2 use crate::config::StripUnconfigured;
4 use crate::hygiene::{ExpnData, ExpnKind, SyntaxContext};
5 use crate::mbe::macro_rules::annotate_err_with_kind;
6 use crate::module::{parse_external_mod, push_directory, Directory, DirectoryOwnership};
7 use crate::placeholders::{placeholder, PlaceholderExpander};
8 use crate::proc_macro::collect_derives;
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::{self as ast, AttrItem, Block, LitKind, NodeId, PatKind, Path};
16 use rustc_ast::{ItemKind, MacArgs, MacCallStmt, MacStmtStyle, StmtKind, Unsafe};
17 use rustc_ast_pretty::pprust;
18 use rustc_attr::{self as attr, is_builtin_attr, HasAttrs};
19 use rustc_data_structures::map_in_place::MapInPlace;
20 use rustc_data_structures::stack::ensure_sufficient_stack;
21 use rustc_errors::{struct_span_err, Applicability, PResult};
22 use rustc_feature::Features;
23 use rustc_parse::parser::{AttemptLocalParseRecovery, Parser};
24 use rustc_parse::validate_attr;
25 use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
26 use rustc_session::lint::BuiltinLintDiagnostics;
27 use rustc_session::parse::{feature_err, ParseSess};
28 use rustc_session::Limit;
29 use rustc_span::symbol::{sym, Ident, Symbol};
30 use rustc_span::{ExpnId, FileName, Span, DUMMY_SP};
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 crate fn dummy(self, span: Span) -> AstFragment {
209 self.make_from(DummyResult::any(span)).expect("couldn't create a dummy AST fragment")
212 /// Fragment supports macro expansion and not just inert attributes, `cfg` and `cfg_attr`.
213 pub fn supports_macro_expansion(self) -> bool {
215 AstFragmentKind::OptExpr
216 | AstFragmentKind::Expr
217 | AstFragmentKind::Pat
218 | AstFragmentKind::Ty
219 | AstFragmentKind::Stmts
220 | AstFragmentKind::Items
221 | AstFragmentKind::TraitItems
222 | AstFragmentKind::ImplItems
223 | AstFragmentKind::ForeignItems => true,
224 AstFragmentKind::Arms
225 | AstFragmentKind::Fields
226 | AstFragmentKind::FieldPats
227 | AstFragmentKind::GenericParams
228 | AstFragmentKind::Params
229 | AstFragmentKind::StructFields
230 | AstFragmentKind::Variants => false,
234 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
238 let mut items = items.into_iter();
240 AstFragmentKind::Arms => {
241 AstFragment::Arms(items.map(Annotatable::expect_arm).collect())
243 AstFragmentKind::Fields => {
244 AstFragment::Fields(items.map(Annotatable::expect_field).collect())
246 AstFragmentKind::FieldPats => {
247 AstFragment::FieldPats(items.map(Annotatable::expect_field_pattern).collect())
249 AstFragmentKind::GenericParams => {
250 AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect())
252 AstFragmentKind::Params => {
253 AstFragment::Params(items.map(Annotatable::expect_param).collect())
255 AstFragmentKind::StructFields => {
256 AstFragment::StructFields(items.map(Annotatable::expect_struct_field).collect())
258 AstFragmentKind::Variants => {
259 AstFragment::Variants(items.map(Annotatable::expect_variant).collect())
261 AstFragmentKind::Items => {
262 AstFragment::Items(items.map(Annotatable::expect_item).collect())
264 AstFragmentKind::ImplItems => {
265 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect())
267 AstFragmentKind::TraitItems => {
268 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect())
270 AstFragmentKind::ForeignItems => {
271 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect())
273 AstFragmentKind::Stmts => {
274 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect())
276 AstFragmentKind::Expr => AstFragment::Expr(
277 items.next().expect("expected exactly one expression").expect_expr(),
279 AstFragmentKind::OptExpr => {
280 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
282 AstFragmentKind::Pat | AstFragmentKind::Ty => {
283 panic!("patterns and types aren't annotatable")
289 pub struct Invocation {
290 pub kind: InvocationKind,
291 pub fragment_kind: AstFragmentKind,
292 pub expansion_data: ExpansionData,
295 pub enum InvocationKind {
301 attr: ast::Attribute,
303 // Required for resolving derive helper attributes.
305 // We temporarily report errors for attribute macros placed after derives
312 /// "Invocation" that contains all derives from an item,
313 /// broken into multiple `Derive` invocations when expanded.
314 /// FIXME: Find a way to remove it.
321 impl InvocationKind {
322 fn placeholder_visibility(&self) -> Option<ast::Visibility> {
323 // HACK: For unnamed fields placeholders should have the same visibility as the actual
324 // fields because for tuple structs/variants resolve determines visibilities of their
325 // constructor using these field visibilities before attributes on them are are expanded.
326 // The assumption is that the attribute expansion cannot change field visibilities,
327 // and it holds because only inert attributes are supported in this position.
329 InvocationKind::Attr { item: Annotatable::StructField(field), .. }
330 | InvocationKind::Derive { item: Annotatable::StructField(field), .. }
331 | InvocationKind::DeriveContainer { item: Annotatable::StructField(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,
347 InvocationKind::DeriveContainer { item, .. } => item.span(),
352 pub struct MacroExpander<'a, 'b> {
353 pub cx: &'a mut ExtCtxt<'b>,
354 monotonic: bool, // cf. `cx.monotonic_expander()`
357 impl<'a, 'b> MacroExpander<'a, 'b> {
358 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
359 MacroExpander { cx, monotonic }
362 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
363 let mut module = ModuleData {
364 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
365 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
366 FileName::Real(name) => name.into_local_path(),
367 other => PathBuf::from(other.to_string()),
370 module.directory.pop();
371 self.cx.root_path = module.directory.clone();
372 self.cx.current_expansion.module = Rc::new(module);
374 let orig_mod_span = krate.module.inner;
376 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
379 kind: ast::ItemKind::Mod(krate.module),
380 ident: Ident::invalid(),
381 id: ast::DUMMY_NODE_ID,
382 vis: ast::Visibility {
383 span: krate.span.shrink_to_lo(),
384 kind: ast::VisibilityKind::Public,
390 match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
391 Some(ast::Item { attrs, kind: ast::ItemKind::Mod(module), .. }) => {
393 krate.module = module;
396 // Resolution failed so we return an empty expansion
397 krate.attrs = vec![];
398 krate.module = ast::Mod {
399 inner: orig_mod_span,
400 unsafety: Unsafe::No,
405 Some(ast::Item { span, kind, .. }) => {
406 krate.attrs = vec![];
407 krate.module = ast::Mod {
408 inner: orig_mod_span,
409 unsafety: Unsafe::No,
416 "expected crate top-level item to be a module after macro expansion, found {} {}",
417 kind.article(), kind.descr()
422 self.cx.trace_macros_diag();
426 // Recursively expand all macro invocations in this AST fragment.
427 pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
428 let orig_expansion_data = self.cx.current_expansion.clone();
429 let orig_force_mode = self.cx.force_mode;
430 self.cx.current_expansion.depth = 0;
432 // Collect all macro invocations and replace them with placeholders.
433 let (mut fragment_with_placeholders, mut invocations) =
434 self.collect_invocations(input_fragment, &[]);
436 // Optimization: if we resolve all imports now,
437 // we'll be able to immediately resolve most of imported macros.
438 self.resolve_imports();
440 // Resolve paths in all invocations and produce output expanded fragments for them, but
441 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
442 // The output fragments also go through expansion recursively until no invocations are left.
443 // Unresolved macros produce dummy outputs as a recovery measure.
444 invocations.reverse();
445 let mut expanded_fragments = Vec::new();
446 let mut undetermined_invocations = Vec::new();
447 let (mut progress, mut force) = (false, !self.monotonic);
449 let (invoc, res) = if let Some(invoc) = invocations.pop() {
452 self.resolve_imports();
453 if undetermined_invocations.is_empty() {
456 invocations = mem::take(&mut undetermined_invocations);
457 force = !mem::replace(&mut progress, false);
458 if force && self.monotonic {
459 self.cx.sess.delay_span_bug(
460 invocations.last().unwrap().0.span(),
461 "expansion entered force mode without producing any errors",
467 let res = match res {
470 let eager_expansion_root = if self.monotonic {
471 invoc.expansion_data.id
473 orig_expansion_data.id
475 match self.cx.resolver.resolve_macro_invocation(
477 eager_expansion_root,
481 Err(Indeterminate) => {
482 // Cannot resolve, will retry this invocation later.
483 undetermined_invocations.push((invoc, None));
490 let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
491 self.cx.current_expansion = invoc.expansion_data.clone();
492 self.cx.force_mode = force;
494 // FIXME(jseyfried): Refactor out the following logic
495 let fragment_kind = invoc.fragment_kind;
496 let (expanded_fragment, new_invocations) = match res {
497 InvocationRes::Single(ext) => match self.expand_invoc(invoc, &ext.kind) {
498 ExpandResult::Ready(fragment) => self.collect_invocations(fragment, &[]),
499 ExpandResult::Retry(invoc) => {
503 "expansion entered force mode but is still stuck",
506 // Cannot expand, will retry this invocation later.
507 undetermined_invocations
508 .push((invoc, Some(InvocationRes::Single(ext))));
513 InvocationRes::DeriveContainer(_exts) => {
514 // FIXME: Consider using the derive resolutions (`_exts`) immediately,
515 // instead of enqueuing the derives to be resolved again later.
516 let (derives, mut item) = match invoc.kind {
517 InvocationKind::DeriveContainer { derives, item } => (derives, item),
520 let (item, derive_placeholders) = if !item.derive_allowed() {
521 self.error_derive_forbidden_on_non_adt(&derives, &item);
522 item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
525 let mut item = StripUnconfigured {
527 features: self.cx.ecfg.features,
529 .fully_configure(item);
530 item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
532 invocations.reserve(derives.len());
533 let derive_placeholders = derives
536 let expn_id = ExpnId::fresh(None);
539 kind: InvocationKind::Derive { path, item: item.clone() },
541 expansion_data: ExpansionData {
543 ..self.cx.current_expansion.clone()
548 NodeId::placeholder_from_expn_id(expn_id)
550 .collect::<Vec<_>>();
551 (item, derive_placeholders)
554 let fragment = fragment_kind.expect_from_annotatables(::std::iter::once(item));
555 self.collect_invocations(fragment, &derive_placeholders)
560 if expanded_fragments.len() < depth {
561 expanded_fragments.push(Vec::new());
563 expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
564 invocations.extend(new_invocations.into_iter().rev());
567 self.cx.current_expansion = orig_expansion_data;
568 self.cx.force_mode = orig_force_mode;
570 // Finally incorporate all the expanded macros into the input AST fragment.
571 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
572 while let Some(expanded_fragments) = expanded_fragments.pop() {
573 for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
575 .add(NodeId::placeholder_from_expn_id(expn_id), expanded_fragment);
578 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
579 fragment_with_placeholders
582 fn error_derive_forbidden_on_non_adt(&self, derives: &[Path], item: &Annotatable) {
583 let attr = self.cx.sess.find_by_name(item.attrs(), sym::derive);
584 let span = attr.map_or(item.span(), |attr| attr.span);
585 let mut err = struct_span_err!(
589 "`derive` may only be applied to structs, enums and unions",
591 if let Some(ast::Attribute { style: ast::AttrStyle::Inner, .. }) = attr {
592 let trait_list = derives.iter().map(|t| pprust::path_to_string(t)).collect::<Vec<_>>();
593 let suggestion = format!("#[derive({})]", trait_list.join(", "));
596 "try an outer attribute",
598 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
599 Applicability::MaybeIncorrect,
605 fn resolve_imports(&mut self) {
607 self.cx.resolver.resolve_imports();
611 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
612 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
613 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
614 /// prepares data for resolving paths of macro invocations.
615 fn collect_invocations(
617 mut fragment: AstFragment,
618 extra_placeholders: &[NodeId],
619 ) -> (AstFragment, Vec<(Invocation, Option<InvocationRes>)>) {
620 // Resolve `$crate`s in the fragment for pretty-printing.
621 self.cx.resolver.resolve_dollar_crates();
624 let mut collector = InvocationCollector {
625 cfg: StripUnconfigured { sess: &self.cx.sess, features: self.cx.ecfg.features },
627 invocations: Vec::new(),
628 monotonic: self.monotonic,
630 fragment.mut_visit_with(&mut collector);
631 fragment.add_placeholders(extra_placeholders);
632 collector.invocations
638 .visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
641 (fragment, invocations)
644 fn error_recursion_limit_reached(&mut self) {
645 let expn_data = self.cx.current_expansion.id.expn_data();
646 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
650 &format!("recursion limit reached while expanding `{}`", expn_data.kind.descr()),
653 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate (`{}`)",
654 suggested_limit, self.cx.ecfg.crate_name,
657 self.cx.trace_macros_diag();
660 /// A macro's expansion does not fit in this fragment kind.
661 /// For example, a non-type macro in a type position.
662 fn error_wrong_fragment_kind(&mut self, kind: AstFragmentKind, mac: &ast::MacCall, span: Span) {
664 "non-{kind} macro in {kind} position: {path}",
666 path = pprust::path_to_string(&mac.path),
668 self.cx.span_err(span, &msg);
669 self.cx.trace_macros_diag();
675 ext: &SyntaxExtensionKind,
676 ) -> ExpandResult<AstFragment, Invocation> {
677 let recursion_limit =
678 self.cx.reduced_recursion_limit.unwrap_or(self.cx.ecfg.recursion_limit);
679 if !recursion_limit.value_within_limit(self.cx.current_expansion.depth) {
680 if self.cx.reduced_recursion_limit.is_none() {
681 self.error_recursion_limit_reached();
684 // Reduce the recursion limit by half each time it triggers.
685 self.cx.reduced_recursion_limit = Some(recursion_limit / 2);
687 return ExpandResult::Ready(invoc.fragment_kind.dummy(invoc.span()));
690 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
691 ExpandResult::Ready(match invoc.kind {
692 InvocationKind::Bang { mac, .. } => match ext {
693 SyntaxExtensionKind::Bang(expander) => {
694 let tok_result = match expander.expand(self.cx, span, mac.args.inner_tokens()) {
695 Err(_) => return ExpandResult::Ready(fragment_kind.dummy(span)),
698 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
700 SyntaxExtensionKind::LegacyBang(expander) => {
701 let prev = self.cx.current_expansion.prior_type_ascription;
702 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
703 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
704 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
707 self.error_wrong_fragment_kind(fragment_kind, &mac, span);
708 fragment_kind.dummy(span)
710 self.cx.current_expansion.prior_type_ascription = prev;
715 InvocationKind::Attr { attr, mut item, derives, after_derive } => match ext {
716 SyntaxExtensionKind::Attr(expander) => {
717 self.gate_proc_macro_input(&item);
718 self.gate_proc_macro_attr_item(span, &item);
719 let tokens = item.into_tokens(&self.cx.sess.parse_sess);
720 let attr_item = attr.unwrap_normal_item();
721 if let MacArgs::Eq(..) = attr_item.args {
722 self.cx.span_err(span, "key-value macro attributes are not supported");
724 let inner_tokens = attr_item.args.inner_tokens();
725 let tok_result = match expander.expand(self.cx, span, inner_tokens, tokens) {
726 Err(_) => return ExpandResult::Ready(fragment_kind.dummy(span)),
729 self.parse_ast_fragment(tok_result, fragment_kind, &attr_item.path, span)
731 SyntaxExtensionKind::LegacyAttr(expander) => {
732 match validate_attr::parse_meta(&self.cx.sess.parse_sess, &attr) {
734 let items = match expander.expand(self.cx, span, &meta, item) {
735 ExpandResult::Ready(items) => items,
736 ExpandResult::Retry(item) => {
737 // Reassemble the original invocation for retrying.
738 return ExpandResult::Retry(Invocation {
739 kind: InvocationKind::Attr {
749 fragment_kind.expect_from_annotatables(items)
753 fragment_kind.dummy(span)
757 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
758 self.cx.sess.mark_attr_known(&attr);
760 self.cx.sess.mark_attr_used(&attr);
762 item.visit_attrs(|attrs| attrs.push(attr));
763 fragment_kind.expect_from_annotatables(iter::once(item))
767 InvocationKind::Derive { path, item } => match ext {
768 SyntaxExtensionKind::Derive(expander)
769 | SyntaxExtensionKind::LegacyDerive(expander) => {
770 if let SyntaxExtensionKind::Derive(..) = ext {
771 self.gate_proc_macro_input(&item);
773 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
774 let items = match expander.expand(self.cx, span, &meta, item) {
775 ExpandResult::Ready(items) => items,
776 ExpandResult::Retry(item) => {
777 // Reassemble the original invocation for retrying.
778 return ExpandResult::Retry(Invocation {
779 kind: InvocationKind::Derive { path: meta.path, item },
784 fragment_kind.expect_from_annotatables(items)
788 InvocationKind::DeriveContainer { .. } => unreachable!(),
792 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
793 let kind = match item {
795 | Annotatable::TraitItem(_)
796 | Annotatable::ImplItem(_)
797 | Annotatable::ForeignItem(_) => return,
798 Annotatable::Stmt(stmt) => {
799 // Attributes are stable on item statements,
800 // but unstable on all other kinds of statements
806 Annotatable::Expr(_) => "expressions",
808 | Annotatable::Field(..)
809 | Annotatable::FieldPat(..)
810 | Annotatable::GenericParam(..)
811 | Annotatable::Param(..)
812 | Annotatable::StructField(..)
813 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
815 if self.cx.ecfg.proc_macro_hygiene() {
819 &self.cx.sess.parse_sess,
820 sym::proc_macro_hygiene,
822 &format!("custom attributes cannot be applied to {}", kind),
827 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
828 struct GateProcMacroInput<'a> {
829 parse_sess: &'a ParseSess,
832 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
833 fn visit_item(&mut self, item: &'ast ast::Item) {
835 ast::ItemKind::Mod(module) if !module.inline => {
838 sym::proc_macro_hygiene,
840 "non-inline modules in proc macro input are unstable",
847 visit::walk_item(self, item);
851 if !self.cx.ecfg.proc_macro_hygiene() {
853 .visit_with(&mut GateProcMacroInput { parse_sess: &self.cx.sess.parse_sess });
857 fn parse_ast_fragment(
860 kind: AstFragmentKind,
864 let mut parser = self.cx.new_parser_from_tts(toks);
865 match parse_ast_fragment(&mut parser, kind) {
867 ensure_complete_parse(&mut parser, path, kind.name(), span);
872 annotate_err_with_kind(&mut err, kind, span);
874 self.cx.trace_macros_diag();
881 pub fn parse_ast_fragment<'a>(
882 this: &mut Parser<'a>,
883 kind: AstFragmentKind,
884 ) -> PResult<'a, AstFragment> {
886 AstFragmentKind::Items => {
887 let mut items = SmallVec::new();
888 while let Some(item) = this.parse_item()? {
891 AstFragment::Items(items)
893 AstFragmentKind::TraitItems => {
894 let mut items = SmallVec::new();
895 while let Some(item) = this.parse_trait_item()? {
898 AstFragment::TraitItems(items)
900 AstFragmentKind::ImplItems => {
901 let mut items = SmallVec::new();
902 while let Some(item) = this.parse_impl_item()? {
905 AstFragment::ImplItems(items)
907 AstFragmentKind::ForeignItems => {
908 let mut items = SmallVec::new();
909 while let Some(item) = this.parse_foreign_item()? {
912 AstFragment::ForeignItems(items)
914 AstFragmentKind::Stmts => {
915 let mut stmts = SmallVec::new();
916 // Won't make progress on a `}`.
917 while this.token != token::Eof && this.token != token::CloseDelim(token::Brace) {
918 if let Some(stmt) = this.parse_full_stmt(AttemptLocalParseRecovery::Yes)? {
922 AstFragment::Stmts(stmts)
924 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
925 AstFragmentKind::OptExpr => {
926 if this.token != token::Eof {
927 AstFragment::OptExpr(Some(this.parse_expr()?))
929 AstFragment::OptExpr(None)
932 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
933 AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat(None)?),
934 AstFragmentKind::Arms
935 | AstFragmentKind::Fields
936 | AstFragmentKind::FieldPats
937 | AstFragmentKind::GenericParams
938 | AstFragmentKind::Params
939 | AstFragmentKind::StructFields
940 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
944 pub fn ensure_complete_parse<'a>(
945 this: &mut Parser<'a>,
950 if this.token != token::Eof {
951 let token = pprust::token_to_string(&this.token);
952 let msg = format!("macro expansion ignores token `{}` and any following", token);
953 // Avoid emitting backtrace info twice.
954 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
955 let mut err = this.struct_span_err(def_site_span, &msg);
956 err.span_label(span, "caused by the macro expansion here");
958 "the usage of `{}!` is likely invalid in {} context",
959 pprust::path_to_string(macro_path),
963 let semi_span = this.sess.source_map().next_point(span);
965 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
966 match this.sess.source_map().span_to_snippet(semi_full_span) {
967 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
970 "you might be missing a semicolon here",
972 Applicability::MaybeIncorrect,
981 struct InvocationCollector<'a, 'b> {
982 cx: &'a mut ExtCtxt<'b>,
983 cfg: StripUnconfigured<'a>,
984 invocations: Vec<(Invocation, Option<InvocationRes>)>,
988 impl<'a, 'b> InvocationCollector<'a, 'b> {
989 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
990 // Expansion data for all the collected invocations is set upon their resolution,
991 // with exception of the derive container case which is not resolved and can get
992 // its expansion data immediately.
993 let expn_data = match &kind {
994 InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
995 parent: self.cx.current_expansion.id,
997 ExpnKind::Macro(MacroKind::Attr, sym::derive),
999 self.cx.sess.parse_sess.edition,
1005 let expn_id = ExpnId::fresh(expn_data);
1006 let vis = kind.placeholder_visibility();
1007 self.invocations.push((
1011 expansion_data: ExpansionData {
1013 depth: self.cx.current_expansion.depth + 1,
1014 ..self.cx.current_expansion.clone()
1019 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
1026 kind: AstFragmentKind,
1028 self.collect(kind, InvocationKind::Bang { mac, span })
1033 (attr, derives, after_derive): (Option<ast::Attribute>, Vec<Path>, bool),
1035 kind: AstFragmentKind,
1040 Some(attr) => InvocationKind::Attr { attr, item, derives, after_derive },
1041 None => InvocationKind::DeriveContainer { derives, item },
1048 attrs: &mut Vec<ast::Attribute>,
1049 after_derive: &mut bool,
1050 ) -> Option<ast::Attribute> {
1054 if a.has_name(sym::derive) {
1055 *after_derive = true;
1057 !self.cx.sess.is_attr_known(a) && !is_builtin_attr(a)
1059 .map(|i| attrs.remove(i))
1062 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1065 item: &mut impl HasAttrs,
1066 ) -> Option<(Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)> {
1067 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1069 item.visit_attrs(|mut attrs| {
1070 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1071 traits = collect_derives(&mut self.cx, &mut attrs);
1074 if attr.is_some() || !traits.is_empty() { Some((attr, traits, after_derive)) } else { None }
1077 /// Alternative to `take_first_attr()` that ignores `#[derive]` so invocations fallthrough
1078 /// to the unused-attributes lint (making it an error on statements and expressions
1079 /// is a breaking change)
1080 fn take_first_attr_no_derive(
1082 nonitem: &mut impl HasAttrs,
1083 ) -> Option<(Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)> {
1084 let (mut attr, mut after_derive) = (None, false);
1086 nonitem.visit_attrs(|mut attrs| {
1087 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1090 attr.map(|attr| (Some(attr), Vec::new(), after_derive))
1093 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1094 self.cfg.configure(node)
1097 // Detect use of feature-gated or invalid attributes on macro invocations
1098 // since they will not be detected after macro expansion.
1099 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1100 let features = self.cx.ecfg.features.unwrap();
1101 for attr in attrs.iter() {
1102 rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
1103 validate_attr::check_meta(&self.cx.sess.parse_sess, attr);
1105 // macros are expanded before any lint passes so this warning has to be hardcoded
1106 if attr.has_name(sym::derive) {
1110 .struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1111 .note("this may become a hard error in a future release")
1115 if attr.doc_str().is_some() {
1116 self.cx.sess.parse_sess.buffer_lint_with_diagnostic(
1117 &UNUSED_DOC_COMMENTS,
1120 "unused doc comment",
1121 BuiltinLintDiagnostics::UnusedDocComment(attr.span),
1128 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1129 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1130 self.cfg.configure_expr(expr);
1131 visit_clobber(expr.deref_mut(), |mut expr| {
1132 self.cfg.configure_expr_kind(&mut expr.kind);
1134 if let Some(attr) = self.take_first_attr_no_derive(&mut expr) {
1135 // Collect the invoc regardless of whether or not attributes are permitted here
1136 // expansion will eat the attribute so it won't error later.
1137 if let Some(attr) = attr.0.as_ref() {
1138 self.cfg.maybe_emit_expr_attr_err(attr)
1141 // AstFragmentKind::Expr requires the macro to emit an expression.
1143 .collect_attr(attr, Annotatable::Expr(P(expr)), AstFragmentKind::Expr)
1148 if let ast::ExprKind::MacCall(mac) = expr.kind {
1149 self.check_attributes(&expr.attrs);
1150 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
1152 ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
1158 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1159 let mut arm = configure!(self, arm);
1161 if let Some(attr) = self.take_first_attr(&mut arm) {
1163 .collect_attr(attr, Annotatable::Arm(arm), AstFragmentKind::Arms)
1167 noop_flat_map_arm(arm, self)
1170 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
1171 let mut field = configure!(self, field);
1173 if let Some(attr) = self.take_first_attr(&mut field) {
1175 .collect_attr(attr, Annotatable::Field(field), AstFragmentKind::Fields)
1179 noop_flat_map_field(field, self)
1182 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
1183 let mut fp = configure!(self, fp);
1185 if let Some(attr) = self.take_first_attr(&mut fp) {
1187 .collect_attr(attr, Annotatable::FieldPat(fp), AstFragmentKind::FieldPats)
1188 .make_field_patterns();
1191 noop_flat_map_field_pattern(fp, self)
1194 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1195 let mut p = configure!(self, p);
1197 if let Some(attr) = self.take_first_attr(&mut p) {
1199 .collect_attr(attr, Annotatable::Param(p), AstFragmentKind::Params)
1203 noop_flat_map_param(p, self)
1206 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
1207 let mut sf = configure!(self, sf);
1209 if let Some(attr) = self.take_first_attr(&mut sf) {
1211 .collect_attr(attr, Annotatable::StructField(sf), AstFragmentKind::StructFields)
1212 .make_struct_fields();
1215 noop_flat_map_struct_field(sf, self)
1218 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1219 let mut variant = configure!(self, variant);
1221 if let Some(attr) = self.take_first_attr(&mut variant) {
1223 .collect_attr(attr, Annotatable::Variant(variant), AstFragmentKind::Variants)
1227 noop_flat_map_variant(variant, self)
1230 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1231 let expr = configure!(self, expr);
1232 expr.filter_map(|mut expr| {
1233 self.cfg.configure_expr_kind(&mut expr.kind);
1235 if let Some(attr) = self.take_first_attr_no_derive(&mut expr) {
1236 if let Some(attr) = attr.0.as_ref() {
1237 self.cfg.maybe_emit_expr_attr_err(attr)
1241 .collect_attr(attr, Annotatable::Expr(P(expr)), AstFragmentKind::OptExpr)
1243 .map(|expr| expr.into_inner());
1246 if let ast::ExprKind::MacCall(mac) = expr.kind {
1247 self.check_attributes(&expr.attrs);
1248 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1250 .map(|expr| expr.into_inner())
1253 noop_visit_expr(&mut expr, self);
1260 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1261 self.cfg.configure_pat(pat);
1263 PatKind::MacCall(_) => {}
1264 _ => return noop_visit_pat(pat, self),
1267 visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
1268 PatKind::MacCall(mac) => {
1269 self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat()
1271 _ => unreachable!(),
1275 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1276 let mut stmt = configure!(self, stmt);
1278 // we'll expand attributes on expressions separately
1279 if !stmt.is_expr() {
1280 let attr = if stmt.is_item() {
1281 self.take_first_attr(&mut stmt)
1283 // Ignore derives on non-item statements for backwards compatibility.
1284 // This will result in a unused attribute warning
1285 self.take_first_attr_no_derive(&mut stmt)
1288 if let Some(attr) = attr {
1290 .collect_attr(attr, Annotatable::Stmt(P(stmt)), AstFragmentKind::Stmts)
1295 if let StmtKind::MacCall(mac) = stmt.kind {
1296 let MacCallStmt { mac, style, attrs, tokens: _ } = mac.into_inner();
1297 self.check_attributes(&attrs);
1298 let mut placeholder =
1299 self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts).make_stmts();
1301 // If this is a macro invocation with a semicolon, then apply that
1302 // semicolon to the final statement produced by expansion.
1303 if style == MacStmtStyle::Semicolon {
1304 if let Some(stmt) = placeholder.pop() {
1305 placeholder.push(stmt.add_trailing_semicolon());
1312 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1313 let ast::Stmt { id, kind, span } = stmt;
1314 noop_flat_map_stmt_kind(kind, self)
1316 .map(|kind| ast::Stmt { id, kind, span })
1320 fn visit_block(&mut self, block: &mut P<Block>) {
1321 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1322 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1323 noop_visit_block(block, self);
1324 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1327 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1328 let mut item = configure!(self, item);
1330 if let Some(attr) = self.take_first_attr(&mut item) {
1332 .collect_attr(attr, Annotatable::Item(item), AstFragmentKind::Items)
1336 let mut attrs = mem::take(&mut item.attrs); // We do this to please borrowck.
1337 let ident = item.ident;
1338 let span = item.span;
1341 ast::ItemKind::MacCall(..) => {
1343 self.check_attributes(&item.attrs);
1344 item.and_then(|item| match item.kind {
1345 ItemKind::MacCall(mac) => {
1346 self.collect_bang(mac, span, AstFragmentKind::Items).make_items()
1348 _ => unreachable!(),
1351 ast::ItemKind::Mod(ref mut old_mod @ ast::Mod { .. }) if ident != Ident::invalid() => {
1352 let sess = &self.cx.sess.parse_sess;
1353 let orig_ownership = self.cx.current_expansion.directory_ownership;
1354 let mut module = (*self.cx.current_expansion.module).clone();
1356 let pushed = &mut false; // Record `parse_external_mod` pushing so we can pop.
1357 let dir = Directory { ownership: orig_ownership, path: module.directory };
1358 let Directory { ownership, path } = if old_mod.inline {
1359 // Inline `mod foo { ... }`, but we still need to push directories.
1361 push_directory(&self.cx.sess, ident, &item.attrs, dir)
1363 // We have an outline `mod foo;` so we need to parse the file.
1364 let (new_mod, dir) = parse_external_mod(
1374 let krate = ast::Crate {
1375 span: new_mod.inner,
1378 proc_macros: vec![],
1380 if let Some(extern_mod_loaded) = self.cx.extern_mod_loaded {
1381 extern_mod_loaded(&krate);
1384 *old_mod = krate.module;
1385 item.attrs = krate.attrs;
1386 // File can have inline attributes, e.g., `#![cfg(...)]` & co. => Reconfigure.
1387 item = match self.configure(item) {
1391 sess.included_mod_stack.borrow_mut().pop();
1393 return Default::default();
1399 // Set the module info before we flat map.
1400 self.cx.current_expansion.directory_ownership = ownership;
1401 module.directory = path;
1402 module.mod_path.push(ident);
1404 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1406 let result = noop_flat_map_item(item, self);
1408 // Restore the module info.
1409 self.cx.current_expansion.module = orig_module;
1410 self.cx.current_expansion.directory_ownership = orig_ownership;
1412 sess.included_mod_stack.borrow_mut().pop();
1418 noop_flat_map_item(item, self)
1423 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1424 let mut item = configure!(self, item);
1426 if let Some(attr) = self.take_first_attr(&mut item) {
1428 .collect_attr(attr, Annotatable::TraitItem(item), AstFragmentKind::TraitItems)
1429 .make_trait_items();
1433 ast::AssocItemKind::MacCall(..) => {
1434 self.check_attributes(&item.attrs);
1435 item.and_then(|item| match item.kind {
1436 ast::AssocItemKind::MacCall(mac) => self
1437 .collect_bang(mac, item.span, AstFragmentKind::TraitItems)
1438 .make_trait_items(),
1439 _ => unreachable!(),
1442 _ => noop_flat_map_assoc_item(item, self),
1446 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1447 let mut item = configure!(self, item);
1449 if let Some(attr) = self.take_first_attr(&mut item) {
1451 .collect_attr(attr, Annotatable::ImplItem(item), AstFragmentKind::ImplItems)
1456 ast::AssocItemKind::MacCall(..) => {
1457 self.check_attributes(&item.attrs);
1458 item.and_then(|item| match item.kind {
1459 ast::AssocItemKind::MacCall(mac) => self
1460 .collect_bang(mac, item.span, AstFragmentKind::ImplItems)
1462 _ => unreachable!(),
1465 _ => noop_flat_map_assoc_item(item, self),
1469 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1471 ast::TyKind::MacCall(_) => {}
1472 _ => return noop_visit_ty(ty, self),
1475 visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1476 ast::TyKind::MacCall(mac) => {
1477 self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty()
1479 _ => unreachable!(),
1483 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1484 self.cfg.configure_foreign_mod(foreign_mod);
1485 noop_visit_foreign_mod(foreign_mod, self);
1488 fn flat_map_foreign_item(
1490 mut foreign_item: P<ast::ForeignItem>,
1491 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
1492 if let Some(attr) = self.take_first_attr(&mut foreign_item) {
1496 Annotatable::ForeignItem(foreign_item),
1497 AstFragmentKind::ForeignItems,
1499 .make_foreign_items();
1502 match foreign_item.kind {
1503 ast::ForeignItemKind::MacCall(..) => {
1504 self.check_attributes(&foreign_item.attrs);
1505 foreign_item.and_then(|item| match item.kind {
1506 ast::ForeignItemKind::MacCall(mac) => self
1507 .collect_bang(mac, item.span, AstFragmentKind::ForeignItems)
1508 .make_foreign_items(),
1509 _ => unreachable!(),
1512 _ => noop_flat_map_foreign_item(foreign_item, self),
1516 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1518 ast::ItemKind::MacroDef(..) => {}
1520 self.cfg.configure_item_kind(item);
1521 noop_visit_item_kind(item, self);
1526 fn flat_map_generic_param(
1528 param: ast::GenericParam,
1529 ) -> SmallVec<[ast::GenericParam; 1]> {
1530 let mut param = configure!(self, param);
1532 if let Some(attr) = self.take_first_attr(&mut param) {
1536 Annotatable::GenericParam(param),
1537 AstFragmentKind::GenericParams,
1539 .make_generic_params();
1542 noop_flat_map_generic_param(param, self)
1545 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1546 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1547 // contents="file contents")]` attributes
1548 if !self.cx.sess.check_name(at, sym::doc) {
1549 return noop_visit_attribute(at, self);
1552 if let Some(list) = at.meta_item_list() {
1553 if !list.iter().any(|it| it.has_name(sym::include)) {
1554 return noop_visit_attribute(at, self);
1557 let mut items = vec![];
1559 for mut it in list {
1560 if !it.has_name(sym::include) {
1562 noop_visit_meta_list_item(&mut it, self);
1568 if let Some(file) = it.value_str() {
1569 let err_count = self.cx.sess.parse_sess.span_diagnostic.err_count();
1570 self.check_attributes(slice::from_ref(at));
1571 if self.cx.sess.parse_sess.span_diagnostic.err_count() > err_count {
1572 // avoid loading the file if they haven't enabled the feature
1573 return noop_visit_attribute(at, self);
1576 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1577 Ok(filename) => filename,
1584 match self.cx.source_map().load_file(&filename) {
1585 Ok(source_file) => {
1586 let src = source_file
1589 .expect("freshly loaded file should have a source");
1590 let src_interned = Symbol::intern(src.as_str());
1592 let include_info = vec![
1593 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1594 Ident::with_dummy_span(sym::file),
1598 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1599 Ident::with_dummy_span(sym::contents),
1605 let include_ident = Ident::with_dummy_span(sym::include);
1606 let item = attr::mk_list_item(include_ident, include_info);
1607 items.push(ast::NestedMetaItem::MetaItem(item));
1610 let lit_span = it.name_value_literal_span().unwrap();
1612 if e.kind() == ErrorKind::InvalidData {
1616 &format!("{} wasn't a utf-8 file", filename.display()),
1618 .span_label(lit_span, "contains invalid utf-8")
1621 let mut err = self.cx.struct_span_err(
1623 &format!("couldn't read {}: {}", filename.display(), e),
1625 err.span_label(lit_span, "couldn't read file");
1634 .struct_span_err(it.span(), "expected path to external documentation");
1636 // Check if the user erroneously used `doc(include(...))` syntax.
1637 let literal = it.meta_item_list().and_then(|list| {
1638 if list.len() == 1 {
1639 list[0].literal().map(|literal| &literal.kind)
1645 let (path, applicability) = match &literal {
1646 Some(LitKind::Str(path, ..)) => {
1647 (path.to_string(), Applicability::MachineApplicable)
1649 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1652 err.span_suggestion(
1654 "provide a file path with `=`",
1655 format!("include = \"{}\"", path),
1663 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1664 *at = ast::Attribute {
1665 kind: ast::AttrKind::Normal(
1666 AttrItem { path: meta.path, args: meta.kind.mac_args(meta.span), tokens: None },
1674 noop_visit_attribute(at, self)
1678 fn visit_id(&mut self, id: &mut ast::NodeId) {
1680 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1681 *id = self.cx.resolver.next_node_id()
1685 fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
1686 self.cfg.configure_fn_decl(&mut fn_decl);
1687 noop_visit_fn_decl(fn_decl, self);
1691 pub struct ExpansionConfig<'feat> {
1692 pub crate_name: String,
1693 pub features: Option<&'feat Features>,
1694 pub recursion_limit: Limit,
1695 pub trace_mac: bool,
1696 pub should_test: bool, // If false, strip `#[test]` nodes
1697 pub keep_macs: bool,
1698 pub span_debug: bool, // If true, use verbose debugging for `proc_macro::Span`
1699 pub proc_macro_backtrace: bool, // If true, show backtraces for proc-macro panics
1702 impl<'feat> ExpansionConfig<'feat> {
1703 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1707 recursion_limit: Limit::new(1024),
1712 proc_macro_backtrace: false,
1716 fn proc_macro_hygiene(&self) -> bool {
1717 self.features.map_or(false, |features| features.proc_macro_hygiene)