1 use crate::ast::{self, Block, Ident, LitKind, NodeId, PatKind, Path};
2 use crate::ast::{MacStmtStyle, StmtKind, ItemKind};
3 use crate::attr::{self, HasAttrs};
4 use crate::source_map::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
5 use crate::config::StripUnconfigured;
6 use crate::ext::base::*;
7 use crate::ext::derive::{add_derived_markers, collect_derives};
8 use crate::ext::hygiene::{Mark, SyntaxContext};
9 use crate::ext::placeholders::{placeholder, PlaceholderExpander};
10 use crate::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
11 use crate::mut_visit::*;
12 use crate::parse::{DirectoryOwnership, PResult, ParseSess};
13 use crate::parse::token;
14 use crate::parse::parser::Parser;
16 use crate::symbol::Symbol;
17 use crate::symbol::{kw, sym};
18 use crate::tokenstream::{TokenStream, TokenTree};
19 use crate::visit::{self, Visitor};
20 use crate::util::map_in_place::MapInPlace;
22 use errors::{Applicability, FatalError};
23 use smallvec::{smallvec, SmallVec};
24 use syntax_pos::{Span, DUMMY_SP, FileName};
25 use syntax_pos::hygiene::ExpnFormat;
27 use rustc_data_structures::fx::FxHashMap;
28 use rustc_data_structures::sync::Lrc;
30 use std::io::ErrorKind;
32 use std::ops::DerefMut;
34 use std::path::PathBuf;
36 macro_rules! ast_fragments {
38 $($Kind:ident($AstTy:ty) {
40 $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
41 $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident;)?
45 /// A fragment of AST that can be produced by a single macro expansion.
46 /// Can also serve as an input and intermediate result for macro expansion operations.
47 pub enum AstFragment {
48 OptExpr(Option<P<ast::Expr>>),
52 /// "Discriminant" of an AST fragment.
53 #[derive(Copy, Clone, PartialEq, Eq)]
54 pub enum AstFragmentKind {
59 impl AstFragmentKind {
60 pub fn name(self) -> &'static str {
62 AstFragmentKind::OptExpr => "expression",
63 $(AstFragmentKind::$Kind => $kind_name,)*
67 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
69 AstFragmentKind::OptExpr =>
70 result.make_expr().map(Some).map(AstFragment::OptExpr),
71 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
77 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
79 AstFragment::OptExpr(expr) => expr,
80 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
84 $(pub fn $make_ast(self) -> $AstTy {
86 AstFragment::$Kind(ast) => ast,
87 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
91 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
93 AstFragment::OptExpr(opt_expr) => {
94 visit_clobber(opt_expr, |opt_expr| {
95 if let Some(expr) = opt_expr {
96 vis.filter_map_expr(expr)
102 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)*)*
103 $($(AstFragment::$Kind(ast) =>
104 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)*)*
108 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
110 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
111 AstFragment::OptExpr(None) => {}
112 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)*)*
113 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
114 visitor.$visit_ast_elt(ast_elt);
120 impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
121 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
122 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
124 $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
125 visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
127 $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
128 self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
132 impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
133 $(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
135 Some(self.make(AstFragmentKind::$Kind).$make_ast())
142 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
143 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
144 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
145 Stmts(SmallVec<[ast::Stmt; 1]>) {
146 "statement"; many fn flat_map_stmt; fn visit_stmt; fn make_stmts;
148 Items(SmallVec<[P<ast::Item>; 1]>) {
149 "item"; many fn flat_map_item; fn visit_item; fn make_items;
151 TraitItems(SmallVec<[ast::TraitItem; 1]>) {
152 "trait item"; many fn flat_map_trait_item; fn visit_trait_item; fn make_trait_items;
154 ImplItems(SmallVec<[ast::ImplItem; 1]>) {
155 "impl item"; many fn flat_map_impl_item; fn visit_impl_item; fn make_impl_items;
157 ForeignItems(SmallVec<[ast::ForeignItem; 1]>) {
158 "foreign item"; many fn flat_map_foreign_item; fn visit_foreign_item; fn make_foreign_items;
162 impl AstFragmentKind {
163 fn dummy(self, span: Span) -> Option<AstFragment> {
164 self.make_from(DummyResult::any(span))
167 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
169 let mut items = items.into_iter();
171 AstFragmentKind::Items =>
172 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
173 AstFragmentKind::ImplItems =>
174 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
175 AstFragmentKind::TraitItems =>
176 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
177 AstFragmentKind::ForeignItems =>
178 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
179 AstFragmentKind::Stmts =>
180 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
181 AstFragmentKind::Expr => AstFragment::Expr(
182 items.next().expect("expected exactly one expression").expect_expr()
184 AstFragmentKind::OptExpr =>
185 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
186 AstFragmentKind::Pat | AstFragmentKind::Ty =>
187 panic!("patterns and types aren't annotatable"),
192 fn macro_bang_format(path: &ast::Path) -> ExpnFormat {
193 // We don't want to format a path using pretty-printing,
194 // `format!("{}", path)`, because that tries to insert
195 // line-breaks and is slow.
196 let mut path_str = String::with_capacity(64);
197 for (i, segment) in path.segments.iter().enumerate() {
199 path_str.push_str("::");
201 if segment.ident.name != kw::PathRoot {
202 path_str.push_str(&segment.ident.as_str())
206 MacroBang(Symbol::intern(&path_str))
209 pub struct Invocation {
210 pub kind: InvocationKind,
211 fragment_kind: AstFragmentKind,
212 pub expansion_data: ExpansionData,
215 pub enum InvocationKind {
218 ident: Option<Ident>,
222 attr: Option<ast::Attribute>,
225 // We temporarily report errors for attribute macros placed after derives
235 pub 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, // cf. `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.source_map().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(smallvec![P(ast::Item {
273 node: ast::ItemKind::Mod(krate.module),
274 ident: Ident::invalid(),
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,
296 self.cx.trace_macros_diag();
300 // Fully expand all macro invocations in this AST fragment.
301 fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
302 let orig_expansion_data = self.cx.current_expansion.clone();
303 self.cx.current_expansion.depth = 0;
305 // Collect all macro invocations and replace them with placeholders.
306 let (mut fragment_with_placeholders, mut invocations)
307 = self.collect_invocations(input_fragment, &[]);
309 // Optimization: if we resolve all imports now,
310 // we'll be able to immediately resolve most of imported macros.
311 self.resolve_imports();
313 // Resolve paths in all invocations and produce output expanded fragments for them, but
314 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
315 // The output fragments also go through expansion recursively until no invocations are left.
316 // Unresolved macros produce dummy outputs as a recovery measure.
317 invocations.reverse();
318 let mut expanded_fragments = Vec::new();
319 let mut derives: FxHashMap<Mark, Vec<_>> = FxHashMap::default();
320 let mut undetermined_invocations = Vec::new();
321 let (mut progress, mut force) = (false, !self.monotonic);
323 let invoc = if let Some(invoc) = invocations.pop() {
326 self.resolve_imports();
327 if undetermined_invocations.is_empty() { break }
328 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
329 force = !mem::replace(&mut progress, false);
334 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
335 let ext = match self.cx.resolver.resolve_macro_invocation(&invoc, scope, force) {
336 Ok(ext) => Some(ext),
337 Err(Determinacy::Determined) => None,
338 Err(Determinacy::Undetermined) => {
339 undetermined_invocations.push(invoc);
345 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
346 self.cx.current_expansion = invoc.expansion_data.clone();
348 self.cx.current_expansion.mark = scope;
349 // FIXME(jseyfried): Refactor out the following logic
350 let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
351 if let Some(ext) = ext {
352 let (invoc_fragment_kind, invoc_span) = (invoc.fragment_kind, invoc.span());
353 let fragment = self.expand_invoc(invoc, &*ext).unwrap_or_else(|| {
354 invoc_fragment_kind.dummy(invoc_span).unwrap()
356 self.collect_invocations(fragment, &[])
357 } else if let InvocationKind::Attr { attr: None, traits, item, .. } = invoc.kind {
358 if !item.derive_allowed() {
359 let attr = attr::find_by_name(item.attrs(), sym::derive)
360 .expect("`derive` attribute should exist");
361 let span = attr.span;
362 let mut err = self.cx.mut_span_err(span,
363 "`derive` may only be applied to \
364 structs, enums and unions");
365 if let ast::AttrStyle::Inner = attr.style {
366 let trait_list = traits.iter()
367 .map(|t| t.to_string()).collect::<Vec<_>>();
368 let suggestion = format!("#[derive({})]", trait_list.join(", "));
370 span, "try an outer attribute", suggestion,
371 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
372 Applicability::MaybeIncorrect
378 let mut item = self.fully_configure(item);
379 item.visit_attrs(|attrs| attrs.retain(|a| a.path != sym::derive));
380 let mut item_with_markers = item.clone();
381 add_derived_markers(&mut self.cx, item.span(), &traits, &mut item_with_markers);
382 let derives = derives.entry(invoc.expansion_data.mark).or_default();
384 derives.reserve(traits.len());
385 invocations.reserve(traits.len());
386 for path in &traits {
387 let mark = Mark::fresh(self.cx.current_expansion.mark);
389 let item = match self.cx.resolver.resolve_macro_path(
390 path, MacroKind::Derive, Mark::root(), Vec::new(), false) {
391 Ok(ext) => match *ext {
392 BuiltinDerive(..) => item_with_markers.clone(),
397 invocations.push(Invocation {
398 kind: InvocationKind::Derive { path: path.clone(), item: item },
399 fragment_kind: invoc.fragment_kind,
400 expansion_data: ExpansionData {
402 ..invoc.expansion_data.clone()
406 let fragment = invoc.fragment_kind
407 .expect_from_annotatables(::std::iter::once(item_with_markers));
408 self.collect_invocations(fragment, derives)
413 self.collect_invocations(invoc.fragment_kind.dummy(invoc.span()).unwrap(), &[])
416 if expanded_fragments.len() < depth {
417 expanded_fragments.push(Vec::new());
419 expanded_fragments[depth - 1].push((mark, expanded_fragment));
420 if !self.cx.ecfg.single_step {
421 invocations.extend(new_invocations.into_iter().rev());
425 self.cx.current_expansion = orig_expansion_data;
427 // Finally incorporate all the expanded macros into the input AST fragment.
428 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
429 while let Some(expanded_fragments) = expanded_fragments.pop() {
430 for (mark, expanded_fragment) in expanded_fragments.into_iter().rev() {
431 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
432 placeholder_expander.add(NodeId::placeholder_from_mark(mark),
433 expanded_fragment, derives);
436 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
437 fragment_with_placeholders
440 fn resolve_imports(&mut self) {
442 self.cx.resolver.resolve_imports();
446 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
447 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
448 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
449 /// prepares data for resolving paths of macro invocations.
450 fn collect_invocations(&mut self, mut fragment: AstFragment, derives: &[Mark])
451 -> (AstFragment, Vec<Invocation>) {
452 // Resolve `$crate`s in the fragment for pretty-printing.
453 self.cx.resolver.resolve_dollar_crates(&fragment);
456 let mut collector = InvocationCollector {
457 cfg: StripUnconfigured {
458 sess: self.cx.parse_sess,
459 features: self.cx.ecfg.features,
462 invocations: Vec::new(),
463 monotonic: self.monotonic,
465 fragment.mut_visit_with(&mut collector);
466 collector.invocations
470 self.cx.resolver.visit_ast_fragment_with_placeholders(
471 self.cx.current_expansion.mark, &fragment, derives);
474 (fragment, invocations)
477 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
478 let mut cfg = StripUnconfigured {
479 sess: self.cx.parse_sess,
480 features: self.cx.ecfg.features,
482 // Since the item itself has already been configured by the InvocationCollector,
483 // we know that fold result vector will contain exactly one element
485 Annotatable::Item(item) => {
486 Annotatable::Item(cfg.flat_map_item(item).pop().unwrap())
488 Annotatable::TraitItem(item) => {
489 Annotatable::TraitItem(
490 item.map(|item| cfg.flat_map_trait_item(item).pop().unwrap()))
492 Annotatable::ImplItem(item) => {
493 Annotatable::ImplItem(item.map(|item| cfg.flat_map_impl_item(item).pop().unwrap()))
495 Annotatable::ForeignItem(item) => {
496 Annotatable::ForeignItem(
497 item.map(|item| cfg.flat_map_foreign_item(item).pop().unwrap())
500 Annotatable::Stmt(stmt) => {
501 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
503 Annotatable::Expr(mut expr) => {
504 Annotatable::Expr({ cfg.visit_expr(&mut expr); expr })
509 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtension) -> Option<AstFragment> {
510 if invoc.fragment_kind == AstFragmentKind::ForeignItems &&
511 !self.cx.ecfg.macros_in_extern_enabled() {
512 if let SyntaxExtension::NonMacroAttr { .. } = *ext {} else {
513 emit_feature_err(&self.cx.parse_sess, sym::macros_in_extern,
514 invoc.span(), GateIssue::Language,
515 "macro invocations in `extern {}` blocks are experimental");
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, mut item) = match invoc.kind {
547 InvocationKind::Attr { attr, item, .. } => (attr?, item),
551 if let NonMacroAttr { mark_used: false } = *ext {} else {
552 // Macro attrs are always used when expanded,
553 // non-macro attrs are considered used when the field says so.
554 attr::mark_used(&attr);
556 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
557 call_site: attr.span,
559 format: MacroAttribute(Symbol::intern(&attr.path.to_string())),
560 allow_internal_unstable: None,
561 allow_internal_unsafe: false,
562 local_inner_macros: false,
563 edition: ext.edition(self.cx.parse_sess.edition),
567 NonMacroAttr { .. } => {
568 attr::mark_known(&attr);
569 item.visit_attrs(|attrs| attrs.push(attr));
570 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
572 MultiModifier(ref mac) => {
573 let meta = attr.parse_meta(self.cx.parse_sess)
574 .map_err(|mut e| { e.emit(); }).ok()?;
575 let item = mac.expand(self.cx, attr.span, &meta, item);
576 Some(invoc.fragment_kind.expect_from_annotatables(item))
578 MultiDecorator(ref mac) => {
579 let mut items = Vec::new();
580 let meta = attr.parse_meta(self.cx.parse_sess)
581 .expect("derive meta should already have been parsed");
582 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
584 Some(invoc.fragment_kind.expect_from_annotatables(items))
586 AttrProcMacro(ref mac, ..) => {
587 self.gate_proc_macro_attr_item(attr.span, &item);
588 let item_tok = TokenTree::Token(DUMMY_SP, token::Interpolated(Lrc::new(match item {
589 Annotatable::Item(item) => token::NtItem(item),
590 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
591 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
592 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
593 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
594 Annotatable::Expr(expr) => token::NtExpr(expr),
596 let input = self.extract_proc_macro_attr_input(attr.tokens, attr.span);
597 let tok_result = mac.expand(self.cx, attr.span, input, item_tok);
598 let res = self.parse_ast_fragment(tok_result, invoc.fragment_kind,
599 &attr.path, attr.span);
600 self.gate_proc_macro_expansion(attr.span, &res);
603 ProcMacroDerive(..) | BuiltinDerive(..) => {
604 self.cx.span_err(attr.span, &format!("`{}` is a derive macro", attr.path));
605 self.cx.trace_macros_diag();
606 invoc.fragment_kind.dummy(attr.span)
609 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
610 self.cx.span_err(attr.span, msg);
611 self.cx.trace_macros_diag();
612 invoc.fragment_kind.dummy(attr.span)
617 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
618 let mut trees = tokens.trees();
620 Some(TokenTree::Delimited(_, _, tts)) => {
621 if trees.next().is_none() {
625 Some(TokenTree::Token(..)) => {}
626 None => return TokenStream::empty(),
628 self.cx.span_err(span, "custom attribute invocations must be \
629 of the form #[foo] or #[foo(..)], the macro name must only be \
630 followed by a delimiter token");
634 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
635 let (kind, gate) = match *item {
636 Annotatable::Item(ref item) => {
638 ItemKind::Mod(_) if self.cx.ecfg.proc_macro_hygiene() => return,
639 ItemKind::Mod(_) => ("modules", sym::proc_macro_hygiene),
643 Annotatable::TraitItem(_) => return,
644 Annotatable::ImplItem(_) => return,
645 Annotatable::ForeignItem(_) => return,
646 Annotatable::Stmt(_) |
647 Annotatable::Expr(_) if self.cx.ecfg.proc_macro_hygiene() => return,
648 Annotatable::Stmt(_) => ("statements", sym::proc_macro_hygiene),
649 Annotatable::Expr(_) => ("expressions", sym::proc_macro_hygiene),
656 &format!("custom attributes cannot be applied to {}", kind),
660 fn gate_proc_macro_expansion(&self, span: Span, fragment: &Option<AstFragment>) {
661 if self.cx.ecfg.proc_macro_hygiene() {
664 let fragment = match fragment {
665 Some(fragment) => fragment,
669 fragment.visit_with(&mut DisallowMacros {
671 parse_sess: self.cx.parse_sess,
674 struct DisallowMacros<'a> {
676 parse_sess: &'a ParseSess,
679 impl<'ast, 'a> Visitor<'ast> for DisallowMacros<'a> {
680 fn visit_item(&mut self, i: &'ast ast::Item) {
681 if let ast::ItemKind::MacroDef(_) = i.node {
684 sym::proc_macro_hygiene,
687 "procedural macros cannot expand to macro definitions",
690 visit::walk_item(self, i);
693 fn visit_mac(&mut self, _mac: &'ast ast::Mac) {
699 /// Expand a macro invocation. Returns the resulting expanded AST fragment.
700 fn expand_bang_invoc(&mut self,
702 ext: &SyntaxExtension)
703 -> Option<AstFragment> {
704 let (mark, kind) = (invoc.expansion_data.mark, invoc.fragment_kind);
705 let (mac, ident, span) = match invoc.kind {
706 InvocationKind::Bang { mac, ident, span } => (mac, ident, span),
709 let path = &mac.node.path;
711 let ident = ident.unwrap_or_else(|| Ident::invalid());
712 let validate_and_set_expn_info = |this: &mut Self, // arg instead of capture
713 def_site_span: Option<Span>,
714 allow_internal_unstable,
715 allow_internal_unsafe,
717 // can't infer this type
718 unstable_feature: Option<(Symbol, u32)>,
721 // feature-gate the macro invocation
722 if let Some((feature, issue)) = unstable_feature {
723 let crate_span = this.cx.current_expansion.crate_span.unwrap();
724 // don't stability-check macros in the same crate
725 // (the only time this is null is for syntax extensions registered as macros)
726 if def_site_span.map_or(false, |def_span| !crate_span.contains(def_span))
727 && !span.allows_unstable(feature)
728 && 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, span,
734 GateIssue::Library(Some(issue)), &explain);
735 this.cx.trace_macros_diag();
739 if ident.name != kw::Invalid {
740 let msg = format!("macro {}! expects no ident argument, given '{}'", path, ident);
741 this.cx.span_err(path.span, &msg);
742 this.cx.trace_macros_diag();
743 return Err(kind.dummy(span));
745 mark.set_expn_info(ExpnInfo {
747 def_site: def_site_span,
748 format: macro_bang_format(path),
749 allow_internal_unstable,
750 allow_internal_unsafe,
757 let opt_expanded = match *ext {
758 DeclMacro { ref expander, def_info, edition, .. } => {
759 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
760 None, false, false, None,
764 kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
771 ref allow_internal_unstable,
772 allow_internal_unsafe,
777 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
778 allow_internal_unstable.clone(),
779 allow_internal_unsafe,
785 kind.make_from(expander.expand(
789 def_info.map(|(_, s)| s),
794 IdentTT { ref expander, span: tt_span, ref allow_internal_unstable } => {
795 if ident.name == kw::Invalid {
796 self.cx.span_err(path.span,
797 &format!("macro {}! expects an ident argument", path));
798 self.cx.trace_macros_diag();
801 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
804 format: macro_bang_format(path),
805 allow_internal_unstable: allow_internal_unstable.clone(),
806 allow_internal_unsafe: false,
807 local_inner_macros: false,
808 edition: self.cx.parse_sess.edition,
811 let input: Vec<_> = mac.node.stream().into_trees().collect();
812 kind.make_from(expander.expand(self.cx, span, ident, input))
816 MultiDecorator(..) | MultiModifier(..) |
817 AttrProcMacro(..) | SyntaxExtension::NonMacroAttr { .. } => {
818 self.cx.span_err(path.span,
819 &format!("`{}` can only be used in attributes", path));
820 self.cx.trace_macros_diag();
824 ProcMacroDerive(..) | BuiltinDerive(..) => {
825 self.cx.span_err(path.span, &format!("`{}` is a derive macro", path));
826 self.cx.trace_macros_diag();
830 SyntaxExtension::ProcMacro { ref expander, ref allow_internal_unstable, edition } => {
831 if ident.name != kw::Invalid {
833 format!("macro {}! expects no ident argument, given '{}'", path, ident);
834 self.cx.span_err(path.span, &msg);
835 self.cx.trace_macros_diag();
838 self.gate_proc_macro_expansion_kind(span, kind);
839 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
841 // FIXME procedural macros do not have proper span info
842 // yet, when they do, we should use it here.
844 format: macro_bang_format(path),
845 // FIXME probably want to follow macro_rules macros here.
846 allow_internal_unstable: allow_internal_unstable.clone(),
847 allow_internal_unsafe: false,
848 local_inner_macros: false,
852 let tok_result = expander.expand(self.cx, span, mac.node.stream());
853 let result = self.parse_ast_fragment(tok_result, kind, path, span);
854 self.gate_proc_macro_expansion(span, &result);
860 if opt_expanded.is_some() {
863 let msg = format!("non-{kind} macro in {kind} position: {name}",
864 name = path.segments[0].ident.name, kind = kind.name());
865 self.cx.span_err(path.span, &msg);
866 self.cx.trace_macros_diag();
871 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
872 let kind = match kind {
873 AstFragmentKind::Expr => "expressions",
874 AstFragmentKind::OptExpr => "expressions",
875 AstFragmentKind::Pat => "patterns",
876 AstFragmentKind::Ty => "types",
877 AstFragmentKind::Stmts => "statements",
878 AstFragmentKind::Items => return,
879 AstFragmentKind::TraitItems => return,
880 AstFragmentKind::ImplItems => return,
881 AstFragmentKind::ForeignItems => return,
883 if self.cx.ecfg.proc_macro_hygiene() {
888 sym::proc_macro_hygiene,
891 &format!("procedural macros cannot be expanded to {}", kind),
895 /// Expand a derive invocation. Returns the resulting expanded AST fragment.
896 fn expand_derive_invoc(&mut self,
898 ext: &SyntaxExtension)
899 -> Option<AstFragment> {
900 let (path, item) = match invoc.kind {
901 InvocationKind::Derive { path, item } => (path, item),
904 if !item.derive_allowed() {
908 let pretty_name = Symbol::intern(&format!("derive({})", path));
909 let span = path.span;
910 let attr = ast::Attribute {
912 tokens: TokenStream::empty(),
914 id: ast::AttrId(0), style: ast::AttrStyle::Outer, is_sugared_doc: false,
917 let mut expn_info = ExpnInfo {
920 format: MacroAttribute(pretty_name),
921 allow_internal_unstable: None,
922 allow_internal_unsafe: false,
923 local_inner_macros: false,
924 edition: ext.edition(self.cx.parse_sess.edition),
928 ProcMacroDerive(ref ext, ..) => {
929 invoc.expansion_data.mark.set_expn_info(expn_info);
930 let span = span.with_ctxt(self.cx.backtrace());
931 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
932 path: Path::from_ident(Ident::invalid()),
934 node: ast::MetaItemKind::Word,
936 let items = ext.expand(self.cx, span, &dummy, item);
937 Some(invoc.fragment_kind.expect_from_annotatables(items))
939 BuiltinDerive(func) => {
940 expn_info.allow_internal_unstable = Some(vec![
942 Symbol::intern("derive_clone_copy"),
943 Symbol::intern("derive_eq"),
944 Symbol::intern("libstd_sys_internals"), // RustcDeserialize and RustcSerialize
946 invoc.expansion_data.mark.set_expn_info(expn_info);
947 let span = span.with_ctxt(self.cx.backtrace());
948 let mut items = Vec::new();
949 func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
950 Some(invoc.fragment_kind.expect_from_annotatables(items))
953 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
954 self.cx.span_err(span, msg);
955 self.cx.trace_macros_diag();
956 invoc.fragment_kind.dummy(span)
961 fn parse_ast_fragment(&mut self,
963 kind: AstFragmentKind,
966 -> Option<AstFragment> {
967 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
968 match parser.parse_ast_fragment(kind, false) {
970 parser.ensure_complete_parse(path, kind.name(), span);
976 self.cx.trace_macros_diag();
983 impl<'a> Parser<'a> {
984 pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warnings: bool)
985 -> PResult<'a, AstFragment> {
987 AstFragmentKind::Items => {
988 let mut items = SmallVec::new();
989 while let Some(item) = self.parse_item()? {
992 AstFragment::Items(items)
994 AstFragmentKind::TraitItems => {
995 let mut items = SmallVec::new();
996 while self.token != token::Eof {
997 items.push(self.parse_trait_item(&mut false)?);
999 AstFragment::TraitItems(items)
1001 AstFragmentKind::ImplItems => {
1002 let mut items = SmallVec::new();
1003 while self.token != token::Eof {
1004 items.push(self.parse_impl_item(&mut false)?);
1006 AstFragment::ImplItems(items)
1008 AstFragmentKind::ForeignItems => {
1009 let mut items = SmallVec::new();
1010 while self.token != token::Eof {
1011 items.push(self.parse_foreign_item()?);
1013 AstFragment::ForeignItems(items)
1015 AstFragmentKind::Stmts => {
1016 let mut stmts = SmallVec::new();
1017 while self.token != token::Eof &&
1018 // won't make progress on a `}`
1019 self.token != token::CloseDelim(token::Brace) {
1020 if let Some(stmt) = self.parse_full_stmt(macro_legacy_warnings)? {
1024 AstFragment::Stmts(stmts)
1026 AstFragmentKind::Expr => AstFragment::Expr(self.parse_expr()?),
1027 AstFragmentKind::OptExpr => {
1028 if self.token != token::Eof {
1029 AstFragment::OptExpr(Some(self.parse_expr()?))
1031 AstFragment::OptExpr(None)
1034 AstFragmentKind::Ty => AstFragment::Ty(self.parse_ty()?),
1035 AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat(None)?),
1039 pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span: Span) {
1040 if self.token != token::Eof {
1041 let msg = format!("macro expansion ignores token `{}` and any following",
1042 self.this_token_to_string());
1043 // Avoid emitting backtrace info twice.
1044 let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
1045 let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
1046 err.span_label(span, "caused by the macro expansion here");
1048 "the usage of `{}!` is likely invalid in {} context",
1053 let semi_span = self.sess.source_map().next_point(span);
1055 let semi_full_span = semi_span.to(self.sess.source_map().next_point(semi_span));
1056 match self.sess.source_map().span_to_snippet(semi_full_span) {
1057 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
1058 err.span_suggestion(
1060 "you might be missing a semicolon here",
1062 Applicability::MaybeIncorrect,
1072 struct InvocationCollector<'a, 'b: 'a> {
1073 cx: &'a mut ExtCtxt<'b>,
1074 cfg: StripUnconfigured<'a>,
1075 invocations: Vec<Invocation>,
1079 impl<'a, 'b> InvocationCollector<'a, 'b> {
1080 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1081 let mark = Mark::fresh(self.cx.current_expansion.mark);
1082 self.invocations.push(Invocation {
1085 expansion_data: ExpansionData {
1087 depth: self.cx.current_expansion.depth + 1,
1088 ..self.cx.current_expansion.clone()
1091 placeholder(fragment_kind, NodeId::placeholder_from_mark(mark))
1094 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
1095 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
1098 fn collect_attr(&mut self,
1099 attr: Option<ast::Attribute>,
1102 kind: AstFragmentKind,
1105 self.collect(kind, InvocationKind::Attr { attr, traits, item, after_derive })
1108 fn find_attr_invoc(&self, attrs: &mut Vec<ast::Attribute>, after_derive: &mut bool)
1109 -> Option<ast::Attribute> {
1110 let attr = attrs.iter()
1112 if a.path == sym::derive {
1113 *after_derive = true;
1115 !attr::is_known(a) && !is_builtin_attr(a)
1117 .map(|i| attrs.remove(i));
1118 if let Some(attr) = &attr {
1119 if !self.cx.ecfg.enable_custom_inner_attributes() &&
1120 attr.style == ast::AttrStyle::Inner && attr.path != sym::test {
1121 emit_feature_err(&self.cx.parse_sess, sym::custom_inner_attributes,
1122 attr.span, GateIssue::Language,
1123 "non-builtin inner attributes are unstable");
1129 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1130 fn classify_item<T>(&mut self, item: &mut T)
1131 -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)
1134 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1136 item.visit_attrs(|mut attrs| {
1137 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1138 traits = collect_derives(&mut self.cx, &mut attrs);
1141 (attr, traits, after_derive)
1144 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1145 /// to the unused-attributes lint (making it an error on statements and expressions
1146 /// is a breaking change)
1147 fn classify_nonitem<T: HasAttrs>(&mut self, nonitem: &mut T)
1148 -> (Option<ast::Attribute>, /* after_derive */ bool) {
1149 let (mut attr, mut after_derive) = (None, false);
1151 nonitem.visit_attrs(|mut attrs| {
1152 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1155 (attr, after_derive)
1158 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1159 self.cfg.configure(node)
1162 // Detect use of feature-gated or invalid attributes on macro invocations
1163 // since they will not be detected after macro expansion.
1164 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1165 let features = self.cx.ecfg.features.unwrap();
1166 for attr in attrs.iter() {
1167 self.check_attribute_inner(attr, features);
1169 // macros are expanded before any lint passes so this warning has to be hardcoded
1170 if attr.path == sym::derive {
1171 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1172 .note("this may become a hard error in a future release")
1178 fn check_attribute(&mut self, at: &ast::Attribute) {
1179 let features = self.cx.ecfg.features.unwrap();
1180 self.check_attribute_inner(at, features);
1183 fn check_attribute_inner(&mut self, at: &ast::Attribute, features: &Features) {
1184 feature_gate::check_attribute(at, self.cx.parse_sess, features);
1188 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1189 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1190 self.cfg.configure_expr(expr);
1191 visit_clobber(expr.deref_mut(), |mut expr| {
1192 self.cfg.configure_expr_kind(&mut expr.node);
1194 // ignore derives so they remain unused
1195 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1198 // Collect the invoc regardless of whether or not attributes are permitted here
1199 // expansion will eat the attribute so it won't error later.
1200 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1202 // AstFragmentKind::Expr requires the macro to emit an expression.
1203 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1204 AstFragmentKind::Expr, after_derive)
1209 if let ast::ExprKind::Mac(mac) = expr.node {
1210 self.check_attributes(&expr.attrs);
1211 self.collect_bang(mac, expr.span, AstFragmentKind::Expr)
1215 noop_visit_expr(&mut expr, self);
1221 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1222 let expr = configure!(self, expr);
1223 expr.filter_map(|mut expr| {
1224 self.cfg.configure_expr_kind(&mut expr.node);
1226 // Ignore derives so they remain unused.
1227 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1230 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1232 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1233 AstFragmentKind::OptExpr, after_derive)
1235 .map(|expr| expr.into_inner())
1238 if let ast::ExprKind::Mac(mac) = expr.node {
1239 self.check_attributes(&expr.attrs);
1240 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1242 .map(|expr| expr.into_inner())
1244 Some({ noop_visit_expr(&mut expr, self); expr })
1249 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1250 self.cfg.configure_pat(pat);
1252 PatKind::Mac(_) => {}
1253 _ => return noop_visit_pat(pat, self),
1256 visit_clobber(pat, |mut pat| {
1257 match mem::replace(&mut pat.node, PatKind::Wild) {
1258 PatKind::Mac(mac) =>
1259 self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1260 _ => unreachable!(),
1265 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1266 let mut stmt = configure!(self, stmt);
1268 // we'll expand attributes on expressions separately
1269 if !stmt.is_expr() {
1270 let (attr, derives, after_derive) = if stmt.is_item() {
1271 self.classify_item(&mut stmt)
1273 // ignore derives on non-item statements so it falls through
1274 // to the unused-attributes lint
1275 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1276 (attr, vec![], after_derive)
1279 if attr.is_some() || !derives.is_empty() {
1280 return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt)),
1281 AstFragmentKind::Stmts, after_derive).make_stmts();
1285 if let StmtKind::Mac(mac) = stmt.node {
1286 let (mac, style, attrs) = mac.into_inner();
1287 self.check_attributes(&attrs);
1288 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1291 // If this is a macro invocation with a semicolon, then apply that
1292 // semicolon to the final statement produced by expansion.
1293 if style == MacStmtStyle::Semicolon {
1294 if let Some(stmt) = placeholder.pop() {
1295 placeholder.push(stmt.add_trailing_semicolon());
1302 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1303 let ast::Stmt { id, node, span } = stmt;
1304 noop_flat_map_stmt_kind(node, self).into_iter().map(|node| {
1305 ast::Stmt { id, node, span }
1310 fn visit_block(&mut self, block: &mut P<Block>) {
1311 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1312 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1313 noop_visit_block(block, self);
1314 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1317 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1318 let mut item = configure!(self, item);
1320 let (attr, traits, after_derive) = self.classify_item(&mut item);
1321 if attr.is_some() || !traits.is_empty() {
1322 return self.collect_attr(attr, traits, Annotatable::Item(item),
1323 AstFragmentKind::Items, after_derive).make_items();
1327 ast::ItemKind::Mac(..) => {
1328 self.check_attributes(&item.attrs);
1329 item.and_then(|item| match item.node {
1330 ItemKind::Mac(mac) => {
1331 self.collect(AstFragmentKind::Items, InvocationKind::Bang {
1333 ident: Some(item.ident),
1337 _ => unreachable!(),
1340 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1341 if item.ident == Ident::invalid() {
1342 return noop_flat_map_item(item, self);
1345 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1346 let mut module = (*self.cx.current_expansion.module).clone();
1347 module.mod_path.push(item.ident);
1349 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1350 // In the non-inline case, `inner` is never the dummy span (cf. `parse_item_mod`).
1351 // Thus, if `inner` is the dummy span, we know the module is inline.
1352 let inline_module = item.span.contains(inner) || inner.is_dummy();
1355 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
1356 self.cx.current_expansion.directory_ownership =
1357 DirectoryOwnership::Owned { relative: None };
1358 module.directory.push(&*path.as_str());
1360 module.directory.push(&*item.ident.as_str());
1363 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1364 let mut path = match path {
1365 FileName::Real(path) => path,
1366 other => PathBuf::from(other.to_string()),
1368 let directory_ownership = match path.file_name().unwrap().to_str() {
1369 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1370 Some(_) => DirectoryOwnership::Owned {
1371 relative: Some(item.ident),
1373 None => DirectoryOwnership::UnownedViaMod(false),
1376 module.directory = path;
1377 self.cx.current_expansion.directory_ownership = directory_ownership;
1381 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1382 let result = noop_flat_map_item(item, self);
1383 self.cx.current_expansion.module = orig_module;
1384 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1388 _ => noop_flat_map_item(item, self),
1392 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
1393 let mut item = configure!(self, item);
1395 let (attr, traits, after_derive) = self.classify_item(&mut item);
1396 if attr.is_some() || !traits.is_empty() {
1397 return self.collect_attr(attr, traits, Annotatable::TraitItem(P(item)),
1398 AstFragmentKind::TraitItems, after_derive).make_trait_items()
1402 ast::TraitItemKind::Macro(mac) => {
1403 let ast::TraitItem { attrs, span, .. } = item;
1404 self.check_attributes(&attrs);
1405 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1407 _ => noop_flat_map_trait_item(item, self),
1411 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
1412 let mut item = configure!(self, item);
1414 let (attr, traits, after_derive) = self.classify_item(&mut item);
1415 if attr.is_some() || !traits.is_empty() {
1416 return self.collect_attr(attr, traits, Annotatable::ImplItem(P(item)),
1417 AstFragmentKind::ImplItems, after_derive).make_impl_items();
1421 ast::ImplItemKind::Macro(mac) => {
1422 let ast::ImplItem { attrs, span, .. } = item;
1423 self.check_attributes(&attrs);
1424 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1426 _ => noop_flat_map_impl_item(item, self),
1430 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1432 ast::TyKind::Mac(_) => {}
1433 _ => return noop_visit_ty(ty, self),
1436 visit_clobber(ty, |mut ty| {
1437 match mem::replace(&mut ty.node, ast::TyKind::Err) {
1438 ast::TyKind::Mac(mac) =>
1439 self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1440 _ => unreachable!(),
1445 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1446 self.cfg.configure_foreign_mod(foreign_mod);
1447 noop_visit_foreign_mod(foreign_mod, self);
1450 fn flat_map_foreign_item(&mut self, mut foreign_item: ast::ForeignItem)
1451 -> SmallVec<[ast::ForeignItem; 1]>
1453 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1455 if attr.is_some() || !traits.is_empty() {
1456 return self.collect_attr(attr, traits, Annotatable::ForeignItem(P(foreign_item)),
1457 AstFragmentKind::ForeignItems, after_derive)
1458 .make_foreign_items();
1461 if let ast::ForeignItemKind::Macro(mac) = foreign_item.node {
1462 self.check_attributes(&foreign_item.attrs);
1463 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1464 .make_foreign_items();
1467 noop_flat_map_foreign_item(foreign_item, self)
1470 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1472 ast::ItemKind::MacroDef(..) => {}
1474 self.cfg.configure_item_kind(item);
1475 noop_visit_item_kind(item, self);
1480 fn visit_generic_param(&mut self, param: &mut ast::GenericParam) {
1481 self.cfg.disallow_cfg_on_generic_param(¶m);
1482 noop_visit_generic_param(param, self)
1485 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1486 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1487 // contents="file contents")]` attributes
1488 if !at.check_name(sym::doc) {
1489 return noop_visit_attribute(at, self);
1492 if let Some(list) = at.meta_item_list() {
1493 if !list.iter().any(|it| it.check_name(sym::include)) {
1494 return noop_visit_attribute(at, self);
1497 let mut items = vec![];
1499 for mut it in list {
1500 if !it.check_name(sym::include) {
1501 items.push({ noop_visit_meta_list_item(&mut it, self); it });
1505 if let Some(file) = it.value_str() {
1506 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1507 self.check_attribute(&at);
1508 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1509 // avoid loading the file if they haven't enabled the feature
1510 return noop_visit_attribute(at, self);
1513 let filename = self.cx.root_path.join(file.to_string());
1514 match fs::read_to_string(&filename) {
1516 let src_interned = Symbol::intern(&src);
1518 // Add this input file to the code map to make it available as
1519 // dependency information
1520 self.cx.source_map().new_source_file(filename.into(), src);
1522 let include_info = vec![
1523 ast::NestedMetaItem::MetaItem(
1524 attr::mk_name_value_item_str(
1525 Ident::with_empty_ctxt(sym::file),
1526 dummy_spanned(file),
1529 ast::NestedMetaItem::MetaItem(
1530 attr::mk_name_value_item_str(
1531 Ident::with_empty_ctxt(sym::contents),
1532 dummy_spanned(src_interned),
1537 let include_ident = Ident::with_empty_ctxt(sym::include);
1538 let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
1539 items.push(ast::NestedMetaItem::MetaItem(item));
1544 .and_then(|item| item.name_value_literal())
1547 if e.kind() == ErrorKind::InvalidData {
1551 &format!("{} wasn't a utf-8 file", filename.display()),
1553 .span_label(lit.span, "contains invalid utf-8")
1556 let mut err = self.cx.struct_span_err(
1558 &format!("couldn't read {}: {}", filename.display(), e),
1560 err.span_label(lit.span, "couldn't read file");
1562 if e.kind() == ErrorKind::NotFound {
1563 err.help("external doc paths are relative to the crate root");
1571 let mut err = self.cx.struct_span_err(
1573 &format!("expected path to external documentation"),
1576 // Check if the user erroneously used `doc(include(...))` syntax.
1577 let literal = it.meta_item_list().and_then(|list| {
1578 if list.len() == 1 {
1579 list[0].literal().map(|literal| &literal.node)
1585 let (path, applicability) = match &literal {
1586 Some(LitKind::Str(path, ..)) => {
1587 (path.to_string(), Applicability::MachineApplicable)
1589 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1592 err.span_suggestion(
1594 "provide a file path with `=`",
1595 format!("include = \"{}\"", path),
1603 let meta = attr::mk_list_item(DUMMY_SP, Ident::with_empty_ctxt(sym::doc), items);
1605 ast::AttrStyle::Inner => *at = attr::mk_spanned_attr_inner(at.span, at.id, meta),
1606 ast::AttrStyle::Outer => *at = attr::mk_spanned_attr_outer(at.span, at.id, meta),
1609 noop_visit_attribute(at, self)
1613 fn visit_id(&mut self, id: &mut ast::NodeId) {
1615 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1616 *id = self.cx.resolver.next_node_id()
1621 pub struct ExpansionConfig<'feat> {
1622 pub crate_name: String,
1623 pub features: Option<&'feat Features>,
1624 pub recursion_limit: usize,
1625 pub trace_mac: bool,
1626 pub should_test: bool, // If false, strip `#[test]` nodes
1627 pub single_step: bool,
1628 pub keep_macs: bool,
1631 macro_rules! feature_tests {
1632 ($( fn $getter:ident = $field:ident, )*) => {
1634 pub fn $getter(&self) -> bool {
1635 match self.features {
1636 Some(&Features { $field: true, .. }) => true,
1644 impl<'feat> ExpansionConfig<'feat> {
1645 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1649 recursion_limit: 1024,
1658 fn enable_asm = asm,
1659 fn enable_custom_test_frameworks = custom_test_frameworks,
1660 fn enable_global_asm = global_asm,
1661 fn enable_log_syntax = log_syntax,
1662 fn enable_concat_idents = concat_idents,
1663 fn enable_trace_macros = trace_macros,
1664 fn enable_allow_internal_unstable = allow_internal_unstable,
1665 fn enable_format_args_nl = format_args_nl,
1666 fn macros_in_extern_enabled = macros_in_extern,
1667 fn proc_macro_hygiene = proc_macro_hygiene,
1670 fn enable_custom_inner_attributes(&self) -> bool {
1671 self.features.map_or(false, |features| {
1672 features.custom_inner_attributes || features.custom_attribute || features.rustc_attrs
1677 // A Marker adds the given mark to the syntax context.
1679 pub struct Marker(pub Mark);
1681 impl MutVisitor for Marker {
1682 fn visit_span(&mut self, span: &mut Span) {
1683 *span = span.apply_mark(self.0)
1686 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1687 noop_visit_mac(mac, self)