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::build::AstBuilder;
19 use ext::derive::{add_derived_markers, collect_derives};
20 use ext::hygiene::{self, Mark, SyntaxContext};
21 use ext::placeholders::{placeholder, PlaceholderExpander};
22 use feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
25 use parse::{DirectoryOwnership, PResult, ParseSess};
26 use parse::token::{self, Token};
27 use parse::parser::Parser;
31 use syntax_pos::{Span, DUMMY_SP, FileName};
32 use syntax_pos::hygiene::ExpnFormat;
33 use tokenstream::{TokenStream, TokenTree};
34 use util::small_vector::SmallVector;
35 use visit::{self, Visitor};
37 use std::collections::HashMap;
42 use std::path::PathBuf;
44 macro_rules! ast_fragments {
46 $($Kind:ident($AstTy:ty) {
48 // FIXME: HACK: this should be `$(one ...)?` and `$(many ...)?` but `?` macro
49 // repetition was removed from 2015 edition in #51587 because of ambiguities.
50 $(one fn $fold_ast:ident; fn $visit_ast:ident;)*
51 $(many fn $fold_ast_elt:ident; fn $visit_ast_elt:ident;)*
55 /// A fragment of AST that can be produced by a single macro expansion.
56 /// Can also serve as an input and intermediate result for macro expansion operations.
57 pub enum AstFragment {
58 OptExpr(Option<P<ast::Expr>>),
62 /// "Discriminant" of an AST fragment.
63 #[derive(Copy, Clone, PartialEq, Eq)]
64 pub enum AstFragmentKind {
69 impl AstFragmentKind {
70 pub fn name(self) -> &'static str {
72 AstFragmentKind::OptExpr => "expression",
73 $(AstFragmentKind::$Kind => $kind_name,)*
77 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
79 AstFragmentKind::OptExpr =>
80 result.make_expr().map(Some).map(AstFragment::OptExpr),
81 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
87 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
89 AstFragment::OptExpr(expr) => expr,
90 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
94 $(pub fn $make_ast(self) -> $AstTy {
96 AstFragment::$Kind(ast) => ast,
97 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
101 pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
103 AstFragment::OptExpr(expr) =>
104 AstFragment::OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
105 $($(AstFragment::$Kind(ast) =>
106 AstFragment::$Kind(folder.$fold_ast(ast)),)*)*
107 $($(AstFragment::$Kind(ast) =>
108 AstFragment::$Kind(ast.into_iter()
109 .flat_map(|ast| folder.$fold_ast_elt(ast))
114 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
116 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
117 AstFragment::OptExpr(None) => {}
118 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)*)*
119 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
120 visitor.$visit_ast_elt(ast_elt);
126 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
127 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
128 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
130 $($(fn $fold_ast(&mut self, ast: $AstTy) -> $AstTy {
131 self.expand_fragment(AstFragment::$Kind(ast)).$make_ast()
133 $($(fn $fold_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
134 self.expand_fragment(AstFragment::$Kind(SmallVector::one(ast_elt))).$make_ast()
138 impl<'a> MacResult for ::ext::tt::macro_rules::ParserAnyMacro<'a> {
139 $(fn $make_ast(self: Box<::ext::tt::macro_rules::ParserAnyMacro<'a>>)
141 Some(self.make(AstFragmentKind::$Kind).$make_ast())
148 Expr(P<ast::Expr>) { "expression"; one fn fold_expr; fn visit_expr; fn make_expr; }
149 Pat(P<ast::Pat>) { "pattern"; one fn fold_pat; fn visit_pat; fn make_pat; }
150 Ty(P<ast::Ty>) { "type"; one fn fold_ty; fn visit_ty; fn make_ty; }
151 Stmts(SmallVector<ast::Stmt>) { "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts; }
152 Items(SmallVector<P<ast::Item>>) { "item"; many fn fold_item; fn visit_item; fn make_items; }
153 TraitItems(SmallVector<ast::TraitItem>) {
154 "trait item"; many fn fold_trait_item; fn visit_trait_item; fn make_trait_items;
156 ImplItems(SmallVector<ast::ImplItem>) {
157 "impl item"; many fn fold_impl_item; fn visit_impl_item; fn make_impl_items;
159 ForeignItems(SmallVector<ast::ForeignItem>) {
160 "foreign item"; many fn fold_foreign_item; fn visit_foreign_item; fn make_foreign_items;
164 impl AstFragmentKind {
165 fn dummy(self, span: Span) -> Option<AstFragment> {
166 self.make_from(DummyResult::any(span))
169 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
171 let mut items = items.into_iter();
173 AstFragmentKind::Items =>
174 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
175 AstFragmentKind::ImplItems =>
176 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
177 AstFragmentKind::TraitItems =>
178 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
179 AstFragmentKind::ForeignItems =>
180 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
181 AstFragmentKind::Stmts =>
182 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
183 AstFragmentKind::Expr => AstFragment::Expr(
184 items.next().expect("expected exactly one expression").expect_expr()
186 AstFragmentKind::OptExpr =>
187 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
188 AstFragmentKind::Pat | AstFragmentKind::Ty =>
189 panic!("patterns and types aren't annotatable"),
194 fn macro_bang_format(path: &ast::Path) -> ExpnFormat {
195 // We don't want to format a path using pretty-printing,
196 // `format!("{}", path)`, because that tries to insert
197 // line-breaks and is slow.
198 let mut path_str = String::with_capacity(64);
199 for (i, segment) in path.segments.iter().enumerate() {
201 path_str.push_str("::");
204 if segment.ident.name != keywords::CrateRoot.name() &&
205 segment.ident.name != keywords::DollarCrate.name()
207 path_str.push_str(&segment.ident.as_str())
211 MacroBang(Symbol::intern(&path_str))
214 pub struct Invocation {
215 pub kind: InvocationKind,
216 fragment_kind: AstFragmentKind,
217 pub expansion_data: ExpansionData,
220 pub enum InvocationKind {
223 ident: Option<Ident>,
227 attr: Option<ast::Attribute>,
238 pub fn span(&self) -> Span {
240 InvocationKind::Bang { span, .. } => span,
241 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.span,
242 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
243 InvocationKind::Derive { ref path, .. } => path.span,
247 pub fn path_span(&self) -> Span {
249 InvocationKind::Bang { ref mac, .. } => mac.node.path.span,
250 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.path.span,
251 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
252 InvocationKind::Derive { ref path, .. } => path.span,
257 pub struct MacroExpander<'a, 'b:'a> {
258 pub cx: &'a mut ExtCtxt<'b>,
259 monotonic: bool, // c.f. `cx.monotonic_expander()`
262 impl<'a, 'b> MacroExpander<'a, 'b> {
263 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
264 MacroExpander { cx: cx, monotonic: monotonic }
267 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
268 let mut module = ModuleData {
269 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
270 directory: match self.cx.codemap().span_to_unmapped_path(krate.span) {
271 FileName::Real(path) => path,
272 other => PathBuf::from(other.to_string()),
275 module.directory.pop();
276 self.cx.root_path = module.directory.clone();
277 self.cx.current_expansion.module = Rc::new(module);
278 self.cx.current_expansion.crate_span = Some(krate.span);
280 let orig_mod_span = krate.module.inner;
282 let krate_item = AstFragment::Items(SmallVector::one(P(ast::Item {
285 node: ast::ItemKind::Mod(krate.module),
286 ident: keywords::Invalid.ident(),
287 id: ast::DUMMY_NODE_ID,
288 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
292 match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
293 Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
295 krate.module = module;
298 // Resolution failed so we return an empty expansion
299 krate.attrs = vec![];
300 krate.module = ast::Mod {
301 inner: orig_mod_span,
307 self.cx.trace_macros_diag();
311 // Fully expand all macro invocations in this AST fragment.
312 fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
313 let orig_expansion_data = self.cx.current_expansion.clone();
314 self.cx.current_expansion.depth = 0;
316 // Collect all macro invocations and replace them with placeholders.
317 let (fragment_with_placeholders, mut invocations)
318 = self.collect_invocations(input_fragment, &[]);
320 // Optimization: if we resolve all imports now,
321 // we'll be able to immediately resolve most of imported macros.
322 self.resolve_imports();
324 // Resolve paths in all invocations and produce ouput expanded fragments for them, but
325 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
326 // The output fragments also go through expansion recursively until no invocations are left.
327 // Unresolved macros produce dummy outputs as a recovery measure.
328 invocations.reverse();
329 let mut expanded_fragments = Vec::new();
330 let mut derives = HashMap::new();
331 let mut undetermined_invocations = Vec::new();
332 let (mut progress, mut force) = (false, !self.monotonic);
334 let invoc = if let Some(invoc) = invocations.pop() {
337 self.resolve_imports();
338 if undetermined_invocations.is_empty() { break }
339 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
340 force = !mem::replace(&mut progress, false);
345 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
346 let ext = match self.cx.resolver.resolve_invoc(&invoc, scope, force) {
347 Ok(ext) => Some(ext),
348 Err(Determinacy::Determined) => None,
349 Err(Determinacy::Undetermined) => {
350 undetermined_invocations.push(invoc);
356 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
357 self.cx.current_expansion = invoc.expansion_data.clone();
359 self.cx.current_expansion.mark = scope;
360 // FIXME(jseyfried): Refactor out the following logic
361 let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
362 if let Some(ext) = ext {
363 let dummy = invoc.fragment_kind.dummy(invoc.span()).unwrap();
364 let fragment = self.expand_invoc(invoc, &*ext).unwrap_or(dummy);
365 self.collect_invocations(fragment, &[])
366 } else if let InvocationKind::Attr { attr: None, traits, item } = invoc.kind {
367 if !item.derive_allowed() {
368 let attr = attr::find_by_name(item.attrs(), "derive")
369 .expect("`derive` attribute should exist");
370 let span = attr.span;
371 let mut err = self.cx.mut_span_err(span,
372 "`derive` may only be applied to \
373 structs, enums and unions");
374 if let ast::AttrStyle::Inner = attr.style {
375 let trait_list = traits.iter()
376 .map(|t| t.to_string()).collect::<Vec<_>>();
377 let suggestion = format!("#[derive({})]", trait_list.join(", "));
378 err.span_suggestion_with_applicability(
379 span, "try an outer attribute", suggestion,
380 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
381 Applicability::MaybeIncorrect
387 let item = self.fully_configure(item)
388 .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
389 let item_with_markers =
390 add_derived_markers(&mut self.cx, item.span(), &traits, item.clone());
391 let derives = derives.entry(invoc.expansion_data.mark).or_insert_with(Vec::new);
393 for path in &traits {
394 let mark = Mark::fresh(self.cx.current_expansion.mark);
396 let item = match self.cx.resolver.resolve_macro(
397 Mark::root(), path, MacroKind::Derive, false) {
398 Ok(ext) => match *ext {
399 BuiltinDerive(..) => item_with_markers.clone(),
404 invocations.push(Invocation {
405 kind: InvocationKind::Derive { path: path.clone(), item: item },
406 fragment_kind: invoc.fragment_kind,
407 expansion_data: ExpansionData {
409 ..invoc.expansion_data.clone()
413 let fragment = invoc.fragment_kind
414 .expect_from_annotatables(::std::iter::once(item_with_markers));
415 self.collect_invocations(fragment, derives)
420 self.collect_invocations(invoc.fragment_kind.dummy(invoc.span()).unwrap(), &[])
423 if expanded_fragments.len() < depth {
424 expanded_fragments.push(Vec::new());
426 expanded_fragments[depth - 1].push((mark, expanded_fragment));
427 if !self.cx.ecfg.single_step {
428 invocations.extend(new_invocations.into_iter().rev());
432 self.cx.current_expansion = orig_expansion_data;
434 // Finally incorporate all the expanded macros into the input AST fragment.
435 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
436 while let Some(expanded_fragments) = expanded_fragments.pop() {
437 for (mark, expanded_fragment) in expanded_fragments.into_iter().rev() {
438 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
439 placeholder_expander.add(NodeId::placeholder_from_mark(mark),
440 expanded_fragment, derives);
443 fragment_with_placeholders.fold_with(&mut placeholder_expander)
446 fn resolve_imports(&mut self) {
448 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
449 self.cx.resolver.resolve_imports();
450 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
454 /// Collect all macro invocations reachable at this time in this AST fragment, and replace
455 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
456 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
457 /// prepares data for resolving paths of macro invocations.
458 fn collect_invocations(&mut self, fragment: AstFragment, derives: &[Mark])
459 -> (AstFragment, Vec<Invocation>) {
460 let (fragment_with_placeholders, invocations) = {
461 let mut collector = InvocationCollector {
462 cfg: StripUnconfigured {
463 should_test: self.cx.ecfg.should_test,
464 sess: self.cx.parse_sess,
465 features: self.cx.ecfg.features,
468 invocations: Vec::new(),
469 monotonic: self.monotonic,
470 tests_nameable: true,
472 (fragment.fold_with(&mut collector), collector.invocations)
476 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
477 let mark = self.cx.current_expansion.mark;
478 self.cx.resolver.visit_ast_fragment_with_placeholders(mark, &fragment_with_placeholders,
480 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
483 (fragment_with_placeholders, invocations)
486 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
487 let mut cfg = StripUnconfigured {
488 should_test: self.cx.ecfg.should_test,
489 sess: self.cx.parse_sess,
490 features: self.cx.ecfg.features,
492 // Since the item itself has already been configured by the InvocationCollector,
493 // we know that fold result vector will contain exactly one element
495 Annotatable::Item(item) => {
496 Annotatable::Item(cfg.fold_item(item).pop().unwrap())
498 Annotatable::TraitItem(item) => {
499 Annotatable::TraitItem(item.map(|item| cfg.fold_trait_item(item).pop().unwrap()))
501 Annotatable::ImplItem(item) => {
502 Annotatable::ImplItem(item.map(|item| cfg.fold_impl_item(item).pop().unwrap()))
504 Annotatable::ForeignItem(item) => {
505 Annotatable::ForeignItem(
506 item.map(|item| cfg.fold_foreign_item(item).pop().unwrap())
509 Annotatable::Stmt(stmt) => {
510 Annotatable::Stmt(stmt.map(|stmt| cfg.fold_stmt(stmt).pop().unwrap()))
512 Annotatable::Expr(expr) => {
513 Annotatable::Expr(cfg.fold_expr(expr))
518 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtension) -> Option<AstFragment> {
519 let result = match invoc.kind {
520 InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext)?,
521 InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext)?,
522 InvocationKind::Derive { .. } => self.expand_derive_invoc(invoc, ext)?,
525 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
526 let info = self.cx.current_expansion.mark.expn_info().unwrap();
527 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
528 let mut err = self.cx.struct_span_err(info.call_site,
529 &format!("recursion limit reached while expanding the macro `{}`",
530 info.format.name()));
532 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
535 self.cx.trace_macros_diag();
542 fn expand_attr_invoc(&mut self,
544 ext: &SyntaxExtension)
545 -> Option<AstFragment> {
546 let (attr, item) = match invoc.kind {
547 InvocationKind::Attr { attr, item, .. } => (attr?, item),
551 attr::mark_used(&attr);
552 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
553 call_site: attr.span,
555 format: MacroAttribute(Symbol::intern(&attr.path.to_string())),
556 allow_internal_unstable: false,
557 allow_internal_unsafe: false,
558 local_inner_macros: false,
559 edition: ext.edition(),
564 attr::mark_known(&attr);
565 let item = item.map_attrs(|mut attrs| { attrs.push(attr); attrs });
566 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
568 MultiModifier(ref mac) => {
569 let meta = attr.parse_meta(self.cx.parse_sess)
570 .map_err(|mut e| { e.emit(); }).ok()?;
571 let item = mac.expand(self.cx, attr.span, &meta, item);
572 Some(invoc.fragment_kind.expect_from_annotatables(item))
574 MultiDecorator(ref mac) => {
575 let mut items = Vec::new();
576 let meta = attr.parse_meta(self.cx.parse_sess)
577 .expect("derive meta should already have been parsed");
578 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
580 Some(invoc.fragment_kind.expect_from_annotatables(items))
582 AttrProcMacro(ref mac, ..) => {
583 self.gate_proc_macro_attr_item(attr.span, &item);
584 let item_tok = TokenTree::Token(DUMMY_SP, Token::interpolated(match item {
585 Annotatable::Item(item) => token::NtItem(item),
586 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
587 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
588 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
589 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
590 Annotatable::Expr(expr) => token::NtExpr(expr),
592 let input = self.extract_proc_macro_attr_input(attr.tokens, attr.span);
593 let tok_result = mac.expand(self.cx, attr.span, input, item_tok);
594 let res = self.parse_ast_fragment(tok_result, invoc.fragment_kind,
595 &attr.path, attr.span);
596 self.gate_proc_macro_expansion(attr.span, &res);
599 ProcMacroDerive(..) | BuiltinDerive(..) => {
600 self.cx.span_err(attr.span, &format!("`{}` is a derive mode", attr.path));
601 self.cx.trace_macros_diag();
602 invoc.fragment_kind.dummy(attr.span)
605 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
606 self.cx.span_err(attr.span, msg);
607 self.cx.trace_macros_diag();
608 invoc.fragment_kind.dummy(attr.span)
613 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
614 let mut trees = tokens.trees();
616 Some(TokenTree::Delimited(_, delim)) => {
617 if trees.next().is_none() {
618 return delim.tts.into()
621 Some(TokenTree::Token(..)) => {}
622 None => return TokenStream::empty(),
624 self.cx.span_err(span, "custom attribute invocations must be \
625 of the form #[foo] or #[foo(..)], the macro name must only be \
626 followed by a delimiter token");
630 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
631 let (kind, gate) = match *item {
632 Annotatable::Item(ref item) => {
634 ItemKind::Mod(_) if self.cx.ecfg.proc_macro_mod() => return,
635 ItemKind::Mod(_) => ("modules", "proc_macro_mod"),
639 Annotatable::TraitItem(_) => return,
640 Annotatable::ImplItem(_) => return,
641 Annotatable::ForeignItem(_) => return,
642 Annotatable::Stmt(_) |
643 Annotatable::Expr(_) if self.cx.ecfg.proc_macro_expr() => return,
644 Annotatable::Stmt(_) => ("statements", "proc_macro_expr"),
645 Annotatable::Expr(_) => ("expressions", "proc_macro_expr"),
652 &format!("custom attributes cannot be applied to {}", kind),
656 fn gate_proc_macro_expansion(&self, span: Span, fragment: &Option<AstFragment>) {
657 if self.cx.ecfg.proc_macro_gen() {
660 let fragment = match fragment {
661 Some(fragment) => fragment,
665 fragment.visit_with(&mut DisallowModules {
667 parse_sess: self.cx.parse_sess,
670 struct DisallowModules<'a> {
672 parse_sess: &'a ParseSess,
675 impl<'ast, 'a> Visitor<'ast> for DisallowModules<'a> {
676 fn visit_item(&mut self, i: &'ast ast::Item) {
677 let name = match i.node {
678 ast::ItemKind::Mod(_) => Some("modules"),
679 ast::ItemKind::MacroDef(_) => Some("macro definitions"),
682 if let Some(name) = name {
688 &format!("procedural macros cannot expand to {}", name),
691 visit::walk_item(self, i);
694 fn visit_mac(&mut self, _mac: &'ast ast::Mac) {
700 /// Expand a macro invocation. Returns the resulting expanded AST fragment.
701 fn expand_bang_invoc(&mut self,
703 ext: &SyntaxExtension)
704 -> Option<AstFragment> {
705 let (mark, kind) = (invoc.expansion_data.mark, invoc.fragment_kind);
706 let (mac, ident, span) = match invoc.kind {
707 InvocationKind::Bang { mac, ident, span } => (mac, ident, span),
710 let path = &mac.node.path;
712 let ident = ident.unwrap_or_else(|| keywords::Invalid.ident());
713 let validate_and_set_expn_info = |this: &mut Self, // arg instead of capture
714 def_site_span: Option<Span>,
715 allow_internal_unstable,
716 allow_internal_unsafe,
718 // can't infer this type
719 unstable_feature: Option<(Symbol, u32)>,
722 // feature-gate the macro invocation
723 if let Some((feature, issue)) = unstable_feature {
724 let crate_span = this.cx.current_expansion.crate_span.unwrap();
725 // don't stability-check macros in the same crate
726 // (the only time this is null is for syntax extensions registered as macros)
727 if def_site_span.map_or(false, |def_span| !crate_span.contains(def_span))
728 && !span.allows_unstable() && this.cx.ecfg.features.map_or(true, |feats| {
729 // macro features will count as lib features
730 !feats.declared_lib_features.iter().any(|&(feat, _)| feat == feature)
732 let explain = format!("macro {}! is unstable", path);
733 emit_feature_err(this.cx.parse_sess, &*feature.as_str(), span,
734 GateIssue::Library(Some(issue)), &explain);
735 this.cx.trace_macros_diag();
736 return Err(kind.dummy(span));
740 if ident.name != keywords::Invalid.name() {
741 let msg = format!("macro {}! expects no ident argument, given '{}'", path, ident);
742 this.cx.span_err(path.span, &msg);
743 this.cx.trace_macros_diag();
744 return Err(kind.dummy(span));
746 mark.set_expn_info(ExpnInfo {
748 def_site: def_site_span,
749 format: macro_bang_format(path),
750 allow_internal_unstable,
751 allow_internal_unsafe,
758 let opt_expanded = match *ext {
759 DeclMacro { ref expander, def_info, edition, .. } => {
760 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
761 false, false, false, None,
765 kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
772 allow_internal_unstable,
773 allow_internal_unsafe,
778 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
779 allow_internal_unstable,
780 allow_internal_unsafe,
786 kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
790 IdentTT(ref expander, tt_span, allow_internal_unstable) => {
791 if ident.name == keywords::Invalid.name() {
792 self.cx.span_err(path.span,
793 &format!("macro {}! expects an ident argument", path));
794 self.cx.trace_macros_diag();
797 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
800 format: macro_bang_format(path),
801 allow_internal_unstable,
802 allow_internal_unsafe: false,
803 local_inner_macros: false,
804 edition: hygiene::default_edition(),
807 let input: Vec<_> = mac.node.stream().into_trees().collect();
808 kind.make_from(expander.expand(self.cx, span, ident, input))
812 MultiDecorator(..) | MultiModifier(..) |
813 AttrProcMacro(..) | SyntaxExtension::NonMacroAttr => {
814 self.cx.span_err(path.span,
815 &format!("`{}` can only be used in attributes", path));
816 self.cx.trace_macros_diag();
820 ProcMacroDerive(..) | BuiltinDerive(..) => {
821 self.cx.span_err(path.span, &format!("`{}` is a derive mode", path));
822 self.cx.trace_macros_diag();
826 SyntaxExtension::ProcMacro { ref expander, allow_internal_unstable, edition } => {
827 if ident.name != keywords::Invalid.name() {
829 format!("macro {}! expects no ident argument, given '{}'", path, ident);
830 self.cx.span_err(path.span, &msg);
831 self.cx.trace_macros_diag();
834 self.gate_proc_macro_expansion_kind(span, kind);
835 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
837 // FIXME procedural macros do not have proper span info
838 // yet, when they do, we should use it here.
840 format: macro_bang_format(path),
841 // FIXME probably want to follow macro_rules macros here.
842 allow_internal_unstable,
843 allow_internal_unsafe: false,
844 local_inner_macros: false,
848 let tok_result = expander.expand(self.cx, span, mac.node.stream());
849 let result = self.parse_ast_fragment(tok_result, kind, path, span);
850 self.gate_proc_macro_expansion(span, &result);
856 if opt_expanded.is_some() {
859 let msg = format!("non-{kind} macro in {kind} position: {name}",
860 name = path.segments[0].ident.name, kind = kind.name());
861 self.cx.span_err(path.span, &msg);
862 self.cx.trace_macros_diag();
867 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
868 let kind = match kind {
869 AstFragmentKind::Expr => "expressions",
870 AstFragmentKind::OptExpr => "expressions",
871 AstFragmentKind::Pat => "patterns",
872 AstFragmentKind::Ty => "types",
873 AstFragmentKind::Stmts => "statements",
874 AstFragmentKind::Items => return,
875 AstFragmentKind::TraitItems => return,
876 AstFragmentKind::ImplItems => return,
877 AstFragmentKind::ForeignItems => return,
879 if self.cx.ecfg.proc_macro_non_items() {
884 "proc_macro_non_items",
887 &format!("procedural macros cannot be expanded to {}", kind),
891 /// Expand a derive invocation. Returns the resulting expanded AST fragment.
892 fn expand_derive_invoc(&mut self,
894 ext: &SyntaxExtension)
895 -> Option<AstFragment> {
896 let (path, item) = match invoc.kind {
897 InvocationKind::Derive { path, item } => (path, item),
900 if !item.derive_allowed() {
904 let pretty_name = Symbol::intern(&format!("derive({})", path));
905 let span = path.span;
906 let attr = ast::Attribute {
908 tokens: TokenStream::empty(),
910 id: ast::AttrId(0), style: ast::AttrStyle::Outer, is_sugared_doc: false,
913 let mut expn_info = ExpnInfo {
916 format: MacroAttribute(pretty_name),
917 allow_internal_unstable: false,
918 allow_internal_unsafe: false,
919 local_inner_macros: false,
920 edition: ext.edition(),
924 ProcMacroDerive(ref ext, ..) => {
925 invoc.expansion_data.mark.set_expn_info(expn_info);
926 let span = span.with_ctxt(self.cx.backtrace());
927 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
928 ident: Path::from_ident(keywords::Invalid.ident()),
930 node: ast::MetaItemKind::Word,
932 let items = ext.expand(self.cx, span, &dummy, item);
933 Some(invoc.fragment_kind.expect_from_annotatables(items))
935 BuiltinDerive(func) => {
936 expn_info.allow_internal_unstable = true;
937 invoc.expansion_data.mark.set_expn_info(expn_info);
938 let span = span.with_ctxt(self.cx.backtrace());
939 let mut items = Vec::new();
940 func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
941 Some(invoc.fragment_kind.expect_from_annotatables(items))
944 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
945 self.cx.span_err(span, msg);
946 self.cx.trace_macros_diag();
947 invoc.fragment_kind.dummy(span)
952 fn parse_ast_fragment(&mut self,
954 kind: AstFragmentKind,
957 -> Option<AstFragment> {
958 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
959 match parser.parse_ast_fragment(kind, false) {
961 parser.ensure_complete_parse(path, kind.name(), span);
967 self.cx.trace_macros_diag();
974 impl<'a> Parser<'a> {
975 pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warnings: bool)
976 -> PResult<'a, AstFragment> {
978 AstFragmentKind::Items => {
979 let mut items = SmallVector::new();
980 while let Some(item) = self.parse_item()? {
983 AstFragment::Items(items)
985 AstFragmentKind::TraitItems => {
986 let mut items = SmallVector::new();
987 while self.token != token::Eof {
988 items.push(self.parse_trait_item(&mut false)?);
990 AstFragment::TraitItems(items)
992 AstFragmentKind::ImplItems => {
993 let mut items = SmallVector::new();
994 while self.token != token::Eof {
995 items.push(self.parse_impl_item(&mut false)?);
997 AstFragment::ImplItems(items)
999 AstFragmentKind::ForeignItems => {
1000 let mut items = SmallVector::new();
1001 while self.token != token::Eof {
1002 if let Some(item) = self.parse_foreign_item()? {
1006 AstFragment::ForeignItems(items)
1008 AstFragmentKind::Stmts => {
1009 let mut stmts = SmallVector::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>,
1053 /// Test functions need to be nameable. Tests inside functions or in other
1054 /// unnameable locations need to be ignored. `tests_nameable` tracks whether
1055 /// any test functions found in the current context would be nameable.
1056 tests_nameable: bool,
1059 impl<'a, 'b> InvocationCollector<'a, 'b> {
1060 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1061 let mark = Mark::fresh(self.cx.current_expansion.mark);
1062 self.invocations.push(Invocation {
1065 expansion_data: ExpansionData {
1067 depth: self.cx.current_expansion.depth + 1,
1068 ..self.cx.current_expansion.clone()
1071 placeholder(fragment_kind, NodeId::placeholder_from_mark(mark))
1074 /// Folds the item allowing tests to be expanded because they are still nameable.
1075 /// This should probably only be called with module items
1076 fn fold_nameable(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
1077 fold::noop_fold_item(item, self)
1080 /// Folds the item but doesn't allow tests to occur within it
1081 fn fold_unnameable(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
1082 let was_nameable = mem::replace(&mut self.tests_nameable, false);
1083 let items = fold::noop_fold_item(item, self);
1084 self.tests_nameable = was_nameable;
1088 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
1089 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
1092 fn collect_attr(&mut self,
1093 attr: Option<ast::Attribute>,
1096 kind: AstFragmentKind)
1098 self.collect(kind, InvocationKind::Attr { attr, traits, item })
1101 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1102 fn classify_item<T>(&mut self, mut item: T) -> (Option<ast::Attribute>, Vec<Path>, T)
1105 let (mut attr, mut traits) = (None, Vec::new());
1107 item = item.map_attrs(|mut attrs| {
1108 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1110 attr = Some(legacy_attr_invoc);
1114 if self.cx.ecfg.use_extern_macros_enabled() {
1115 attr = find_attr_invoc(&mut attrs);
1117 traits = collect_derives(&mut self.cx, &mut attrs);
1121 (attr, traits, item)
1124 /// Alternative of `classify_item()` that ignores `#[derive]` so invocations fallthrough
1125 /// to the unused-attributes lint (making it an error on statements and expressions
1126 /// is a breaking change)
1127 fn classify_nonitem<T: HasAttrs>(&mut self, mut item: T) -> (Option<ast::Attribute>, T) {
1128 let mut attr = None;
1130 item = item.map_attrs(|mut attrs| {
1131 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs,
1133 attr = Some(legacy_attr_invoc);
1137 if self.cx.ecfg.use_extern_macros_enabled() {
1138 attr = find_attr_invoc(&mut attrs);
1146 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1147 self.cfg.configure(node)
1150 // Detect use of feature-gated or invalid attributes on macro invocations
1151 // since they will not be detected after macro expansion.
1152 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1153 let features = self.cx.ecfg.features.unwrap();
1154 for attr in attrs.iter() {
1155 self.check_attribute_inner(attr, features);
1157 // macros are expanded before any lint passes so this warning has to be hardcoded
1158 if attr.path == "derive" {
1159 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1160 .note("this may become a hard error in a future release")
1166 fn check_attribute(&mut self, at: &ast::Attribute) {
1167 let features = self.cx.ecfg.features.unwrap();
1168 self.check_attribute_inner(at, features);
1171 fn check_attribute_inner(&mut self, at: &ast::Attribute, features: &Features) {
1172 feature_gate::check_attribute(at, self.cx.parse_sess, features);
1176 pub fn find_attr_invoc(attrs: &mut Vec<ast::Attribute>) -> Option<ast::Attribute> {
1178 .position(|a| !attr::is_known(a) && !is_builtin_attr(a))
1179 .map(|i| attrs.remove(i))
1182 impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
1183 fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
1184 let mut expr = self.cfg.configure_expr(expr).into_inner();
1185 expr.node = self.cfg.configure_expr_kind(expr.node);
1187 // ignore derives so they remain unused
1188 let (attr, expr) = self.classify_nonitem(expr);
1191 // collect the invoc regardless of whether or not attributes are permitted here
1192 // expansion will eat the attribute so it won't error later
1193 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1195 // AstFragmentKind::Expr requires the macro to emit an expression
1196 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1197 AstFragmentKind::Expr).make_expr();
1200 if let ast::ExprKind::Mac(mac) = expr.node {
1201 self.check_attributes(&expr.attrs);
1202 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr()
1204 P(noop_fold_expr(expr, self))
1208 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1209 let mut expr = configure!(self, expr).into_inner();
1210 expr.node = self.cfg.configure_expr_kind(expr.node);
1212 // ignore derives so they remain unused
1213 let (attr, expr) = self.classify_nonitem(expr);
1216 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1218 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1219 AstFragmentKind::OptExpr)
1223 if let ast::ExprKind::Mac(mac) = expr.node {
1224 self.check_attributes(&expr.attrs);
1225 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr).make_opt_expr()
1227 Some(P(noop_fold_expr(expr, self)))
1231 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
1232 let pat = self.cfg.configure_pat(pat);
1234 PatKind::Mac(_) => {}
1235 _ => return noop_fold_pat(pat, self),
1238 pat.and_then(|pat| match pat.node {
1239 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1240 _ => unreachable!(),
1244 fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
1245 let mut stmt = match self.cfg.configure_stmt(stmt) {
1247 None => return SmallVector::new(),
1250 // we'll expand attributes on expressions separately
1251 if !stmt.is_expr() {
1252 let (attr, derives, stmt_) = if stmt.is_item() {
1253 self.classify_item(stmt)
1255 // ignore derives on non-item statements so it falls through
1256 // to the unused-attributes lint
1257 let (attr, stmt) = self.classify_nonitem(stmt);
1258 (attr, vec![], stmt)
1261 if attr.is_some() || !derives.is_empty() {
1262 return self.collect_attr(attr, derives,
1263 Annotatable::Stmt(P(stmt_)), AstFragmentKind::Stmts)
1270 if let StmtKind::Mac(mac) = stmt.node {
1271 let (mac, style, attrs) = mac.into_inner();
1272 self.check_attributes(&attrs);
1273 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1276 // If this is a macro invocation with a semicolon, then apply that
1277 // semicolon to the final statement produced by expansion.
1278 if style == MacStmtStyle::Semicolon {
1279 if let Some(stmt) = placeholder.pop() {
1280 placeholder.push(stmt.add_trailing_semicolon());
1287 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1288 let ast::Stmt { id, node, span } = stmt;
1289 noop_fold_stmt_kind(node, self).into_iter().map(|node| {
1290 ast::Stmt { id, node, span }
1295 fn fold_block(&mut self, block: P<Block>) -> P<Block> {
1296 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1297 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1298 let result = noop_fold_block(block, self);
1299 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1303 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
1304 let item = configure!(self, item);
1306 let (attr, traits, mut item) = self.classify_item(item);
1307 if attr.is_some() || !traits.is_empty() {
1308 let item = Annotatable::Item(item);
1309 return self.collect_attr(attr, traits, item, AstFragmentKind::Items).make_items();
1313 ast::ItemKind::Mac(..) => {
1314 self.check_attributes(&item.attrs);
1315 item.and_then(|item| match item.node {
1316 ItemKind::Mac(mac) => {
1317 self.collect(AstFragmentKind::Items, InvocationKind::Bang {
1319 ident: Some(item.ident),
1323 _ => unreachable!(),
1326 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1327 if item.ident == keywords::Invalid.ident() {
1328 return self.fold_nameable(item);
1331 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1332 let mut module = (*self.cx.current_expansion.module).clone();
1333 module.mod_path.push(item.ident);
1335 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1336 // In the non-inline case, `inner` is never the dummy span (c.f. `parse_item_mod`).
1337 // Thus, if `inner` is the dummy span, we know the module is inline.
1338 let inline_module = item.span.contains(inner) || inner.is_dummy();
1341 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, "path") {
1342 self.cx.current_expansion.directory_ownership =
1343 DirectoryOwnership::Owned { relative: None };
1344 module.directory.push(&*path.as_str());
1346 module.directory.push(&*item.ident.as_str());
1349 let path = self.cx.parse_sess.codemap().span_to_unmapped_path(inner);
1350 let mut path = match path {
1351 FileName::Real(path) => path,
1352 other => PathBuf::from(other.to_string()),
1354 let directory_ownership = match path.file_name().unwrap().to_str() {
1355 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1356 Some(_) => DirectoryOwnership::Owned {
1357 relative: Some(item.ident),
1359 None => DirectoryOwnership::UnownedViaMod(false),
1362 module.directory = path;
1363 self.cx.current_expansion.directory_ownership = directory_ownership;
1367 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1368 let result = self.fold_nameable(item);
1369 self.cx.current_expansion.module = orig_module;
1370 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1373 // Ensure that test functions are accessible from the test harness.
1374 // #[test] fn foo() {}
1376 // #[test] pub fn foo_gensym(){}
1378 // use foo_gensym as foo;
1379 ast::ItemKind::Fn(..) if self.cx.ecfg.should_test => {
1380 if self.tests_nameable && item.attrs.iter().any(|attr| is_test_or_bench(attr)) {
1381 let orig_ident = item.ident;
1382 let orig_vis = item.vis.clone();
1384 // Publicize the item under gensymed name to avoid pollution
1385 item = item.map(|mut item| {
1386 item.vis = respan(item.vis.span, ast::VisibilityKind::Public);
1387 item.ident = item.ident.gensym();
1391 // Use the gensymed name under the item's original visibility
1392 let mut use_item = self.cx.item_use_simple_(
1396 self.cx.path(item.ident.span,
1397 vec![keywords::SelfValue.ident(), item.ident]));
1399 // #[allow(unused)] because the test function probably isn't being referenced
1400 use_item = use_item.map(|mut ui| {
1402 self.cx.attribute(DUMMY_SP, attr::mk_list_item(DUMMY_SP,
1403 Ident::from_str("allow"), vec![
1404 attr::mk_nested_word_item(Ident::from_str("unused"))
1413 self.fold_unnameable(item).into_iter()
1414 .chain(self.fold_unnameable(use_item)))
1416 self.fold_unnameable(item)
1419 _ => self.fold_unnameable(item),
1423 fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
1424 let item = configure!(self, item);
1426 let (attr, traits, item) = self.classify_item(item);
1427 if attr.is_some() || !traits.is_empty() {
1428 let item = Annotatable::TraitItem(P(item));
1429 return self.collect_attr(attr, traits, item, AstFragmentKind::TraitItems)
1434 ast::TraitItemKind::Macro(mac) => {
1435 let ast::TraitItem { attrs, span, .. } = item;
1436 self.check_attributes(&attrs);
1437 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1439 _ => fold::noop_fold_trait_item(item, self),
1443 fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
1444 let item = configure!(self, item);
1446 let (attr, traits, item) = self.classify_item(item);
1447 if attr.is_some() || !traits.is_empty() {
1448 let item = Annotatable::ImplItem(P(item));
1449 return self.collect_attr(attr, traits, item, AstFragmentKind::ImplItems)
1454 ast::ImplItemKind::Macro(mac) => {
1455 let ast::ImplItem { attrs, span, .. } = item;
1456 self.check_attributes(&attrs);
1457 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1459 _ => fold::noop_fold_impl_item(item, self),
1463 fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
1464 let ty = match ty.node {
1465 ast::TyKind::Mac(_) => ty.into_inner(),
1466 _ => return fold::noop_fold_ty(ty, self),
1470 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1471 _ => unreachable!(),
1475 fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
1476 noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
1479 fn fold_foreign_item(&mut self,
1480 foreign_item: ast::ForeignItem) -> SmallVector<ast::ForeignItem> {
1481 let (attr, traits, foreign_item) = self.classify_item(foreign_item);
1483 let explain = if self.cx.ecfg.use_extern_macros_enabled() {
1484 feature_gate::EXPLAIN_PROC_MACROS_IN_EXTERN
1486 feature_gate::EXPLAIN_MACROS_IN_EXTERN
1489 if attr.is_some() || !traits.is_empty() {
1490 if !self.cx.ecfg.macros_in_extern_enabled() {
1491 if let Some(ref attr) = attr {
1492 emit_feature_err(&self.cx.parse_sess, "macros_in_extern", attr.span,
1493 GateIssue::Language, explain);
1497 let item = Annotatable::ForeignItem(P(foreign_item));
1498 return self.collect_attr(attr, traits, item, AstFragmentKind::ForeignItems)
1499 .make_foreign_items();
1502 if let ast::ForeignItemKind::Macro(mac) = foreign_item.node {
1503 self.check_attributes(&foreign_item.attrs);
1505 if !self.cx.ecfg.macros_in_extern_enabled() {
1506 emit_feature_err(&self.cx.parse_sess, "macros_in_extern", foreign_item.span,
1507 GateIssue::Language, explain);
1510 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1511 .make_foreign_items();
1514 noop_fold_foreign_item(foreign_item, self)
1517 fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
1519 ast::ItemKind::MacroDef(..) => item,
1520 _ => noop_fold_item_kind(self.cfg.configure_item_kind(item), self),
1524 fn fold_generic_param(&mut self, param: ast::GenericParam) -> ast::GenericParam {
1525 self.cfg.disallow_cfg_on_generic_param(¶m);
1526 noop_fold_generic_param(param, self)
1529 fn fold_attribute(&mut self, at: ast::Attribute) -> Option<ast::Attribute> {
1530 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1531 // contents="file contents")]` attributes
1532 if !at.check_name("doc") {
1533 return noop_fold_attribute(at, self);
1536 if let Some(list) = at.meta_item_list() {
1537 if !list.iter().any(|it| it.check_name("include")) {
1538 return noop_fold_attribute(at, self);
1541 let mut items = vec![];
1544 if !it.check_name("include") {
1545 items.push(noop_fold_meta_list_item(it, self));
1549 if let Some(file) = it.value_str() {
1550 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1551 self.check_attribute(&at);
1552 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1553 // avoid loading the file if they haven't enabled the feature
1554 return noop_fold_attribute(at, self);
1557 let mut buf = vec![];
1558 let filename = self.cx.root_path.join(file.to_string());
1560 match File::open(&filename).and_then(|mut f| f.read_to_end(&mut buf)) {
1563 self.cx.span_err(at.span,
1564 &format!("couldn't read {}: {}",
1570 match String::from_utf8(buf) {
1572 let src_interned = Symbol::intern(&src);
1574 // Add this input file to the code map to make it available as
1575 // dependency information
1576 self.cx.codemap().new_filemap(filename.into(), src);
1578 let include_info = vec![
1579 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1580 attr::mk_name_value_item_str(Ident::from_str("file"),
1581 dummy_spanned(file)))),
1582 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1583 attr::mk_name_value_item_str(Ident::from_str("contents"),
1584 dummy_spanned(src_interned)))),
1587 let include_ident = Ident::from_str("include");
1588 let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
1589 items.push(dummy_spanned(ast::NestedMetaItemKind::MetaItem(item)));
1592 self.cx.span_err(at.span,
1593 &format!("{} wasn't a utf-8 file",
1594 filename.display()));
1598 items.push(noop_fold_meta_list_item(it, self));
1602 let meta = attr::mk_list_item(DUMMY_SP, Ident::from_str("doc"), items);
1604 ast::AttrStyle::Inner =>
1605 Some(attr::mk_spanned_attr_inner(at.span, at.id, meta)),
1606 ast::AttrStyle::Outer =>
1607 Some(attr::mk_spanned_attr_outer(at.span, at.id, meta)),
1610 noop_fold_attribute(at, self)
1614 fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
1616 assert_eq!(id, ast::DUMMY_NODE_ID);
1617 self.cx.resolver.next_node_id()
1624 pub struct ExpansionConfig<'feat> {
1625 pub crate_name: String,
1626 pub features: Option<&'feat Features>,
1627 pub recursion_limit: usize,
1628 pub trace_mac: bool,
1629 pub should_test: bool, // If false, strip `#[test]` nodes
1630 pub single_step: bool,
1631 pub keep_macs: bool,
1634 macro_rules! feature_tests {
1635 ($( fn $getter:ident = $field:ident, )*) => {
1637 pub fn $getter(&self) -> bool {
1638 match self.features {
1639 Some(&Features { $field: true, .. }) => true,
1647 impl<'feat> ExpansionConfig<'feat> {
1648 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1652 recursion_limit: 1024,
1661 fn enable_quotes = quote,
1662 fn enable_asm = asm,
1663 fn enable_global_asm = global_asm,
1664 fn enable_log_syntax = log_syntax,
1665 fn enable_concat_idents = concat_idents,
1666 fn enable_trace_macros = trace_macros,
1667 fn enable_allow_internal_unstable = allow_internal_unstable,
1668 fn enable_custom_derive = custom_derive,
1669 fn enable_format_args_nl = format_args_nl,
1670 fn macros_in_extern_enabled = macros_in_extern,
1671 fn proc_macro_mod = proc_macro_mod,
1672 fn proc_macro_gen = proc_macro_gen,
1673 fn proc_macro_expr = proc_macro_expr,
1674 fn proc_macro_non_items = proc_macro_non_items,
1677 pub fn use_extern_macros_enabled(&self) -> bool {
1678 self.features.map_or(false, |features| features.use_extern_macros())
1682 // A Marker adds the given mark to the syntax context.
1684 pub struct Marker(pub Mark);
1686 impl Folder for Marker {
1687 fn new_span(&mut self, span: Span) -> Span {
1688 span.apply_mark(self.0)
1691 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1692 noop_fold_mac(mac, self)