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::parse::{feature_err, ParseSess};
18 use rustc_span::source_map::respan;
19 use rustc_span::symbol::{sym, Symbol};
20 use rustc_span::{FileName, Span, DUMMY_SP};
21 use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
22 use syntax::ast::{ItemKind, MacArgs, MacStmtStyle, StmtKind};
23 use syntax::mut_visit::*;
26 use syntax::tokenstream::{TokenStream, TokenTree};
27 use syntax::util::map_in_place::MapInPlace;
28 use syntax::visit::{self, Visitor};
30 use smallvec::{smallvec, SmallVec};
31 use std::io::ErrorKind;
32 use std::ops::DerefMut;
33 use std::path::PathBuf;
35 use std::{iter, mem, slice};
37 macro_rules! ast_fragments {
39 $($Kind:ident($AstTy:ty) {
41 $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
42 $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident;)?
46 /// A fragment of AST that can be produced by a single macro expansion.
47 /// Can also serve as an input and intermediate result for macro expansion operations.
48 pub enum AstFragment {
49 OptExpr(Option<P<ast::Expr>>),
53 /// "Discriminant" of an AST fragment.
54 #[derive(Copy, Clone, PartialEq, Eq)]
55 pub enum AstFragmentKind {
60 impl AstFragmentKind {
61 pub fn name(self) -> &'static str {
63 AstFragmentKind::OptExpr => "expression",
64 $(AstFragmentKind::$Kind => $kind_name,)*
68 fn make_from<'a>(self, result: Box<dyn MacResult + 'a>) -> Option<AstFragment> {
70 AstFragmentKind::OptExpr =>
71 result.make_expr().map(Some).map(AstFragment::OptExpr),
72 $(AstFragmentKind::$Kind => result.$make_ast().map(AstFragment::$Kind),)*
78 pub fn add_placeholders(&mut self, placeholders: &[NodeId]) {
79 if placeholders.is_empty() {
83 $($(AstFragment::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| {
84 // We are repeating through arguments with `many`, to do that we have to
85 // mention some macro variable from those arguments even if it's not used.
86 macro _repeating($flat_map_ast_elt) {}
87 placeholder(AstFragmentKind::$Kind, *id, None).$make_ast()
89 _ => panic!("unexpected AST fragment kind")
93 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
95 AstFragment::OptExpr(expr) => expr,
96 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
100 $(pub fn $make_ast(self) -> $AstTy {
102 AstFragment::$Kind(ast) => ast,
103 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
107 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
109 AstFragment::OptExpr(opt_expr) => {
110 visit_clobber(opt_expr, |opt_expr| {
111 if let Some(expr) = opt_expr {
112 vis.filter_map_expr(expr)
118 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
119 $($(AstFragment::$Kind(ast) =>
120 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
124 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
126 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
127 AstFragment::OptExpr(None) => {}
128 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
129 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
130 visitor.$visit_ast_elt(ast_elt);
136 impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
137 $(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>)
139 Some(self.make(AstFragmentKind::$Kind).$make_ast())
146 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
147 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
148 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
149 Stmts(SmallVec<[ast::Stmt; 1]>) {
150 "statement"; many fn flat_map_stmt; fn visit_stmt; fn make_stmts;
152 Items(SmallVec<[P<ast::Item>; 1]>) {
153 "item"; many fn flat_map_item; fn visit_item; fn make_items;
155 TraitItems(SmallVec<[P<ast::AssocItem>; 1]>) {
156 "trait item"; many fn flat_map_trait_item; fn visit_trait_item; fn make_trait_items;
158 ImplItems(SmallVec<[P<ast::AssocItem>; 1]>) {
159 "impl item"; many fn flat_map_impl_item; fn visit_impl_item; fn make_impl_items;
161 ForeignItems(SmallVec<[P<ast::ForeignItem>; 1]>) {
163 many fn flat_map_foreign_item;
164 fn visit_foreign_item;
165 fn make_foreign_items;
167 Arms(SmallVec<[ast::Arm; 1]>) {
168 "match arm"; many fn flat_map_arm; fn visit_arm; fn make_arms;
170 Fields(SmallVec<[ast::Field; 1]>) {
171 "field expression"; many fn flat_map_field; fn visit_field; fn make_fields;
173 FieldPats(SmallVec<[ast::FieldPat; 1]>) {
175 many fn flat_map_field_pattern;
176 fn visit_field_pattern;
177 fn make_field_patterns;
179 GenericParams(SmallVec<[ast::GenericParam; 1]>) {
181 many fn flat_map_generic_param;
182 fn visit_generic_param;
183 fn make_generic_params;
185 Params(SmallVec<[ast::Param; 1]>) {
186 "function parameter"; many fn flat_map_param; fn visit_param; fn make_params;
188 StructFields(SmallVec<[ast::StructField; 1]>) {
190 many fn flat_map_struct_field;
191 fn visit_struct_field;
192 fn make_struct_fields;
194 Variants(SmallVec<[ast::Variant; 1]>) {
195 "variant"; many fn flat_map_variant; fn visit_variant; fn make_variants;
199 impl AstFragmentKind {
200 fn dummy(self, span: Span) -> AstFragment {
201 self.make_from(DummyResult::any(span)).expect("couldn't create a dummy AST fragment")
204 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(
208 let mut items = items.into_iter();
210 AstFragmentKind::Arms => {
211 AstFragment::Arms(items.map(Annotatable::expect_arm).collect())
213 AstFragmentKind::Fields => {
214 AstFragment::Fields(items.map(Annotatable::expect_field).collect())
216 AstFragmentKind::FieldPats => {
217 AstFragment::FieldPats(items.map(Annotatable::expect_field_pattern).collect())
219 AstFragmentKind::GenericParams => {
220 AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect())
222 AstFragmentKind::Params => {
223 AstFragment::Params(items.map(Annotatable::expect_param).collect())
225 AstFragmentKind::StructFields => {
226 AstFragment::StructFields(items.map(Annotatable::expect_struct_field).collect())
228 AstFragmentKind::Variants => {
229 AstFragment::Variants(items.map(Annotatable::expect_variant).collect())
231 AstFragmentKind::Items => {
232 AstFragment::Items(items.map(Annotatable::expect_item).collect())
234 AstFragmentKind::ImplItems => {
235 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect())
237 AstFragmentKind::TraitItems => {
238 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect())
240 AstFragmentKind::ForeignItems => {
241 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect())
243 AstFragmentKind::Stmts => {
244 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect())
246 AstFragmentKind::Expr => AstFragment::Expr(
247 items.next().expect("expected exactly one expression").expect_expr(),
249 AstFragmentKind::OptExpr => {
250 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr))
252 AstFragmentKind::Pat | AstFragmentKind::Ty => {
253 panic!("patterns and types aren't annotatable")
259 pub struct Invocation {
260 pub kind: InvocationKind,
261 pub fragment_kind: AstFragmentKind,
262 pub expansion_data: ExpansionData,
265 pub enum InvocationKind {
271 attr: ast::Attribute,
273 // Required for resolving derive helper attributes.
275 // We temporarily report errors for attribute macros placed after derives
282 /// "Invocation" that contains all derives from an item,
283 /// broken into multiple `Derive` invocations when expanded.
284 /// FIXME: Find a way to remove it.
291 impl InvocationKind {
292 fn placeholder_visibility(&self) -> Option<ast::Visibility> {
293 // HACK: For unnamed fields placeholders should have the same visibility as the actual
294 // fields because for tuple structs/variants resolve determines visibilities of their
295 // constructor using these field visibilities before attributes on them are are expanded.
296 // The assumption is that the attribute expansion cannot change field visibilities,
297 // and it holds because only inert attributes are supported in this position.
299 InvocationKind::Attr { item: Annotatable::StructField(field), .. }
300 | InvocationKind::Derive { item: Annotatable::StructField(field), .. }
301 | InvocationKind::DeriveContainer { item: Annotatable::StructField(field), .. }
302 if field.ident.is_none() =>
304 Some(field.vis.clone())
312 pub fn span(&self) -> Span {
314 InvocationKind::Bang { span, .. } => *span,
315 InvocationKind::Attr { attr, .. } => attr.span,
316 InvocationKind::Derive { path, .. } => path.span,
317 InvocationKind::DeriveContainer { item, .. } => item.span(),
322 pub struct MacroExpander<'a, 'b> {
323 pub cx: &'a mut ExtCtxt<'b>,
324 monotonic: bool, // cf. `cx.monotonic_expander()`
327 impl<'a, 'b> MacroExpander<'a, 'b> {
328 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
329 MacroExpander { cx, monotonic }
332 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
333 let mut module = ModuleData {
334 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
335 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
336 FileName::Real(path) => path,
337 other => PathBuf::from(other.to_string()),
340 module.directory.pop();
341 self.cx.root_path = module.directory.clone();
342 self.cx.current_expansion.module = Rc::new(module);
344 let orig_mod_span = krate.module.inner;
346 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
349 kind: ast::ItemKind::Mod(krate.module),
350 ident: Ident::invalid(),
351 id: ast::DUMMY_NODE_ID,
352 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
356 match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
357 Some(ast::Item { attrs, kind: ast::ItemKind::Mod(module), .. }) => {
359 krate.module = module;
362 // Resolution failed so we return an empty expansion
363 krate.attrs = vec![];
364 krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
366 Some(ast::Item { span, kind, .. }) => {
367 krate.attrs = vec![];
368 krate.module = ast::Mod { inner: orig_mod_span, items: vec![], inline: true };
372 "expected crate top-level item to be a module after macro expansion, found a {}",
373 kind.descriptive_variant()
378 self.cx.trace_macros_diag();
382 // Recursively expand all macro invocations in this AST fragment.
383 pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
384 let orig_expansion_data = self.cx.current_expansion.clone();
385 self.cx.current_expansion.depth = 0;
387 // Collect all macro invocations and replace them with placeholders.
388 let (mut fragment_with_placeholders, mut invocations) =
389 self.collect_invocations(input_fragment, &[]);
391 // Optimization: if we resolve all imports now,
392 // we'll be able to immediately resolve most of imported macros.
393 self.resolve_imports();
395 // Resolve paths in all invocations and produce output expanded fragments for them, but
396 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
397 // The output fragments also go through expansion recursively until no invocations are left.
398 // Unresolved macros produce dummy outputs as a recovery measure.
399 invocations.reverse();
400 let mut expanded_fragments = Vec::new();
401 let mut undetermined_invocations = Vec::new();
402 let (mut progress, mut force) = (false, !self.monotonic);
404 let invoc = if let Some(invoc) = invocations.pop() {
407 self.resolve_imports();
408 if undetermined_invocations.is_empty() {
411 invocations = mem::take(&mut undetermined_invocations);
412 force = !mem::replace(&mut progress, false);
416 let eager_expansion_root =
417 if self.monotonic { invoc.expansion_data.id } else { orig_expansion_data.id };
418 let res = match self.cx.resolver.resolve_macro_invocation(
420 eager_expansion_root,
424 Err(Indeterminate) => {
425 undetermined_invocations.push(invoc);
431 let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
432 self.cx.current_expansion = invoc.expansion_data.clone();
434 // FIXME(jseyfried): Refactor out the following logic
435 let (expanded_fragment, new_invocations) = match res {
436 InvocationRes::Single(ext) => {
437 let fragment = self.expand_invoc(invoc, &ext.kind);
438 self.collect_invocations(fragment, &[])
440 InvocationRes::DeriveContainer(_exts) => {
441 // FIXME: Consider using the derive resolutions (`_exts`) immediately,
442 // instead of enqueuing the derives to be resolved again later.
443 let (derives, item) = match invoc.kind {
444 InvocationKind::DeriveContainer { derives, item } => (derives, item),
447 if !item.derive_allowed() {
448 let attr = attr::find_by_name(item.attrs(), sym::derive)
449 .expect("`derive` attribute should exist");
450 let span = attr.span;
451 let mut err = self.cx.struct_span_err(
453 "`derive` may only be applied to structs, enums and unions",
455 if let ast::AttrStyle::Inner = attr.style {
456 let trait_list = derives
458 .map(|t| pprust::path_to_string(t))
459 .collect::<Vec<_>>();
460 let suggestion = format!("#[derive({})]", trait_list.join(", "));
463 "try an outer attribute",
465 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
466 Applicability::MaybeIncorrect,
472 let mut item = self.fully_configure(item);
473 item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
475 let mut derive_placeholders = Vec::with_capacity(derives.len());
476 invocations.reserve(derives.len());
477 for path in derives {
478 let expn_id = ExpnId::fresh(None);
479 derive_placeholders.push(NodeId::placeholder_from_expn_id(expn_id));
480 invocations.push(Invocation {
481 kind: InvocationKind::Derive { path, item: item.clone() },
482 fragment_kind: invoc.fragment_kind,
483 expansion_data: ExpansionData {
485 ..invoc.expansion_data.clone()
490 invoc.fragment_kind.expect_from_annotatables(::std::iter::once(item));
491 self.collect_invocations(fragment, &derive_placeholders)
495 if expanded_fragments.len() < depth {
496 expanded_fragments.push(Vec::new());
498 expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
499 if !self.cx.ecfg.single_step {
500 invocations.extend(new_invocations.into_iter().rev());
504 self.cx.current_expansion = orig_expansion_data;
506 // Finally incorporate all the expanded macros into the input AST fragment.
507 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
508 while let Some(expanded_fragments) = expanded_fragments.pop() {
509 for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
511 .add(NodeId::placeholder_from_expn_id(expn_id), expanded_fragment);
514 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
515 fragment_with_placeholders
518 fn resolve_imports(&mut self) {
520 self.cx.resolver.resolve_imports();
524 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
525 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
526 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
527 /// prepares data for resolving paths of macro invocations.
528 fn collect_invocations(
530 mut fragment: AstFragment,
531 extra_placeholders: &[NodeId],
532 ) -> (AstFragment, Vec<Invocation>) {
533 // Resolve `$crate`s in the fragment for pretty-printing.
534 self.cx.resolver.resolve_dollar_crates();
537 let mut collector = InvocationCollector {
538 cfg: StripUnconfigured {
539 sess: self.cx.parse_sess,
540 features: self.cx.ecfg.features,
543 invocations: Vec::new(),
544 monotonic: self.monotonic,
546 fragment.mut_visit_with(&mut collector);
547 fragment.add_placeholders(extra_placeholders);
548 collector.invocations
554 .visit_ast_fragment_with_placeholders(self.cx.current_expansion.id, &fragment);
557 (fragment, invocations)
560 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
562 StripUnconfigured { sess: self.cx.parse_sess, features: self.cx.ecfg.features };
563 // Since the item itself has already been configured by the InvocationCollector,
564 // we know that fold result vector will contain exactly one element
566 Annotatable::Item(item) => Annotatable::Item(cfg.flat_map_item(item).pop().unwrap()),
567 Annotatable::TraitItem(item) => {
568 Annotatable::TraitItem(cfg.flat_map_trait_item(item).pop().unwrap())
570 Annotatable::ImplItem(item) => {
571 Annotatable::ImplItem(cfg.flat_map_impl_item(item).pop().unwrap())
573 Annotatable::ForeignItem(item) => {
574 Annotatable::ForeignItem(cfg.flat_map_foreign_item(item).pop().unwrap())
576 Annotatable::Stmt(stmt) => {
577 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
579 Annotatable::Expr(mut expr) => Annotatable::Expr({
580 cfg.visit_expr(&mut expr);
583 Annotatable::Arm(arm) => Annotatable::Arm(cfg.flat_map_arm(arm).pop().unwrap()),
584 Annotatable::Field(field) => {
585 Annotatable::Field(cfg.flat_map_field(field).pop().unwrap())
587 Annotatable::FieldPat(fp) => {
588 Annotatable::FieldPat(cfg.flat_map_field_pattern(fp).pop().unwrap())
590 Annotatable::GenericParam(param) => {
591 Annotatable::GenericParam(cfg.flat_map_generic_param(param).pop().unwrap())
593 Annotatable::Param(param) => {
594 Annotatable::Param(cfg.flat_map_param(param).pop().unwrap())
596 Annotatable::StructField(sf) => {
597 Annotatable::StructField(cfg.flat_map_struct_field(sf).pop().unwrap())
599 Annotatable::Variant(v) => Annotatable::Variant(cfg.flat_map_variant(v).pop().unwrap()),
603 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment {
604 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
605 let expn_data = self.cx.current_expansion.id.expn_data();
606 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
607 let mut err = self.cx.struct_span_err(
609 &format!("recursion limit reached while expanding `{}`", expn_data.kind.descr()),
612 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
616 self.cx.trace_macros_diag();
620 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
622 InvocationKind::Bang { mac, .. } => match ext {
623 SyntaxExtensionKind::Bang(expander) => {
624 self.gate_proc_macro_expansion_kind(span, fragment_kind);
625 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
626 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
628 SyntaxExtensionKind::LegacyBang(expander) => {
629 let prev = self.cx.current_expansion.prior_type_ascription;
630 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
631 let tok_result = expander.expand(self.cx, span, mac.args.inner_tokens());
632 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
636 "non-{kind} macro in {kind} position: {path}",
637 kind = fragment_kind.name(),
638 path = pprust::path_to_string(&mac.path),
640 self.cx.span_err(span, &msg);
641 self.cx.trace_macros_diag();
642 fragment_kind.dummy(span)
644 self.cx.current_expansion.prior_type_ascription = prev;
649 InvocationKind::Attr { attr, mut item, .. } => match ext {
650 SyntaxExtensionKind::Attr(expander) => {
651 self.gate_proc_macro_input(&item);
652 self.gate_proc_macro_attr_item(span, &item);
653 let item_tok = TokenTree::token(
654 token::Interpolated(Lrc::new(match item {
655 Annotatable::Item(item) => token::NtItem(item),
656 Annotatable::TraitItem(item) => token::NtTraitItem(item),
657 Annotatable::ImplItem(item) => token::NtImplItem(item),
658 Annotatable::ForeignItem(item) => token::NtForeignItem(item),
659 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
660 Annotatable::Expr(expr) => token::NtExpr(expr),
662 | Annotatable::Field(..)
663 | Annotatable::FieldPat(..)
664 | Annotatable::GenericParam(..)
665 | Annotatable::Param(..)
666 | Annotatable::StructField(..)
667 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
672 let item = attr.unwrap_normal_item();
673 if let MacArgs::Eq(..) = item.args {
674 self.cx.span_err(span, "key-value macro attributes are not supported");
677 expander.expand(self.cx, span, item.args.inner_tokens(), item_tok);
678 self.parse_ast_fragment(tok_result, fragment_kind, &item.path, span)
680 SyntaxExtensionKind::LegacyAttr(expander) => {
681 match validate_attr::parse_meta(self.cx.parse_sess, &attr) {
683 let item = expander.expand(self.cx, span, &meta, item);
684 fragment_kind.expect_from_annotatables(item)
688 fragment_kind.dummy(span)
692 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
693 attr::mark_known(&attr);
695 attr::mark_used(&attr);
697 item.visit_attrs(|attrs| attrs.push(attr));
698 fragment_kind.expect_from_annotatables(iter::once(item))
702 InvocationKind::Derive { path, item } => match ext {
703 SyntaxExtensionKind::Derive(expander)
704 | SyntaxExtensionKind::LegacyDerive(expander) => {
705 if !item.derive_allowed() {
706 return fragment_kind.dummy(span);
708 if let SyntaxExtensionKind::Derive(..) = ext {
709 self.gate_proc_macro_input(&item);
711 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
712 let items = expander.expand(self.cx, span, &meta, item);
713 fragment_kind.expect_from_annotatables(items)
717 InvocationKind::DeriveContainer { .. } => unreachable!(),
721 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
722 let kind = match item {
724 | Annotatable::TraitItem(_)
725 | Annotatable::ImplItem(_)
726 | Annotatable::ForeignItem(_) => return,
727 Annotatable::Stmt(_) => "statements",
728 Annotatable::Expr(_) => "expressions",
730 | Annotatable::Field(..)
731 | Annotatable::FieldPat(..)
732 | Annotatable::GenericParam(..)
733 | Annotatable::Param(..)
734 | Annotatable::StructField(..)
735 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
737 if self.cx.ecfg.proc_macro_hygiene() {
742 sym::proc_macro_hygiene,
744 &format!("custom attributes cannot be applied to {}", kind),
749 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
750 struct GateProcMacroInput<'a> {
751 parse_sess: &'a ParseSess,
754 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
755 fn visit_item(&mut self, item: &'ast ast::Item) {
757 ast::ItemKind::Mod(module) if !module.inline => {
760 sym::proc_macro_hygiene,
762 "non-inline modules in proc macro input are unstable",
769 visit::walk_item(self, item);
772 fn visit_mac(&mut self, _: &'ast ast::Mac) {}
775 if !self.cx.ecfg.proc_macro_hygiene() {
776 annotatable.visit_with(&mut GateProcMacroInput { parse_sess: self.cx.parse_sess });
780 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
781 let kind = match kind {
782 AstFragmentKind::Expr | AstFragmentKind::OptExpr => "expressions",
783 AstFragmentKind::Pat => "patterns",
784 AstFragmentKind::Stmts => "statements",
786 | AstFragmentKind::Items
787 | AstFragmentKind::TraitItems
788 | AstFragmentKind::ImplItems
789 | AstFragmentKind::ForeignItems => return,
790 AstFragmentKind::Arms
791 | AstFragmentKind::Fields
792 | AstFragmentKind::FieldPats
793 | AstFragmentKind::GenericParams
794 | AstFragmentKind::Params
795 | AstFragmentKind::StructFields
796 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
798 if self.cx.ecfg.proc_macro_hygiene() {
803 sym::proc_macro_hygiene,
805 &format!("procedural macros cannot be expanded to {}", kind),
810 fn parse_ast_fragment(
813 kind: AstFragmentKind,
817 let mut parser = self.cx.new_parser_from_tts(toks);
818 match parse_ast_fragment(&mut parser, kind, false) {
820 ensure_complete_parse(&mut parser, path, kind.name(), span);
825 annotate_err_with_kind(&mut err, kind, span);
827 self.cx.trace_macros_diag();
834 pub fn parse_ast_fragment<'a>(
835 this: &mut Parser<'a>,
836 kind: AstFragmentKind,
837 macro_legacy_warnings: bool,
838 ) -> PResult<'a, AstFragment> {
840 AstFragmentKind::Items => {
841 let mut items = SmallVec::new();
842 while let Some(item) = this.parse_item()? {
845 AstFragment::Items(items)
847 AstFragmentKind::TraitItems => {
848 let mut items = SmallVec::new();
849 while this.token != token::Eof {
850 items.push(this.parse_trait_item(&mut false)?);
852 AstFragment::TraitItems(items)
854 AstFragmentKind::ImplItems => {
855 let mut items = SmallVec::new();
856 while this.token != token::Eof {
857 items.push(this.parse_impl_item(&mut false)?);
859 AstFragment::ImplItems(items)
861 AstFragmentKind::ForeignItems => {
862 let mut items = SmallVec::new();
863 while this.token != token::Eof {
864 items.push(this.parse_foreign_item(DUMMY_SP)?);
866 AstFragment::ForeignItems(items)
868 AstFragmentKind::Stmts => {
869 let mut stmts = SmallVec::new();
870 while this.token != token::Eof &&
871 // won't make progress on a `}`
872 this.token != token::CloseDelim(token::Brace)
874 if let Some(stmt) = this.parse_full_stmt(macro_legacy_warnings)? {
878 AstFragment::Stmts(stmts)
880 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
881 AstFragmentKind::OptExpr => {
882 if this.token != token::Eof {
883 AstFragment::OptExpr(Some(this.parse_expr()?))
885 AstFragment::OptExpr(None)
888 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
889 AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat(None)?),
890 AstFragmentKind::Arms
891 | AstFragmentKind::Fields
892 | AstFragmentKind::FieldPats
893 | AstFragmentKind::GenericParams
894 | AstFragmentKind::Params
895 | AstFragmentKind::StructFields
896 | AstFragmentKind::Variants => panic!("unexpected AST fragment kind"),
900 pub fn ensure_complete_parse<'a>(
901 this: &mut Parser<'a>,
906 if this.token != token::Eof {
907 let token = pprust::token_to_string(&this.token);
908 let msg = format!("macro expansion ignores token `{}` and any following", token);
909 // Avoid emitting backtrace info twice.
910 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
911 let mut err = this.struct_span_err(def_site_span, &msg);
912 err.span_label(span, "caused by the macro expansion here");
914 "the usage of `{}!` is likely invalid in {} context",
915 pprust::path_to_string(macro_path),
919 let semi_span = this.sess.source_map().next_point(span);
921 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
922 match this.sess.source_map().span_to_snippet(semi_full_span) {
923 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
926 "you might be missing a semicolon here",
928 Applicability::MaybeIncorrect,
937 struct InvocationCollector<'a, 'b> {
938 cx: &'a mut ExtCtxt<'b>,
939 cfg: StripUnconfigured<'a>,
940 invocations: Vec<Invocation>,
944 impl<'a, 'b> InvocationCollector<'a, 'b> {
945 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
946 // Expansion data for all the collected invocations is set upon their resolution,
947 // with exception of the derive container case which is not resolved and can get
948 // its expansion data immediately.
949 let expn_data = match &kind {
950 InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
951 parent: self.cx.current_expansion.id,
953 ExpnKind::Macro(MacroKind::Attr, sym::derive),
955 self.cx.parse_sess.edition,
960 let expn_id = ExpnId::fresh(expn_data);
961 let vis = kind.placeholder_visibility();
962 self.invocations.push(Invocation {
965 expansion_data: ExpansionData {
967 depth: self.cx.current_expansion.depth + 1,
968 ..self.cx.current_expansion.clone()
971 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
974 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
975 self.collect(kind, InvocationKind::Bang { mac, span })
980 attr: Option<ast::Attribute>,
983 kind: AstFragmentKind,
989 Some(attr) => InvocationKind::Attr { attr, item, derives, after_derive },
990 None => InvocationKind::DeriveContainer { derives, item },
997 attrs: &mut Vec<ast::Attribute>,
998 after_derive: &mut bool,
999 ) -> Option<ast::Attribute> {
1003 if a.has_name(sym::derive) {
1004 *after_derive = true;
1006 !attr::is_known(a) && !is_builtin_attr(a)
1008 .map(|i| attrs.remove(i));
1009 if let Some(attr) = &attr {
1010 if !self.cx.ecfg.custom_inner_attributes()
1011 && attr.style == ast::AttrStyle::Inner
1012 && !attr.has_name(sym::test)
1015 &self.cx.parse_sess,
1016 sym::custom_inner_attributes,
1018 "non-builtin inner attributes are unstable",
1026 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1027 fn classify_item<T>(
1030 ) -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)
1034 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1036 item.visit_attrs(|mut attrs| {
1037 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1038 traits = collect_derives(&mut self.cx, &mut attrs);
1041 (attr, traits, after_derive)
1044 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1045 /// to the unused-attributes lint (making it an error on statements and expressions
1046 /// is a breaking change)
1047 fn classify_nonitem<T: HasAttrs>(
1050 ) -> (Option<ast::Attribute>, /* after_derive */ bool) {
1051 let (mut attr, mut after_derive) = (None, false);
1053 nonitem.visit_attrs(|mut attrs| {
1054 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1057 (attr, after_derive)
1060 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1061 self.cfg.configure(node)
1064 // Detect use of feature-gated or invalid attributes on macro invocations
1065 // since they will not be detected after macro expansion.
1066 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1067 let features = self.cx.ecfg.features.unwrap();
1068 for attr in attrs.iter() {
1069 rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.parse_sess, features);
1070 validate_attr::check_meta(self.cx.parse_sess, attr);
1072 // macros are expanded before any lint passes so this warning has to be hardcoded
1073 if attr.has_name(sym::derive) {
1075 .struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1076 .note("this may become a hard error in a future release")
1083 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1084 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1085 self.cfg.configure_expr(expr);
1086 visit_clobber(expr.deref_mut(), |mut expr| {
1087 self.cfg.configure_expr_kind(&mut expr.kind);
1089 // ignore derives so they remain unused
1090 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1093 // Collect the invoc regardless of whether or not attributes are permitted here
1094 // expansion will eat the attribute so it won't error later.
1095 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1097 // AstFragmentKind::Expr requires the macro to emit an expression.
1102 Annotatable::Expr(P(expr)),
1103 AstFragmentKind::Expr,
1110 if let ast::ExprKind::Mac(mac) = expr.kind {
1111 self.check_attributes(&expr.attrs);
1112 self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
1114 noop_visit_expr(&mut expr, self);
1120 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1121 let mut arm = configure!(self, arm);
1123 let (attr, traits, after_derive) = self.classify_item(&mut arm);
1124 if attr.is_some() || !traits.is_empty() {
1129 Annotatable::Arm(arm),
1130 AstFragmentKind::Arms,
1136 noop_flat_map_arm(arm, self)
1139 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
1140 let mut field = configure!(self, field);
1142 let (attr, traits, after_derive) = self.classify_item(&mut field);
1143 if attr.is_some() || !traits.is_empty() {
1148 Annotatable::Field(field),
1149 AstFragmentKind::Fields,
1155 noop_flat_map_field(field, self)
1158 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
1159 let mut fp = configure!(self, fp);
1161 let (attr, traits, after_derive) = self.classify_item(&mut fp);
1162 if attr.is_some() || !traits.is_empty() {
1167 Annotatable::FieldPat(fp),
1168 AstFragmentKind::FieldPats,
1171 .make_field_patterns();
1174 noop_flat_map_field_pattern(fp, self)
1177 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1178 let mut p = configure!(self, p);
1180 let (attr, traits, after_derive) = self.classify_item(&mut p);
1181 if attr.is_some() || !traits.is_empty() {
1186 Annotatable::Param(p),
1187 AstFragmentKind::Params,
1193 noop_flat_map_param(p, self)
1196 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
1197 let mut sf = configure!(self, sf);
1199 let (attr, traits, after_derive) = self.classify_item(&mut sf);
1200 if attr.is_some() || !traits.is_empty() {
1205 Annotatable::StructField(sf),
1206 AstFragmentKind::StructFields,
1209 .make_struct_fields();
1212 noop_flat_map_struct_field(sf, self)
1215 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1216 let mut variant = configure!(self, variant);
1218 let (attr, traits, after_derive) = self.classify_item(&mut variant);
1219 if attr.is_some() || !traits.is_empty() {
1224 Annotatable::Variant(variant),
1225 AstFragmentKind::Variants,
1231 noop_flat_map_variant(variant, self)
1234 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1235 let expr = configure!(self, expr);
1236 expr.filter_map(|mut expr| {
1237 self.cfg.configure_expr_kind(&mut expr.kind);
1239 // Ignore derives so they remain unused.
1240 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1243 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1249 Annotatable::Expr(P(expr)),
1250 AstFragmentKind::OptExpr,
1254 .map(|expr| expr.into_inner());
1257 if let ast::ExprKind::Mac(mac) = expr.kind {
1258 self.check_attributes(&expr.attrs);
1259 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1261 .map(|expr| expr.into_inner())
1264 noop_visit_expr(&mut expr, self);
1271 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1272 self.cfg.configure_pat(pat);
1274 PatKind::Mac(_) => {}
1275 _ => return noop_visit_pat(pat, self),
1278 visit_clobber(pat, |mut pat| match mem::replace(&mut pat.kind, PatKind::Wild) {
1279 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1280 _ => unreachable!(),
1284 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1285 let mut stmt = configure!(self, stmt);
1287 // we'll expand attributes on expressions separately
1288 if !stmt.is_expr() {
1289 let (attr, derives, after_derive) = if stmt.is_item() {
1290 self.classify_item(&mut stmt)
1292 // ignore derives on non-item statements so it falls through
1293 // to the unused-attributes lint
1294 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1295 (attr, vec![], after_derive)
1298 if attr.is_some() || !derives.is_empty() {
1303 Annotatable::Stmt(P(stmt)),
1304 AstFragmentKind::Stmts,
1311 if let StmtKind::Mac(mac) = stmt.kind {
1312 let (mac, style, attrs) = mac.into_inner();
1313 self.check_attributes(&attrs);
1314 let mut placeholder =
1315 self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts).make_stmts();
1317 // If this is a macro invocation with a semicolon, then apply that
1318 // semicolon to the final statement produced by expansion.
1319 if style == MacStmtStyle::Semicolon {
1320 if let Some(stmt) = placeholder.pop() {
1321 placeholder.push(stmt.add_trailing_semicolon());
1328 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1329 let ast::Stmt { id, kind, span } = stmt;
1330 noop_flat_map_stmt_kind(kind, self)
1332 .map(|kind| ast::Stmt { id, kind, span })
1336 fn visit_block(&mut self, block: &mut P<Block>) {
1337 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1338 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1339 noop_visit_block(block, self);
1340 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1343 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1344 let mut item = configure!(self, item);
1346 let (attr, traits, after_derive) = self.classify_item(&mut item);
1347 if attr.is_some() || !traits.is_empty() {
1352 Annotatable::Item(item),
1353 AstFragmentKind::Items,
1360 ast::ItemKind::Mac(..) => {
1361 self.check_attributes(&item.attrs);
1362 item.and_then(|item| match item.kind {
1363 ItemKind::Mac(mac) => self
1365 AstFragmentKind::Items,
1366 InvocationKind::Bang { mac, span: item.span },
1369 _ => unreachable!(),
1372 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1373 if item.ident == Ident::invalid() {
1374 return noop_flat_map_item(item, self);
1377 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1378 let mut module = (*self.cx.current_expansion.module).clone();
1379 module.mod_path.push(item.ident);
1381 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1382 // In the non-inline case, `inner` is never the dummy span (cf. `parse_item_mod`).
1383 // Thus, if `inner` is the dummy span, we know the module is inline.
1384 let inline_module = item.span.contains(inner) || inner.is_dummy();
1387 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
1388 self.cx.current_expansion.directory_ownership =
1389 DirectoryOwnership::Owned { relative: None };
1390 module.directory.push(&*path.as_str());
1392 module.directory.push(&*item.ident.as_str());
1395 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1396 let mut path = match path {
1397 FileName::Real(path) => path,
1398 other => PathBuf::from(other.to_string()),
1400 let directory_ownership = match path.file_name().unwrap().to_str() {
1401 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1402 Some(_) => DirectoryOwnership::Owned { relative: Some(item.ident) },
1403 None => DirectoryOwnership::UnownedViaMod,
1406 module.directory = path;
1407 self.cx.current_expansion.directory_ownership = directory_ownership;
1411 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1412 let result = noop_flat_map_item(item, self);
1413 self.cx.current_expansion.module = orig_module;
1414 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1418 _ => noop_flat_map_item(item, self),
1422 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1423 let mut item = configure!(self, item);
1425 let (attr, traits, after_derive) = self.classify_item(&mut item);
1426 if attr.is_some() || !traits.is_empty() {
1431 Annotatable::TraitItem(item),
1432 AstFragmentKind::TraitItems,
1435 .make_trait_items();
1439 ast::AssocItemKind::Macro(..) => {
1440 self.check_attributes(&item.attrs);
1441 item.and_then(|item| match item.kind {
1442 ast::AssocItemKind::Macro(mac) => self
1443 .collect_bang(mac, item.span, AstFragmentKind::TraitItems)
1444 .make_trait_items(),
1445 _ => unreachable!(),
1448 _ => noop_flat_map_assoc_item(item, self),
1452 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
1453 let mut item = configure!(self, item);
1455 let (attr, traits, after_derive) = self.classify_item(&mut item);
1456 if attr.is_some() || !traits.is_empty() {
1461 Annotatable::ImplItem(item),
1462 AstFragmentKind::ImplItems,
1469 ast::AssocItemKind::Macro(..) => {
1470 self.check_attributes(&item.attrs);
1471 item.and_then(|item| match item.kind {
1472 ast::AssocItemKind::Macro(mac) => self
1473 .collect_bang(mac, item.span, AstFragmentKind::ImplItems)
1475 _ => unreachable!(),
1478 _ => noop_flat_map_assoc_item(item, self),
1482 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1484 ast::TyKind::Mac(_) => {}
1485 _ => return noop_visit_ty(ty, self),
1488 visit_clobber(ty, |mut ty| match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1489 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1490 _ => unreachable!(),
1494 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1495 self.cfg.configure_foreign_mod(foreign_mod);
1496 noop_visit_foreign_mod(foreign_mod, self);
1499 fn flat_map_foreign_item(
1501 mut foreign_item: P<ast::ForeignItem>,
1502 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
1503 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1505 if attr.is_some() || !traits.is_empty() {
1510 Annotatable::ForeignItem(foreign_item),
1511 AstFragmentKind::ForeignItems,
1514 .make_foreign_items();
1517 match foreign_item.kind {
1518 ast::ForeignItemKind::Macro(..) => {
1519 self.check_attributes(&foreign_item.attrs);
1520 foreign_item.and_then(|item| match item.kind {
1521 ast::ForeignItemKind::Macro(mac) => self
1522 .collect_bang(mac, item.span, AstFragmentKind::ForeignItems)
1523 .make_foreign_items(),
1524 _ => unreachable!(),
1527 _ => noop_flat_map_foreign_item(foreign_item, self),
1531 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1533 ast::ItemKind::MacroDef(..) => {}
1535 self.cfg.configure_item_kind(item);
1536 noop_visit_item_kind(item, self);
1541 fn flat_map_generic_param(
1543 param: ast::GenericParam,
1544 ) -> SmallVec<[ast::GenericParam; 1]> {
1545 let mut param = configure!(self, param);
1547 let (attr, traits, after_derive) = self.classify_item(&mut param);
1548 if attr.is_some() || !traits.is_empty() {
1553 Annotatable::GenericParam(param),
1554 AstFragmentKind::GenericParams,
1557 .make_generic_params();
1560 noop_flat_map_generic_param(param, self)
1563 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1564 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1565 // contents="file contents")]` attributes
1566 if !at.check_name(sym::doc) {
1567 return noop_visit_attribute(at, self);
1570 if let Some(list) = at.meta_item_list() {
1571 if !list.iter().any(|it| it.check_name(sym::include)) {
1572 return noop_visit_attribute(at, self);
1575 let mut items = vec![];
1577 for mut it in list {
1578 if !it.check_name(sym::include) {
1580 noop_visit_meta_list_item(&mut it, self);
1586 if let Some(file) = it.value_str() {
1587 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1588 self.check_attributes(slice::from_ref(at));
1589 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1590 // avoid loading the file if they haven't enabled the feature
1591 return noop_visit_attribute(at, self);
1594 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1595 Ok(filename) => filename,
1602 match self.cx.source_map().load_file(&filename) {
1603 Ok(source_file) => {
1604 let src = source_file
1607 .expect("freshly loaded file should have a source");
1608 let src_interned = Symbol::intern(src.as_str());
1610 let include_info = vec![
1611 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1612 Ident::with_dummy_span(sym::file),
1616 ast::NestedMetaItem::MetaItem(attr::mk_name_value_item_str(
1617 Ident::with_dummy_span(sym::contents),
1623 let include_ident = Ident::with_dummy_span(sym::include);
1624 let item = attr::mk_list_item(include_ident, include_info);
1625 items.push(ast::NestedMetaItem::MetaItem(item));
1629 it.meta_item().and_then(|item| item.name_value_literal()).unwrap();
1631 if e.kind() == ErrorKind::InvalidData {
1635 &format!("{} wasn't a utf-8 file", filename.display()),
1637 .span_label(lit.span, "contains invalid utf-8")
1640 let mut err = self.cx.struct_span_err(
1642 &format!("couldn't read {}: {}", filename.display(), e),
1644 err.span_label(lit.span, "couldn't read file");
1651 let mut err = self.cx.struct_span_err(
1653 &format!("expected path to external documentation"),
1656 // Check if the user erroneously used `doc(include(...))` syntax.
1657 let literal = it.meta_item_list().and_then(|list| {
1658 if list.len() == 1 {
1659 list[0].literal().map(|literal| &literal.kind)
1665 let (path, applicability) = match &literal {
1666 Some(LitKind::Str(path, ..)) => {
1667 (path.to_string(), Applicability::MachineApplicable)
1669 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1672 err.span_suggestion(
1674 "provide a file path with `=`",
1675 format!("include = \"{}\"", path),
1683 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1684 *at = ast::Attribute {
1685 kind: ast::AttrKind::Normal(AttrItem {
1687 args: meta.kind.mac_args(meta.span),
1694 noop_visit_attribute(at, self)
1698 fn visit_id(&mut self, id: &mut ast::NodeId) {
1700 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1701 *id = self.cx.resolver.next_node_id()
1705 fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
1706 self.cfg.configure_fn_decl(&mut fn_decl);
1707 noop_visit_fn_decl(fn_decl, self);
1711 pub struct ExpansionConfig<'feat> {
1712 pub crate_name: String,
1713 pub features: Option<&'feat Features>,
1714 pub recursion_limit: usize,
1715 pub trace_mac: bool,
1716 pub should_test: bool, // If false, strip `#[test]` nodes
1717 pub single_step: bool,
1718 pub keep_macs: bool,
1721 impl<'feat> ExpansionConfig<'feat> {
1722 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1726 recursion_limit: 1024,
1734 fn proc_macro_hygiene(&self) -> bool {
1735 self.features.map_or(false, |features| features.proc_macro_hygiene)
1737 fn custom_inner_attributes(&self) -> bool {
1738 self.features.map_or(false, |features| features.custom_inner_attributes)