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) {
506 let attr = attr::find_by_name(item.attrs(), sym::derive);
507 let span = attr.map_or(item.span(), |attr| attr.span);
510 .struct_span_err(span, "`derive` may only be applied to structs, enums and unions");
511 if let Some(ast::Attribute { style: ast::AttrStyle::Inner, .. }) = attr {
512 let trait_list = derives.iter().map(|t| pprust::path_to_string(t)).collect::<Vec<_>>();
513 let suggestion = format!("#[derive({})]", trait_list.join(", "));
516 "try an outer attribute",
518 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
519 Applicability::MaybeIncorrect,
525 fn resolve_imports(&mut self) {
527 self.cx.resolver.resolve_imports();
531 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
532 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
533 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
534 /// prepares data for resolving paths of macro invocations.
535 fn collect_invocations(
537 mut fragment: AstFragment,
538 extra_placeholders: &[NodeId],
539 ) -> (AstFragment, Vec<Invocation>) {
540 // Resolve `$crate`s in the fragment for pretty-printing.
541 self.cx.resolver.resolve_dollar_crates();
544 let mut collector = InvocationCollector {
545 cfg: StripUnconfigured {
546 sess: self.cx.parse_sess,
547 features: self.cx.ecfg.features,
550 invocations: Vec::new(),
551 monotonic: self.monotonic,
553 fragment.mut_visit_with(&mut collector);
554 fragment.add_placeholders(extra_placeholders);
555 collector.invocations
561 .visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
564 (fragment, invocations)
567 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
569 StripUnconfigured { sess: self.cx.parse_sess, features: self.cx.ecfg.features };
570 // Since the item itself has already been configured by the InvocationCollector,
571 // we know that fold result vector will contain exactly one element
573 Annotatable::Item(item) => Annotatable::Item(cfg.flat_map_item(item).pop().unwrap()),
574 Annotatable::TraitItem(item) => {
575 Annotatable::TraitItem(cfg.flat_map_trait_item(item).pop().unwrap())
577 Annotatable::ImplItem(item) => {
578 Annotatable::ImplItem(cfg.flat_map_impl_item(item).pop().unwrap())
580 Annotatable::ForeignItem(item) => {
581 Annotatable::ForeignItem(cfg.flat_map_foreign_item(item).pop().unwrap())
583 Annotatable::Stmt(stmt) => {
584 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
586 Annotatable::Expr(mut expr) => Annotatable::Expr({
587 cfg.visit_expr(&mut expr);
590 Annotatable::Arm(arm) => Annotatable::Arm(cfg.flat_map_arm(arm).pop().unwrap()),
591 Annotatable::Field(field) => {
592 Annotatable::Field(cfg.flat_map_field(field).pop().unwrap())
594 Annotatable::FieldPat(fp) => {
595 Annotatable::FieldPat(cfg.flat_map_field_pattern(fp).pop().unwrap())
597 Annotatable::GenericParam(param) => {
598 Annotatable::GenericParam(cfg.flat_map_generic_param(param).pop().unwrap())
600 Annotatable::Param(param) => {
601 Annotatable::Param(cfg.flat_map_param(param).pop().unwrap())
603 Annotatable::StructField(sf) => {
604 Annotatable::StructField(cfg.flat_map_struct_field(sf).pop().unwrap())
606 Annotatable::Variant(v) => Annotatable::Variant(cfg.flat_map_variant(v).pop().unwrap()),
610 fn error_recursion_limit_reached(&mut self) {
611 let expn_data = self.cx.current_expansion.id.expn_data();
612 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
616 &format!("recursion limit reached while expanding `{}`", expn_data.kind.descr()),
619 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate (`{}`)",
620 suggested_limit, self.cx.ecfg.crate_name,
623 self.cx.trace_macros_diag();
627 /// A macro's expansion does not fit in this fragment kind.
628 /// For example, a non-type macro in a type position.
629 fn error_wrong_fragment_kind(&mut self, kind: AstFragmentKind, mac: &ast::Mac, span: Span) {
631 "non-{kind} macro in {kind} position: {path}",
633 path = pprust::path_to_string(&mac.path),
635 self.cx.span_err(span, &msg);
636 self.cx.trace_macros_diag();
639 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment {
640 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
641 self.error_recursion_limit_reached();
644 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
646 InvocationKind::Bang { mac, .. } => match ext {
647 SyntaxExtensionKind::Bang(expander) => {
648 self.gate_proc_macro_expansion_kind(span, fragment_kind);
649 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
650 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
652 SyntaxExtensionKind::LegacyBang(expander) => {
653 let prev = self.cx.current_expansion.prior_type_ascription;
654 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
655 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
656 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
659 self.error_wrong_fragment_kind(fragment_kind, &mac, span);
660 fragment_kind.dummy(span)
662 self.cx.current_expansion.prior_type_ascription = prev;
667 InvocationKind::Attr { attr, mut item, .. } => match ext {
668 SyntaxExtensionKind::Attr(expander) => {
669 self.gate_proc_macro_input(&item);
670 self.gate_proc_macro_attr_item(span, &item);
671 // `Annotatable` can be converted into tokens directly, but we are packing it
672 // into a nonterminal as a piece of AST to make the produced token stream
673 // look nicer in pretty-printed form. This may be no longer necessary.
674 let item_tok = TokenTree::token(
675 token::Interpolated(Lrc::new(match item {
676 Annotatable::Item(item) => token::NtItem(item),
677 Annotatable::TraitItem(item)
678 | Annotatable::ImplItem(item)
679 | Annotatable::ForeignItem(item) => {
680 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
682 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
683 Annotatable::Expr(expr) => token::NtExpr(expr),
685 | Annotatable::Field(..)
686 | Annotatable::FieldPat(..)
687 | Annotatable::GenericParam(..)
688 | Annotatable::Param(..)
689 | Annotatable::StructField(..)
690 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
695 let item = attr.unwrap_normal_item();
696 if let MacArgs::Eq(..) = item.args {
697 self.cx.span_err(span, "key-value macro attributes are not supported");
700 expander.expand(self.cx, span, item.args.inner_tokens(), item_tok);
701 self.parse_ast_fragment(tok_result, fragment_kind, &item.path, span)
703 SyntaxExtensionKind::LegacyAttr(expander) => {
704 match validate_attr::parse_meta(self.cx.parse_sess, &attr) {
706 let item = expander.expand(self.cx, span, &meta, item);
707 fragment_kind.expect_from_annotatables(item)
711 fragment_kind.dummy(span)
715 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
716 attr::mark_known(&attr);
718 attr::mark_used(&attr);
720 item.visit_attrs(|attrs| attrs.push(attr));
721 fragment_kind.expect_from_annotatables(iter::once(item))
725 InvocationKind::Derive { path, item } => match ext {
726 SyntaxExtensionKind::Derive(expander)
727 | SyntaxExtensionKind::LegacyDerive(expander) => {
728 if !item.derive_allowed() {
729 return fragment_kind.dummy(span);
731 if let SyntaxExtensionKind::Derive(..) = ext {
732 self.gate_proc_macro_input(&item);
734 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
735 let items = expander.expand(self.cx, span, &meta, item);
736 fragment_kind.expect_from_annotatables(items)
740 InvocationKind::DeriveContainer { .. } => unreachable!(),
744 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
745 let kind = match item {
747 | Annotatable::TraitItem(_)
748 | Annotatable::ImplItem(_)
749 | Annotatable::ForeignItem(_) => return,
750 Annotatable::Stmt(_) => "statements",
751 Annotatable::Expr(_) => "expressions",
753 | Annotatable::Field(..)
754 | Annotatable::FieldPat(..)
755 | Annotatable::GenericParam(..)
756 | Annotatable::Param(..)
757 | Annotatable::StructField(..)
758 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
760 if self.cx.ecfg.proc_macro_hygiene() {
765 sym::proc_macro_hygiene,
767 &format!("custom attributes cannot be applied to {}", kind),
772 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
773 struct GateProcMacroInput<'a> {
774 parse_sess: &'a ParseSess,
777 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
778 fn visit_item(&mut self, item: &'ast ast::Item) {
780 ast::ItemKind::Mod(module) if !module.inline => {
783 sym::proc_macro_hygiene,
785 "non-inline modules in proc macro input are unstable",
792 visit::walk_item(self, item);
795 fn visit_mac(&mut self, _: &'ast ast::Mac) {}
798 if !self.cx.ecfg.proc_macro_hygiene() {
799 annotatable.visit_with(&mut GateProcMacroInput { parse_sess: self.cx.parse_sess });
803 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
804 let kind = match kind {
805 AstFragmentKind::Expr | AstFragmentKind::OptExpr => "expressions",
806 AstFragmentKind::Pat => "patterns",
807 AstFragmentKind::Stmts => "statements",
809 | AstFragmentKind::Items
810 | AstFragmentKind::TraitItems
811 | AstFragmentKind::ImplItems
812 | AstFragmentKind::ForeignItems => return,
813 AstFragmentKind::Arms
814 | AstFragmentKind::Fields
815 | AstFragmentKind::FieldPats
816 | AstFragmentKind::GenericParams
817 | AstFragmentKind::Params
818 | AstFragmentKind::StructFields
819 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
821 if self.cx.ecfg.proc_macro_hygiene() {
826 sym::proc_macro_hygiene,
828 &format!("procedural macros cannot be expanded to {}", kind),
833 fn parse_ast_fragment(
836 kind: AstFragmentKind,
840 let mut parser = self.cx.new_parser_from_tts(toks);
841 match parse_ast_fragment(&mut parser, kind) {
843 ensure_complete_parse(&mut parser, path, kind.name(), span);
848 annotate_err_with_kind(&mut err, kind, span);
850 self.cx.trace_macros_diag();
857 pub fn parse_ast_fragment<'a>(
858 this: &mut Parser<'a>,
859 kind: AstFragmentKind,
860 ) -> PResult<'a, AstFragment> {
862 AstFragmentKind::Items => {
863 let mut items = SmallVec::new();
864 while let Some(item) = this.parse_item()? {
867 AstFragment::Items(items)
869 AstFragmentKind::TraitItems => {
870 let mut items = SmallVec::new();
871 while let Some(item) = this.parse_trait_item()? {
874 AstFragment::TraitItems(items)
876 AstFragmentKind::ImplItems => {
877 let mut items = SmallVec::new();
878 while let Some(item) = this.parse_impl_item()? {
881 AstFragment::ImplItems(items)
883 AstFragmentKind::ForeignItems => {
884 let mut items = SmallVec::new();
885 while let Some(item) = this.parse_foreign_item()? {
888 AstFragment::ForeignItems(items)
890 AstFragmentKind::Stmts => {
891 let mut stmts = SmallVec::new();
892 // Won't make progress on a `}`.
893 while this.token != token::Eof && this.token != token::CloseDelim(token::Brace) {
894 if let Some(stmt) = this.parse_full_stmt()? {
898 AstFragment::Stmts(stmts)
900 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
901 AstFragmentKind::OptExpr => {
902 if this.token != token::Eof {
903 AstFragment::OptExpr(Some(this.parse_expr()?))
905 AstFragment::OptExpr(None)
908 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
909 AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat(None)?),
910 AstFragmentKind::Arms
911 | AstFragmentKind::Fields
912 | AstFragmentKind::FieldPats
913 | AstFragmentKind::GenericParams
914 | AstFragmentKind::Params
915 | AstFragmentKind::StructFields
916 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
920 pub fn ensure_complete_parse<'a>(
921 this: &mut Parser<'a>,
926 if this.token != token::Eof {
927 let token = pprust::token_to_string(&this.token);
928 let msg = format!("macro expansion ignores token `{}` and any following", token);
929 // Avoid emitting backtrace info twice.
930 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
931 let mut err = this.struct_span_err(def_site_span, &msg);
932 err.span_label(span, "caused by the macro expansion here");
934 "the usage of `{}!` is likely invalid in {} context",
935 pprust::path_to_string(macro_path),
939 let semi_span = this.sess.source_map().next_point(span);
941 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
942 match this.sess.source_map().span_to_snippet(semi_full_span) {
943 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
946 "you might be missing a semicolon here",
948 Applicability::MaybeIncorrect,
957 struct InvocationCollector<'a, 'b> {
958 cx: &'a mut ExtCtxt<'b>,
959 cfg: StripUnconfigured<'a>,
960 invocations: Vec<Invocation>,
964 impl<'a, 'b> InvocationCollector<'a, 'b> {
965 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
966 // Expansion data for all the collected invocations is set upon their resolution,
967 // with exception of the derive container case which is not resolved and can get
968 // its expansion data immediately.
969 let expn_data = match &kind {
970 InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
971 parent: self.cx.current_expansion.id,
973 ExpnKind::Macro(MacroKind::Attr, sym::derive),
975 self.cx.parse_sess.edition,
980 let expn_id = ExpnId::fresh(expn_data);
981 let vis = kind.placeholder_visibility();
982 self.invocations.push(Invocation {
985 expansion_data: ExpansionData {
987 depth: self.cx.current_expansion.depth + 1,
988 ..self.cx.current_expansion.clone()
991 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
994 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
995 self.collect(kind, InvocationKind::Bang { mac, span })
1000 attr: Option<ast::Attribute>,
1003 kind: AstFragmentKind,
1009 Some(attr) => InvocationKind::Attr { attr, item, derives, after_derive },
1010 None => InvocationKind::DeriveContainer { derives, item },
1017 attrs: &mut Vec<ast::Attribute>,
1018 after_derive: &mut bool,
1019 ) -> Option<ast::Attribute> {
1023 if a.has_name(sym::derive) {
1024 *after_derive = true;
1026 !attr::is_known(a) && !is_builtin_attr(a)
1028 .map(|i| attrs.remove(i));
1029 if let Some(attr) = &attr {
1030 if !self.cx.ecfg.custom_inner_attributes()
1031 && attr.style == ast::AttrStyle::Inner
1032 && !attr.has_name(sym::test)
1035 &self.cx.parse_sess,
1036 sym::custom_inner_attributes,
1038 "non-builtin inner attributes are unstable",
1046 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1049 item: &mut impl HasAttrs,
1050 ) -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool) {
1051 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1053 item.visit_attrs(|mut attrs| {
1054 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1055 traits = collect_derives(&mut self.cx, &mut attrs);
1058 (attr, traits, after_derive)
1061 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1062 /// to the unused-attributes lint (making it an error on statements and expressions
1063 /// is a breaking change)
1064 fn classify_nonitem(
1066 nonitem: &mut impl HasAttrs,
1067 ) -> (Option<ast::Attribute>, /* after_derive */ bool) {
1068 let (mut attr, mut after_derive) = (None, false);
1070 nonitem.visit_attrs(|mut attrs| {
1071 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1074 (attr, after_derive)
1077 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1078 self.cfg.configure(node)
1081 // Detect use of feature-gated or invalid attributes on macro invocations
1082 // since they will not be detected after macro expansion.
1083 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1084 let features = self.cx.ecfg.features.unwrap();
1085 for attr in attrs.iter() {
1086 rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.parse_sess, features);
1087 validate_attr::check_meta(self.cx.parse_sess, attr);
1089 // macros are expanded before any lint passes so this warning has to be hardcoded
1090 if attr.has_name(sym::derive) {
1092 .struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1093 .note("this may become a hard error in a future release")
1097 if attr.doc_str().is_some() {
1098 self.cx.parse_sess.buffer_lint_with_diagnostic(
1099 &UNUSED_DOC_COMMENTS,
1102 "unused doc comment",
1103 BuiltinLintDiagnostics::UnusedDocComment(attr.span),
1110 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1111 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1112 self.cfg.configure_expr(expr);
1113 visit_clobber(expr.deref_mut(), |mut expr| {
1114 self.cfg.configure_expr_kind(&mut expr.kind);
1116 // ignore derives so they remain unused
1117 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1120 // Collect the invoc regardless of whether or not attributes are permitted here
1121 // expansion will eat the attribute so it won't error later.
1122 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1124 // AstFragmentKind::Expr requires the macro to emit an expression.
1129 Annotatable::Expr(P(expr)),
1130 AstFragmentKind::Expr,
1137 if let ast::ExprKind::Mac(mac) = expr.kind {
1138 self.check_attributes(&expr.attrs);
1139 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
1141 noop_visit_expr(&mut expr, self);
1147 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1148 let mut arm = configure!(self, arm);
1150 let (attr, traits, after_derive) = self.classify_item(&mut arm);
1151 if attr.is_some() || !traits.is_empty() {
1156 Annotatable::Arm(arm),
1157 AstFragmentKind::Arms,
1163 noop_flat_map_arm(arm, self)
1166 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
1167 let mut field = configure!(self, field);
1169 let (attr, traits, after_derive) = self.classify_item(&mut field);
1170 if attr.is_some() || !traits.is_empty() {
1175 Annotatable::Field(field),
1176 AstFragmentKind::Fields,
1182 noop_flat_map_field(field, self)
1185 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
1186 let mut fp = configure!(self, fp);
1188 let (attr, traits, after_derive) = self.classify_item(&mut fp);
1189 if attr.is_some() || !traits.is_empty() {
1194 Annotatable::FieldPat(fp),
1195 AstFragmentKind::FieldPats,
1198 .make_field_patterns();
1201 noop_flat_map_field_pattern(fp, self)
1204 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1205 let mut p = configure!(self, p);
1207 let (attr, traits, after_derive) = self.classify_item(&mut p);
1208 if attr.is_some() || !traits.is_empty() {
1213 Annotatable::Param(p),
1214 AstFragmentKind::Params,
1220 noop_flat_map_param(p, self)
1223 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
1224 let mut sf = configure!(self, sf);
1226 let (attr, traits, after_derive) = self.classify_item(&mut sf);
1227 if attr.is_some() || !traits.is_empty() {
1232 Annotatable::StructField(sf),
1233 AstFragmentKind::StructFields,
1236 .make_struct_fields();
1239 noop_flat_map_struct_field(sf, self)
1242 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1243 let mut variant = configure!(self, variant);
1245 let (attr, traits, after_derive) = self.classify_item(&mut variant);
1246 if attr.is_some() || !traits.is_empty() {
1251 Annotatable::Variant(variant),
1252 AstFragmentKind::Variants,
1258 noop_flat_map_variant(variant, self)
1261 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1262 let expr = configure!(self, expr);
1263 expr.filter_map(|mut expr| {
1264 self.cfg.configure_expr_kind(&mut expr.kind);
1266 // Ignore derives so they remain unused.
1267 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1270 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1276 Annotatable::Expr(P(expr)),
1277 AstFragmentKind::OptExpr,
1281 .map(|expr| expr.into_inner());
1284 if let ast::ExprKind::Mac(mac) = expr.kind {
1285 self.check_attributes(&expr.attrs);
1286 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1288 .map(|expr| expr.into_inner())
1291 noop_visit_expr(&mut expr, self);
1298 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1299 self.cfg.configure_pat(pat);
1301 PatKind::Mac(_) => {}
1302 _ => return noop_visit_pat(pat, self),
1305 visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
1306 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1307 _ => unreachable!(),
1311 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1312 let mut stmt = configure!(self, stmt);
1314 // we'll expand attributes on expressions separately
1315 if !stmt.is_expr() {
1316 let (attr, derives, after_derive) = if stmt.is_item() {
1317 self.classify_item(&mut stmt)
1319 // ignore derives on non-item statements so it falls through
1320 // to the unused-attributes lint
1321 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1322 (attr, vec![], after_derive)
1325 if attr.is_some() || !derives.is_empty() {
1330 Annotatable::Stmt(P(stmt)),
1331 AstFragmentKind::Stmts,
1338 if let StmtKind::Mac(mac) = stmt.kind {
1339 let (mac, style, attrs) = mac.into_inner();
1340 self.check_attributes(&attrs);
1341 let mut placeholder =
1342 self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts).make_stmts();
1344 // If this is a macro invocation with a semicolon, then apply that
1345 // semicolon to the final statement produced by expansion.
1346 if style == MacStmtStyle::Semicolon {
1347 if let Some(stmt) = placeholder.pop() {
1348 placeholder.push(stmt.add_trailing_semicolon());
1355 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1356 let ast::Stmt { id, kind, span } = stmt;
1357 noop_flat_map_stmt_kind(kind, self)
1359 .map(|kind| ast::Stmt { id, kind, span })
1363 fn visit_block(&mut self, block: &mut P<Block>) {
1364 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1365 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1366 noop_visit_block(block, self);
1367 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1370 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1371 let mut item = configure!(self, item);
1373 let (attr, traits, after_derive) = self.classify_item(&mut item);
1374 if attr.is_some() || !traits.is_empty() {
1379 Annotatable::Item(item),
1380 AstFragmentKind::Items,
1387 ast::ItemKind::Mac(..) => {
1388 self.check_attributes(&item.attrs);
1389 item.and_then(|item| match item.kind {
1390 ItemKind::Mac(mac) => self
1392 AstFragmentKind::Items,
1393 InvocationKind::Bang { mac, span: item.span },
1396 _ => unreachable!(),
1399 ast::ItemKind::Mod(ast::Mod { inner, inline, .. })
1400 if item.ident != Ident::invalid() =>
1402 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1403 let mut module = (*self.cx.current_expansion.module).clone();
1404 module.mod_path.push(item.ident);
1407 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
1408 self.cx.current_expansion.directory_ownership =
1409 DirectoryOwnership::Owned { relative: None };
1410 module.directory.push(&*path.as_str());
1412 module.directory.push(&*item.ident.as_str());
1415 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1416 let mut path = match path {
1417 FileName::Real(path) => path,
1418 other => PathBuf::from(other.to_string()),
1420 let directory_ownership = match path.file_name().unwrap().to_str() {
1421 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1422 Some(_) => DirectoryOwnership::Owned { relative: Some(item.ident) },
1423 None => DirectoryOwnership::UnownedViaMod,
1426 module.directory = path;
1427 self.cx.current_expansion.directory_ownership = directory_ownership;
1431 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1432 let result = noop_flat_map_item(item, self);
1433 self.cx.current_expansion.module = orig_module;
1434 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1438 _ => noop_flat_map_item(item, self),
1442 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1443 let mut item = configure!(self, item);
1445 let (attr, traits, after_derive) = self.classify_item(&mut item);
1446 if attr.is_some() || !traits.is_empty() {
1451 Annotatable::TraitItem(item),
1452 AstFragmentKind::TraitItems,
1455 .make_trait_items();
1459 ast::AssocItemKind::Macro(..) => {
1460 self.check_attributes(&item.attrs);
1461 item.and_then(|item| match item.kind {
1462 ast::AssocItemKind::Macro(mac) => self
1463 .collect_bang(mac, item.span, AstFragmentKind::TraitItems)
1464 .make_trait_items(),
1465 _ => unreachable!(),
1468 _ => noop_flat_map_assoc_item(item, self),
1472 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1473 let mut item = configure!(self, item);
1475 let (attr, traits, after_derive) = self.classify_item(&mut item);
1476 if attr.is_some() || !traits.is_empty() {
1481 Annotatable::ImplItem(item),
1482 AstFragmentKind::ImplItems,
1489 ast::AssocItemKind::Macro(..) => {
1490 self.check_attributes(&item.attrs);
1491 item.and_then(|item| match item.kind {
1492 ast::AssocItemKind::Macro(mac) => self
1493 .collect_bang(mac, item.span, AstFragmentKind::ImplItems)
1495 _ => unreachable!(),
1498 _ => noop_flat_map_assoc_item(item, self),
1502 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1504 ast::TyKind::Mac(_) => {}
1505 _ => return noop_visit_ty(ty, self),
1508 visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1509 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1510 _ => unreachable!(),
1514 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1515 self.cfg.configure_foreign_mod(foreign_mod);
1516 noop_visit_foreign_mod(foreign_mod, self);
1519 fn flat_map_foreign_item(
1521 mut foreign_item: P<ast::ForeignItem>,
1522 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
1523 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1525 if attr.is_some() || !traits.is_empty() {
1530 Annotatable::ForeignItem(foreign_item),
1531 AstFragmentKind::ForeignItems,
1534 .make_foreign_items();
1537 match foreign_item.kind {
1538 ast::ForeignItemKind::Macro(..) => {
1539 self.check_attributes(&foreign_item.attrs);
1540 foreign_item.and_then(|item| match item.kind {
1541 ast::ForeignItemKind::Macro(mac) => self
1542 .collect_bang(mac, item.span, AstFragmentKind::ForeignItems)
1543 .make_foreign_items(),
1544 _ => unreachable!(),
1547 _ => noop_flat_map_foreign_item(foreign_item, self),
1551 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1553 ast::ItemKind::MacroDef(..) => {}
1555 self.cfg.configure_item_kind(item);
1556 noop_visit_item_kind(item, self);
1561 fn flat_map_generic_param(
1563 param: ast::GenericParam,
1564 ) -> SmallVec<[ast::GenericParam; 1]> {
1565 let mut param = configure!(self, param);
1567 let (attr, traits, after_derive) = self.classify_item(&mut param);
1568 if attr.is_some() || !traits.is_empty() {
1573 Annotatable::GenericParam(param),
1574 AstFragmentKind::GenericParams,
1577 .make_generic_params();
1580 noop_flat_map_generic_param(param, self)
1583 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1584 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1585 // contents="file contents")]` attributes
1586 if !at.check_name(sym::doc) {
1587 return noop_visit_attribute(at, self);
1590 if let Some(list) = at.meta_item_list() {
1591 if !list.iter().any(|it| it.check_name(sym::include)) {
1592 return noop_visit_attribute(at, self);
1595 let mut items = vec![];
1597 for mut it in list {
1598 if !it.check_name(sym::include) {
1600 noop_visit_meta_list_item(&mut it, self);
1606 if let Some(file) = it.value_str() {
1607 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1608 self.check_attributes(slice::from_ref(at));
1609 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1610 // avoid loading the file if they haven't enabled the feature
1611 return noop_visit_attribute(at, self);
1614 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1615 Ok(filename) => filename,
1622 match self.cx.source_map().load_file(&filename) {
1623 Ok(source_file) => {
1624 let src = source_file
1627 .expect("freshly loaded file should have a source");
1628 let src_interned = Symbol::intern(src.as_str());
1630 let include_info = vec![
1631 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1632 Ident::with_dummy_span(sym::file),
1636 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1637 Ident::with_dummy_span(sym::contents),
1643 let include_ident = Ident::with_dummy_span(sym::include);
1644 let item = attr::mk_list_item(include_ident, include_info);
1645 items.push(ast::NestedMetaItem::MetaItem(item));
1649 it.meta_item().and_then(|item| item.name_value_literal()).unwrap();
1651 if e.kind() == ErrorKind::InvalidData {
1655 &format!("{} wasn't a utf-8 file", filename.display()),
1657 .span_label(lit.span, "contains invalid utf-8")
1660 let mut err = self.cx.struct_span_err(
1662 &format!("couldn't read {}: {}", filename.display(), e),
1664 err.span_label(lit.span, "couldn't read file");
1673 .struct_span_err(it.span(), "expected path to external documentation");
1675 // Check if the user erroneously used `doc(include(...))` syntax.
1676 let literal = it.meta_item_list().and_then(|list| {
1677 if list.len() == 1 {
1678 list[0].literal().map(|literal| &literal.kind)
1684 let (path, applicability) = match &literal {
1685 Some(LitKind::Str(path, ..)) => {
1686 (path.to_string(), Applicability::MachineApplicable)
1688 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1691 err.span_suggestion(
1693 "provide a file path with `=`",
1694 format!("include = \"{}\"", path),
1702 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1703 *at = ast::Attribute {
1704 kind: ast::AttrKind::Normal(AttrItem {
1706 args: meta.kind.mac_args(meta.span),
1713 noop_visit_attribute(at, self)
1717 fn visit_id(&mut self, id: &mut ast::NodeId) {
1719 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1720 *id = self.cx.resolver.next_node_id()
1724 fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
1725 self.cfg.configure_fn_decl(&mut fn_decl);
1726 noop_visit_fn_decl(fn_decl, self);
1730 pub struct ExpansionConfig<'feat> {
1731 pub crate_name: String,
1732 pub features: Option<&'feat Features>,
1733 pub recursion_limit: usize,
1734 pub trace_mac: bool,
1735 pub should_test: bool, // If false, strip `#[test]` nodes
1736 pub single_step: bool,
1737 pub keep_macs: bool,
1740 impl<'feat> ExpansionConfig<'feat> {
1741 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1745 recursion_limit: 1024,
1753 fn proc_macro_hygiene(&self) -> bool {
1754 self.features.map_or(false, |features| features.proc_macro_hygiene)
1756 fn custom_inner_attributes(&self) -> bool {
1757 self.features.map_or(false, |features| features.custom_inner_attributes)