2 use crate::proc_macro::collect_derives;
3 use crate::hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind};
4 use crate::mbe::macro_rules::annotate_err_with_kind;
5 use crate::placeholders::{placeholder, PlaceholderExpander};
6 use crate::config::StripUnconfigured;
8 use rustc_feature::Features;
9 use rustc_parse::configure;
10 use rustc_parse::DirectoryOwnership;
11 use rustc_parse::parser::Parser;
12 use rustc_parse::validate_attr;
13 use syntax::ast::{self, AttrItem, Block, Ident, LitKind, NodeId, PatKind, Path};
14 use syntax::ast::{MacStmtStyle, StmtKind, ItemKind};
15 use syntax::attr::{self, HasAttrs, is_builtin_attr};
16 use syntax::source_map::respan;
17 use syntax::feature_gate::{self, feature_err};
18 use syntax::mut_visit::*;
19 use syntax::print::pprust;
21 use syntax::sess::ParseSess;
22 use syntax::symbol::{sym, Symbol};
24 use syntax::tokenstream::{TokenStream, TokenTree};
25 use syntax::visit::{self, Visitor};
26 use syntax::util::map_in_place::MapInPlace;
28 use errors::{PResult, Applicability, FatalError};
29 use smallvec::{smallvec, SmallVec};
30 use syntax_pos::{Span, DUMMY_SP, FileName};
32 use rustc_data_structures::sync::Lrc;
33 use std::io::ErrorKind;
34 use std::{iter, mem, slice};
35 use std::ops::DerefMut;
37 use std::path::PathBuf;
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;)?
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::$Kind(ast) => ast.extend(placeholders.iter().flat_map(|id| {
86 // We are repeating through arguments with `many`, to do that we have to
87 // mention some macro variable from those arguments even if it's not used.
88 #[cfg_attr(bootstrap, allow(unused_macros))]
89 macro _repeating($flat_map_ast_elt) {}
90 placeholder(AstFragmentKind::$Kind, *id, None).$make_ast()
92 _ => panic!("unexpected AST fragment kind")
96 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
98 AstFragment::OptExpr(expr) => expr,
99 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
103 $(pub fn $make_ast(self) -> $AstTy {
105 AstFragment::$Kind(ast) => ast,
106 _ => panic!("AstFragment::make_* called on the wrong kind of fragment"),
110 pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
112 AstFragment::OptExpr(opt_expr) => {
113 visit_clobber(opt_expr, |opt_expr| {
114 if let Some(expr) = opt_expr {
115 vis.filter_map_expr(expr)
121 $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)?)*
122 $($(AstFragment::$Kind(ast) =>
123 ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)?)*
127 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
129 AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
130 AstFragment::OptExpr(None) => {}
131 $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
132 $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
133 visitor.$visit_ast_elt(ast_elt);
139 impl<'a> MacResult for crate::mbe::macro_rules::ParserAnyMacro<'a> {
140 $(fn $make_ast(self: Box<crate::mbe::macro_rules::ParserAnyMacro<'a>>)
142 Some(self.make(AstFragmentKind::$Kind).$make_ast())
149 Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
150 Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
151 Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
152 Stmts(SmallVec<[ast::Stmt; 1]>) {
153 "statement"; many fn flat_map_stmt; fn visit_stmt; fn make_stmts;
155 Items(SmallVec<[P<ast::Item>; 1]>) {
156 "item"; many fn flat_map_item; fn visit_item; fn make_items;
158 TraitItems(SmallVec<[ast::TraitItem; 1]>) {
159 "trait item"; many fn flat_map_trait_item; fn visit_trait_item; fn make_trait_items;
161 ImplItems(SmallVec<[ast::ImplItem; 1]>) {
162 "impl item"; many fn flat_map_impl_item; fn visit_impl_item; fn make_impl_items;
164 ForeignItems(SmallVec<[ast::ForeignItem; 1]>) {
166 many fn flat_map_foreign_item;
167 fn visit_foreign_item;
168 fn make_foreign_items;
170 Arms(SmallVec<[ast::Arm; 1]>) {
171 "match arm"; many fn flat_map_arm; fn visit_arm; fn make_arms;
173 Fields(SmallVec<[ast::Field; 1]>) {
174 "field expression"; many fn flat_map_field; fn visit_field; fn make_fields;
176 FieldPats(SmallVec<[ast::FieldPat; 1]>) {
178 many fn flat_map_field_pattern;
179 fn visit_field_pattern;
180 fn make_field_patterns;
182 GenericParams(SmallVec<[ast::GenericParam; 1]>) {
184 many fn flat_map_generic_param;
185 fn visit_generic_param;
186 fn make_generic_params;
188 Params(SmallVec<[ast::Param; 1]>) {
189 "function parameter"; many fn flat_map_param; fn visit_param; fn make_params;
191 StructFields(SmallVec<[ast::StructField; 1]>) {
193 many fn flat_map_struct_field;
194 fn visit_struct_field;
195 fn make_struct_fields;
197 Variants(SmallVec<[ast::Variant; 1]>) {
198 "variant"; many fn flat_map_variant; fn visit_variant; fn make_variants;
202 impl AstFragmentKind {
203 fn dummy(self, span: Span) -> AstFragment {
204 self.make_from(DummyResult::any(span)).expect("couldn't create a dummy AST fragment")
207 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I)
209 let mut items = items.into_iter();
211 AstFragmentKind::Arms =>
212 AstFragment::Arms(items.map(Annotatable::expect_arm).collect()),
213 AstFragmentKind::Fields =>
214 AstFragment::Fields(items.map(Annotatable::expect_field).collect()),
215 AstFragmentKind::FieldPats =>
216 AstFragment::FieldPats(items.map(Annotatable::expect_field_pattern).collect()),
217 AstFragmentKind::GenericParams =>
218 AstFragment::GenericParams(items.map(Annotatable::expect_generic_param).collect()),
219 AstFragmentKind::Params =>
220 AstFragment::Params(items.map(Annotatable::expect_param).collect()),
221 AstFragmentKind::StructFields => AstFragment::StructFields(
222 items.map(Annotatable::expect_struct_field).collect()
224 AstFragmentKind::Variants =>
225 AstFragment::Variants(items.map(Annotatable::expect_variant).collect()),
226 AstFragmentKind::Items =>
227 AstFragment::Items(items.map(Annotatable::expect_item).collect()),
228 AstFragmentKind::ImplItems =>
229 AstFragment::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
230 AstFragmentKind::TraitItems =>
231 AstFragment::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
232 AstFragmentKind::ForeignItems =>
233 AstFragment::ForeignItems(items.map(Annotatable::expect_foreign_item).collect()),
234 AstFragmentKind::Stmts =>
235 AstFragment::Stmts(items.map(Annotatable::expect_stmt).collect()),
236 AstFragmentKind::Expr => AstFragment::Expr(
237 items.next().expect("expected exactly one expression").expect_expr()
239 AstFragmentKind::OptExpr =>
240 AstFragment::OptExpr(items.next().map(Annotatable::expect_expr)),
241 AstFragmentKind::Pat | AstFragmentKind::Ty =>
242 panic!("patterns and types aren't annotatable"),
247 pub struct Invocation {
248 pub kind: InvocationKind,
249 pub fragment_kind: AstFragmentKind,
250 pub expansion_data: ExpansionData,
253 pub enum InvocationKind {
259 attr: ast::Attribute,
261 // Required for resolving derive helper attributes.
263 // We temporarily report errors for attribute macros placed after derives
270 /// "Invocation" that contains all derives from an item,
271 /// broken into multiple `Derive` invocations when expanded.
272 /// FIXME: Find a way to remove it.
279 impl InvocationKind {
280 fn placeholder_visibility(&self) -> Option<ast::Visibility> {
281 // HACK: For unnamed fields placeholders should have the same visibility as the actual
282 // fields because for tuple structs/variants resolve determines visibilities of their
283 // constructor using these field visibilities before attributes on them are are expanded.
284 // The assumption is that the attribute expansion cannot change field visibilities,
285 // and it holds because only inert attributes are supported in this position.
287 InvocationKind::Attr { item: Annotatable::StructField(field), .. } |
288 InvocationKind::Derive { item: Annotatable::StructField(field), .. } |
289 InvocationKind::DeriveContainer { item: Annotatable::StructField(field), .. }
290 if field.ident.is_none() => Some(field.vis.clone()),
297 pub fn span(&self) -> Span {
299 InvocationKind::Bang { span, .. } => *span,
300 InvocationKind::Attr { attr, .. } => attr.span,
301 InvocationKind::Derive { path, .. } => path.span,
302 InvocationKind::DeriveContainer { item, .. } => item.span(),
307 pub struct MacroExpander<'a, 'b> {
308 pub cx: &'a mut ExtCtxt<'b>,
309 monotonic: bool, // cf. `cx.monotonic_expander()`
312 impl<'a, 'b> MacroExpander<'a, 'b> {
313 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
314 MacroExpander { cx, monotonic }
317 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
318 let mut module = ModuleData {
319 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
320 directory: match self.cx.source_map().span_to_unmapped_path(krate.span) {
321 FileName::Real(path) => path,
322 other => PathBuf::from(other.to_string()),
325 module.directory.pop();
326 self.cx.root_path = module.directory.clone();
327 self.cx.current_expansion.module = Rc::new(module);
329 let orig_mod_span = krate.module.inner;
331 let krate_item = AstFragment::Items(smallvec![P(ast::Item {
334 kind: ast::ItemKind::Mod(krate.module),
335 ident: Ident::invalid(),
336 id: ast::DUMMY_NODE_ID,
337 vis: respan(krate.span.shrink_to_lo(), ast::VisibilityKind::Public),
341 match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
342 Some(ast::Item { attrs, kind: ast::ItemKind::Mod(module), .. }) => {
344 krate.module = module;
347 // Resolution failed so we return an empty expansion
348 krate.attrs = vec![];
349 krate.module = ast::Mod {
350 inner: orig_mod_span,
357 self.cx.trace_macros_diag();
361 // Recursively expand all macro invocations in this AST fragment.
362 pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
363 let orig_expansion_data = self.cx.current_expansion.clone();
364 self.cx.current_expansion.depth = 0;
366 // Collect all macro invocations and replace them with placeholders.
367 let (mut fragment_with_placeholders, mut invocations)
368 = self.collect_invocations(input_fragment, &[]);
370 // Optimization: if we resolve all imports now,
371 // we'll be able to immediately resolve most of imported macros.
372 self.resolve_imports();
374 // Resolve paths in all invocations and produce output expanded fragments for them, but
375 // do not insert them into our input AST fragment yet, only store in `expanded_fragments`.
376 // The output fragments also go through expansion recursively until no invocations are left.
377 // Unresolved macros produce dummy outputs as a recovery measure.
378 invocations.reverse();
379 let mut expanded_fragments = Vec::new();
380 let mut undetermined_invocations = Vec::new();
381 let (mut progress, mut force) = (false, !self.monotonic);
383 let invoc = if let Some(invoc) = invocations.pop() {
386 self.resolve_imports();
387 if undetermined_invocations.is_empty() { break }
388 invocations = mem::take(&mut undetermined_invocations);
389 force = !mem::replace(&mut progress, false);
393 let eager_expansion_root =
394 if self.monotonic { invoc.expansion_data.id } else { orig_expansion_data.id };
395 let res = match self.cx.resolver.resolve_macro_invocation(
396 &invoc, eager_expansion_root, force
399 Err(Indeterminate) => {
400 undetermined_invocations.push(invoc);
406 let ExpansionData { depth, id: expn_id, .. } = invoc.expansion_data;
407 self.cx.current_expansion = invoc.expansion_data.clone();
409 // FIXME(jseyfried): Refactor out the following logic
410 let (expanded_fragment, new_invocations) = match res {
411 InvocationRes::Single(ext) => {
412 let fragment = self.expand_invoc(invoc, &ext.kind);
413 self.collect_invocations(fragment, &[])
415 InvocationRes::DeriveContainer(_exts) => {
416 // FIXME: Consider using the derive resolutions (`_exts`) immediately,
417 // instead of enqueuing the derives to be resolved again later.
418 let (derives, item) = match invoc.kind {
419 InvocationKind::DeriveContainer { derives, item } => (derives, item),
422 if !item.derive_allowed() {
423 let attr = attr::find_by_name(item.attrs(), sym::derive)
424 .expect("`derive` attribute should exist");
425 let span = attr.span;
426 let mut err = self.cx.struct_span_err(span,
427 "`derive` may only be applied to structs, enums and unions");
428 if let ast::AttrStyle::Inner = attr.style {
429 let trait_list = derives.iter()
430 .map(|t| pprust::path_to_string(t))
431 .collect::<Vec<_>>();
432 let suggestion = format!("#[derive({})]", trait_list.join(", "));
434 span, "try an outer attribute", suggestion,
435 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
436 Applicability::MaybeIncorrect
442 let mut item = self.fully_configure(item);
443 item.visit_attrs(|attrs| attrs.retain(|a| !a.has_name(sym::derive)));
445 let mut derive_placeholders = Vec::with_capacity(derives.len());
446 invocations.reserve(derives.len());
447 for path in derives {
448 let expn_id = ExpnId::fresh(None);
449 derive_placeholders.push(NodeId::placeholder_from_expn_id(expn_id));
450 invocations.push(Invocation {
451 kind: InvocationKind::Derive { path, item: item.clone() },
452 fragment_kind: invoc.fragment_kind,
453 expansion_data: ExpansionData {
455 ..invoc.expansion_data.clone()
459 let fragment = invoc.fragment_kind
460 .expect_from_annotatables(::std::iter::once(item));
461 self.collect_invocations(fragment, &derive_placeholders)
465 if expanded_fragments.len() < depth {
466 expanded_fragments.push(Vec::new());
468 expanded_fragments[depth - 1].push((expn_id, expanded_fragment));
469 if !self.cx.ecfg.single_step {
470 invocations.extend(new_invocations.into_iter().rev());
474 self.cx.current_expansion = orig_expansion_data;
476 // Finally incorporate all the expanded macros into the input AST fragment.
477 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
478 while let Some(expanded_fragments) = expanded_fragments.pop() {
479 for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
480 placeholder_expander.add(NodeId::placeholder_from_expn_id(expn_id),
484 fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
485 fragment_with_placeholders
488 fn resolve_imports(&mut self) {
490 self.cx.resolver.resolve_imports();
494 /// Collects all macro invocations reachable at this time in this AST fragment, and replace
495 /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
496 /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
497 /// prepares data for resolving paths of macro invocations.
498 fn collect_invocations(&mut self, mut fragment: AstFragment, extra_placeholders: &[NodeId])
499 -> (AstFragment, Vec<Invocation>) {
500 // Resolve `$crate`s in the fragment for pretty-printing.
501 self.cx.resolver.resolve_dollar_crates();
504 let mut collector = InvocationCollector {
505 cfg: StripUnconfigured {
506 sess: self.cx.parse_sess,
507 features: self.cx.ecfg.features,
510 invocations: Vec::new(),
511 monotonic: self.monotonic,
513 fragment.mut_visit_with(&mut collector);
514 fragment.add_placeholders(extra_placeholders);
515 collector.invocations
519 self.cx.resolver.visit_ast_fragment_with_placeholders(
520 self.cx.current_expansion.id, &fragment
524 (fragment, invocations)
527 fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
528 let mut cfg = StripUnconfigured {
529 sess: self.cx.parse_sess,
530 features: self.cx.ecfg.features,
532 // Since the item itself has already been configured by the InvocationCollector,
533 // we know that fold result vector will contain exactly one element
535 Annotatable::Item(item) => {
536 Annotatable::Item(cfg.flat_map_item(item).pop().unwrap())
538 Annotatable::TraitItem(item) => {
539 Annotatable::TraitItem(
540 item.map(|item| cfg.flat_map_trait_item(item).pop().unwrap()))
542 Annotatable::ImplItem(item) => {
543 Annotatable::ImplItem(item.map(|item| cfg.flat_map_impl_item(item).pop().unwrap()))
545 Annotatable::ForeignItem(item) => {
546 Annotatable::ForeignItem(
547 item.map(|item| cfg.flat_map_foreign_item(item).pop().unwrap())
550 Annotatable::Stmt(stmt) => {
551 Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
553 Annotatable::Expr(mut expr) => {
554 Annotatable::Expr({ cfg.visit_expr(&mut expr); expr })
556 Annotatable::Arm(arm) => {
557 Annotatable::Arm(cfg.flat_map_arm(arm).pop().unwrap())
559 Annotatable::Field(field) => {
560 Annotatable::Field(cfg.flat_map_field(field).pop().unwrap())
562 Annotatable::FieldPat(fp) => {
563 Annotatable::FieldPat(cfg.flat_map_field_pattern(fp).pop().unwrap())
565 Annotatable::GenericParam(param) => {
566 Annotatable::GenericParam(cfg.flat_map_generic_param(param).pop().unwrap())
568 Annotatable::Param(param) => {
569 Annotatable::Param(cfg.flat_map_param(param).pop().unwrap())
571 Annotatable::StructField(sf) => {
572 Annotatable::StructField(cfg.flat_map_struct_field(sf).pop().unwrap())
574 Annotatable::Variant(v) => {
575 Annotatable::Variant(cfg.flat_map_variant(v).pop().unwrap())
580 fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment {
581 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
582 let expn_data = self.cx.current_expansion.id.expn_data();
583 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
584 let mut err = self.cx.struct_span_err(expn_data.call_site,
585 &format!("recursion limit reached while expanding the macro `{}`",
586 expn_data.kind.descr()));
588 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
591 self.cx.trace_macros_diag();
595 let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
597 InvocationKind::Bang { mac, .. } => match ext {
598 SyntaxExtensionKind::Bang(expander) => {
599 self.gate_proc_macro_expansion_kind(span, fragment_kind);
600 let tok_result = expander.expand(self.cx, span, mac.stream());
601 self.parse_ast_fragment(tok_result, fragment_kind, &mac.path, span)
603 SyntaxExtensionKind::LegacyBang(expander) => {
604 let prev = self.cx.current_expansion.prior_type_ascription;
605 self.cx.current_expansion.prior_type_ascription = mac.prior_type_ascription;
606 let tok_result = expander.expand(self.cx, span, mac.stream());
607 let result = if let Some(result) = fragment_kind.make_from(tok_result) {
611 "non-{kind} macro in {kind} position: {path}",
612 kind = fragment_kind.name(),
613 path = pprust::path_to_string(&mac.path),
615 self.cx.span_err(span, &msg);
616 self.cx.trace_macros_diag();
617 fragment_kind.dummy(span)
619 self.cx.current_expansion.prior_type_ascription = prev;
624 InvocationKind::Attr { attr, mut item, .. } => match ext {
625 SyntaxExtensionKind::Attr(expander) => {
626 self.gate_proc_macro_input(&item);
627 self.gate_proc_macro_attr_item(span, &item);
628 let item_tok = TokenTree::token(token::Interpolated(Lrc::new(match item {
629 Annotatable::Item(item) => token::NtItem(item),
630 Annotatable::TraitItem(item) => token::NtTraitItem(item.into_inner()),
631 Annotatable::ImplItem(item) => token::NtImplItem(item.into_inner()),
632 Annotatable::ForeignItem(item) => token::NtForeignItem(item.into_inner()),
633 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
634 Annotatable::Expr(expr) => token::NtExpr(expr),
636 | Annotatable::Field(..)
637 | Annotatable::FieldPat(..)
638 | Annotatable::GenericParam(..)
639 | Annotatable::Param(..)
640 | Annotatable::StructField(..)
641 | Annotatable::Variant(..)
642 => panic!("unexpected annotatable"),
643 })), DUMMY_SP).into();
644 let item = attr.unwrap_normal_item();
645 let input = self.extract_proc_macro_attr_input(item.tokens, span);
646 let tok_result = expander.expand(self.cx, span, input, item_tok);
647 self.parse_ast_fragment(tok_result, fragment_kind, &item.path, span)
649 SyntaxExtensionKind::LegacyAttr(expander) => {
650 match validate_attr::parse_meta(self.cx.parse_sess, &attr) {
652 let item = expander.expand(self.cx, span, &meta, item);
653 fragment_kind.expect_from_annotatables(item)
657 fragment_kind.dummy(span)
661 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
662 attr::mark_known(&attr);
664 attr::mark_used(&attr);
666 item.visit_attrs(|attrs| attrs.push(attr));
667 fragment_kind.expect_from_annotatables(iter::once(item))
671 InvocationKind::Derive { path, item } => match ext {
672 SyntaxExtensionKind::Derive(expander) |
673 SyntaxExtensionKind::LegacyDerive(expander) => {
674 if !item.derive_allowed() {
675 return fragment_kind.dummy(span);
677 if let SyntaxExtensionKind::Derive(..) = ext {
678 self.gate_proc_macro_input(&item);
680 let meta = ast::MetaItem { kind: ast::MetaItemKind::Word, span, path };
681 let items = expander.expand(self.cx, span, &meta, item);
682 fragment_kind.expect_from_annotatables(items)
686 InvocationKind::DeriveContainer { .. } => unreachable!()
690 fn extract_proc_macro_attr_input(&self, tokens: TokenStream, span: Span) -> TokenStream {
691 let mut trees = tokens.trees();
693 Some(TokenTree::Delimited(_, _, tts)) => {
694 if trees.next().is_none() {
698 Some(TokenTree::Token(..)) => {}
699 None => return TokenStream::default(),
701 self.cx.span_err(span, "custom attribute invocations must be \
702 of the form `#[foo]` or `#[foo(..)]`, the macro name must only be \
703 followed by a delimiter token");
704 TokenStream::default()
707 fn gate_proc_macro_attr_item(&self, span: Span, item: &Annotatable) {
708 let kind = match item {
709 Annotatable::Item(item) => match &item.kind {
710 ItemKind::Mod(m) if m.inline => "modules",
713 Annotatable::TraitItem(_)
714 | Annotatable::ImplItem(_)
715 | Annotatable::ForeignItem(_) => return,
716 Annotatable::Stmt(_) => "statements",
717 Annotatable::Expr(_) => "expressions",
719 | Annotatable::Field(..)
720 | Annotatable::FieldPat(..)
721 | Annotatable::GenericParam(..)
722 | Annotatable::Param(..)
723 | Annotatable::StructField(..)
724 | Annotatable::Variant(..)
725 => panic!("unexpected annotatable"),
727 if self.cx.ecfg.proc_macro_hygiene() {
732 sym::proc_macro_hygiene,
734 &format!("custom attributes cannot be applied to {}", kind),
739 fn gate_proc_macro_input(&self, annotatable: &Annotatable) {
740 struct GateProcMacroInput<'a> {
741 parse_sess: &'a ParseSess,
744 impl<'ast, 'a> Visitor<'ast> for GateProcMacroInput<'a> {
745 fn visit_item(&mut self, item: &'ast ast::Item) {
747 ast::ItemKind::Mod(module) if !module.inline => {
750 sym::proc_macro_hygiene,
752 "non-inline modules in proc macro input are unstable",
759 visit::walk_item(self, item);
762 fn visit_mac(&mut self, _: &'ast ast::Mac) {}
765 if !self.cx.ecfg.proc_macro_hygiene() {
766 annotatable.visit_with(&mut GateProcMacroInput { parse_sess: self.cx.parse_sess });
770 fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
771 let kind = match kind {
772 AstFragmentKind::Expr |
773 AstFragmentKind::OptExpr => "expressions",
774 AstFragmentKind::Pat => "patterns",
775 AstFragmentKind::Stmts => "statements",
776 AstFragmentKind::Ty |
777 AstFragmentKind::Items |
778 AstFragmentKind::TraitItems |
779 AstFragmentKind::ImplItems |
780 AstFragmentKind::ForeignItems => return,
781 AstFragmentKind::Arms
782 | AstFragmentKind::Fields
783 | AstFragmentKind::FieldPats
784 | AstFragmentKind::GenericParams
785 | AstFragmentKind::Params
786 | AstFragmentKind::StructFields
787 | AstFragmentKind::Variants
788 => panic!("unexpected AST fragment kind"),
790 if self.cx.ecfg.proc_macro_hygiene() {
795 sym::proc_macro_hygiene,
797 &format!("procedural macros cannot be expanded to {}", kind),
802 fn parse_ast_fragment(
805 kind: AstFragmentKind,
809 let mut parser = self.cx.new_parser_from_tts(toks);
810 match parse_ast_fragment(&mut parser, kind, false) {
812 ensure_complete_parse(&mut parser, path, kind.name(), span);
817 annotate_err_with_kind(&mut err, kind, span);
819 self.cx.trace_macros_diag();
826 pub fn parse_ast_fragment<'a>(
827 this: &mut Parser<'a>,
828 kind: AstFragmentKind,
829 macro_legacy_warnings: bool,
830 ) -> PResult<'a, AstFragment> {
832 AstFragmentKind::Items => {
833 let mut items = SmallVec::new();
834 while let Some(item) = this.parse_item()? {
837 AstFragment::Items(items)
839 AstFragmentKind::TraitItems => {
840 let mut items = SmallVec::new();
841 while this.token != token::Eof {
842 items.push(this.parse_trait_item(&mut false)?);
844 AstFragment::TraitItems(items)
846 AstFragmentKind::ImplItems => {
847 let mut items = SmallVec::new();
848 while this.token != token::Eof {
849 items.push(this.parse_impl_item(&mut false)?);
851 AstFragment::ImplItems(items)
853 AstFragmentKind::ForeignItems => {
854 let mut items = SmallVec::new();
855 while this.token != token::Eof {
856 items.push(this.parse_foreign_item(DUMMY_SP)?);
858 AstFragment::ForeignItems(items)
860 AstFragmentKind::Stmts => {
861 let mut stmts = SmallVec::new();
862 while this.token != token::Eof &&
863 // won't make progress on a `}`
864 this.token != token::CloseDelim(token::Brace) {
865 if let Some(stmt) = this.parse_full_stmt(macro_legacy_warnings)? {
869 AstFragment::Stmts(stmts)
871 AstFragmentKind::Expr => AstFragment::Expr(this.parse_expr()?),
872 AstFragmentKind::OptExpr => {
873 if this.token != token::Eof {
874 AstFragment::OptExpr(Some(this.parse_expr()?))
876 AstFragment::OptExpr(None)
879 AstFragmentKind::Ty => AstFragment::Ty(this.parse_ty()?),
880 AstFragmentKind::Pat => AstFragment::Pat(this.parse_pat(None)?),
881 AstFragmentKind::Arms
882 | AstFragmentKind::Fields
883 | AstFragmentKind::FieldPats
884 | AstFragmentKind::GenericParams
885 | AstFragmentKind::Params
886 | AstFragmentKind::StructFields
887 | AstFragmentKind::Variants
888 => panic!("unexpected AST fragment kind"),
892 pub fn ensure_complete_parse<'a>(
893 this: &mut Parser<'a>,
898 if this.token != token::Eof {
899 let msg = format!("macro expansion ignores token `{}` and any following",
900 this.this_token_to_string());
901 // Avoid emitting backtrace info twice.
902 let def_site_span = this.token.span.with_ctxt(SyntaxContext::root());
903 let mut err = this.struct_span_err(def_site_span, &msg);
904 err.span_label(span, "caused by the macro expansion here");
906 "the usage of `{}!` is likely invalid in {} context",
907 pprust::path_to_string(macro_path),
911 let semi_span = this.sess.source_map().next_point(span);
913 let semi_full_span = semi_span.to(this.sess.source_map().next_point(semi_span));
914 match this.sess.source_map().span_to_snippet(semi_full_span) {
915 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
918 "you might be missing a semicolon here",
920 Applicability::MaybeIncorrect,
929 struct InvocationCollector<'a, 'b> {
930 cx: &'a mut ExtCtxt<'b>,
931 cfg: StripUnconfigured<'a>,
932 invocations: Vec<Invocation>,
936 impl<'a, 'b> InvocationCollector<'a, 'b> {
937 fn collect(&mut self, fragment_kind: AstFragmentKind, kind: InvocationKind) -> AstFragment {
938 // Expansion data for all the collected invocations is set upon their resolution,
939 // with exception of the derive container case which is not resolved and can get
940 // its expansion data immediately.
941 let expn_data = match &kind {
942 InvocationKind::DeriveContainer { item, .. } => Some(ExpnData {
943 parent: self.cx.current_expansion.id,
945 ExpnKind::Macro(MacroKind::Attr, sym::derive),
946 item.span(), self.cx.parse_sess.edition,
951 let expn_id = ExpnId::fresh(expn_data);
952 let vis = kind.placeholder_visibility();
953 self.invocations.push(Invocation {
956 expansion_data: ExpansionData {
958 depth: self.cx.current_expansion.depth + 1,
959 ..self.cx.current_expansion.clone()
962 placeholder(fragment_kind, NodeId::placeholder_from_expn_id(expn_id), vis)
965 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: AstFragmentKind) -> AstFragment {
966 self.collect(kind, InvocationKind::Bang { mac, span })
969 fn collect_attr(&mut self,
970 attr: Option<ast::Attribute>,
973 kind: AstFragmentKind,
976 self.collect(kind, match attr {
977 Some(attr) => InvocationKind::Attr { attr, item, derives, after_derive },
978 None => InvocationKind::DeriveContainer { derives, item },
982 fn find_attr_invoc(&self, attrs: &mut Vec<ast::Attribute>, after_derive: &mut bool)
983 -> Option<ast::Attribute> {
984 let attr = attrs.iter()
986 if a.has_name(sym::derive) {
987 *after_derive = true;
989 !attr::is_known(a) && !is_builtin_attr(a)
991 .map(|i| attrs.remove(i));
992 if let Some(attr) = &attr {
993 if !self.cx.ecfg.custom_inner_attributes() &&
994 attr.style == ast::AttrStyle::Inner && !attr.has_name(sym::test) {
996 &self.cx.parse_sess, sym::custom_inner_attributes, attr.span,
997 "non-builtin inner attributes are unstable"
1005 /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
1006 fn classify_item<T>(&mut self, item: &mut T)
1007 -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)
1010 let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
1012 item.visit_attrs(|mut attrs| {
1013 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1014 traits = collect_derives(&mut self.cx, &mut attrs);
1017 (attr, traits, after_derive)
1020 /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
1021 /// to the unused-attributes lint (making it an error on statements and expressions
1022 /// is a breaking change)
1023 fn classify_nonitem<T: HasAttrs>(&mut self, nonitem: &mut T)
1024 -> (Option<ast::Attribute>, /* after_derive */ bool) {
1025 let (mut attr, mut after_derive) = (None, false);
1027 nonitem.visit_attrs(|mut attrs| {
1028 attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
1031 (attr, after_derive)
1034 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
1035 self.cfg.configure(node)
1038 // Detect use of feature-gated or invalid attributes on macro invocations
1039 // since they will not be detected after macro expansion.
1040 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
1041 let features = self.cx.ecfg.features.unwrap();
1042 for attr in attrs.iter() {
1043 feature_gate::check_attribute(attr, self.cx.parse_sess, features);
1044 validate_attr::check_meta(self.cx.parse_sess, attr);
1046 // macros are expanded before any lint passes so this warning has to be hardcoded
1047 if attr.has_name(sym::derive) {
1048 self.cx.struct_span_warn(attr.span, "`#[derive]` does nothing on macro invocations")
1049 .note("this may become a hard error in a future release")
1056 impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
1057 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
1058 self.cfg.configure_expr(expr);
1059 visit_clobber(expr.deref_mut(), |mut expr| {
1060 self.cfg.configure_expr_kind(&mut expr.kind);
1062 // ignore derives so they remain unused
1063 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1066 // Collect the invoc regardless of whether or not attributes are permitted here
1067 // expansion will eat the attribute so it won't error later.
1068 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1070 // AstFragmentKind::Expr requires the macro to emit an expression.
1071 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1072 AstFragmentKind::Expr, after_derive)
1077 if let ast::ExprKind::Mac(mac) = expr.kind {
1078 self.check_attributes(&expr.attrs);
1079 self.collect_bang(mac, expr.span, AstFragmentKind::Expr)
1083 noop_visit_expr(&mut expr, self);
1089 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
1090 let mut arm = configure!(self, arm);
1092 let (attr, traits, after_derive) = self.classify_item(&mut arm);
1093 if attr.is_some() || !traits.is_empty() {
1094 return self.collect_attr(attr, traits, Annotatable::Arm(arm),
1095 AstFragmentKind::Arms, after_derive)
1099 noop_flat_map_arm(arm, self)
1102 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
1103 let mut field = configure!(self, field);
1105 let (attr, traits, after_derive) = self.classify_item(&mut field);
1106 if attr.is_some() || !traits.is_empty() {
1107 return self.collect_attr(attr, traits, Annotatable::Field(field),
1108 AstFragmentKind::Fields, after_derive)
1112 noop_flat_map_field(field, self)
1115 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
1116 let mut fp = configure!(self, fp);
1118 let (attr, traits, after_derive) = self.classify_item(&mut fp);
1119 if attr.is_some() || !traits.is_empty() {
1120 return self.collect_attr(attr, traits, Annotatable::FieldPat(fp),
1121 AstFragmentKind::FieldPats, after_derive)
1122 .make_field_patterns();
1125 noop_flat_map_field_pattern(fp, self)
1128 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
1129 let mut p = configure!(self, p);
1131 let (attr, traits, after_derive) = self.classify_item(&mut p);
1132 if attr.is_some() || !traits.is_empty() {
1133 return self.collect_attr(attr, traits, Annotatable::Param(p),
1134 AstFragmentKind::Params, after_derive)
1138 noop_flat_map_param(p, self)
1141 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
1142 let mut sf = configure!(self, sf);
1144 let (attr, traits, after_derive) = self.classify_item(&mut sf);
1145 if attr.is_some() || !traits.is_empty() {
1146 return self.collect_attr(attr, traits, Annotatable::StructField(sf),
1147 AstFragmentKind::StructFields, after_derive)
1148 .make_struct_fields();
1151 noop_flat_map_struct_field(sf, self)
1154 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
1155 let mut variant = configure!(self, variant);
1157 let (attr, traits, after_derive) = self.classify_item(&mut variant);
1158 if attr.is_some() || !traits.is_empty() {
1159 return self.collect_attr(attr, traits, Annotatable::Variant(variant),
1160 AstFragmentKind::Variants, after_derive)
1164 noop_flat_map_variant(variant, self)
1167 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
1168 let expr = configure!(self, expr);
1169 expr.filter_map(|mut expr| {
1170 self.cfg.configure_expr_kind(&mut expr.kind);
1172 // Ignore derives so they remain unused.
1173 let (attr, after_derive) = self.classify_nonitem(&mut expr);
1176 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
1178 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
1179 AstFragmentKind::OptExpr, after_derive)
1181 .map(|expr| expr.into_inner())
1184 if let ast::ExprKind::Mac(mac) = expr.kind {
1185 self.check_attributes(&expr.attrs);
1186 self.collect_bang(mac, expr.span, AstFragmentKind::OptExpr)
1188 .map(|expr| expr.into_inner())
1190 Some({ noop_visit_expr(&mut expr, self); expr })
1195 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
1196 self.cfg.configure_pat(pat);
1198 PatKind::Mac(_) => {}
1199 _ => return noop_visit_pat(pat, self),
1202 visit_clobber(pat, |mut pat| {
1203 match mem::replace(&mut pat.kind, PatKind::Wild) {
1204 PatKind::Mac(mac) =>
1205 self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
1206 _ => unreachable!(),
1211 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
1212 let mut stmt = configure!(self, stmt);
1214 // we'll expand attributes on expressions separately
1215 if !stmt.is_expr() {
1216 let (attr, derives, after_derive) = if stmt.is_item() {
1217 self.classify_item(&mut stmt)
1219 // ignore derives on non-item statements so it falls through
1220 // to the unused-attributes lint
1221 let (attr, after_derive) = self.classify_nonitem(&mut stmt);
1222 (attr, vec![], after_derive)
1225 if attr.is_some() || !derives.is_empty() {
1226 return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt)),
1227 AstFragmentKind::Stmts, after_derive).make_stmts();
1231 if let StmtKind::Mac(mac) = stmt.kind {
1232 let (mac, style, attrs) = mac.into_inner();
1233 self.check_attributes(&attrs);
1234 let mut placeholder = self.collect_bang(mac, stmt.span, AstFragmentKind::Stmts)
1237 // If this is a macro invocation with a semicolon, then apply that
1238 // semicolon to the final statement produced by expansion.
1239 if style == MacStmtStyle::Semicolon {
1240 if let Some(stmt) = placeholder.pop() {
1241 placeholder.push(stmt.add_trailing_semicolon());
1248 // The placeholder expander gives ids to statements, so we avoid folding the id here.
1249 let ast::Stmt { id, kind, span } = stmt;
1250 noop_flat_map_stmt_kind(kind, self).into_iter().map(|kind| {
1251 ast::Stmt { id, kind, span }
1256 fn visit_block(&mut self, block: &mut P<Block>) {
1257 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
1258 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
1259 noop_visit_block(block, self);
1260 self.cx.current_expansion.directory_ownership = old_directory_ownership;
1263 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
1264 let mut item = configure!(self, item);
1266 let (attr, traits, after_derive) = self.classify_item(&mut item);
1267 if attr.is_some() || !traits.is_empty() {
1268 return self.collect_attr(attr, traits, Annotatable::Item(item),
1269 AstFragmentKind::Items, after_derive).make_items();
1273 ast::ItemKind::Mac(..) => {
1274 self.check_attributes(&item.attrs);
1275 item.and_then(|item| match item.kind {
1276 ItemKind::Mac(mac) => self.collect(
1277 AstFragmentKind::Items, InvocationKind::Bang { mac, span: item.span }
1279 _ => unreachable!(),
1282 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
1283 if item.ident == Ident::invalid() {
1284 return noop_flat_map_item(item, self);
1287 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
1288 let mut module = (*self.cx.current_expansion.module).clone();
1289 module.mod_path.push(item.ident);
1291 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
1292 // In the non-inline case, `inner` is never the dummy span (cf. `parse_item_mod`).
1293 // Thus, if `inner` is the dummy span, we know the module is inline.
1294 let inline_module = item.span.contains(inner) || inner.is_dummy();
1297 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, sym::path) {
1298 self.cx.current_expansion.directory_ownership =
1299 DirectoryOwnership::Owned { relative: None };
1300 module.directory.push(&*path.as_str());
1302 module.directory.push(&*item.ident.as_str());
1305 let path = self.cx.parse_sess.source_map().span_to_unmapped_path(inner);
1306 let mut path = match path {
1307 FileName::Real(path) => path,
1308 other => PathBuf::from(other.to_string()),
1310 let directory_ownership = match path.file_name().unwrap().to_str() {
1311 Some("mod.rs") => DirectoryOwnership::Owned { relative: None },
1312 Some(_) => DirectoryOwnership::Owned {
1313 relative: Some(item.ident),
1315 None => DirectoryOwnership::UnownedViaMod,
1318 module.directory = path;
1319 self.cx.current_expansion.directory_ownership = directory_ownership;
1323 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
1324 let result = noop_flat_map_item(item, self);
1325 self.cx.current_expansion.module = orig_module;
1326 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
1330 _ => noop_flat_map_item(item, self),
1334 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
1335 let mut item = configure!(self, item);
1337 let (attr, traits, after_derive) = self.classify_item(&mut item);
1338 if attr.is_some() || !traits.is_empty() {
1339 return self.collect_attr(attr, traits, Annotatable::TraitItem(P(item)),
1340 AstFragmentKind::TraitItems, after_derive).make_trait_items()
1344 ast::TraitItemKind::Macro(mac) => {
1345 let ast::TraitItem { attrs, span, .. } = item;
1346 self.check_attributes(&attrs);
1347 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
1349 _ => noop_flat_map_trait_item(item, self),
1353 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
1354 let mut item = configure!(self, item);
1356 let (attr, traits, after_derive) = self.classify_item(&mut item);
1357 if attr.is_some() || !traits.is_empty() {
1358 return self.collect_attr(attr, traits, Annotatable::ImplItem(P(item)),
1359 AstFragmentKind::ImplItems, after_derive).make_impl_items();
1363 ast::ImplItemKind::Macro(mac) => {
1364 let ast::ImplItem { attrs, span, .. } = item;
1365 self.check_attributes(&attrs);
1366 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
1368 _ => noop_flat_map_impl_item(item, self),
1372 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
1374 ast::TyKind::Mac(_) => {}
1375 _ => return noop_visit_ty(ty, self),
1378 visit_clobber(ty, |mut ty| {
1379 match mem::replace(&mut ty.kind, ast::TyKind::Err) {
1380 ast::TyKind::Mac(mac) =>
1381 self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
1382 _ => unreachable!(),
1387 fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
1388 self.cfg.configure_foreign_mod(foreign_mod);
1389 noop_visit_foreign_mod(foreign_mod, self);
1392 fn flat_map_foreign_item(&mut self, mut foreign_item: ast::ForeignItem)
1393 -> SmallVec<[ast::ForeignItem; 1]>
1395 let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
1397 if attr.is_some() || !traits.is_empty() {
1398 return self.collect_attr(attr, traits, Annotatable::ForeignItem(P(foreign_item)),
1399 AstFragmentKind::ForeignItems, after_derive)
1400 .make_foreign_items();
1403 if let ast::ForeignItemKind::Macro(mac) = foreign_item.kind {
1404 self.check_attributes(&foreign_item.attrs);
1405 return self.collect_bang(mac, foreign_item.span, AstFragmentKind::ForeignItems)
1406 .make_foreign_items();
1409 noop_flat_map_foreign_item(foreign_item, self)
1412 fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
1414 ast::ItemKind::MacroDef(..) => {}
1416 self.cfg.configure_item_kind(item);
1417 noop_visit_item_kind(item, self);
1422 fn flat_map_generic_param(
1424 param: ast::GenericParam
1425 ) -> SmallVec<[ast::GenericParam; 1]>
1427 let mut param = configure!(self, param);
1429 let (attr, traits, after_derive) = self.classify_item(&mut param);
1430 if attr.is_some() || !traits.is_empty() {
1431 return self.collect_attr(attr, traits, Annotatable::GenericParam(param),
1432 AstFragmentKind::GenericParams, after_derive)
1433 .make_generic_params();
1436 noop_flat_map_generic_param(param, self)
1439 fn visit_attribute(&mut self, at: &mut ast::Attribute) {
1440 // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
1441 // contents="file contents")]` attributes
1442 if !at.check_name(sym::doc) {
1443 return noop_visit_attribute(at, self);
1446 if let Some(list) = at.meta_item_list() {
1447 if !list.iter().any(|it| it.check_name(sym::include)) {
1448 return noop_visit_attribute(at, self);
1451 let mut items = vec![];
1453 for mut it in list {
1454 if !it.check_name(sym::include) {
1455 items.push({ noop_visit_meta_list_item(&mut it, self); it });
1459 if let Some(file) = it.value_str() {
1460 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
1461 self.check_attributes(slice::from_ref(at));
1462 if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
1463 // avoid loading the file if they haven't enabled the feature
1464 return noop_visit_attribute(at, self);
1467 let filename = match self.cx.resolve_path(&*file.as_str(), it.span()) {
1468 Ok(filename) => filename,
1475 match self.cx.source_map().load_file(&filename) {
1476 Ok(source_file) => {
1477 let src = source_file.src.as_ref()
1478 .expect("freshly loaded file should have a source");
1479 let src_interned = Symbol::intern(src.as_str());
1481 let include_info = vec![
1482 ast::NestedMetaItem::MetaItem(
1483 attr::mk_name_value_item_str(
1484 Ident::with_dummy_span(sym::file),
1489 ast::NestedMetaItem::MetaItem(
1490 attr::mk_name_value_item_str(
1491 Ident::with_dummy_span(sym::contents),
1498 let include_ident = Ident::with_dummy_span(sym::include);
1499 let item = attr::mk_list_item(include_ident, include_info);
1500 items.push(ast::NestedMetaItem::MetaItem(item));
1505 .and_then(|item| item.name_value_literal())
1508 if e.kind() == ErrorKind::InvalidData {
1512 &format!("{} wasn't a utf-8 file", filename.display()),
1514 .span_label(lit.span, "contains invalid utf-8")
1517 let mut err = self.cx.struct_span_err(
1519 &format!("couldn't read {}: {}", filename.display(), e),
1521 err.span_label(lit.span, "couldn't read file");
1528 let mut err = self.cx.struct_span_err(
1530 &format!("expected path to external documentation"),
1533 // Check if the user erroneously used `doc(include(...))` syntax.
1534 let literal = it.meta_item_list().and_then(|list| {
1535 if list.len() == 1 {
1536 list[0].literal().map(|literal| &literal.kind)
1542 let (path, applicability) = match &literal {
1543 Some(LitKind::Str(path, ..)) => {
1544 (path.to_string(), Applicability::MachineApplicable)
1546 _ => (String::from("<path>"), Applicability::HasPlaceholders),
1549 err.span_suggestion(
1551 "provide a file path with `=`",
1552 format!("include = \"{}\"", path),
1560 let meta = attr::mk_list_item(Ident::with_dummy_span(sym::doc), items);
1561 *at = attr::Attribute {
1562 kind: ast::AttrKind::Normal(
1563 AttrItem { path: meta.path, tokens: meta.kind.tokens(meta.span) },
1570 noop_visit_attribute(at, self)
1574 fn visit_id(&mut self, id: &mut ast::NodeId) {
1576 debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
1577 *id = self.cx.resolver.next_node_id()
1581 fn visit_fn_decl(&mut self, mut fn_decl: &mut P<ast::FnDecl>) {
1582 self.cfg.configure_fn_decl(&mut fn_decl);
1583 noop_visit_fn_decl(fn_decl, self);
1587 pub struct ExpansionConfig<'feat> {
1588 pub crate_name: String,
1589 pub features: Option<&'feat Features>,
1590 pub recursion_limit: usize,
1591 pub trace_mac: bool,
1592 pub should_test: bool, // If false, strip `#[test]` nodes
1593 pub single_step: bool,
1594 pub keep_macs: bool,
1597 impl<'feat> ExpansionConfig<'feat> {
1598 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1602 recursion_limit: 1024,
1610 fn proc_macro_hygiene(&self) -> bool {
1611 self.features.map_or(false, |features| features.proc_macro_hygiene)
1613 fn custom_inner_attributes(&self) -> bool {
1614 self.features.map_or(false, |features| features.custom_inner_attributes)