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::errors::{Applicability, FatalError};
7 use crate::ext::base::*;
8 use crate::ext::derive::{add_derived_markers, collect_derives};
9 use crate::ext::hygiene::{self, Mark, SyntaxContext};
10 use crate::ext::placeholders::{placeholder, PlaceholderExpander};
11 use crate::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
12 use crate::mut_visit::*;
13 use crate::parse::{DirectoryOwnership, PResult, ParseSess};
14 use crate::parse::token::{self, Token};
15 use crate::parse::parser::Parser;
17 use crate::symbol::Symbol;
18 use crate::symbol::keywords;
19 use crate::tokenstream::{TokenStream, TokenTree};
20 use crate::visit::{self, Visitor};
21 use crate::util::map_in_place::MapInPlace;
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;
29 use std::io::ErrorKind;
31 use std::ops::DerefMut;
33 use std::path::PathBuf;
35 macro_rules! ast_fragments {
37 $($Kind:ident($AstTy:ty) {
39 // FIXME: HACK: this should be `$(one ...)?` and `$(many ...)?` but `?` macro
40 // repetition was removed from 2015 edition in #51587 because of ambiguities.
41 $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)*
42 $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident;)*
46 /// A fragment of AST that can be produced by a single macro expansion.
47 /// Can also serve as an input and intermediate result for macro expansion operations.
48 pub enum AstFragment {
49 OptExpr(Option<P<ast::Expr>>),
53 /// "Discriminant" of an AST fragment.
54 #[derive(Copy, Clone, PartialEq, Eq)]
55 pub enum AstFragmentKind {
60 impl AstFragmentKind {
61 pub fn name(self) -> &'static str {
63 AstFragmentKind::OptExpr => "expression",
64 $(AstFragmentKind::$Kind => $kind_name,)*
68 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
70 AstFragmentKind::OptExpr =>
71 result.make_expr().map(Some).map(AstFragment::OptExpr),
72 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
78 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
80 AstFragment::OptExpr(expr) => expr,
81 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
85 $(pub fn $make_ast(self) -> $AstTy {
87 AstFragment::$Kind(ast) => ast,
88 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
92 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
94 AstFragment::OptExpr(opt_expr) => {
95 visit_clobber(opt_expr, |opt_expr| {
96 if let Some(expr) = opt_expr {
97 vis.filter_map_expr(expr)
103 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)*)*
104 $($(AstFragment::$Kind(ast) =>
105 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)*)*
109 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
111 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
112 AstFragment::OptExpr(None) => {}
113 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)*)*
114 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
115 visitor.$visit_ast_elt(ast_elt);
121 impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
122 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
123 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
125 $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
126 visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
128 $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
129 self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
133 impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
134 $(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
136 Some(self.make(AstFragmentKind::$Kind).$make_ast())
143 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
144 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
145 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
146 Stmts(SmallVec<[ast::Stmt; 1]>) {
147 "statement"; many fn flat_map_stmt; fn visit_stmt; fn make_stmts;
149 Items(SmallVec<[P<ast::Item>; 1]>) {
150 "item"; many fn flat_map_item; fn visit_item; fn make_items;
152 TraitItems(SmallVec<[ast::TraitItem; 1]>) {
153 "trait item"; many fn flat_map_trait_item; fn visit_trait_item; fn make_trait_items;
155 ImplItems(SmallVec<[ast::ImplItem; 1]>) {
156 "impl item"; many fn flat_map_impl_item; fn visit_impl_item; fn make_impl_items;
158 ForeignItems(SmallVec<[ast::ForeignItem; 1]>) {
159 "foreign item"; many fn flat_map_foreign_item; fn visit_foreign_item; fn make_foreign_items;
163 impl AstFragmentKind {
164 fn dummy(self, span: Span) -> Option<AstFragment> {
165 self.make_from(DummyResult::any(span))
168 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
170 let mut items = items.into_iter();
172 AstFragmentKind::Items =>
173 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
174 AstFragmentKind::ImplItems =>
175 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
176 AstFragmentKind::TraitItems =>
177 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
178 AstFragmentKind::ForeignItems =>
179 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
180 AstFragmentKind::Stmts =>
181 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
182 AstFragmentKind::Expr => AstFragment::Expr(
183 items.next().expect("expected exactly one expression").expect_expr()
185 AstFragmentKind::OptExpr =>
186 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
187 AstFragmentKind::Pat | AstFragmentKind::Ty =>
188 panic!("patterns and types aren't annotatable"),
193 fn macro_bang_format(path: &ast::Path) -> ExpnFormat {
194 // We don't want to format a path using pretty-printing,
195 // `format!("{}", path)`, because that tries to insert
196 // line-breaks and is slow.
197 let mut path_str = String::with_capacity(64);
198 for (i, segment) in path.segments.iter().enumerate() {
200 path_str.push_str("::");
202 if segment.ident.name != keywords::PathRoot.name() {
203 path_str.push_str(&segment.ident.as_str())
207 MacroBang(Symbol::intern(&path_str))
210 pub struct Invocation {
211 pub kind: InvocationKind,
212 fragment_kind: AstFragmentKind,
213 pub expansion_data: ExpansionData,
216 pub enum InvocationKind {
219 ident: Option<Ident>,
223 attr: Option<ast::Attribute>,
226 // We temporarily report errors for attribute macros placed after derives
236 pub fn span(&self) -> Span {
238 InvocationKind::Bang { span, .. } => span,
239 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.span,
240 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
241 InvocationKind::Derive { ref path, .. } => path.span,
246 pub struct MacroExpander<'a, 'b:'a> {
247 pub cx: &'a mut ExtCtxt<'b>,
248 monotonic: bool, // cf. `cx.monotonic_expander()`
251 impl<'a, 'b> MacroExpander<'a, 'b> {
252 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
253 MacroExpander { cx: cx, monotonic: monotonic }
256 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
257 let mut module = ModuleData {
258 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
259 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
260 FileName::Real(path) => path,
261 other => PathBuf::from(other.to_string()),
264 module.directory.pop();
265 self.cx.root_path = module.directory.clone();
266 self.cx.current_expansion.module = Rc::new(module);
267 self.cx.current_expansion.crate_span = Some(krate.span);
269 let orig_mod_span = krate.module.inner;
271 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
274 node: ast::ItemKind::Mod(krate.module),
275 ident: keywords::Invalid.ident(),
276 id: ast::DUMMY_NODE_ID,
277 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
281 match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
282 Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
284 krate.module = module;
287 // Resolution failed so we return an empty expansion
288 krate.attrs = vec![];
289 krate.module = ast::Mod {
290 inner: orig_mod_span,
297 self.cx.trace_macros_diag();
301 // Fully expand all macro invocations in this AST fragment.
302 fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
303 let orig_expansion_data = self.cx.current_expansion.clone();
304 self.cx.current_expansion.depth = 0;
306 // Collect all macro invocations and replace them with placeholders.
307 let (mut fragment_with_placeholders, mut invocations)
308 = self.collect_invocations(input_fragment, &[]);
310 // Optimization: if we resolve all imports now,
311 // we'll be able to immediately resolve most of imported macros.
312 self.resolve_imports();
314 // Resolve paths in all invocations and produce output expanded fragments for them, but
315 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
316 // The output fragments also go through expansion recursively until no invocations are left.
317 // Unresolved macros produce dummy outputs as a recovery measure.
318 invocations.reverse();
319 let mut expanded_fragments = Vec::new();
320 let mut derives: FxHashMap<Mark, Vec<_>> = FxHashMap::default();
321 let mut undetermined_invocations = Vec::new();
322 let (mut progress, mut force) = (false, !self.monotonic);
324 let invoc = if let Some(invoc) = invocations.pop() {
327 self.resolve_imports();
328 if undetermined_invocations.is_empty() { break }
329 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
330 force = !mem::replace(&mut progress, false);
335 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
336 let ext = match self.cx.resolver.resolve_macro_invocation(&invoc, scope, force) {
337 Ok(ext) => Some(ext),
338 Err(Determinacy::Determined) => None,
339 Err(Determinacy::Undetermined) => {
340 undetermined_invocations.push(invoc);
346 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
347 self.cx.current_expansion = invoc.expansion_data.clone();
349 self.cx.current_expansion.mark = scope;
350 // FIXME(jseyfried): Refactor out the following logic
351 let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
352 if let Some(ext) = ext {
353 let (invoc_fragment_kind, invoc_span) = (invoc.fragment_kind, invoc.span());
354 let fragment = self.expand_invoc(invoc, &*ext).unwrap_or_else(|| {
355 invoc_fragment_kind.dummy(invoc_span).unwrap()
357 self.collect_invocations(fragment, &[])
358 } else if let InvocationKind::Attr { attr: None, traits, item, .. } = invoc.kind {
359 if !item.derive_allowed() {
360 let attr = attr::find_by_name(item.attrs(), "derive")
361 .expect("`derive` attribute should exist");
362 let span = attr.span;
363 let mut err = self.cx.mut_span_err(span,
364 "`derive` may only be applied to \
365 structs, enums and unions");
366 if let ast::AttrStyle::Inner = attr.style {
367 let trait_list = traits.iter()
368 .map(|t| t.to_string()).collect::<Vec<_>>();
369 let suggestion = format!("#[derive({})]", trait_list.join(", "));
371 span, "try an outer attribute", suggestion,
372 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
373 Applicability::MaybeIncorrect
379 let mut item = self.fully_configure(item);
380 item.visit_attrs(|attrs| attrs.retain(|a| a.path != "derive"));
381 let mut item_with_markers = item.clone();
382 add_derived_markers(&mut self.cx, item.span(), &traits, &mut item_with_markers);
383 let derives = derives.entry(invoc.expansion_data.mark).or_default();
385 derives.reserve(traits.len());
386 invocations.reserve(traits.len());
387 for path in &traits {
388 let mark = Mark::fresh(self.cx.current_expansion.mark);
390 let item = match self.cx.resolver.resolve_macro_path(
391 path, MacroKind::Derive, Mark::root(), Vec::new(), false) {
392 Ok(ext) => match *ext {
393 BuiltinDerive(..) => item_with_markers.clone(),
398 invocations.push(Invocation {
399 kind: InvocationKind::Derive { path: path.clone(), item: item },
400 fragment_kind: invoc.fragment_kind,
401 expansion_data: ExpansionData {
403 ..invoc.expansion_data.clone()
407 let fragment = invoc.fragment_kind
408 .expect_from_annotatables(::std::iter::once(item_with_markers));
409 self.collect_invocations(fragment, derives)
414 self.collect_invocations(invoc.fragment_kind.dummy(invoc.span()).unwrap(), &[])
417 if expanded_fragments.len() < depth {
418 expanded_fragments.push(Vec::new());
420 expanded_fragments[depth - 1].push((mark, expanded_fragment));
421 if !self.cx.ecfg.single_step {
422 invocations.extend(new_invocations.into_iter().rev());
426 self.cx.current_expansion = orig_expansion_data;
428 // Finally incorporate all the expanded macros into the input AST fragment.
429 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
430 while let Some(expanded_fragments) = expanded_fragments.pop() {
431 for (mark, expanded_fragment) in expanded_fragments.into_iter().rev() {
432 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
433 placeholder_expander.add(NodeId::placeholder_from_mark(mark),
434 expanded_fragment, derives);
437 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
438 fragment_with_placeholders
441 fn resolve_imports(&mut self) {
443 self.cx.resolver.resolve_imports();
447 /// Collect all macro invocations reachable at this time in this AST fragment, and replace
448 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
449 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
450 /// prepares data for resolving paths of macro invocations.
451 fn collect_invocations(&mut self, mut fragment: AstFragment, derives: &[Mark])
452 -> (AstFragment, Vec<Invocation>) {
453 // Resolve `$crate`s in the fragment for pretty-printing.
454 self.cx.resolver.resolve_dollar_crates(&fragment);
457 let mut collector = InvocationCollector {
458 cfg: StripUnconfigured {
459 sess: self.cx.parse_sess,
460 features: self.cx.ecfg.features,
463 invocations: Vec::new(),
464 monotonic: self.monotonic,
466 fragment.mut_visit_with(&mut collector);
467 collector.invocations
471 self.cx.resolver.visit_ast_fragment_with_placeholders(
472 self.cx.current_expansion.mark, &fragment, derives);
475 (fragment, invocations)
478 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
479 let mut cfg = StripUnconfigured {
480 sess: self.cx.parse_sess,
481 features: self.cx.ecfg.features,
483 // Since the item itself has already been configured by the InvocationCollector,
484 // we know that fold result vector will contain exactly one element
486 Annotatable::Item(item) => {
487 Annotatable::Item(cfg.flat_map_item(item).pop().unwrap())
489 Annotatable::TraitItem(item) => {
490 Annotatable::TraitItem(
491 item.map(|item| cfg.flat_map_trait_item(item).pop().unwrap()))
493 Annotatable::ImplItem(item) => {
494 Annotatable::ImplItem(item.map(|item| cfg.flat_map_impl_item(item).pop().unwrap()))
496 Annotatable::ForeignItem(item) => {
497 Annotatable::ForeignItem(
498 item.map(|item| cfg.flat_map_foreign_item(item).pop().unwrap())
501 Annotatable::Stmt(stmt) => {
502 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
504 Annotatable::Expr(mut expr) => {
505 Annotatable::Expr({ cfg.visit_expr(&mut expr); expr })
510 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtension) -> Option<AstFragment> {
511 if invoc.fragment_kind == AstFragmentKind::ForeignItems &&
512 !self.cx.ecfg.macros_in_extern_enabled() {
513 if let SyntaxExtension::NonMacroAttr { .. } = *ext {} else {
514 emit_feature_err(&self.cx.parse_sess, "macros_in_extern",
515 invoc.span(), GateIssue::Language,
516 "macro invocations in `extern {}` blocks are experimental");
520 let result = match invoc.kind {
521 InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext)?,
522 InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext)?,
523 InvocationKind::Derive { .. } => self.expand_derive_invoc(invoc, ext)?,
526 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
527 let info = self.cx.current_expansion.mark.expn_info().unwrap();
528 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
529 let mut err = self.cx.struct_span_err(info.call_site,
530 &format!("recursion limit reached while expanding the macro `{}`",
531 info.format.name()));
533 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
536 self.cx.trace_macros_diag();
543 fn expand_attr_invoc(&mut self,
545 ext: &SyntaxExtension)
546 -> Option<AstFragment> {
547 let (attr, mut item) = match invoc.kind {
548 InvocationKind::Attr { attr, item, .. } => (attr?, item),
552 if let NonMacroAttr { mark_used: false } = *ext {} else {
553 // Macro attrs are always used when expanded,
554 // non-macro attrs are considered used when the field says so.
555 attr::mark_used(&attr);
557 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
558 call_site: attr.span,
560 format: MacroAttribute(Symbol::intern(&attr.path.to_string())),
561 allow_internal_unstable: false,
562 allow_internal_unsafe: false,
563 local_inner_macros: false,
564 edition: ext.edition(),
568 NonMacroAttr { .. } => {
569 attr::mark_known(&attr);
570 item.visit_attrs(|attrs| attrs.push(attr));
571 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
573 MultiModifier(ref mac) => {
574 let meta = attr.parse_meta(self.cx.parse_sess)
575 .map_err(|mut e| { e.emit(); }).ok()?;
576 let item = mac.expand(self.cx, attr.span, &meta, item);
577 Some(invoc.fragment_kind.expect_from_annotatables(item))
579 MultiDecorator(ref mac) => {
580 let mut items = Vec::new();
581 let meta = attr.parse_meta(self.cx.parse_sess)
582 .expect("derive meta should already have been parsed");
583 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
585 Some(invoc.fragment_kind.expect_from_annotatables(items))
587 AttrProcMacro(ref mac, ..) => {
588 self.gate_proc_macro_attr_item(attr.span, &item);
589 let item_tok = TokenTree::Token(DUMMY_SP, Token::interpolated(match item {
590 Annotatable::Item(item) => token::NtItem(item),
591 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
592 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
593 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
594 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
595 Annotatable::Expr(expr) => token::NtExpr(expr),
597 let input = self.extract_proc_macro_attr_input(attr.tokens, attr.span);
598 let tok_result = mac.expand(self.cx, attr.span, input, item_tok);
599 let res = self.parse_ast_fragment(tok_result, invoc.fragment_kind,
600 &attr.path, attr.span);
601 self.gate_proc_macro_expansion(attr.span, &res);
604 ProcMacroDerive(..) | BuiltinDerive(..) => {
605 self.cx.span_err(attr.span, &format!("`{}` is a derive mode", attr.path));
606 self.cx.trace_macros_diag();
607 invoc.fragment_kind.dummy(attr.span)
610 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
611 self.cx.span_err(attr.span, msg);
612 self.cx.trace_macros_diag();
613 invoc.fragment_kind.dummy(attr.span)
618 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
619 let mut trees = tokens.trees();
621 Some(TokenTree::Delimited(_, _, tts)) => {
622 if trees.next().is_none() {
626 Some(TokenTree::Token(..)) => {}
627 None => return TokenStream::empty(),
629 self.cx.span_err(span, "custom attribute invocations must be \
630 of the form #[foo] or #[foo(..)], the macro name must only be \
631 followed by a delimiter token");
635 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
636 let (kind, gate) = match *item {
637 Annotatable::Item(ref item) => {
639 ItemKind::Mod(_) if self.cx.ecfg.proc_macro_hygiene() => return,
640 ItemKind::Mod(_) => ("modules", "proc_macro_hygiene"),
644 Annotatable::TraitItem(_) => return,
645 Annotatable::ImplItem(_) => return,
646 Annotatable::ForeignItem(_) => return,
647 Annotatable::Stmt(_) |
648 Annotatable::Expr(_) if self.cx.ecfg.proc_macro_hygiene() => return,
649 Annotatable::Stmt(_) => ("statements", "proc_macro_hygiene"),
650 Annotatable::Expr(_) => ("expressions", "proc_macro_hygiene"),
657 &format!("custom attributes cannot be applied to {}", kind),
661 fn gate_proc_macro_expansion(&self, span: Span, fragment: &Option<AstFragment>) {
662 if self.cx.ecfg.proc_macro_hygiene() {
665 let fragment = match fragment {
666 Some(fragment) => fragment,
670 fragment.visit_with(&mut DisallowMacros {
672 parse_sess: self.cx.parse_sess,
675 struct DisallowMacros<'a> {
677 parse_sess: &'a ParseSess,
680 impl<'ast, 'a> Visitor<'ast> for DisallowMacros<'a> {
681 fn visit_item(&mut self, i: &'ast ast::Item) {
682 if let ast::ItemKind::MacroDef(_) = i.node {
685 "proc_macro_hygiene",
688 "procedural macros cannot expand to macro definitions",
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();
739 if ident.name != keywords::Invalid.name() {
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 false, false, false, None,
764 kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
771 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,
779 allow_internal_unsafe,
785 kind.make_from(expander.expand(
789 def_info.map(|(_, s)| s),
794 IdentTT(ref expander, tt_span, allow_internal_unstable) => {
795 if ident.name == keywords::Invalid.name() {
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,
806 allow_internal_unsafe: false,
807 local_inner_macros: false,
808 edition: hygiene::default_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 mode", path));
826 self.cx.trace_macros_diag();
830 SyntaxExtension::ProcMacro { ref expander, allow_internal_unstable, edition } => {
831 if ident.name != keywords::Invalid.name() {
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,
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 "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: false,
922 allow_internal_unsafe: false,
923 local_inner_macros: false,
924 edition: ext.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 ident: Path::from_ident(keywords::Invalid.ident()),
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 = true;
941 invoc.expansion_data.mark.set_expn_info(expn_info);
942 let span = span.with_ctxt(self.cx.backtrace());
943 let mut items = Vec::new();
944 func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
945 Some(invoc.fragment_kind.expect_from_annotatables(items))
948 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
949 self.cx.span_err(span, msg);
950 self.cx.trace_macros_diag();
951 invoc.fragment_kind.dummy(span)
956 fn parse_ast_fragment(&mut self,
958 kind: AstFragmentKind,
961 -> Option<AstFragment> {
962 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
963 match parser.parse_ast_fragment(kind, false) {
965 parser.ensure_complete_parse(path, kind.name(), span);
971 self.cx.trace_macros_diag();
978 impl<'a> Parser<'a> {
979 pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warnings: bool)
980 -> PResult<'a, AstFragment> {
982 AstFragmentKind::Items => {
983 let mut items = SmallVec::new();
984 while let Some(item) = self.parse_item()? {
987 AstFragment::Items(items)
989 AstFragmentKind::TraitItems => {
990 let mut items = SmallVec::new();
991 while self.token != token::Eof {
992 items.push(self.parse_trait_item(&mut false)?);
994 AstFragment::TraitItems(items)
996 AstFragmentKind::ImplItems => {
997 let mut items = SmallVec::new();
998 while self.token != token::Eof {
999 items.push(self.parse_impl_item(&mut false)?);
1001 AstFragment::ImplItems(items)
1003 AstFragmentKind::ForeignItems => {
1004 let mut items = SmallVec::new();
1005 while self.token != token::Eof {
1006 items.push(self.parse_foreign_item()?);
1008 AstFragment::ForeignItems(items)
1010 AstFragmentKind::Stmts => {
1011 let mut stmts = SmallVec::new();
1012 while self.token != token::Eof &&
1013 // won't make progress on a `}`
1014 self.token != token::CloseDelim(token::Brace) {
1015 if let Some(stmt) = self.parse_full_stmt(macro_legacy_warnings)? {
1019 AstFragment::Stmts(stmts)
1021 AstFragmentKind::Expr => AstFragment::Expr(self.parse_expr()?),
1022 AstFragmentKind::OptExpr => {
1023 if self.token != token::Eof {
1024 AstFragment::OptExpr(Some(self.parse_expr()?))
1026 AstFragment::OptExpr(None)
1029 AstFragmentKind::Ty => AstFragment::Ty(self.parse_ty()?),
1030 AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat(None)?),
1034 pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span: Span) {
1035 if self.token != token::Eof {
1036 let msg = format!("macro expansion ignores token `{}` and any following",
1037 self.this_token_to_string());
1038 // Avoid emitting backtrace info twice.
1039 let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
1040 let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
1041 err.span_label(span, "caused by the macro expansion here");
1043 "the usage of `{}!` is likely invalid in {} context",
1048 let semi_span = self.sess.source_map().next_point(span);
1050 let semi_full_span = semi_span.to(self.sess.source_map().next_point(semi_span));
1051 match self.sess.source_map().span_to_snippet(semi_full_span) {
1052 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
1053 err.span_suggestion(
1055 "you might be missing a semicolon here",
1057 Applicability::MaybeIncorrect,
1067 struct InvocationCollector<'a, 'b: 'a> {
1068 cx: &'a mut ExtCtxt<'b>,
1069 cfg: StripUnconfigured<'a>,
1070 invocations: Vec<Invocation>,
1074 impl<'a, 'b> InvocationCollector<'a, 'b> {
1075 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1076 let mark = Mark::fresh(self.cx.current_expansion.mark);
1077 self.invocations.push(Invocation {
1080 expansion_data: ExpansionData {
1082 depth: self.cx.current_expansion.depth + 1,
1083 ..self.cx.current_expansion.clone()
1086 placeholder(fragment_kind, NodeId::placeholder_from_mark(mark))
1089 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
1090 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
1093 fn collect_attr(&mut self,
1094 attr: Option<ast::Attribute>,
1097 kind: AstFragmentKind,
1100 self.collect(kind, InvocationKind::Attr { attr, traits, item, after_derive })
1103 fn find_attr_invoc(&self, attrs: &mut Vec<ast::Attribute>, after_derive: &mut bool)
1104 -> Option<ast::Attribute> {
1105 let attr = attrs.iter()
1107 if a.path == "derive" {
1108 *after_derive = true;
1110 !attr::is_known(a) && !is_builtin_attr(a)
1112 .map(|i| attrs.remove(i));
1113 if let Some(attr) = &attr {
1114 if !self.cx.ecfg.enable_custom_inner_attributes() &&
1115 attr.style == ast::AttrStyle::Inner && attr.path != "test" {
1116 emit_feature_err(&self.cx.parse_sess, "custom_inner_attributes",
1117 attr.span, GateIssue::Language,
1118 "non-builtin inner attributes are unstable");
1124 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1125 fn classify_item<T>(&mut self, item: &mut T)
1126 -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)
1129 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1131 item.visit_attrs(|mut attrs| {
1132 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1133 traits = collect_derives(&mut self.cx, &mut attrs);
1136 (attr, traits, after_derive)
1139 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1140 /// to the unused-attributes lint (making it an error on statements and expressions
1141 /// is a breaking change)
1142 fn classify_nonitem<T: HasAttrs>(&mut self, nonitem: &mut T)
1143 -> (Option<ast::Attribute>, /* after_derive */ bool) {
1144 let (mut attr, mut after_derive) = (None, false);
1146 nonitem.visit_attrs(|mut attrs| {
1147 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1150 (attr, after_derive)
1153 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1154 self.cfg.configure(node)
1157 // Detect use of feature-gated or invalid attributes on macro invocations
1158 // since they will not be detected after macro expansion.
1159 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1160 let features = self.cx.ecfg.features.unwrap();
1161 for attr in attrs.iter() {
1162 self.check_attribute_inner(attr, features);
1164 // macros are expanded before any lint passes so this warning has to be hardcoded
1165 if attr.path == "derive" {
1166 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1167 .note("this may become a hard error in a future release")
1173 fn check_attribute(&mut self, at: &ast::Attribute) {
1174 let features = self.cx.ecfg.features.unwrap();
1175 self.check_attribute_inner(at, features);
1178 fn check_attribute_inner(&mut self, at: &ast::Attribute, features: &Features) {
1179 feature_gate::check_attribute(at, self.cx.parse_sess, features);
1183 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1184 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1185 self.cfg.configure_expr(expr);
1186 visit_clobber(expr.deref_mut(), |mut expr| {
1187 self.cfg.configure_expr_kind(&mut expr.node);
1189 // ignore derives so they remain unused
1190 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1193 // Collect the invoc regardless of whether or not attributes are permitted here
1194 // expansion will eat the attribute so it won't error later.
1195 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1197 // AstFragmentKind::Expr requires the macro to emit an expression.
1198 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1199 AstFragmentKind::Expr, after_derive)
1204 if let ast::ExprKind::Mac(mac) = expr.node {
1205 self.check_attributes(&expr.attrs);
1206 self.collect_bang(mac, expr.span, AstFragmentKind::Expr)
1210 noop_visit_expr(&mut expr, self);
1216 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1217 let expr = configure!(self, expr);
1218 expr.filter_map(|mut expr| {
1219 self.cfg.configure_expr_kind(&mut expr.node);
1221 // Ignore derives so they remain unused.
1222 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1225 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1227 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1228 AstFragmentKind::OptExpr, after_derive)
1230 .map(|expr| expr.into_inner())
1233 if let ast::ExprKind::Mac(mac) = expr.node {
1234 self.check_attributes(&expr.attrs);
1235 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1237 .map(|expr| expr.into_inner())
1239 Some({ noop_visit_expr(&mut expr, self); expr })
1244 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1245 self.cfg.configure_pat(pat);
1247 PatKind::Mac(_) => {}
1248 _ => return noop_visit_pat(pat, self),
1251 visit_clobber(pat, |mut pat| {
1252 match mem::replace(&mut pat.node, PatKind::Wild) {
1253 PatKind::Mac(mac) =>
1254 self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1255 _ => unreachable!(),
1260 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1261 let mut stmt = configure!(self, stmt);
1263 // we'll expand attributes on expressions separately
1264 if !stmt.is_expr() {
1265 let (attr, derives, after_derive) = if stmt.is_item() {
1266 self.classify_item(&mut stmt)
1268 // ignore derives on non-item statements so it falls through
1269 // to the unused-attributes lint
1270 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1271 (attr, vec![], after_derive)
1274 if attr.is_some() || !derives.is_empty() {
1275 return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt)),
1276 AstFragmentKind::Stmts, after_derive).make_stmts();
1280 if let StmtKind::Mac(mac) = stmt.node {
1281 let (mac, style, attrs) = mac.into_inner();
1282 self.check_attributes(&attrs);
1283 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1286 // If this is a macro invocation with a semicolon, then apply that
1287 // semicolon to the final statement produced by expansion.
1288 if style == MacStmtStyle::Semicolon {
1289 if let Some(stmt) = placeholder.pop() {
1290 placeholder.push(stmt.add_trailing_semicolon());
1297 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1298 let ast::Stmt { id, node, span } = stmt;
1299 noop_flat_map_stmt_kind(node, self).into_iter().map(|node| {
1300 ast::Stmt { id, node, span }
1305 fn visit_block(&mut self, block: &mut P<Block>) {
1306 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1307 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1308 noop_visit_block(block, self);
1309 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1312 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1313 let mut item = configure!(self, item);
1315 let (attr, traits, after_derive) = self.classify_item(&mut item);
1316 if attr.is_some() || !traits.is_empty() {
1317 return self.collect_attr(attr, traits, Annotatable::Item(item),
1318 AstFragmentKind::Items, after_derive).make_items();
1322 ast::ItemKind::Mac(..) => {
1323 self.check_attributes(&item.attrs);
1324 item.and_then(|item| match item.node {
1325 ItemKind::Mac(mac) => {
1326 self.collect(AstFragmentKind::Items, InvocationKind::Bang {
1328 ident: Some(item.ident),
1332 _ => unreachable!(),
1335 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1336 if item.ident == keywords::Invalid.ident() {
1337 return noop_flat_map_item(item, self);
1340 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1341 let mut module = (*self.cx.current_expansion.module).clone();
1342 module.mod_path.push(item.ident);
1344 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1345 // In the non-inline case, `inner` is never the dummy span (cf. `parse_item_mod`).
1346 // Thus, if `inner` is the dummy span, we know the module is inline.
1347 let inline_module = item.span.contains(inner) || inner.is_dummy();
1350 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, "path") {
1351 self.cx.current_expansion.directory_ownership =
1352 DirectoryOwnership::Owned { relative: None };
1353 module.directory.push(&*path.as_str());
1355 module.directory.push(&*item.ident.as_str());
1358 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1359 let mut path = match path {
1360 FileName::Real(path) => path,
1361 other => PathBuf::from(other.to_string()),
1363 let directory_ownership = match path.file_name().unwrap().to_str() {
1364 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1365 Some(_) => DirectoryOwnership::Owned {
1366 relative: Some(item.ident),
1368 None => DirectoryOwnership::UnownedViaMod(false),
1371 module.directory = path;
1372 self.cx.current_expansion.directory_ownership = directory_ownership;
1376 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1377 let result = noop_flat_map_item(item, self);
1378 self.cx.current_expansion.module = orig_module;
1379 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1383 _ => noop_flat_map_item(item, self),
1387 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
1388 let mut item = configure!(self, item);
1390 let (attr, traits, after_derive) = self.classify_item(&mut item);
1391 if attr.is_some() || !traits.is_empty() {
1392 return self.collect_attr(attr, traits, Annotatable::TraitItem(P(item)),
1393 AstFragmentKind::TraitItems, after_derive).make_trait_items()
1397 ast::TraitItemKind::Macro(mac) => {
1398 let ast::TraitItem { attrs, span, .. } = item;
1399 self.check_attributes(&attrs);
1400 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1402 _ => noop_flat_map_trait_item(item, self),
1406 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
1407 let mut item = configure!(self, item);
1409 let (attr, traits, after_derive) = self.classify_item(&mut item);
1410 if attr.is_some() || !traits.is_empty() {
1411 return self.collect_attr(attr, traits, Annotatable::ImplItem(P(item)),
1412 AstFragmentKind::ImplItems, after_derive).make_impl_items();
1416 ast::ImplItemKind::Macro(mac) => {
1417 let ast::ImplItem { attrs, span, .. } = item;
1418 self.check_attributes(&attrs);
1419 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1421 _ => noop_flat_map_impl_item(item, self),
1425 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1427 ast::TyKind::Mac(_) => {}
1428 _ => return noop_visit_ty(ty, self),
1431 visit_clobber(ty, |mut ty| {
1432 match mem::replace(&mut ty.node, ast::TyKind::Err) {
1433 ast::TyKind::Mac(mac) =>
1434 self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1435 _ => unreachable!(),
1440 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1441 self.cfg.configure_foreign_mod(foreign_mod);
1442 noop_visit_foreign_mod(foreign_mod, self);
1445 fn flat_map_foreign_item(&mut self, mut foreign_item: ast::ForeignItem)
1446 -> SmallVec<[ast::ForeignItem; 1]>
1448 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1450 if attr.is_some() || !traits.is_empty() {
1451 return self.collect_attr(attr, traits, Annotatable::ForeignItem(P(foreign_item)),
1452 AstFragmentKind::ForeignItems, after_derive)
1453 .make_foreign_items();
1456 if let ast::ForeignItemKind::Macro(mac) = foreign_item.node {
1457 self.check_attributes(&foreign_item.attrs);
1458 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1459 .make_foreign_items();
1462 noop_flat_map_foreign_item(foreign_item, self)
1465 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1467 ast::ItemKind::MacroDef(..) => {}
1469 self.cfg.configure_item_kind(item);
1470 noop_visit_item_kind(item, self);
1475 fn visit_generic_param(&mut self, param: &mut ast::GenericParam) {
1476 self.cfg.disallow_cfg_on_generic_param(¶m);
1477 noop_visit_generic_param(param, self)
1480 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1481 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1482 // contents="file contents")]` attributes
1483 if !at.check_name("doc") {
1484 return noop_visit_attribute(at, self);
1487 if let Some(list) = at.meta_item_list() {
1488 if !list.iter().any(|it| it.check_name("include")) {
1489 return noop_visit_attribute(at, self);
1492 let mut items = vec![];
1494 for mut it in list {
1495 if !it.check_name("include") {
1496 items.push({ noop_visit_meta_list_item(&mut it, self); it });
1500 if let Some(file) = it.value_str() {
1501 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1502 self.check_attribute(&at);
1503 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1504 // avoid loading the file if they haven't enabled the feature
1505 return noop_visit_attribute(at, self);
1508 let filename = self.cx.root_path.join(file.to_string());
1509 match fs::read_to_string(&filename) {
1511 let src_interned = Symbol::intern(&src);
1513 // Add this input file to the code map to make it available as
1514 // dependency information
1515 self.cx.source_map().new_source_file(filename.into(), src);
1517 let include_info = vec![
1518 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1519 attr::mk_name_value_item_str(
1520 Ident::from_str("file"),
1521 dummy_spanned(file),
1524 dummy_spanned(ast::NestedMetaItemKind::MetaItem(
1525 attr::mk_name_value_item_str(
1526 Ident::from_str("contents"),
1527 dummy_spanned(src_interned),
1532 let include_ident = Ident::from_str("include");
1533 let item = attr::mk_list_item(DUMMY_SP, include_ident, include_info);
1534 items.push(dummy_spanned(ast::NestedMetaItemKind::MetaItem(item)));
1539 .and_then(|item| item.name_value_literal())
1542 if e.kind() == ErrorKind::InvalidData {
1546 &format!("{} wasn't a utf-8 file", filename.display()),
1548 .span_label(lit.span, "contains invalid utf-8")
1551 let mut err = self.cx.struct_span_err(
1553 &format!("couldn't read {}: {}", filename.display(), e),
1555 err.span_label(lit.span, "couldn't read file");
1557 if e.kind() == ErrorKind::NotFound {
1558 err.help("external doc paths are relative to the crate root");
1566 let mut err = self.cx.struct_span_err(
1568 &format!("expected path to external documentation"),
1571 // Check if the user erroneously used `doc(include(...))` syntax.
1572 let literal = it.meta_item_list().and_then(|list| {
1573 if list.len() == 1 {
1574 list[0].literal().map(|literal| &literal.node)
1580 let (path, applicability) = match &literal {
1581 Some(LitKind::Str(path, ..)) => {
1582 (path.to_string(), Applicability::MachineApplicable)
1584 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1587 err.span_suggestion(
1589 "provide a file path with `=`",
1590 format!("include = \"{}\"", path),
1598 let meta = attr::mk_list_item(DUMMY_SP, Ident::from_str("doc"), items);
1600 ast::AttrStyle::Inner => *at = attr::mk_spanned_attr_inner(at.span, at.id, meta),
1601 ast::AttrStyle::Outer => *at = attr::mk_spanned_attr_outer(at.span, at.id, meta),
1604 noop_visit_attribute(at, self)
1608 fn visit_id(&mut self, id: &mut ast::NodeId) {
1610 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1611 *id = self.cx.resolver.next_node_id()
1616 pub struct ExpansionConfig<'feat> {
1617 pub crate_name: String,
1618 pub features: Option<&'feat Features>,
1619 pub recursion_limit: usize,
1620 pub trace_mac: bool,
1621 pub should_test: bool, // If false, strip `#[test]` nodes
1622 pub single_step: bool,
1623 pub keep_macs: bool,
1626 macro_rules! feature_tests {
1627 ($( fn $getter:ident = $field:ident, )*) => {
1629 pub fn $getter(&self) -> bool {
1630 match self.features {
1631 Some(&Features { $field: true, .. }) => true,
1639 impl<'feat> ExpansionConfig<'feat> {
1640 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1644 recursion_limit: 1024,
1653 fn enable_asm = asm,
1654 fn enable_custom_test_frameworks = custom_test_frameworks,
1655 fn enable_global_asm = global_asm,
1656 fn enable_log_syntax = log_syntax,
1657 fn enable_concat_idents = concat_idents,
1658 fn enable_trace_macros = trace_macros,
1659 fn enable_allow_internal_unstable = allow_internal_unstable,
1660 fn enable_format_args_nl = format_args_nl,
1661 fn macros_in_extern_enabled = macros_in_extern,
1662 fn proc_macro_hygiene = proc_macro_hygiene,
1665 fn enable_custom_inner_attributes(&self) -> bool {
1666 self.features.map_or(false, |features| {
1667 features.custom_inner_attributes || features.custom_attribute || features.rustc_attrs
1672 // A Marker adds the given mark to the syntax context.
1674 pub struct Marker(pub Mark);
1676 impl MutVisitor for Marker {
1677 fn visit_span(&mut self, span: &mut Span) {
1678 *span = span.apply_mark(self.0)
1681 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1682 noop_visit_mac(mac, self)