2 use crate::config::StripUnconfigured;
4 use crate::hygiene::SyntaxContext;
5 use crate::mbe::macro_rules::annotate_err_with_kind;
6 use crate::module::{mod_dir_path, parse_external_mod, DirOwnership, ParsedExternalMod};
7 use crate::placeholders::{placeholder, PlaceholderExpander};
10 use rustc_ast::mut_visit::*;
11 use rustc_ast::ptr::P;
13 use rustc_ast::tokenstream::TokenStream;
14 use rustc_ast::visit::{self, AssocCtxt, Visitor};
15 use rustc_ast::{AstLike, AttrItem, Block, Inline, ItemKind, LitKind, MacArgs};
16 use rustc_ast::{MacCallStmt, MacStmtStyle, MetaItemKind, ModKind, NestedMetaItem};
17 use rustc_ast::{NodeId, PatKind, Path, StmtKind, Unsafe};
18 use rustc_ast_pretty::pprust;
19 use rustc_attr::{self as attr, is_builtin_attr};
20 use rustc_data_structures::map_in_place::MapInPlace;
21 use rustc_data_structures::stack::ensure_sufficient_stack;
22 use rustc_data_structures::sync::Lrc;
23 use rustc_errors::{Applicability, PResult};
24 use rustc_feature::Features;
25 use rustc_parse::parser::{AttemptLocalParseRecovery, ForceCollect, Parser, RecoverComma};
26 use rustc_parse::validate_attr;
27 use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
28 use rustc_session::lint::BuiltinLintDiagnostics;
29 use rustc_session::parse::{feature_err, ParseSess};
30 use rustc_session::Limit;
31 use rustc_span::symbol::{sym, Ident, Symbol};
32 use rustc_span::{ExpnId, FileName, Span, DUMMY_SP};
34 use smallvec::{smallvec, SmallVec};
35 use std::io::ErrorKind;
36 use std::ops::DerefMut;
37 use std::path::PathBuf;
39 use std::{iter, mem, slice};
41 macro_rules! ast_fragments {
43 $($Kind:ident($AstTy:ty) {
45 $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
46 $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident($($args:tt)*);)?
50 /// A fragment of AST that can be produced by a single macro expansion.
51 /// Can also serve as an input and intermediate result for macro expansion operations.
52 pub enum AstFragment {
53 OptExpr(Option<P<ast::Expr>>),
57 /// "Discriminant" of an AST fragment.
58 #[derive(Copy, Clone, PartialEq, Eq)]
59 pub enum AstFragmentKind {
64 impl AstFragmentKind {
65 pub fn name(self) -> &'static str {
67 AstFragmentKind::OptExpr => "expression",
68 $(AstFragmentKind::$Kind => $kind_name,)*
72 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
74 AstFragmentKind::OptExpr =>
75 result.make_expr().map(Some).map(AstFragment::OptExpr),
76 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
82 pub fn add_placeholders(&mut self, placeholders: &[NodeId]) {
83 if placeholders.is_empty() {
87 $($(AstFragment::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| {
88 // We are repeating through arguments with `many`, to do that we have to
89 // mention some macro variable from those arguments even if it's not used.
90 macro _repeating($flat_map_ast_elt) {}
91 placeholder(AstFragmentKind::$Kind, *id, None).$make_ast()
93 _ => panic!("unexpected AST fragment kind")
97 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
99 AstFragment::OptExpr(expr) => expr,
100 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
104 $(pub fn $make_ast(self) -> $AstTy {
106 AstFragment::$Kind(ast) => ast,
107 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
111 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
113 AstFragment::OptExpr(opt_expr) => {
114 visit_clobber(opt_expr, |opt_expr| {
115 if let Some(expr) = opt_expr {
116 vis.filter_map_expr(expr)
122 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
123 $($(AstFragment::$Kind(ast) =>
124 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
128 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
130 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
131 AstFragment::OptExpr(None) => {}
132 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
133 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
134 visitor.$visit_ast_elt(ast_elt, $($args)*);
140 impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
141 $(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>)
143 Some(self.make(AstFragmentKind::$Kind).$make_ast())
150 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
151 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
152 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
153 Stmts(SmallVec<[ast::Stmt; 1]>) {
154 "statement"; many fn flat_map_stmt; fn visit_stmt(); fn make_stmts;
156 Items(SmallVec<[P<ast::Item>; 1]>) {
157 "item"; many fn flat_map_item; fn visit_item(); fn make_items;
159 TraitItems(SmallVec<[P<ast::AssocItem>; 1]>) {
161 many fn flat_map_trait_item;
162 fn visit_assoc_item(AssocCtxt::Trait);
165 ImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
167 many fn flat_map_impl_item;
168 fn visit_assoc_item(AssocCtxt::Impl);
171 ForeignItems(SmallVec<[P<ast::ForeignItem>; 1]>) {
173 many fn flat_map_foreign_item;
174 fn visit_foreign_item();
175 fn make_foreign_items;
177 Arms(SmallVec<[ast::Arm; 1]>) {
178 "match arm"; many fn flat_map_arm; fn visit_arm(); fn make_arms;
180 Fields(SmallVec<[ast::ExprField; 1]>) {
181 "field expression"; many fn flat_map_expr_field; fn visit_expr_field(); fn make_expr_fields;
183 FieldPats(SmallVec<[ast::PatField; 1]>) {
185 many fn flat_map_pat_field;
186 fn visit_pat_field();
189 GenericParams(SmallVec<[ast::GenericParam; 1]>) {
191 many fn flat_map_generic_param;
192 fn visit_generic_param();
193 fn make_generic_params;
195 Params(SmallVec<[ast::Param; 1]>) {
196 "function parameter"; many fn flat_map_param; fn visit_param(); fn make_params;
198 StructFields(SmallVec<[ast::FieldDef; 1]>) {
200 many fn flat_map_field_def;
201 fn visit_field_def();
204 Variants(SmallVec<[ast::Variant; 1]>) {
205 "variant"; many fn flat_map_variant; fn visit_variant(); fn make_variants;
209 pub enum SupportsMacroExpansion {
211 Yes { supports_inner_attrs: bool },
214 impl AstFragmentKind {
215 crate fn dummy(self, span: Span) -> AstFragment {
216 self.make_from(DummyResult::any(span)).expect("couldn't create a dummy AST fragment")
219 pub fn supports_macro_expansion(self) -> SupportsMacroExpansion {
221 AstFragmentKind::OptExpr
222 | AstFragmentKind::Expr
223 | AstFragmentKind::Stmts
224 | AstFragmentKind::Ty
225 | AstFragmentKind::Pat => SupportsMacroExpansion::Yes { supports_inner_attrs: false },
226 AstFragmentKind::Items
227 | AstFragmentKind::TraitItems
228 | AstFragmentKind::ImplItems
229 | AstFragmentKind::ForeignItems => {
230 SupportsMacroExpansion::Yes { supports_inner_attrs: true }
232 AstFragmentKind::Arms
233 | AstFragmentKind::Fields
234 | AstFragmentKind::FieldPats
235 | AstFragmentKind::GenericParams
236 | AstFragmentKind::Params
237 | AstFragmentKind::StructFields
238 | AstFragmentKind::Variants => SupportsMacroExpansion::No,
242 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
246 let mut items = items.into_iter();
248 AstFragmentKind::Arms => {
249 AstFragment::Arms(items.map(Annotatable::expect_arm).collect())
251 AstFragmentKind::Fields => {
252 AstFragment::Fields(items.map(Annotatable::expect_expr_field).collect())
254 AstFragmentKind::FieldPats => {
255 AstFragment::FieldPats(items.map(Annotatable::expect_pat_field).collect())
257 AstFragmentKind::GenericParams => {
258 AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect())
260 AstFragmentKind::Params => {
261 AstFragment::Params(items.map(Annotatable::expect_param).collect())
263 AstFragmentKind::StructFields => {
264 AstFragment::StructFields(items.map(Annotatable::expect_field_def).collect())
266 AstFragmentKind::Variants => {
267 AstFragment::Variants(items.map(Annotatable::expect_variant).collect())
269 AstFragmentKind::Items => {
270 AstFragment::Items(items.map(Annotatable::expect_item).collect())
272 AstFragmentKind::ImplItems => {
273 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect())
275 AstFragmentKind::TraitItems => {
276 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect())
278 AstFragmentKind::ForeignItems => {
279 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect())
281 AstFragmentKind::Stmts => {
282 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect())
284 AstFragmentKind::Expr => AstFragment::Expr(
285 items.next().expect("expected exactly one expression").expect_expr(),
287 AstFragmentKind::OptExpr => {
288 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
290 AstFragmentKind::Pat | AstFragmentKind::Ty => {
291 panic!("patterns and types aren't annotatable")
297 pub struct Invocation {
298 pub kind: InvocationKind,
299 pub fragment_kind: AstFragmentKind,
300 pub expansion_data: ExpansionData,
303 pub enum InvocationKind {
309 attr: ast::Attribute,
310 // Re-insertion position for inert attributes.
313 // Required for resolving derive helper attributes.
322 impl InvocationKind {
323 fn placeholder_visibility(&self) -> Option<ast::Visibility> {
324 // HACK: For unnamed fields placeholders should have the same visibility as the actual
325 // fields because for tuple structs/variants resolve determines visibilities of their
326 // constructor using these field visibilities before attributes on them are are expanded.
327 // The assumption is that the attribute expansion cannot change field visibilities,
328 // and it holds because only inert attributes are supported in this position.
330 InvocationKind::Attr { item: Annotatable::FieldDef(field), .. }
331 | InvocationKind::Derive { item: Annotatable::FieldDef(field), .. }
332 if field.ident.is_none() =>
334 Some(field.vis.clone())
342 pub fn span(&self) -> Span {
344 InvocationKind::Bang { span, .. } => *span,
345 InvocationKind::Attr { attr, .. } => attr.span,
346 InvocationKind::Derive { path, .. } => path.span,
351 pub struct MacroExpander<'a, 'b> {
352 pub cx: &'a mut ExtCtxt<'b>,
353 monotonic: bool, // cf. `cx.monotonic_expander()`
356 impl<'a, 'b> MacroExpander<'a, 'b> {
357 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
358 MacroExpander { cx, monotonic }
361 // FIXME: Avoid visiting the crate as a `Mod` item,
362 // make crate a first class expansion target instead.
363 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
364 let file_path = match self.cx.source_map().span_to_unmapped_path(krate.span) {
365 FileName::Real(name) => name.into_local_path(),
366 other => PathBuf::from(other.to_string()),
368 let dir_path = file_path.parent().unwrap_or(&file_path).to_owned();
369 self.cx.root_path = dir_path.clone();
370 self.cx.current_expansion.module = Rc::new(ModuleData {
371 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
372 file_path_stack: vec![file_path],
376 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
379 kind: ast::ItemKind::Mod(
381 ModKind::Loaded(krate.items, Inline::Yes, krate.span)
383 ident: Ident::invalid(),
384 id: ast::DUMMY_NODE_ID,
385 vis: ast::Visibility {
386 span: krate.span.shrink_to_lo(),
387 kind: ast::VisibilityKind::Public,
393 match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
396 kind: ast::ItemKind::Mod(_, ModKind::Loaded(items, ..)),
403 // Resolution failed so we return an empty expansion
404 krate.attrs = vec![];
405 krate.items = vec![];
407 Some(ast::Item { span, kind, .. }) => {
408 krate.attrs = vec![];
409 krate.items = vec![];
413 "expected crate top-level item to be a module after macro expansion, found {} {}",
414 kind.article(), kind.descr()
419 self.cx.trace_macros_diag();
423 // Recursively expand all macro invocations in this AST fragment.
424 pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
425 let orig_expansion_data = self.cx.current_expansion.clone();
426 let orig_force_mode = self.cx.force_mode;
427 self.cx.current_expansion.depth = 0;
429 // Collect all macro invocations and replace them with placeholders.
430 let (mut fragment_with_placeholders, mut invocations) =
431 self.collect_invocations(input_fragment, &[]);
433 // Optimization: if we resolve all imports now,
434 // we'll be able to immediately resolve most of imported macros.
435 self.resolve_imports();
437 // Resolve paths in all invocations and produce output expanded fragments for them, but
438 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
439 // The output fragments also go through expansion recursively until no invocations are left.
440 // Unresolved macros produce dummy outputs as a recovery measure.
441 invocations.reverse();
442 let mut expanded_fragments = Vec::new();
443 let mut undetermined_invocations = Vec::new();
444 let (mut progress, mut force) = (false, !self.monotonic);
446 let (invoc, ext) = if let Some(invoc) = invocations.pop() {
449 self.resolve_imports();
450 if undetermined_invocations.is_empty() {
453 invocations = mem::take(&mut undetermined_invocations);
454 force = !mem::replace(&mut progress, false);
455 if force && self.monotonic {
456 self.cx.sess.delay_span_bug(
457 invocations.last().unwrap().0.span(),
458 "expansion entered force mode without producing any errors",
464 let ext = match ext {
467 let eager_expansion_root = if self.monotonic {
468 invoc.expansion_data.id
470 orig_expansion_data.id
472 match self.cx.resolver.resolve_macro_invocation(
474 eager_expansion_root,
478 Err(Indeterminate) => {
479 // Cannot resolve, will retry this invocation later.
480 undetermined_invocations.push((invoc, None));
487 let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
488 self.cx.current_expansion = invoc.expansion_data.clone();
489 self.cx.force_mode = force;
491 let fragment_kind = invoc.fragment_kind;
492 let (expanded_fragment, new_invocations) = match self.expand_invoc(invoc, &ext.kind) {
493 ExpandResult::Ready(fragment) => {
494 let mut derive_invocations = Vec::new();
495 let derive_placeholders = self
498 .take_derive_resolutions(expn_id)
500 enum AnnotatableRef<'a> {
501 Item(&'a P<ast::Item>),
504 let item = match &fragment {
505 AstFragment::Items(items) => match &items[..] {
506 [item] => AnnotatableRef::Item(item),
509 AstFragment::Stmts(stmts) => match &stmts[..] {
510 [stmt] => AnnotatableRef::Stmt(stmt),
516 derive_invocations.reserve(derives.len());
519 .map(|(path, _exts)| {
520 // FIXME: Consider using the derive resolutions (`_exts`)
521 // instead of enqueuing the derives to be resolved again later.
522 let expn_id = ExpnId::fresh(None);
523 derive_invocations.push((
525 kind: InvocationKind::Derive {
528 AnnotatableRef::Item(item) => {
529 Annotatable::Item(item.clone())
531 AnnotatableRef::Stmt(stmt) => {
532 Annotatable::Stmt(P(stmt.clone()))
537 expansion_data: ExpansionData {
539 ..self.cx.current_expansion.clone()
544 NodeId::placeholder_from_expn_id(expn_id)
548 .unwrap_or_default();
550 let (fragment, collected_invocations) =
551 self.collect_invocations(fragment, &derive_placeholders);
552 // We choose to expand any derive invocations associated with this macro invocation
553 // *before* any macro invocations collected from the output fragment
554 derive_invocations.extend(collected_invocations);
555 (fragment, derive_invocations)
557 ExpandResult::Retry(invoc) => {
561 "expansion entered force mode but is still stuck",
564 // Cannot expand, will retry this invocation later.
565 undetermined_invocations.push((invoc, Some(ext)));
572 if expanded_fragments.len() < depth {
573 expanded_fragments.push(Vec::new());
575 expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
576 invocations.extend(new_invocations.into_iter().rev());
579 self.cx.current_expansion = orig_expansion_data;
580 self.cx.force_mode = orig_force_mode;
582 // Finally incorporate all the expanded macros into the input AST fragment.
583 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
584 while let Some(expanded_fragments) = expanded_fragments.pop() {
585 for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
587 .add(NodeId::placeholder_from_expn_id(expn_id), expanded_fragment);
590 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
591 fragment_with_placeholders
594 fn resolve_imports(&mut self) {
596 self.cx.resolver.resolve_imports();
600 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
601 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
602 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
603 /// prepares data for resolving paths of macro invocations.
604 fn collect_invocations(
606 mut fragment: AstFragment,
607 extra_placeholders: &[NodeId],
608 ) -> (AstFragment, Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>) {
609 // Resolve `$crate`s in the fragment for pretty-printing.
610 self.cx.resolver.resolve_dollar_crates();
613 let mut collector = InvocationCollector {
614 // Non-derive macro invocations cannot see the results of cfg expansion - they
615 // will either be removed along with the item, or invoked before the cfg/cfg_attr
616 // attribute is expanded. Therefore, we don't need to configure the tokens
617 // Derive macros *can* see the results of cfg-expansion - they are handled
618 // specially in `fully_expand_fragment`
619 cfg: StripUnconfigured {
621 features: self.cx.ecfg.features,
622 config_tokens: false,
625 invocations: Vec::new(),
626 monotonic: self.monotonic,
628 fragment.mut_visit_with(&mut collector);
629 fragment.add_placeholders(extra_placeholders);
630 collector.invocations
636 .visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
639 (fragment, invocations)
642 fn error_recursion_limit_reached(&mut self) {
643 let expn_data = self.cx.current_expansion.id.expn_data();
644 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
648 &format!("recursion limit reached while expanding `{}`", expn_data.kind.descr()),
651 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate (`{}`)",
652 suggested_limit, self.cx.ecfg.crate_name,
655 self.cx.trace_macros_diag();
658 /// A macro's expansion does not fit in this fragment kind.
659 /// For example, a non-type macro in a type position.
660 fn error_wrong_fragment_kind(&mut self, kind: AstFragmentKind, mac: &ast::MacCall, span: Span) {
662 "non-{kind} macro in {kind} position: {path}",
664 path = pprust::path_to_string(&mac.path),
666 self.cx.span_err(span, &msg);
667 self.cx.trace_macros_diag();
673 ext: &SyntaxExtensionKind,
674 ) -> ExpandResult<AstFragment, Invocation> {
675 let recursion_limit =
676 self.cx.reduced_recursion_limit.unwrap_or(self.cx.ecfg.recursion_limit);
677 if !recursion_limit.value_within_limit(self.cx.current_expansion.depth) {
678 if self.cx.reduced_recursion_limit.is_none() {
679 self.error_recursion_limit_reached();
682 // Reduce the recursion limit by half each time it triggers.
683 self.cx.reduced_recursion_limit = Some(recursion_limit / 2);
685 return ExpandResult::Ready(invoc.fragment_kind.dummy(invoc.span()));
688 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
689 ExpandResult::Ready(match invoc.kind {
690 InvocationKind::Bang { mac, .. } => match ext {
691 SyntaxExtensionKind::Bang(expander) => {
692 let tok_result = match expander.expand(self.cx, span, mac.args.inner_tokens()) {
693 Err(_) => return ExpandResult::Ready(fragment_kind.dummy(span)),
696 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
698 SyntaxExtensionKind::LegacyBang(expander) => {
699 let prev = self.cx.current_expansion.prior_type_ascription;
700 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
701 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
702 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
705 self.error_wrong_fragment_kind(fragment_kind, &mac, span);
706 fragment_kind.dummy(span)
708 self.cx.current_expansion.prior_type_ascription = prev;
713 InvocationKind::Attr { attr, pos, mut item, derives } => match ext {
714 SyntaxExtensionKind::Attr(expander) => {
715 self.gate_proc_macro_input(&item);
716 self.gate_proc_macro_attr_item(span, &item);
717 let mut fake_tokens = false;
718 if let Annotatable::Item(item_inner) = &item {
719 if let ItemKind::Mod(_, mod_kind) = &item_inner.kind {
720 // FIXME: Collect tokens and use them instead of generating
721 // fake ones. These are unstable, so it needs to be
722 // fixed prior to stabilization
723 // Fake tokens when we are invoking an inner attribute, and:
724 fake_tokens = matches!(attr.style, ast::AttrStyle::Inner) &&
725 // We are invoking an attribute on the crate root, or an outline
727 (item_inner.ident.name.is_empty() || !matches!(mod_kind, ast::ModKind::Loaded(_, Inline::Yes, _)));
730 let tokens = if fake_tokens {
731 rustc_parse::fake_token_stream(
732 &self.cx.sess.parse_sess,
733 &item.into_nonterminal(),
736 item.into_tokens(&self.cx.sess.parse_sess)
738 let attr_item = attr.unwrap_normal_item();
739 if let MacArgs::Eq(..) = attr_item.args {
740 self.cx.span_err(span, "key-value macro attributes are not supported");
742 let inner_tokens = attr_item.args.inner_tokens();
743 let tok_result = match expander.expand(self.cx, span, inner_tokens, tokens) {
744 Err(_) => return ExpandResult::Ready(fragment_kind.dummy(span)),
747 self.parse_ast_fragment(tok_result, fragment_kind, &attr_item.path, span)
749 SyntaxExtensionKind::LegacyAttr(expander) => {
750 match validate_attr::parse_meta(&self.cx.sess.parse_sess, &attr) {
752 let items = match expander.expand(self.cx, span, &meta, item) {
753 ExpandResult::Ready(items) => items,
754 ExpandResult::Retry(item) => {
755 // Reassemble the original invocation for retrying.
756 return ExpandResult::Retry(Invocation {
757 kind: InvocationKind::Attr { attr, pos, item, derives },
762 if fragment_kind == AstFragmentKind::Expr && items.is_empty() {
764 "removing an expression is not supported in this position";
765 self.cx.span_err(span, msg);
766 fragment_kind.dummy(span)
768 fragment_kind.expect_from_annotatables(items)
773 fragment_kind.dummy(span)
777 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
778 self.cx.sess.mark_attr_known(&attr);
780 self.cx.sess.mark_attr_used(&attr);
782 item.visit_attrs(|attrs| attrs.insert(pos, attr));
783 fragment_kind.expect_from_annotatables(iter::once(item))
787 InvocationKind::Derive { path, item } => match ext {
788 SyntaxExtensionKind::Derive(expander)
789 | SyntaxExtensionKind::LegacyDerive(expander) => {
790 if let SyntaxExtensionKind::Derive(..) = ext {
791 self.gate_proc_macro_input(&item);
793 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
794 let items = match expander.expand(self.cx, span, &meta, item) {
795 ExpandResult::Ready(items) => items,
796 ExpandResult::Retry(item) => {
797 // Reassemble the original invocation for retrying.
798 return ExpandResult::Retry(Invocation {
799 kind: InvocationKind::Derive { path: meta.path, item },
804 fragment_kind.expect_from_annotatables(items)
811 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
812 let kind = match item {
814 | Annotatable::TraitItem(_)
815 | Annotatable::ImplItem(_)
816 | Annotatable::ForeignItem(_) => return,
817 Annotatable::Stmt(stmt) => {
818 // Attributes are stable on item statements,
819 // but unstable on all other kinds of statements
825 Annotatable::Expr(_) => "expressions",
827 | Annotatable::ExprField(..)
828 | Annotatable::PatField(..)
829 | Annotatable::GenericParam(..)
830 | Annotatable::Param(..)
831 | Annotatable::FieldDef(..)
832 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
834 if self.cx.ecfg.proc_macro_hygiene() {
838 &self.cx.sess.parse_sess,
839 sym::proc_macro_hygiene,
841 &format!("custom attributes cannot be applied to {}", kind),
846 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
847 struct GateProcMacroInput<'a> {
848 parse_sess: &'a ParseSess,
851 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
852 fn visit_item(&mut self, item: &'ast ast::Item) {
854 ast::ItemKind::Mod(_, mod_kind)
855 if !matches!(mod_kind, ModKind::Loaded(_, Inline::Yes, _)) =>
859 sym::proc_macro_hygiene,
861 "non-inline modules in proc macro input are unstable",
868 visit::walk_item(self, item);
872 if !self.cx.ecfg.proc_macro_hygiene() {
874 .visit_with(&mut GateProcMacroInput { parse_sess: &self.cx.sess.parse_sess });
878 fn parse_ast_fragment(
881 kind: AstFragmentKind,
885 let mut parser = self.cx.new_parser_from_tts(toks);
886 match parse_ast_fragment(&mut parser, kind) {
888 ensure_complete_parse(&mut parser, path, kind.name(), span);
892 if err.span.is_dummy() {
895 annotate_err_with_kind(&mut err, kind, span);
897 self.cx.trace_macros_diag();
904 pub fn parse_ast_fragment<'a>(
905 this: &mut Parser<'a>,
906 kind: AstFragmentKind,
907 ) -> PResult<'a, AstFragment> {
909 AstFragmentKind::Items => {
910 let mut items = SmallVec::new();
911 while let Some(item) = this.parse_item(ForceCollect::No)? {
914 AstFragment::Items(items)
916 AstFragmentKind::TraitItems => {
917 let mut items = SmallVec::new();
918 while let Some(item) = this.parse_trait_item(ForceCollect::No)? {
921 AstFragment::TraitItems(items)
923 AstFragmentKind::ImplItems => {
924 let mut items = SmallVec::new();
925 while let Some(item) = this.parse_impl_item(ForceCollect::No)? {
928 AstFragment::ImplItems(items)
930 AstFragmentKind::ForeignItems => {
931 let mut items = SmallVec::new();
932 while let Some(item) = this.parse_foreign_item(ForceCollect::No)? {
935 AstFragment::ForeignItems(items)
937 AstFragmentKind::Stmts => {
938 let mut stmts = SmallVec::new();
939 // Won't make progress on a `}`.
940 while this.token != token::Eof && this.token != token::CloseDelim(token::Brace) {
941 if let Some(stmt) = this.parse_full_stmt(AttemptLocalParseRecovery::Yes)? {
945 AstFragment::Stmts(stmts)
947 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
948 AstFragmentKind::OptExpr => {
949 if this.token != token::Eof {
950 AstFragment::OptExpr(Some(this.parse_expr()?))
952 AstFragment::OptExpr(None)
955 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
956 AstFragmentKind::Pat => {
957 AstFragment::Pat(this.parse_pat_allow_top_alt(None, RecoverComma::No)?)
959 AstFragmentKind::Arms
960 | AstFragmentKind::Fields
961 | AstFragmentKind::FieldPats
962 | AstFragmentKind::GenericParams
963 | AstFragmentKind::Params
964 | AstFragmentKind::StructFields
965 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
969 pub fn ensure_complete_parse<'a>(
970 this: &mut Parser<'a>,
975 if this.token != token::Eof {
976 let token = pprust::token_to_string(&this.token);
977 let msg = format!("macro expansion ignores token `{}` and any following", token);
978 // Avoid emitting backtrace info twice.
979 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
980 let mut err = this.struct_span_err(def_site_span, &msg);
981 err.span_label(span, "caused by the macro expansion here");
983 "the usage of `{}!` is likely invalid in {} context",
984 pprust::path_to_string(macro_path),
988 let semi_span = this.sess.source_map().next_point(span);
990 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
991 match this.sess.source_map().span_to_snippet(semi_full_span) {
992 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
995 "you might be missing a semicolon here",
997 Applicability::MaybeIncorrect,
1006 struct InvocationCollector<'a, 'b> {
1007 cx: &'a mut ExtCtxt<'b>,
1008 cfg: StripUnconfigured<'a>,
1009 invocations: Vec<(Invocation, Option<Lrc<SyntaxExtension>>)>,
1013 impl<'a, 'b> InvocationCollector<'a, 'b> {
1014 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
1015 let expn_id = ExpnId::fresh(None);
1016 let vis = kind.placeholder_visibility();
1017 self.invocations.push((
1021 expansion_data: ExpansionData {
1023 depth: self.cx.current_expansion.depth + 1,
1024 ..self.cx.current_expansion.clone()
1029 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
1036 kind: AstFragmentKind,
1038 self.collect(kind, InvocationKind::Bang { mac, span })
1043 (attr, pos, derives): (ast::Attribute, usize, Vec<Path>),
1045 kind: AstFragmentKind,
1047 self.collect(kind, InvocationKind::Attr { attr, pos, item, derives })
1050 /// If `item` is an attribute invocation, remove the attribute and return it together with
1051 /// its position and derives following it. We have to collect the derives in order to resolve
1052 /// legacy derive helpers (helpers written before derives that introduce them).
1055 item: &mut impl AstLike,
1056 ) -> Option<(ast::Attribute, usize, Vec<Path>)> {
1057 let mut attr = None;
1059 item.visit_attrs(|attrs| {
1062 .position(|a| !self.cx.sess.is_attr_known(a) && !is_builtin_attr(a))
1064 let attr = attrs.remove(attr_pos);
1065 let following_derives = attrs[attr_pos..]
1067 .filter(|a| a.has_name(sym::derive))
1068 .flat_map(|a| a.meta_item_list().unwrap_or_default())
1069 .filter_map(|nested_meta| match nested_meta {
1070 NestedMetaItem::MetaItem(ast::MetaItem {
1071 kind: MetaItemKind::Word,
1079 (attr, attr_pos, following_derives)
1086 fn configure<T: AstLike>(&mut self, node: T) -> Option<T> {
1087 self.cfg.configure(node)
1090 // Detect use of feature-gated or invalid attributes on macro invocations
1091 // since they will not be detected after macro expansion.
1092 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1093 let features = self.cx.ecfg.features.unwrap();
1094 let mut attrs = attrs.iter().peekable();
1095 let mut span: Option<Span> = None;
1096 while let Some(attr) = attrs.next() {
1097 rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
1098 validate_attr::check_meta(&self.cx.sess.parse_sess, attr);
1100 let current_span = if let Some(sp) = span { sp.to(attr.span) } else { attr.span };
1101 span = Some(current_span);
1103 if attrs.peek().map_or(false, |next_attr| next_attr.doc_str().is_some()) {
1107 if attr.doc_str().is_some() {
1108 self.cx.sess.parse_sess.buffer_lint_with_diagnostic(
1109 &UNUSED_DOC_COMMENTS,
1112 "unused doc comment",
1113 BuiltinLintDiagnostics::UnusedDocComment(attr.span),
1120 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1121 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1122 self.cfg.configure_expr(expr);
1123 visit_clobber(expr.deref_mut(), |mut expr| {
1124 if let Some(attr) = self.take_first_attr(&mut expr) {
1125 // Collect the invoc regardless of whether or not attributes are permitted here
1126 // expansion will eat the attribute so it won't error later.
1127 self.cfg.maybe_emit_expr_attr_err(&attr.0);
1129 // AstFragmentKind::Expr requires the macro to emit an expression.
1131 .collect_attr(attr, Annotatable::Expr(P(expr)), AstFragmentKind::Expr)
1136 if let ast::ExprKind::MacCall(mac) = expr.kind {
1137 self.check_attributes(&expr.attrs);
1138 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
1140 ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
1146 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1147 let mut arm = configure!(self, arm);
1149 if let Some(attr) = self.take_first_attr(&mut arm) {
1151 .collect_attr(attr, Annotatable::Arm(arm), AstFragmentKind::Arms)
1155 noop_flat_map_arm(arm, self)
1158 fn flat_map_expr_field(&mut self, field: ast::ExprField) -> SmallVec<[ast::ExprField; 1]> {
1159 let mut field = configure!(self, field);
1161 if let Some(attr) = self.take_first_attr(&mut field) {
1163 .collect_attr(attr, Annotatable::ExprField(field), AstFragmentKind::Fields)
1164 .make_expr_fields();
1167 noop_flat_map_expr_field(field, self)
1170 fn flat_map_pat_field(&mut self, fp: ast::PatField) -> SmallVec<[ast::PatField; 1]> {
1171 let mut fp = configure!(self, fp);
1173 if let Some(attr) = self.take_first_attr(&mut fp) {
1175 .collect_attr(attr, Annotatable::PatField(fp), AstFragmentKind::FieldPats)
1179 noop_flat_map_pat_field(fp, self)
1182 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1183 let mut p = configure!(self, p);
1185 if let Some(attr) = self.take_first_attr(&mut p) {
1187 .collect_attr(attr, Annotatable::Param(p), AstFragmentKind::Params)
1191 noop_flat_map_param(p, self)
1194 fn flat_map_field_def(&mut self, sf: ast::FieldDef) -> SmallVec<[ast::FieldDef; 1]> {
1195 let mut sf = configure!(self, sf);
1197 if let Some(attr) = self.take_first_attr(&mut sf) {
1199 .collect_attr(attr, Annotatable::FieldDef(sf), AstFragmentKind::StructFields)
1203 noop_flat_map_field_def(sf, self)
1206 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1207 let mut variant = configure!(self, variant);
1209 if let Some(attr) = self.take_first_attr(&mut variant) {
1211 .collect_attr(attr, Annotatable::Variant(variant), AstFragmentKind::Variants)
1215 noop_flat_map_variant(variant, self)
1218 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1219 let expr = configure!(self, expr);
1220 expr.filter_map(|mut expr| {
1221 if let Some(attr) = self.take_first_attr(&mut expr) {
1222 self.cfg.maybe_emit_expr_attr_err(&attr.0);
1225 .collect_attr(attr, Annotatable::Expr(P(expr)), AstFragmentKind::OptExpr)
1227 .map(|expr| expr.into_inner());
1230 if let ast::ExprKind::MacCall(mac) = expr.kind {
1231 self.check_attributes(&expr.attrs);
1232 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1234 .map(|expr| expr.into_inner())
1237 noop_visit_expr(&mut expr, self);
1244 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1246 PatKind::MacCall(_) => {}
1247 _ => return noop_visit_pat(pat, self),
1250 visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
1251 PatKind::MacCall(mac) => {
1252 self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat()
1254 _ => unreachable!(),
1258 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1259 let mut stmt = configure!(self, stmt);
1261 // we'll expand attributes on expressions separately
1262 if !stmt.is_expr() {
1263 if let Some(attr) = self.take_first_attr(&mut stmt) {
1265 .collect_attr(attr, Annotatable::Stmt(P(stmt)), AstFragmentKind::Stmts)
1270 if let StmtKind::MacCall(mac) = stmt.kind {
1271 let MacCallStmt { mac, style, attrs, tokens: _ } = mac.into_inner();
1272 self.check_attributes(&attrs);
1273 let mut placeholder =
1274 self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts).make_stmts();
1276 // If this is a macro invocation with a semicolon, then apply that
1277 // semicolon to the final statement produced by expansion.
1278 if style == MacStmtStyle::Semicolon {
1279 if let Some(stmt) = placeholder.pop() {
1280 placeholder.push(stmt.add_trailing_semicolon());
1287 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1288 let ast::Stmt { id, kind, span } = stmt;
1289 noop_flat_map_stmt_kind(kind, self)
1291 .map(|kind| ast::Stmt { id, kind, span })
1295 fn visit_block(&mut self, block: &mut P<Block>) {
1296 let orig_dir_ownership = mem::replace(
1297 &mut self.cx.current_expansion.dir_ownership,
1298 DirOwnership::UnownedViaBlock,
1300 noop_visit_block(block, self);
1301 self.cx.current_expansion.dir_ownership = orig_dir_ownership;
1304 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1305 let mut item = configure!(self, item);
1307 if let Some(attr) = self.take_first_attr(&mut item) {
1309 .collect_attr(attr, Annotatable::Item(item), AstFragmentKind::Items)
1313 let mut attrs = mem::take(&mut item.attrs); // We do this to please borrowck.
1314 let ident = item.ident;
1315 let span = item.span;
1318 ast::ItemKind::MacCall(..) => {
1320 self.check_attributes(&item.attrs);
1321 item.and_then(|item| match item.kind {
1322 ItemKind::MacCall(mac) => {
1323 self.collect_bang(mac, span, AstFragmentKind::Items).make_items()
1325 _ => unreachable!(),
1328 ast::ItemKind::Mod(_, ref mut mod_kind) if ident != Ident::invalid() => {
1329 let (file_path, dir_path, dir_ownership) = match mod_kind {
1330 ModKind::Loaded(_, inline, _) => {
1331 // Inline `mod foo { ... }`, but we still need to push directories.
1332 let (dir_path, dir_ownership) = mod_dir_path(
1336 &self.cx.current_expansion.module,
1337 self.cx.current_expansion.dir_ownership,
1341 (None, dir_path, dir_ownership)
1343 ModKind::Unloaded => {
1344 // We have an outline `mod foo;` so we need to parse the file.
1345 let old_attrs_len = attrs.len();
1346 let ParsedExternalMod {
1352 } = parse_external_mod(
1356 &self.cx.current_expansion.module,
1357 self.cx.current_expansion.dir_ownership,
1361 if let Some(extern_mod_loaded) = self.cx.extern_mod_loaded {
1362 (attrs, items) = extern_mod_loaded(ident, attrs, items, inner_span);
1365 *mod_kind = ModKind::Loaded(items, Inline::No, inner_span);
1367 if item.attrs.len() > old_attrs_len {
1368 // If we loaded an out-of-line module and added some inner attributes,
1369 // then we need to re-configure it and re-collect attributes for
1370 // resolution and expansion.
1371 item = configure!(self, item);
1373 if let Some(attr) = self.take_first_attr(&mut item) {
1377 Annotatable::Item(item),
1378 AstFragmentKind::Items,
1383 (Some(file_path), dir_path, dir_ownership)
1387 // Set the module info before we flat map.
1388 let mut module = self.cx.current_expansion.module.with_dir_path(dir_path);
1389 module.mod_path.push(ident);
1390 if let Some(file_path) = file_path {
1391 module.file_path_stack.push(file_path);
1395 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1396 let orig_dir_ownership =
1397 mem::replace(&mut self.cx.current_expansion.dir_ownership, dir_ownership);
1399 let result = noop_flat_map_item(item, self);
1401 // Restore the module info.
1402 self.cx.current_expansion.dir_ownership = orig_dir_ownership;
1403 self.cx.current_expansion.module = orig_module;
1409 noop_flat_map_item(item, self)
1414 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1415 let mut item = configure!(self, item);
1417 if let Some(attr) = self.take_first_attr(&mut item) {
1419 .collect_attr(attr, Annotatable::TraitItem(item), AstFragmentKind::TraitItems)
1420 .make_trait_items();
1424 ast::AssocItemKind::MacCall(..) => {
1425 self.check_attributes(&item.attrs);
1426 item.and_then(|item| match item.kind {
1427 ast::AssocItemKind::MacCall(mac) => self
1428 .collect_bang(mac, item.span, AstFragmentKind::TraitItems)
1429 .make_trait_items(),
1430 _ => unreachable!(),
1433 _ => noop_flat_map_assoc_item(item, self),
1437 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1438 let mut item = configure!(self, item);
1440 if let Some(attr) = self.take_first_attr(&mut item) {
1442 .collect_attr(attr, Annotatable::ImplItem(item), AstFragmentKind::ImplItems)
1447 ast::AssocItemKind::MacCall(..) => {
1448 self.check_attributes(&item.attrs);
1449 item.and_then(|item| match item.kind {
1450 ast::AssocItemKind::MacCall(mac) => self
1451 .collect_bang(mac, item.span, AstFragmentKind::ImplItems)
1453 _ => unreachable!(),
1456 _ => noop_flat_map_assoc_item(item, self),
1460 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1462 ast::TyKind::MacCall(_) => {}
1463 _ => return noop_visit_ty(ty, self),
1466 visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1467 ast::TyKind::MacCall(mac) => {
1468 self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty()
1470 _ => unreachable!(),
1474 fn flat_map_foreign_item(
1476 foreign_item: P<ast::ForeignItem>,
1477 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
1478 let mut foreign_item = configure!(self, foreign_item);
1480 if let Some(attr) = self.take_first_attr(&mut foreign_item) {
1484 Annotatable::ForeignItem(foreign_item),
1485 AstFragmentKind::ForeignItems,
1487 .make_foreign_items();
1490 match foreign_item.kind {
1491 ast::ForeignItemKind::MacCall(..) => {
1492 self.check_attributes(&foreign_item.attrs);
1493 foreign_item.and_then(|item| match item.kind {
1494 ast::ForeignItemKind::MacCall(mac) => self
1495 .collect_bang(mac, item.span, AstFragmentKind::ForeignItems)
1496 .make_foreign_items(),
1497 _ => unreachable!(),
1500 _ => noop_flat_map_foreign_item(foreign_item, self),
1504 fn flat_map_generic_param(
1506 param: ast::GenericParam,
1507 ) -> SmallVec<[ast::GenericParam; 1]> {
1508 let mut param = configure!(self, param);
1510 if let Some(attr) = self.take_first_attr(&mut param) {
1514 Annotatable::GenericParam(param),
1515 AstFragmentKind::GenericParams,
1517 .make_generic_params();
1520 noop_flat_map_generic_param(param, self)
1523 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1524 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1525 // contents="file contents")]` attributes
1526 if !self.cx.sess.check_name(at, sym::doc) {
1527 return noop_visit_attribute(at, self);
1530 if let Some(list) = at.meta_item_list() {
1531 if !list.iter().any(|it| it.has_name(sym::include)) {
1532 return noop_visit_attribute(at, self);
1535 let mut items = vec![];
1537 for mut it in list {
1538 if !it.has_name(sym::include) {
1540 noop_visit_meta_list_item(&mut it, self);
1546 if let Some(file) = it.value_str() {
1547 let err_count = self.cx.sess.parse_sess.span_diagnostic.err_count();
1548 self.check_attributes(slice::from_ref(at));
1549 if self.cx.sess.parse_sess.span_diagnostic.err_count() > err_count {
1550 // avoid loading the file if they haven't enabled the feature
1551 return noop_visit_attribute(at, self);
1554 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1555 Ok(filename) => filename,
1562 match self.cx.source_map().load_file(&filename) {
1563 Ok(source_file) => {
1564 let src = source_file
1567 .expect("freshly loaded file should have a source");
1568 let src_interned = Symbol::intern(src.as_str());
1570 let include_info = vec![
1571 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1572 Ident::with_dummy_span(sym::file),
1576 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1577 Ident::with_dummy_span(sym::contents),
1583 let include_ident = Ident::with_dummy_span(sym::include);
1584 let item = attr::mk_list_item(include_ident, include_info);
1585 items.push(ast::NestedMetaItem::MetaItem(item));
1588 let lit_span = it.name_value_literal_span().unwrap();
1590 if e.kind() == ErrorKind::InvalidData {
1594 &format!("{} wasn't a utf-8 file", filename.display()),
1596 .span_label(lit_span, "contains invalid utf-8")
1599 let mut err = self.cx.struct_span_err(
1601 &format!("couldn't read {}: {}", filename.display(), e),
1603 err.span_label(lit_span, "couldn't read file");
1612 .struct_span_err(it.span(), "expected path to external documentation");
1614 // Check if the user erroneously used `doc(include(...))` syntax.
1615 let literal = it.meta_item_list().and_then(|list| {
1616 if list.len() == 1 {
1617 list[0].literal().map(|literal| &literal.kind)
1623 let (path, applicability) = match &literal {
1624 Some(LitKind::Str(path, ..)) => {
1625 (path.to_string(), Applicability::MachineApplicable)
1627 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1630 err.span_suggestion(
1632 "provide a file path with `=`",
1633 format!("include = \"{}\"", path),
1641 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1642 *at = ast::Attribute {
1643 kind: ast::AttrKind::Normal(
1644 AttrItem { path: meta.path, args: meta.kind.mac_args(meta.span), tokens: None },
1652 noop_visit_attribute(at, self)
1656 fn visit_id(&mut self, id: &mut ast::NodeId) {
1658 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1659 *id = self.cx.resolver.next_node_id()
1664 pub struct ExpansionConfig<'feat> {
1665 pub crate_name: String,
1666 pub features: Option<&'feat Features>,
1667 pub recursion_limit: Limit,
1668 pub trace_mac: bool,
1669 pub should_test: bool, // If false, strip `#[test]` nodes
1670 pub span_debug: bool, // If true, use verbose debugging for `proc_macro::Span`
1671 pub proc_macro_backtrace: bool, // If true, show backtraces for proc-macro panics
1674 impl<'feat> ExpansionConfig<'feat> {
1675 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1679 recursion_limit: Limit::new(1024),
1683 proc_macro_backtrace: false,
1687 fn proc_macro_hygiene(&self) -> bool {
1688 self.features.map_or(false, |features| features.proc_macro_hygiene)