplItems)
1372 ast::ImplItemKind::Macro(mac) => {
1373 let ast::ImplItem { attrs, span, .. } = item;
1374 self.check_attributes(&attrs);
1375 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1377 _ => fold::noop_fold_impl_item(item, self),
1381 fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
1382 let ty = match ty.node {
1383 ast::TyKind::Mac(_) => ty.into_inner(),
1384 _ => return fold::noop_fold_ty(ty, self),
1388 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1389 _ => unreachable!(),
1393 fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
1394 noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
1397 fn fold_foreign_item(&mut self,
1398 foreign_item: ast::ForeignItem) -> SmallVector<ast::ForeignItem> {
1399 let (attr, traits, foreign_item) = self.classify_item(foreign_item);
1401 let explain = if self.cx.ecfg.proc_macro_enabled() {
1402 feature_gate::EXPLAIN_PROC_MACROS_IN_EXTERN
1404 feature_gate::EXPLAIN_MACROS_IN_EXTERN
1407 if attr.is_some() || !traits.is_empty() {
1408 if !self.cx.ecfg.macros_in_extern_enabled() {
1409 if let Some(ref attr) = attr {
1410 emit_feature_err(&self.cx.parse_sess, "macros_in_extern", attr.span,
1411 GateIssue::Language, explain);
1415 let item = Annotatable::ForeignItem(P(foreign_item));
1416 return self.collect_attr(attr, traits, item, AstFragmentKind::ForeignItems)
1417 .make_foreign_items();
1420 if let ast::ForeignItemKind::Macro(mac) = foreign_item.node {
1421 self.check_attributes(&foreign_item.attrs);
1423 if !self.cx.ecfg.macros_in_extern_enabled() {
1424 emit_feature_err(&self.cx.parse_sess, "macros_in_extern", foreign_item.span,
1425 GateIssue::Language, explain);
1428 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1429 .make_foreign_items();
1432 noop_fold_foreign_item(foreign_item, self)
1435 fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
1437 ast::ItemKind::MacroDef(..) => item,
1438 _ => noop_fold_item_kind(self.cfg.configure_item_kind(item), self),
1442 fn fold_generic_param(&mut self, param: ast::GenericParam) -> ast::GenericParam {
1443 self.cfg.disallow_cfg_on_generic_param(¶m);
1444 noop_fold_generic_param(param, self)
1447 fn fold_attribute(&mut self, at: ast::Attribute) -> Option<ast::Attribute> {
1448 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1449 // contents="file contents")]` attributes
1450 if !at.check_name("doc") {
1451 return noop_fold_attribute(at, self);
1454 if let Some(list) = at.meta_item_list() {
1455 if !list.iter().any(|it| it.check_name("include")) {
1456 return noop_fold_attribute(at, self);
1459 let mut items = vec![];
1462 if !it.check_name("include") {
1463 items.push(noop_fold_meta_list_item(it, self));
1467 if let Some(file) = it.value_str() {
1468 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1469 self.check_attribute(&at);
1470 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1471 // avoid loading the file if they haven't enabled the feature
1472 return noop_fold_attribute(at, self);
1475 let mut buf = vec![];
1476 let filename = self.cx.root_path.join(file.to_string());
1478 match File::open(&filename).and_then(|mut f| f.read_to_end(&mut buf)) {
1481 self.cx.span_err(at.span,
1482 &format!("couldn't read {}: {}",
1488 match String::from_utf8(buf) {
1490 // Add this input file to the code map to make it available as
1491 // dependency information
1492 self.cx.codemap().new_filemap_and_lines(&filename, &src);
1494 let include_info = vec![
1495 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1496 attr::mk_name_value_item_str(Ident::from_str("file"),
1497 dummy_spanned(file)))),
1498 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1499 attr::mk_name_value_item_str(Ident::from_str("contents"),
1500 dummy_spanned(Symbol::intern(&src))))),
1503 let include_ident = Ident::from_str("include");
1504 let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
1505 items.push(dummy_spanned(ast::NestedMetaItemKind::MetaItem(item)));
1508 self.cx.span_err(at.span,
1509 &format!("{} wasn't a utf-8 file",
1510 filename.display()));
1514 items.push(noop_fold_meta_list_item(it, self));
1518 let meta = attr::mk_list_item(DUMMY_SP, Ident::from_str("doc"), items);
1520 ast::AttrStyle::Inner =>
1521 Some(attr::mk_spanned_attr_inner(at.span, at.id, meta)),
1522 ast::AttrStyle::Outer =>
1523 Some(attr::mk_spanned_attr_outer(at.span, at.id, meta)),
1526 noop_fold_attribute(at, self)
1530 fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
1532 assert_eq!(id, ast::DUMMY_NODE_ID);
1533 self.cx.resolver.next_node_id()
1540 pub struct ExpansionConfig<'feat> {
1541 pub crate_name: String,
1542 pub features: Option<&'feat Features>,
1543 pub recursion_limit: usize,
1544 pub trace_mac: bool,
1545 pub should_test: bool, // If false, strip `#[test]` nodes
1546 pub single_step: bool,
1547 pub keep_macs: bool,
1550 macro_rules! feature_tests {
1551 ($( fn $getter:ident = $field:ident, )*) => {
1553 pub fn $getter(&self) -> bool {
1554 match self.features {
1555 Some(&Features { $field: true, .. }) => true,
1563 impl<'feat> ExpansionConfig<'feat> {
1564 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1568 recursion_limit: 1024,
1577 fn enable_quotes = quote,
1578 fn enable_asm = asm,
1579 fn enable_global_asm = global_asm,
1580 fn enable_log_syntax = log_syntax,
1581 fn enable_concat_idents = concat_idents,
1582 fn enable_trace_macros = trace_macros,
1583 fn enable_allow_internal_unstable = allow_internal_unstable,
1584 fn enable_custom_derive = custom_derive,
1585 fn proc_macro_enabled = proc_macro,
1586 fn macros_in_extern_enabled = macros_in_extern,
1587 fn proc_macro_mod = proc_macro_mod,
1588 fn proc_macro_gen = proc_macro_gen,
1589 fn proc_macro_expr = proc_macro_expr,
1590 fn proc_macro_non_items = proc_macro_non_items,
1594 // A Marker adds the given mark to the syntax context.
1596 pub struct Marker(pub Mark);
1598 impl Folder for Marker {
1599 fn new_span(&mut self, span: Span) -> Span {
1600 span.apply_mark(self.0)
1603 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1604 noop_fold_mac(mac, self)