2 use crate::config::StripUnconfigured;
3 use crate::hygiene::{ExpnData, ExpnId, ExpnKind, SyntaxContext};
4 use crate::mbe::macro_rules::annotate_err_with_kind;
5 use crate::placeholders::{placeholder, PlaceholderExpander};
6 use crate::proc_macro::collect_derives;
8 use rustc_ast_pretty::pprust;
9 use rustc_attr::{self as attr, is_builtin_attr, HasAttrs};
10 use rustc_data_structures::sync::Lrc;
11 use rustc_errors::{Applicability, FatalError, PResult};
12 use rustc_feature::Features;
13 use rustc_parse::configure;
14 use rustc_parse::parser::Parser;
15 use rustc_parse::validate_attr;
16 use rustc_parse::DirectoryOwnership;
17 use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
18 use rustc_session::lint::BuiltinLintDiagnostics;
19 use rustc_session::parse::{feature_err, ParseSess};
20 use rustc_span::source_map::respan;
21 use rustc_span::symbol::{sym, Symbol};
22 use rustc_span::{FileName, Span, DUMMY_SP};
23 use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
24 use syntax::ast::{ItemKind, MacArgs, MacStmtStyle, StmtKind};
25 use syntax::mut_visit::*;
28 use syntax::tokenstream::{TokenStream, TokenTree};
29 use syntax::util::map_in_place::MapInPlace;
30 use syntax::visit::{self, AssocCtxt, Visitor};
32 use smallvec::{smallvec, SmallVec};
33 use std::io::ErrorKind;
34 use std::ops::DerefMut;
35 use std::path::PathBuf;
37 use std::{iter, mem, slice};
39 macro_rules! ast_fragments {
41 $($Kind:ident($AstTy:ty) {
43 $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
44 $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident($($args:tt)*);)?
48 /// A fragment of AST that can be produced by a single macro expansion.
49 /// Can also serve as an input and intermediate result for macro expansion operations.
50 pub enum AstFragment {
51 OptExpr(Option<P<ast::Expr>>),
55 /// "Discriminant" of an AST fragment.
56 #[derive(Copy, Clone, PartialEq, Eq)]
57 pub enum AstFragmentKind {
62 impl AstFragmentKind {
63 pub fn name(self) -> &'static str {
65 AstFragmentKind::OptExpr => "expression",
66 $(AstFragmentKind::$Kind => $kind_name,)*
70 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
72 AstFragmentKind::OptExpr =>
73 result.make_expr().map(Some).map(AstFragment::OptExpr),
74 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
80 pub fn add_placeholders(&mut self, placeholders: &[NodeId]) {
81 if placeholders.is_empty() {
85 $($(AstFragment::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| {
86 // We are repeating through arguments with `many`, to do that we have to
87 // mention some macro variable from those arguments even if it's not used.
88 macro _repeating($flat_map_ast_elt) {}
89 placeholder(AstFragmentKind::$Kind, *id, None).$make_ast()
91 _ => panic!("unexpected AST fragment kind")
95 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
97 AstFragment::OptExpr(expr) => expr,
98 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
102 $(pub fn $make_ast(self) -> $AstTy {
104 AstFragment::$Kind(ast) => ast,
105 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
109 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
111 AstFragment::OptExpr(opt_expr) => {
112 visit_clobber(opt_expr, |opt_expr| {
113 if let Some(expr) = opt_expr {
114 vis.filter_map_expr(expr)
120 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
121 $($(AstFragment::$Kind(ast) =>
122 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
126 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
128 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
129 AstFragment::OptExpr(None) => {}
130 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
131 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
132 visitor.$visit_ast_elt(ast_elt, $($args)*);
138 impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
139 $(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>)
141 Some(self.make(AstFragmentKind::$Kind).$make_ast())
148 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
149 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
150 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
151 Stmts(SmallVec<[ast::Stmt; 1]>) {
152 "statement"; many fn flat_map_stmt; fn visit_stmt(); fn make_stmts;
154 Items(SmallVec<[P<ast::Item>; 1]>) {
155 "item"; many fn flat_map_item; fn visit_item(); fn make_items;
157 TraitItems(SmallVec<[P<ast::AssocItem>; 1]>) {
159 many fn flat_map_trait_item;
160 fn visit_assoc_item(AssocCtxt::Trait);
163 ImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
165 many fn flat_map_impl_item;
166 fn visit_assoc_item(AssocCtxt::Impl);
169 ForeignItems(SmallVec<[P<ast::ForeignItem>; 1]>) {
171 many fn flat_map_foreign_item;
172 fn visit_foreign_item();
173 fn make_foreign_items;
175 Arms(SmallVec<[ast::Arm; 1]>) {
176 "match arm"; many fn flat_map_arm; fn visit_arm(); fn make_arms;
178 Fields(SmallVec<[ast::Field; 1]>) {
179 "field expression"; many fn flat_map_field; fn visit_field(); fn make_fields;
181 FieldPats(SmallVec<[ast::FieldPat; 1]>) {
183 many fn flat_map_field_pattern;
184 fn visit_field_pattern();
185 fn make_field_patterns;
187 GenericParams(SmallVec<[ast::GenericParam; 1]>) {
189 many fn flat_map_generic_param;
190 fn visit_generic_param();
191 fn make_generic_params;
193 Params(SmallVec<[ast::Param; 1]>) {
194 "function parameter"; many fn flat_map_param; fn visit_param(); fn make_params;
196 StructFields(SmallVec<[ast::StructField; 1]>) {
198 many fn flat_map_struct_field;
199 fn visit_struct_field();
200 fn make_struct_fields;
202 Variants(SmallVec<[ast::Variant; 1]>) {
203 "variant"; many fn flat_map_variant; fn visit_variant(); fn make_variants;
207 impl AstFragmentKind {
208 fn dummy(self, span: Span) -> AstFragment {
209 self.make_from(DummyResult::any(span)).expect("couldn't create a dummy AST fragment")
212 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
216 let mut items = items.into_iter();
218 AstFragmentKind::Arms => {
219 AstFragment::Arms(items.map(Annotatable::expect_arm).collect())
221 AstFragmentKind::Fields => {
222 AstFragment::Fields(items.map(Annotatable::expect_field).collect())
224 AstFragmentKind::FieldPats => {
225 AstFragment::FieldPats(items.map(Annotatable::expect_field_pattern).collect())
227 AstFragmentKind::GenericParams => {
228 AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect())
230 AstFragmentKind::Params => {
231 AstFragment::Params(items.map(Annotatable::expect_param).collect())
233 AstFragmentKind::StructFields => {
234 AstFragment::StructFields(items.map(Annotatable::expect_struct_field).collect())
236 AstFragmentKind::Variants => {
237 AstFragment::Variants(items.map(Annotatable::expect_variant).collect())
239 AstFragmentKind::Items => {
240 AstFragment::Items(items.map(Annotatable::expect_item).collect())
242 AstFragmentKind::ImplItems => {
243 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect())
245 AstFragmentKind::TraitItems => {
246 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect())
248 AstFragmentKind::ForeignItems => {
249 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect())
251 AstFragmentKind::Stmts => {
252 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect())
254 AstFragmentKind::Expr => AstFragment::Expr(
255 items.next().expect("expected exactly one expression").expect_expr(),
257 AstFragmentKind::OptExpr => {
258 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
260 AstFragmentKind::Pat | AstFragmentKind::Ty => {
261 panic!("patterns and types aren't annotatable")
267 pub struct Invocation {
268 pub kind: InvocationKind,
269 pub fragment_kind: AstFragmentKind,
270 pub expansion_data: ExpansionData,
273 pub enum InvocationKind {
279 attr: ast::Attribute,
281 // Required for resolving derive helper attributes.
283 // We temporarily report errors for attribute macros placed after derives
290 /// "Invocation" that contains all derives from an item,
291 /// broken into multiple `Derive` invocations when expanded.
292 /// FIXME: Find a way to remove it.
299 impl InvocationKind {
300 fn placeholder_visibility(&self) -> Option<ast::Visibility> {
301 // HACK: For unnamed fields placeholders should have the same visibility as the actual
302 // fields because for tuple structs/variants resolve determines visibilities of their
303 // constructor using these field visibilities before attributes on them are are expanded.
304 // The assumption is that the attribute expansion cannot change field visibilities,
305 // and it holds because only inert attributes are supported in this position.
307 InvocationKind::Attr { item: Annotatable::StructField(field), .. }
308 | InvocationKind::Derive { item: Annotatable::StructField(field), .. }
309 | InvocationKind::DeriveContainer { item: Annotatable::StructField(field), .. }
310 if field.ident.is_none() =>
312 Some(field.vis.clone())
320 pub fn span(&self) -> Span {
322 InvocationKind::Bang { span, .. } => *span,
323 InvocationKind::Attr { attr, .. } => attr.span,
324 InvocationKind::Derive { path, .. } => path.span,
325 InvocationKind::DeriveContainer { item, .. } => item.span(),
330 pub struct MacroExpander<'a, 'b> {
331 pub cx: &'a mut ExtCtxt<'b>,
332 monotonic: bool, // cf. `cx.monotonic_expander()`
335 impl<'a, 'b> MacroExpander<'a, 'b> {
336 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
337 MacroExpander { cx, monotonic }
340 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
341 let mut module = ModuleData {
342 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
343 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
344 FileName::Real(path) => path,
345 other => PathBuf::from(other.to_string()),
348 module.directory.pop();
349 self.cx.root_path = module.directory.clone();
350 self.cx.current_expansion.module = Rc::new(module);
352 let orig_mod_span = krate.module.inner;
354 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
357 kind: ast::ItemKind::Mod(krate.module),
358 ident: Ident::invalid(),
359 id: ast::DUMMY_NODE_ID,
360 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
364 match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
365 Some(ast::Item { attrs, kind: ast::ItemKind::Mod(module), .. }) => {
367 krate.module = module;
370 // Resolution failed so we return an empty expansion
371 krate.attrs = vec![];
372 krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
374 Some(ast::Item { span, kind, .. }) => {
375 krate.attrs = vec![];
376 krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
380 "expected crate top-level item to be a module after macro expansion, found {} {}",
381 kind.article(), kind.descr()
386 self.cx.trace_macros_diag();
390 // Recursively expand all macro invocations in this AST fragment.
391 pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
392 let orig_expansion_data = self.cx.current_expansion.clone();
393 self.cx.current_expansion.depth = 0;
395 // Collect all macro invocations and replace them with placeholders.
396 let (mut fragment_with_placeholders, mut invocations) =
397 self.collect_invocations(input_fragment, &[]);
399 // Optimization: if we resolve all imports now,
400 // we'll be able to immediately resolve most of imported macros.
401 self.resolve_imports();
403 // Resolve paths in all invocations and produce output expanded fragments for them, but
404 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
405 // The output fragments also go through expansion recursively until no invocations are left.
406 // Unresolved macros produce dummy outputs as a recovery measure.
407 invocations.reverse();
408 let mut expanded_fragments = Vec::new();
409 let mut undetermined_invocations = Vec::new();
410 let (mut progress, mut force) = (false, !self.monotonic);
412 let invoc = if let Some(invoc) = invocations.pop() {
415 self.resolve_imports();
416 if undetermined_invocations.is_empty() {
419 invocations = mem::take(&mut undetermined_invocations);
420 force = !mem::replace(&mut progress, false);
424 let eager_expansion_root =
425 if self.monotonic { invoc.expansion_data.id } else { orig_expansion_data.id };
426 let res = match self.cx.resolver.resolve_macro_invocation(
428 eager_expansion_root,
432 Err(Indeterminate) => {
433 undetermined_invocations.push(invoc);
439 let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
440 self.cx.current_expansion = invoc.expansion_data.clone();
442 // FIXME(jseyfried): Refactor out the following logic
443 let (expanded_fragment, new_invocations) = match res {
444 InvocationRes::Single(ext) => {
445 let fragment = self.expand_invoc(invoc, &ext.kind);
446 self.collect_invocations(fragment, &[])
448 InvocationRes::DeriveContainer(_exts) => {
449 // FIXME: Consider using the derive resolutions (`_exts`) immediately,
450 // instead of enqueuing the derives to be resolved again later.
451 let (derives, item) = match invoc.kind {
452 InvocationKind::DeriveContainer { derives, item } => (derives, item),
455 if !item.derive_allowed() {
456 self.error_derive_forbidden_on_non_adt(&derives, &item);
459 let mut item = self.fully_configure(item);
460 item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
462 let mut derive_placeholders = Vec::with_capacity(derives.len());
463 invocations.reserve(derives.len());
464 for path in derives {
465 let expn_id = ExpnId::fresh(None);
466 derive_placeholders.push(NodeId::placeholder_from_expn_id(expn_id));
467 invocations.push(Invocation {
468 kind: InvocationKind::Derive { path, item: item.clone() },
469 fragment_kind: invoc.fragment_kind,
470 expansion_data: ExpansionData {
472 ..invoc.expansion_data.clone()
477 invoc.fragment_kind.expect_from_annotatables(::std::iter::once(item));
478 self.collect_invocations(fragment, &derive_placeholders)
482 if expanded_fragments.len() < depth {
483 expanded_fragments.push(Vec::new());
485 expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
486 if !self.cx.ecfg.single_step {
487 invocations.extend(new_invocations.into_iter().rev());
491 self.cx.current_expansion = orig_expansion_data;
493 // Finally incorporate all the expanded macros into the input AST fragment.
494 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
495 while let Some(expanded_fragments) = expanded_fragments.pop() {
496 for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
498 .add(NodeId::placeholder_from_expn_id(expn_id), expanded_fragment);
501 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
502 fragment_with_placeholders
505 fn error_derive_forbidden_on_non_adt(&self, derives: &[Path], item: &Annotatable) {
507 attr::find_by_name(item.attrs(), sym::derive).expect("`derive` attribute should exist");
508 let span = attr.span;
511 .struct_span_err(span, "`derive` may only be applied to structs, enums and unions");
512 if let ast::AttrStyle::Inner = attr.style {
513 let trait_list = derives.iter().map(|t| pprust::path_to_string(t)).collect::<Vec<_>>();
514 let suggestion = format!("#[derive({})]", trait_list.join(", "));
517 "try an outer attribute",
519 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
520 Applicability::MaybeIncorrect,
526 fn resolve_imports(&mut self) {
528 self.cx.resolver.resolve_imports();
532 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
533 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
534 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
535 /// prepares data for resolving paths of macro invocations.
536 fn collect_invocations(
538 mut fragment: AstFragment,
539 extra_placeholders: &[NodeId],
540 ) -> (AstFragment, Vec<Invocation>) {
541 // Resolve `$crate`s in the fragment for pretty-printing.
542 self.cx.resolver.resolve_dollar_crates();
545 let mut collector = InvocationCollector {
546 cfg: StripUnconfigured {
547 sess: self.cx.parse_sess,
548 features: self.cx.ecfg.features,
551 invocations: Vec::new(),
552 monotonic: self.monotonic,
554 fragment.mut_visit_with(&mut collector);
555 fragment.add_placeholders(extra_placeholders);
556 collector.invocations
562 .visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
565 (fragment, invocations)
568 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
570 StripUnconfigured { sess: self.cx.parse_sess, features: self.cx.ecfg.features };
571 // Since the item itself has already been configured by the InvocationCollector,
572 // we know that fold result vector will contain exactly one element
574 Annotatable::Item(item) => Annotatable::Item(cfg.flat_map_item(item).pop().unwrap()),
575 Annotatable::TraitItem(item) => {
576 Annotatable::TraitItem(cfg.flat_map_trait_item(item).pop().unwrap())
578 Annotatable::ImplItem(item) => {
579 Annotatable::ImplItem(cfg.flat_map_impl_item(item).pop().unwrap())
581 Annotatable::ForeignItem(item) => {
582 Annotatable::ForeignItem(cfg.flat_map_foreign_item(item).pop().unwrap())
584 Annotatable::Stmt(stmt) => {
585 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
587 Annotatable::Expr(mut expr) => Annotatable::Expr({
588 cfg.visit_expr(&mut expr);
591 Annotatable::Arm(arm) => Annotatable::Arm(cfg.flat_map_arm(arm).pop().unwrap()),
592 Annotatable::Field(field) => {
593 Annotatable::Field(cfg.flat_map_field(field).pop().unwrap())
595 Annotatable::FieldPat(fp) => {
596 Annotatable::FieldPat(cfg.flat_map_field_pattern(fp).pop().unwrap())
598 Annotatable::GenericParam(param) => {
599 Annotatable::GenericParam(cfg.flat_map_generic_param(param).pop().unwrap())
601 Annotatable::Param(param) => {
602 Annotatable::Param(cfg.flat_map_param(param).pop().unwrap())
604 Annotatable::StructField(sf) => {
605 Annotatable::StructField(cfg.flat_map_struct_field(sf).pop().unwrap())
607 Annotatable::Variant(v) => Annotatable::Variant(cfg.flat_map_variant(v).pop().unwrap()),
611 fn error_recursion_limit_reached(&mut self) {
612 let expn_data = self.cx.current_expansion.id.expn_data();
613 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
617 &format!("recursion limit reached while expanding `{}`", expn_data.kind.descr()),
620 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate (`{}`)",
621 suggested_limit, self.cx.ecfg.crate_name,
624 self.cx.trace_macros_diag();
628 /// A macro's expansion does not fit in this fragment kind.
629 /// For example, a non-type macro in a type position.
630 fn error_wrong_fragment_kind(&mut self, kind: AstFragmentKind, mac: &ast::Mac, span: Span) {
632 "non-{kind} macro in {kind} position: {path}",
634 path = pprust::path_to_string(&mac.path),
636 self.cx.span_err(span, &msg);
637 self.cx.trace_macros_diag();
640 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment {
641 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
642 self.error_recursion_limit_reached();
645 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
647 InvocationKind::Bang { mac, .. } => match ext {
648 SyntaxExtensionKind::Bang(expander) => {
649 self.gate_proc_macro_expansion_kind(span, fragment_kind);
650 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
651 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
653 SyntaxExtensionKind::LegacyBang(expander) => {
654 let prev = self.cx.current_expansion.prior_type_ascription;
655 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
656 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
657 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
660 self.error_wrong_fragment_kind(fragment_kind, &mac, span);
661 fragment_kind.dummy(span)
663 self.cx.current_expansion.prior_type_ascription = prev;
668 InvocationKind::Attr { attr, mut item, .. } => match ext {
669 SyntaxExtensionKind::Attr(expander) => {
670 self.gate_proc_macro_input(&item);
671 self.gate_proc_macro_attr_item(span, &item);
672 let item_tok = TokenTree::token(
673 token::Interpolated(Lrc::new(match item {
674 Annotatable::Item(item) => token::NtItem(item),
675 Annotatable::TraitItem(item) => token::NtTraitItem(item),
676 Annotatable::ImplItem(item) => token::NtImplItem(item),
677 Annotatable::ForeignItem(item) => token::NtForeignItem(item),
678 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
679 Annotatable::Expr(expr) => token::NtExpr(expr),
681 | Annotatable::Field(..)
682 | Annotatable::FieldPat(..)
683 | Annotatable::GenericParam(..)
684 | Annotatable::Param(..)
685 | Annotatable::StructField(..)
686 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
691 let item = attr.unwrap_normal_item();
692 if let MacArgs::Eq(..) = item.args {
693 self.cx.span_err(span, "key-value macro attributes are not supported");
696 expander.expand(self.cx, span, item.args.inner_tokens(), item_tok);
697 self.parse_ast_fragment(tok_result, fragment_kind, &item.path, span)
699 SyntaxExtensionKind::LegacyAttr(expander) => {
700 match validate_attr::parse_meta(self.cx.parse_sess, &attr) {
702 let item = expander.expand(self.cx, span, &meta, item);
703 fragment_kind.expect_from_annotatables(item)
707 fragment_kind.dummy(span)
711 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
712 attr::mark_known(&attr);
714 attr::mark_used(&attr);
716 item.visit_attrs(|attrs| attrs.push(attr));
717 fragment_kind.expect_from_annotatables(iter::once(item))
721 InvocationKind::Derive { path, item } => match ext {
722 SyntaxExtensionKind::Derive(expander)
723 | SyntaxExtensionKind::LegacyDerive(expander) => {
724 if !item.derive_allowed() {
725 return fragment_kind.dummy(span);
727 if let SyntaxExtensionKind::Derive(..) = ext {
728 self.gate_proc_macro_input(&item);
730 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
731 let items = expander.expand(self.cx, span, &meta, item);
732 fragment_kind.expect_from_annotatables(items)
736 InvocationKind::DeriveContainer { .. } => unreachable!(),
740 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
741 let kind = match item {
743 | Annotatable::TraitItem(_)
744 | Annotatable::ImplItem(_)
745 | Annotatable::ForeignItem(_) => return,
746 Annotatable::Stmt(_) => "statements",
747 Annotatable::Expr(_) => "expressions",
749 | Annotatable::Field(..)
750 | Annotatable::FieldPat(..)
751 | Annotatable::GenericParam(..)
752 | Annotatable::Param(..)
753 | Annotatable::StructField(..)
754 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
756 if self.cx.ecfg.proc_macro_hygiene() {
761 sym::proc_macro_hygiene,
763 &format!("custom attributes cannot be applied to {}", kind),
768 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
769 struct GateProcMacroInput<'a> {
770 parse_sess: &'a ParseSess,
773 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
774 fn visit_item(&mut self, item: &'ast ast::Item) {
776 ast::ItemKind::Mod(module) if !module.inline => {
779 sym::proc_macro_hygiene,
781 "non-inline modules in proc macro input are unstable",
788 visit::walk_item(self, item);
791 fn visit_mac(&mut self, _: &'ast ast::Mac) {}
794 if !self.cx.ecfg.proc_macro_hygiene() {
795 annotatable.visit_with(&mut GateProcMacroInput { parse_sess: self.cx.parse_sess });
799 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
800 let kind = match kind {
801 AstFragmentKind::Expr | AstFragmentKind::OptExpr => "expressions",
802 AstFragmentKind::Pat => "patterns",
803 AstFragmentKind::Stmts => "statements",
805 | AstFragmentKind::Items
806 | AstFragmentKind::TraitItems
807 | AstFragmentKind::ImplItems
808 | AstFragmentKind::ForeignItems => return,
809 AstFragmentKind::Arms
810 | AstFragmentKind::Fields
811 | AstFragmentKind::FieldPats
812 | AstFragmentKind::GenericParams
813 | AstFragmentKind::Params
814 | AstFragmentKind::StructFields
815 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
817 if self.cx.ecfg.proc_macro_hygiene() {
822 sym::proc_macro_hygiene,
824 &format!("procedural macros cannot be expanded to {}", kind),
829 fn parse_ast_fragment(
832 kind: AstFragmentKind,
836 let mut parser = self.cx.new_parser_from_tts(toks);
837 match parse_ast_fragment(&mut parser, kind) {
839 ensure_complete_parse(&mut parser, path, kind.name(), span);
844 annotate_err_with_kind(&mut err, kind, span);
846 self.cx.trace_macros_diag();
853 pub fn parse_ast_fragment<'a>(
854 this: &mut Parser<'a>,
855 kind: AstFragmentKind,
856 ) -> PResult<'a, AstFragment> {
858 AstFragmentKind::Items => {
859 let mut items = SmallVec::new();
860 while let Some(item) = this.parse_item()? {
863 AstFragment::Items(items)
865 AstFragmentKind::TraitItems => {
866 let mut items = SmallVec::new();
867 while let Some(item) = this.parse_trait_item()? {
870 AstFragment::TraitItems(items)
872 AstFragmentKind::ImplItems => {
873 let mut items = SmallVec::new();
874 while let Some(item) = this.parse_impl_item()? {
877 AstFragment::ImplItems(items)
879 AstFragmentKind::ForeignItems => {
880 let mut items = SmallVec::new();
881 while let Some(item) = this.parse_foreign_item()? {
884 AstFragment::ForeignItems(items)
886 AstFragmentKind::Stmts => {
887 let mut stmts = SmallVec::new();
888 // Won't make progress on a `}`.
889 while this.token != token::Eof && this.token != token::CloseDelim(token::Brace) {
890 if let Some(stmt) = this.parse_full_stmt()? {
894 AstFragment::Stmts(stmts)
896 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
897 AstFragmentKind::OptExpr => {
898 if this.token != token::Eof {
899 AstFragment::OptExpr(Some(this.parse_expr()?))
901 AstFragment::OptExpr(None)
904 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
905 AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat(None)?),
906 AstFragmentKind::Arms
907 | AstFragmentKind::Fields
908 | AstFragmentKind::FieldPats
909 | AstFragmentKind::GenericParams
910 | AstFragmentKind::Params
911 | AstFragmentKind::StructFields
912 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
916 pub fn ensure_complete_parse<'a>(
917 this: &mut Parser<'a>,
922 if this.token != token::Eof {
923 let token = pprust::token_to_string(&this.token);
924 let msg = format!("macro expansion ignores token `{}` and any following", token);
925 // Avoid emitting backtrace info twice.
926 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
927 let mut err = this.struct_span_err(def_site_span, &msg);
928 err.span_label(span, "caused by the macro expansion here");
930 "the usage of `{}!` is likely invalid in {} context",
931 pprust::path_to_string(macro_path),
935 let semi_span = this.sess.source_map().next_point(span);
937 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
938 match this.sess.source_map().span_to_snippet(semi_full_span) {
939 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
942 "you might be missing a semicolon here",
944 Applicability::MaybeIncorrect,
953 struct InvocationCollector<'a, 'b> {
954 cx: &'a mut ExtCtxt<'b>,
955 cfg: StripUnconfigured<'a>,
956 invocations: Vec<Invocation>,
960 impl<'a, 'b> InvocationCollector<'a, 'b> {
961 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
962 // Expansion data for all the collected invocations is set upon their resolution,
963 // with exception of the derive container case which is not resolved and can get
964 // its expansion data immediately.
965 let expn_data = match &kind {
966 InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
967 parent: self.cx.current_expansion.id,
969 ExpnKind::Macro(MacroKind::Attr, sym::derive),
971 self.cx.parse_sess.edition,
976 let expn_id = ExpnId::fresh(expn_data);
977 let vis = kind.placeholder_visibility();
978 self.invocations.push(Invocation {
981 expansion_data: ExpansionData {
983 depth: self.cx.current_expansion.depth + 1,
984 ..self.cx.current_expansion.clone()
987 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
990 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
991 self.collect(kind, InvocationKind::Bang { mac, span })
996 attr: Option<ast::Attribute>,
999 kind: AstFragmentKind,
1005 Some(attr) => InvocationKind::Attr { attr, item, derives, after_derive },
1006 None => InvocationKind::DeriveContainer { derives, item },
1013 attrs: &mut Vec<ast::Attribute>,
1014 after_derive: &mut bool,
1015 ) -> Option<ast::Attribute> {
1019 if a.has_name(sym::derive) {
1020 *after_derive = true;
1022 !attr::is_known(a) && !is_builtin_attr(a)
1024 .map(|i| attrs.remove(i));
1025 if let Some(attr) = &attr {
1026 if !self.cx.ecfg.custom_inner_attributes()
1027 && attr.style == ast::AttrStyle::Inner
1028 && !attr.has_name(sym::test)
1031 &self.cx.parse_sess,
1032 sym::custom_inner_attributes,
1034 "non-builtin inner attributes are unstable",
1042 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1045 item: &mut impl HasAttrs,
1046 ) -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool) {
1047 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1049 item.visit_attrs(|mut attrs| {
1050 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1051 traits = collect_derives(&mut self.cx, &mut attrs);
1054 (attr, traits, after_derive)
1057 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1058 /// to the unused-attributes lint (making it an error on statements and expressions
1059 /// is a breaking change)
1060 fn classify_nonitem(
1062 nonitem: &mut impl HasAttrs,
1063 ) -> (Option<ast::Attribute>, /* after_derive */ bool) {
1064 let (mut attr, mut after_derive) = (None, false);
1066 nonitem.visit_attrs(|mut attrs| {
1067 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1070 (attr, after_derive)
1073 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1074 self.cfg.configure(node)
1077 // Detect use of feature-gated or invalid attributes on macro invocations
1078 // since they will not be detected after macro expansion.
1079 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1080 let features = self.cx.ecfg.features.unwrap();
1081 for attr in attrs.iter() {
1082 rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.parse_sess, features);
1083 validate_attr::check_meta(self.cx.parse_sess, attr);
1085 // macros are expanded before any lint passes so this warning has to be hardcoded
1086 if attr.has_name(sym::derive) {
1088 .struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1089 .note("this may become a hard error in a future release")
1093 if attr.doc_str().is_some() {
1094 self.cx.parse_sess.buffer_lint_with_diagnostic(
1095 &UNUSED_DOC_COMMENTS,
1098 "unused doc comment",
1099 BuiltinLintDiagnostics::UnusedDocComment(attr.span),
1106 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1107 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1108 self.cfg.configure_expr(expr);
1109 visit_clobber(expr.deref_mut(), |mut expr| {
1110 self.cfg.configure_expr_kind(&mut expr.kind);
1112 // ignore derives so they remain unused
1113 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1116 // Collect the invoc regardless of whether or not attributes are permitted here
1117 // expansion will eat the attribute so it won't error later.
1118 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1120 // AstFragmentKind::Expr requires the macro to emit an expression.
1125 Annotatable::Expr(P(expr)),
1126 AstFragmentKind::Expr,
1133 if let ast::ExprKind::Mac(mac) = expr.kind {
1134 self.check_attributes(&expr.attrs);
1135 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
1137 noop_visit_expr(&mut expr, self);
1143 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1144 let mut arm = configure!(self, arm);
1146 let (attr, traits, after_derive) = self.classify_item(&mut arm);
1147 if attr.is_some() || !traits.is_empty() {
1152 Annotatable::Arm(arm),
1153 AstFragmentKind::Arms,
1159 noop_flat_map_arm(arm, self)
1162 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
1163 let mut field = configure!(self, field);
1165 let (attr, traits, after_derive) = self.classify_item(&mut field);
1166 if attr.is_some() || !traits.is_empty() {
1171 Annotatable::Field(field),
1172 AstFragmentKind::Fields,
1178 noop_flat_map_field(field, self)
1181 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
1182 let mut fp = configure!(self, fp);
1184 let (attr, traits, after_derive) = self.classify_item(&mut fp);
1185 if attr.is_some() || !traits.is_empty() {
1190 Annotatable::FieldPat(fp),
1191 AstFragmentKind::FieldPats,
1194 .make_field_patterns();
1197 noop_flat_map_field_pattern(fp, self)
1200 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1201 let mut p = configure!(self, p);
1203 let (attr, traits, after_derive) = self.classify_item(&mut p);
1204 if attr.is_some() || !traits.is_empty() {
1209 Annotatable::Param(p),
1210 AstFragmentKind::Params,
1216 noop_flat_map_param(p, self)
1219 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
1220 let mut sf = configure!(self, sf);
1222 let (attr, traits, after_derive) = self.classify_item(&mut sf);
1223 if attr.is_some() || !traits.is_empty() {
1228 Annotatable::StructField(sf),
1229 AstFragmentKind::StructFields,
1232 .make_struct_fields();
1235 noop_flat_map_struct_field(sf, self)
1238 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1239 let mut variant = configure!(self, variant);
1241 let (attr, traits, after_derive) = self.classify_item(&mut variant);
1242 if attr.is_some() || !traits.is_empty() {
1247 Annotatable::Variant(variant),
1248 AstFragmentKind::Variants,
1254 noop_flat_map_variant(variant, self)
1257 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1258 let expr = configure!(self, expr);
1259 expr.filter_map(|mut expr| {
1260 self.cfg.configure_expr_kind(&mut expr.kind);
1262 // Ignore derives so they remain unused.
1263 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1266 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1272 Annotatable::Expr(P(expr)),
1273 AstFragmentKind::OptExpr,
1277 .map(|expr| expr.into_inner());
1280 if let ast::ExprKind::Mac(mac) = expr.kind {
1281 self.check_attributes(&expr.attrs);
1282 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1284 .map(|expr| expr.into_inner())
1287 noop_visit_expr(&mut expr, self);
1294 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1295 self.cfg.configure_pat(pat);
1297 PatKind::Mac(_) => {}
1298 _ => return noop_visit_pat(pat, self),
1301 visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
1302 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1303 _ => unreachable!(),
1307 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1308 let mut stmt = configure!(self, stmt);
1310 // we'll expand attributes on expressions separately
1311 if !stmt.is_expr() {
1312 let (attr, derives, after_derive) = if stmt.is_item() {
1313 self.classify_item(&mut stmt)
1315 // ignore derives on non-item statements so it falls through
1316 // to the unused-attributes lint
1317 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1318 (attr, vec![], after_derive)
1321 if attr.is_some() || !derives.is_empty() {
1326 Annotatable::Stmt(P(stmt)),
1327 AstFragmentKind::Stmts,
1334 if let StmtKind::Mac(mac) = stmt.kind {
1335 let (mac, style, attrs) = mac.into_inner();
1336 self.check_attributes(&attrs);
1337 let mut placeholder =
1338 self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts).make_stmts();
1340 // If this is a macro invocation with a semicolon, then apply that
1341 // semicolon to the final statement produced by expansion.
1342 if style == MacStmtStyle::Semicolon {
1343 if let Some(stmt) = placeholder.pop() {
1344 placeholder.push(stmt.add_trailing_semicolon());
1351 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1352 let ast::Stmt { id, kind, span } = stmt;
1353 noop_flat_map_stmt_kind(kind, self)
1355 .map(|kind| ast::Stmt { id, kind, span })
1359 fn visit_block(&mut self, block: &mut P<Block>) {
1360 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1361 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1362 noop_visit_block(block, self);
1363 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1366 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1367 let mut item = configure!(self, item);
1369 let (attr, traits, after_derive) = self.classify_item(&mut item);
1370 if attr.is_some() || !traits.is_empty() {
1375 Annotatable::Item(item),
1376 AstFragmentKind::Items,
1383 ast::ItemKind::Mac(..) => {
1384 self.check_attributes(&item.attrs);
1385 item.and_then(|item| match item.kind {
1386 ItemKind::Mac(mac) => self
1388 AstFragmentKind::Items,
1389 InvocationKind::Bang { mac, span: item.span },
1392 _ => unreachable!(),
1395 ast::ItemKind::Mod(ast::Mod { inner, inline, .. })
1396 if item.ident != Ident::invalid() =>
1398 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1399 let mut module = (*self.cx.current_expansion.module).clone();
1400 module.mod_path.push(item.ident);
1403 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
1404 self.cx.current_expansion.directory_ownership =
1405 DirectoryOwnership::Owned { relative: None };
1406 module.directory.push(&*path.as_str());
1408 module.directory.push(&*item.ident.as_str());
1411 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1412 let mut path = match path {
1413 FileName::Real(path) => path,
1414 other => PathBuf::from(other.to_string()),
1416 let directory_ownership = match path.file_name().unwrap().to_str() {
1417 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1418 Some(_) => DirectoryOwnership::Owned { relative: Some(item.ident) },
1419 None => DirectoryOwnership::UnownedViaMod,
1422 module.directory = path;
1423 self.cx.current_expansion.directory_ownership = directory_ownership;
1427 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1428 let result = noop_flat_map_item(item, self);
1429 self.cx.current_expansion.module = orig_module;
1430 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1434 _ => noop_flat_map_item(item, self),
1438 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1439 let mut item = configure!(self, item);
1441 let (attr, traits, after_derive) = self.classify_item(&mut item);
1442 if attr.is_some() || !traits.is_empty() {
1447 Annotatable::TraitItem(item),
1448 AstFragmentKind::TraitItems,
1451 .make_trait_items();
1455 ast::AssocItemKind::Macro(..) => {
1456 self.check_attributes(&item.attrs);
1457 item.and_then(|item| match item.kind {
1458 ast::AssocItemKind::Macro(mac) => self
1459 .collect_bang(mac, item.span, AstFragmentKind::TraitItems)
1460 .make_trait_items(),
1461 _ => unreachable!(),
1464 _ => noop_flat_map_assoc_item(item, self),
1468 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1469 let mut item = configure!(self, item);
1471 let (attr, traits, after_derive) = self.classify_item(&mut item);
1472 if attr.is_some() || !traits.is_empty() {
1477 Annotatable::ImplItem(item),
1478 AstFragmentKind::ImplItems,
1485 ast::AssocItemKind::Macro(..) => {
1486 self.check_attributes(&item.attrs);
1487 item.and_then(|item| match item.kind {
1488 ast::AssocItemKind::Macro(mac) => self
1489 .collect_bang(mac, item.span, AstFragmentKind::ImplItems)
1491 _ => unreachable!(),
1494 _ => noop_flat_map_assoc_item(item, self),
1498 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1500 ast::TyKind::Mac(_) => {}
1501 _ => return noop_visit_ty(ty, self),
1504 visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1505 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1506 _ => unreachable!(),
1510 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1511 self.cfg.configure_foreign_mod(foreign_mod);
1512 noop_visit_foreign_mod(foreign_mod, self);
1515 fn flat_map_foreign_item(
1517 mut foreign_item: P<ast::ForeignItem>,
1518 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
1519 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1521 if attr.is_some() || !traits.is_empty() {
1526 Annotatable::ForeignItem(foreign_item),
1527 AstFragmentKind::ForeignItems,
1530 .make_foreign_items();
1533 match foreign_item.kind {
1534 ast::ForeignItemKind::Macro(..) => {
1535 self.check_attributes(&foreign_item.attrs);
1536 foreign_item.and_then(|item| match item.kind {
1537 ast::ForeignItemKind::Macro(mac) => self
1538 .collect_bang(mac, item.span, AstFragmentKind::ForeignItems)
1539 .make_foreign_items(),
1540 _ => unreachable!(),
1543 _ => noop_flat_map_foreign_item(foreign_item, self),
1547 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1549 ast::ItemKind::MacroDef(..) => {}
1551 self.cfg.configure_item_kind(item);
1552 noop_visit_item_kind(item, self);
1557 fn flat_map_generic_param(
1559 param: ast::GenericParam,
1560 ) -> SmallVec<[ast::GenericParam; 1]> {
1561 let mut param = configure!(self, param);
1563 let (attr, traits, after_derive) = self.classify_item(&mut param);
1564 if attr.is_some() || !traits.is_empty() {
1569 Annotatable::GenericParam(param),
1570 AstFragmentKind::GenericParams,
1573 .make_generic_params();
1576 noop_flat_map_generic_param(param, self)
1579 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1580 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1581 // contents="file contents")]` attributes
1582 if !at.check_name(sym::doc) {
1583 return noop_visit_attribute(at, self);
1586 if let Some(list) = at.meta_item_list() {
1587 if !list.iter().any(|it| it.check_name(sym::include)) {
1588 return noop_visit_attribute(at, self);
1591 let mut items = vec![];
1593 for mut it in list {
1594 if !it.check_name(sym::include) {
1596 noop_visit_meta_list_item(&mut it, self);
1602 if let Some(file) = it.value_str() {
1603 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1604 self.check_attributes(slice::from_ref(at));
1605 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1606 // avoid loading the file if they haven't enabled the feature
1607 return noop_visit_attribute(at, self);
1610 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1611 Ok(filename) => filename,
1618 match self.cx.source_map().load_file(&filename) {
1619 Ok(source_file) => {
1620 let src = source_file
1623 .expect("freshly loaded file should have a source");
1624 let src_interned = Symbol::intern(src.as_str());
1626 let include_info = vec![
1627 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1628 Ident::with_dummy_span(sym::file),
1632 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1633 Ident::with_dummy_span(sym::contents),
1639 let include_ident = Ident::with_dummy_span(sym::include);
1640 let item = attr::mk_list_item(include_ident, include_info);
1641 items.push(ast::NestedMetaItem::MetaItem(item));
1645 it.meta_item().and_then(|item| item.name_value_literal()).unwrap();
1647 if e.kind() == ErrorKind::InvalidData {
1651 &format!("{} wasn't a utf-8 file", filename.display()),
1653 .span_label(lit.span, "contains invalid utf-8")
1656 let mut err = self.cx.struct_span_err(
1658 &format!("couldn't read {}: {}", filename.display(), e),
1660 err.span_label(lit.span, "couldn't read file");
1667 let mut err = self.cx.struct_span_err(
1669 &format!("expected path to external documentation"),
1672 // Check if the user erroneously used `doc(include(...))` syntax.
1673 let literal = it.meta_item_list().and_then(|list| {
1674 if list.len() == 1 {
1675 list[0].literal().map(|literal| &literal.kind)
1681 let (path, applicability) = match &literal {
1682 Some(LitKind::Str(path, ..)) => {
1683 (path.to_string(), Applicability::MachineApplicable)
1685 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1688 err.span_suggestion(
1690 "provide a file path with `=`",
1691 format!("include = \"{}\"", path),
1699 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1700 *at = ast::Attribute {
1701 kind: ast::AttrKind::Normal(AttrItem {
1703 args: meta.kind.mac_args(meta.span),
1710 noop_visit_attribute(at, self)
1714 fn visit_id(&mut self, id: &mut ast::NodeId) {
1716 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1717 *id = self.cx.resolver.next_node_id()
1721 fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
1722 self.cfg.configure_fn_decl(&mut fn_decl);
1723 noop_visit_fn_decl(fn_decl, self);
1727 pub struct ExpansionConfig<'feat> {
1728 pub crate_name: String,
1729 pub features: Option<&'feat Features>,
1730 pub recursion_limit: usize,
1731 pub trace_mac: bool,
1732 pub should_test: bool, // If false, strip `#[test]` nodes
1733 pub single_step: bool,
1734 pub keep_macs: bool,
1737 impl<'feat> ExpansionConfig<'feat> {
1738 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1742 recursion_limit: 1024,
1750 fn proc_macro_hygiene(&self) -> bool {
1751 self.features.map_or(false, |features| features.proc_macro_hygiene)
1753 fn custom_inner_attributes(&self) -> bool {
1754 self.features.map_or(false, |features| features.custom_inner_attributes)