1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use ast::{self, Block, Ident, NodeId, PatKind, Path};
12 use ast::{MacStmtStyle, StmtKind, ItemKind};
13 use attr::{self, HasAttrs};
14 use codemap::{ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
15 use config::{is_test_or_bench, StripUnconfigured};
16 use errors::FatalError;
18 use ext::derive::{add_derived_markers, collect_derives};
19 use ext::hygiene::Mark;
20 use ext::placeholders::{placeholder, PlaceholderExpander};
21 use feature_gate::{self, Features, is_builtin_attr};
24 use parse::{filemap_to_stream, ParseSess, DirectoryOwnership, PResult, token};
25 use parse::parser::Parser;
31 use syntax_pos::{Span, DUMMY_SP};
32 use tokenstream::TokenStream;
33 use util::small_vector::SmallVector;
36 use std::collections::HashMap;
38 use std::path::PathBuf;
41 macro_rules! expansions {
42 ($($kind:ident: $ty:ty [$($vec:ident, $ty_elt:ty)*], $kind_name:expr, .$make:ident,
43 $(.$fold:ident)* $(lift .$fold_elt:ident)*,
44 $(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => {
45 #[derive(Copy, Clone, PartialEq, Eq)]
46 pub enum ExpansionKind { OptExpr, $( $kind, )* }
47 pub enum Expansion { OptExpr(Option<P<ast::Expr>>), $( $kind($ty), )* }
50 pub fn name(self) -> &'static str {
52 ExpansionKind::OptExpr => "expression",
53 $( ExpansionKind::$kind => $kind_name, )*
57 fn make_from<'a>(self, result: Box<MacResult + 'a>) -> Option<Expansion> {
59 ExpansionKind::OptExpr => result.make_expr().map(Some).map(Expansion::OptExpr),
60 $( ExpansionKind::$kind => result.$make().map(Expansion::$kind), )*
66 pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
68 Expansion::OptExpr(expr) => expr,
69 _ => panic!("Expansion::make_* called on the wrong kind of expansion"),
72 $( pub fn $make(self) -> $ty {
74 Expansion::$kind(ast) => ast,
75 _ => panic!("Expansion::make_* called on the wrong kind of expansion"),
79 pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
80 use self::Expansion::*;
82 OptExpr(expr) => OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
83 $($( $kind(ast) => $kind(folder.$fold(ast)), )*)*
85 $kind(ast.into_iter().flat_map(|ast| folder.$fold_elt(ast)).collect())
90 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
92 Expansion::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
93 Expansion::OptExpr(None) => {}
94 $($( Expansion::$kind(ref ast) => visitor.$visit(ast), )*)*
95 $($( Expansion::$kind(ref ast) => for ast in &ast[..] {
96 visitor.$visit_elt(ast);
102 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
103 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
104 self.expand(Expansion::OptExpr(Some(expr))).make_opt_expr()
106 $($(fn $fold(&mut self, node: $ty) -> $ty {
107 self.expand(Expansion::$kind(node)).$make()
109 $($(fn $fold_elt(&mut self, node: $ty_elt) -> $ty {
110 self.expand(Expansion::$kind(SmallVector::one(node))).$make()
114 impl<'a> MacResult for ::ext::tt::macro_rules::ParserAnyMacro<'a> {
115 $(fn $make(self: Box<::ext::tt::macro_rules::ParserAnyMacro<'a>>) -> Option<$ty> {
116 Some(self.make(ExpansionKind::$kind).$make())
123 Expr: P<ast::Expr> [], "expression", .make_expr, .fold_expr, .visit_expr;
124 Pat: P<ast::Pat> [], "pattern", .make_pat, .fold_pat, .visit_pat;
125 Ty: P<ast::Ty> [], "type", .make_ty, .fold_ty, .visit_ty;
126 Stmts: SmallVector<ast::Stmt> [SmallVector, ast::Stmt],
127 "statement", .make_stmts, lift .fold_stmt, lift .visit_stmt;
128 Items: SmallVector<P<ast::Item>> [SmallVector, P<ast::Item>],
129 "item", .make_items, lift .fold_item, lift .visit_item;
130 TraitItems: SmallVector<ast::TraitItem> [SmallVector, ast::TraitItem],
131 "trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item;
132 ImplItems: SmallVector<ast::ImplItem> [SmallVector, ast::ImplItem],
133 "impl item", .make_impl_items, lift .fold_impl_item, lift .visit_impl_item;
137 fn dummy(self, span: Span) -> Expansion {
138 self.make_from(DummyResult::any(span)).unwrap()
141 fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I) -> Expansion {
142 let items = items.into_iter();
144 ExpansionKind::Items =>
145 Expansion::Items(items.map(Annotatable::expect_item).collect()),
146 ExpansionKind::ImplItems =>
147 Expansion::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
148 ExpansionKind::TraitItems =>
149 Expansion::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
155 pub struct Invocation {
156 pub kind: InvocationKind,
157 expansion_kind: ExpansionKind,
158 pub expansion_data: ExpansionData,
161 pub enum InvocationKind {
164 ident: Option<Ident>,
168 attr: Option<ast::Attribute>,
179 fn span(&self) -> Span {
181 InvocationKind::Bang { span, .. } => span,
182 InvocationKind::Attr { attr: Some(ref attr), .. } => attr.span,
183 InvocationKind::Attr { attr: None, .. } => DUMMY_SP,
184 InvocationKind::Derive { ref path, .. } => path.span,
189 pub struct MacroExpander<'a, 'b:'a> {
190 pub cx: &'a mut ExtCtxt<'b>,
191 monotonic: bool, // c.f. `cx.monotonic_expander()`
194 impl<'a, 'b> MacroExpander<'a, 'b> {
195 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
196 MacroExpander { cx: cx, monotonic: monotonic }
199 pub fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
200 self.cx.crate_root = std_inject::injected_crate_name(&krate);
201 let mut module = ModuleData {
202 mod_path: vec![Ident::from_str(&self.cx.ecfg.crate_name)],
203 directory: PathBuf::from(self.cx.codemap().span_to_filename(krate.span)),
205 module.directory.pop();
206 self.cx.current_expansion.module = Rc::new(module);
208 let krate_item = Expansion::Items(SmallVector::one(P(ast::Item {
211 node: ast::ItemKind::Mod(krate.module),
212 ident: keywords::Invalid.ident(),
213 id: ast::DUMMY_NODE_ID,
214 vis: ast::Visibility::Public,
217 match self.expand(krate_item).make_items().pop().unwrap().unwrap() {
218 ast::Item { attrs, node: ast::ItemKind::Mod(module), .. } => {
220 krate.module = module;
228 // Fully expand all the invocations in `expansion`.
229 fn expand(&mut self, expansion: Expansion) -> Expansion {
230 let orig_expansion_data = self.cx.current_expansion.clone();
231 self.cx.current_expansion.depth = 0;
233 let (expansion, mut invocations) = self.collect_invocations(expansion, &[]);
234 self.resolve_imports();
235 invocations.reverse();
237 let mut expansions = Vec::new();
238 let mut derives = HashMap::new();
239 let mut undetermined_invocations = Vec::new();
240 let (mut progress, mut force) = (false, !self.monotonic);
242 let mut invoc = if let Some(invoc) = invocations.pop() {
245 self.resolve_imports();
246 if undetermined_invocations.is_empty() { break }
247 invocations = mem::replace(&mut undetermined_invocations, Vec::new());
248 force = !mem::replace(&mut progress, false);
253 if self.monotonic { invoc.expansion_data.mark } else { orig_expansion_data.mark };
254 let ext = match self.cx.resolver.resolve_invoc(&mut invoc, scope, force) {
255 Ok(ext) => Some(ext),
256 Err(Determinacy::Determined) => None,
257 Err(Determinacy::Undetermined) => {
258 undetermined_invocations.push(invoc);
264 let ExpansionData { depth, mark, .. } = invoc.expansion_data;
265 self.cx.current_expansion = invoc.expansion_data.clone();
267 self.cx.current_expansion.mark = scope;
268 // FIXME(jseyfried): Refactor out the following logic
269 let (expansion, new_invocations) = if let Some(ext) = ext {
270 if let Some(ext) = ext {
271 let expansion = self.expand_invoc(invoc, ext);
272 self.collect_invocations(expansion, &[])
273 } else if let InvocationKind::Attr { attr: None, traits, item } = invoc.kind {
275 .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
276 let item_with_markers =
277 add_derived_markers(&mut self.cx, item.span(), &traits, item.clone());
278 let derives = derives.entry(invoc.expansion_data.mark).or_insert_with(Vec::new);
280 for path in &traits {
281 let mark = Mark::fresh();
283 let item = match self.cx.resolver.resolve_macro(
284 Mark::root(), path, MacroKind::Derive, false) {
285 Ok(ext) => match *ext {
286 SyntaxExtension::BuiltinDerive(..) => item_with_markers.clone(),
291 invocations.push(Invocation {
292 kind: InvocationKind::Derive { path: path.clone(), item: item },
293 expansion_kind: invoc.expansion_kind,
294 expansion_data: ExpansionData {
296 ..invoc.expansion_data.clone()
300 let expansion = invoc.expansion_kind
301 .expect_from_annotatables(::std::iter::once(item_with_markers));
302 self.collect_invocations(expansion, derives)
307 self.collect_invocations(invoc.expansion_kind.dummy(invoc.span()), &[])
310 if expansions.len() < depth {
311 expansions.push(Vec::new());
313 expansions[depth - 1].push((mark, expansion));
314 if !self.cx.ecfg.single_step {
315 invocations.extend(new_invocations.into_iter().rev());
319 self.cx.current_expansion = orig_expansion_data;
321 let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
322 while let Some(expansions) = expansions.pop() {
323 for (mark, expansion) in expansions.into_iter().rev() {
324 let derives = derives.remove(&mark).unwrap_or_else(Vec::new);
325 placeholder_expander.add(NodeId::placeholder_from_mark(mark), expansion, derives);
329 expansion.fold_with(&mut placeholder_expander)
332 fn resolve_imports(&mut self) {
334 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
335 self.cx.resolver.resolve_imports();
336 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
340 fn collect_invocations(&mut self, expansion: Expansion, derives: &[Mark])
341 -> (Expansion, Vec<Invocation>) {
343 let mut collector = InvocationCollector {
344 cfg: StripUnconfigured {
345 should_test: self.cx.ecfg.should_test,
346 sess: self.cx.parse_sess,
347 features: self.cx.ecfg.features,
350 invocations: Vec::new(),
351 monotonic: self.monotonic,
353 (expansion.fold_with(&mut collector), collector.invocations)
357 let err_count = self.cx.parse_sess.span_diagnostic.err_count();
358 let mark = self.cx.current_expansion.mark;
359 self.cx.resolver.visit_expansion(mark, &result.0, derives);
360 self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
366 fn expand_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
367 let result = match invoc.kind {
368 InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext),
369 InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext),
370 InvocationKind::Derive { .. } => self.expand_derive_invoc(invoc, ext),
373 if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
374 let info = self.cx.current_expansion.mark.expn_info().unwrap();
375 let suggested_limit = self.cx.ecfg.recursion_limit * 2;
376 let mut err = self.cx.struct_span_fatal(info.call_site,
377 &format!("recursion limit reached while expanding the macro `{}`",
378 info.callee.name()));
380 "consider adding a `#![recursion_limit=\"{}\"]` attribute to your crate",
389 fn expand_attr_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
390 let Invocation { expansion_kind: kind, .. } = invoc;
391 let (attr, item) = match invoc.kind {
392 InvocationKind::Attr { attr, item, .. } => (attr.unwrap(), item),
396 attr::mark_used(&attr);
397 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
398 call_site: attr.span,
399 callee: NameAndSpan {
400 format: MacroAttribute(Symbol::intern(&format!("{}", attr.path))),
402 allow_internal_unstable: false,
407 MultiModifier(ref mac) => {
408 let meta = panictry!(attr.parse_meta(&self.cx.parse_sess));
409 let item = mac.expand(self.cx, attr.span, &meta, item);
410 kind.expect_from_annotatables(item)
412 MultiDecorator(ref mac) => {
413 let mut items = Vec::new();
414 let meta = panictry!(attr.parse_meta(&self.cx.parse_sess));
415 mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
417 kind.expect_from_annotatables(items)
419 SyntaxExtension::AttrProcMacro(ref mac) => {
420 let item_toks = stream_for_item(&item, &self.cx.parse_sess);
422 let span = Span { ctxt: self.cx.backtrace(), ..attr.span };
423 let tok_result = mac.expand(self.cx, attr.span, attr.tokens, item_toks);
424 self.parse_expansion(tok_result, kind, &attr.path, span)
426 SyntaxExtension::ProcMacroDerive(..) | SyntaxExtension::BuiltinDerive(..) => {
427 self.cx.span_err(attr.span, &format!("`{}` is a derive mode", attr.path));
428 kind.dummy(attr.span)
431 let msg = &format!("macro `{}` may not be used in attributes", attr.path);
432 self.cx.span_err(attr.span, &msg);
433 kind.dummy(attr.span)
438 /// Expand a macro invocation. Returns the result of expansion.
439 fn expand_bang_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
440 let (mark, kind) = (invoc.expansion_data.mark, invoc.expansion_kind);
441 let (mac, ident, span) = match invoc.kind {
442 InvocationKind::Bang { mac, ident, span } => (mac, ident, span),
445 let path = &mac.node.path;
447 let ident = ident.unwrap_or(keywords::Invalid.ident());
448 let marked_tts = noop_fold_tts(mac.node.stream(), &mut Marker(mark));
449 let opt_expanded = match *ext {
450 NormalTT(ref expandfun, exp_span, allow_internal_unstable) => {
451 if ident.name != keywords::Invalid.name() {
453 format!("macro {}! expects no ident argument, given '{}'", path, ident);
454 self.cx.span_err(path.span, &msg);
455 return kind.dummy(span);
458 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
460 callee: NameAndSpan {
461 format: MacroBang(Symbol::intern(&format!("{}", path))),
463 allow_internal_unstable: allow_internal_unstable,
467 kind.make_from(expandfun.expand(self.cx, span, marked_tts))
470 IdentTT(ref expander, tt_span, allow_internal_unstable) => {
471 if ident.name == keywords::Invalid.name() {
472 self.cx.span_err(path.span,
473 &format!("macro {}! expects an ident argument", path));
474 return kind.dummy(span);
477 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
479 callee: NameAndSpan {
480 format: MacroBang(Symbol::intern(&format!("{}", path))),
482 allow_internal_unstable: allow_internal_unstable,
486 let input: Vec<_> = marked_tts.into_trees().collect();
487 kind.make_from(expander.expand(self.cx, span, ident, input))
490 MultiDecorator(..) | MultiModifier(..) | SyntaxExtension::AttrProcMacro(..) => {
491 self.cx.span_err(path.span,
492 &format!("`{}` can only be used in attributes", path));
493 return kind.dummy(span);
496 SyntaxExtension::ProcMacroDerive(..) | SyntaxExtension::BuiltinDerive(..) => {
497 self.cx.span_err(path.span, &format!("`{}` is a derive mode", path));
498 return kind.dummy(span);
501 SyntaxExtension::ProcMacro(ref expandfun) => {
502 if ident.name != keywords::Invalid.name() {
504 format!("macro {}! expects no ident argument, given '{}'", path, ident);
505 self.cx.span_err(path.span, &msg);
506 return kind.dummy(span);
509 invoc.expansion_data.mark.set_expn_info(ExpnInfo {
511 callee: NameAndSpan {
512 format: MacroBang(Symbol::intern(&format!("{}", path))),
513 // FIXME procedural macros do not have proper span info
514 // yet, when they do, we should use it here.
516 // FIXME probably want to follow macro_rules macros here.
517 allow_internal_unstable: false,
521 let tok_result = expandfun.expand(self.cx, span, marked_tts);
522 Some(self.parse_expansion(tok_result, kind, path, span))
526 let expanded = if let Some(expanded) = opt_expanded {
529 let msg = format!("non-{kind} macro in {kind} position: {name}",
530 name = path.segments[0].identifier.name, kind = kind.name());
531 self.cx.span_err(path.span, &msg);
532 return kind.dummy(span);
535 expanded.fold_with(&mut Marker(mark))
538 /// Expand a derive invocation. Returns the result of expansion.
539 fn expand_derive_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
540 let Invocation { expansion_kind: kind, .. } = invoc;
541 let (path, item) = match invoc.kind {
542 InvocationKind::Derive { path, item } => (path, item),
546 let pretty_name = Symbol::intern(&format!("derive({})", path));
547 let span = path.span;
548 let attr = ast::Attribute {
549 path: path, tokens: TokenStream::empty(), span: span,
551 id: ast::AttrId(0), style: ast::AttrStyle::Outer, is_sugared_doc: false,
554 let mut expn_info = ExpnInfo {
556 callee: NameAndSpan {
557 format: MacroAttribute(pretty_name),
559 allow_internal_unstable: false,
564 SyntaxExtension::ProcMacroDerive(ref ext, _) => {
565 invoc.expansion_data.mark.set_expn_info(expn_info);
566 let span = Span { ctxt: self.cx.backtrace(), ..span };
567 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
568 name: keywords::Invalid.name(),
570 node: ast::MetaItemKind::Word,
572 kind.expect_from_annotatables(ext.expand(self.cx, span, &dummy, item))
574 SyntaxExtension::BuiltinDerive(func) => {
575 expn_info.callee.allow_internal_unstable = true;
576 invoc.expansion_data.mark.set_expn_info(expn_info);
577 let span = Span { ctxt: self.cx.backtrace(), ..span };
578 let mut items = Vec::new();
579 func(self.cx, span, &attr.meta().unwrap(), &item, &mut |a| items.push(a));
580 kind.expect_from_annotatables(items)
583 let msg = &format!("macro `{}` may not be used for derive attributes", attr.path);
584 self.cx.span_err(span, &msg);
590 fn parse_expansion(&mut self, toks: TokenStream, kind: ExpansionKind, path: &Path, span: Span)
592 let mut parser = self.cx.new_parser_from_tts(&toks.into_trees().collect::<Vec<_>>());
593 let expansion = match parser.parse_expansion(kind, false) {
594 Ok(expansion) => expansion,
597 return kind.dummy(span);
600 parser.ensure_complete_parse(path, kind.name(), span);
601 // FIXME better span info
602 expansion.fold_with(&mut ChangeSpan { span: span })
606 impl<'a> Parser<'a> {
607 pub fn parse_expansion(&mut self, kind: ExpansionKind, macro_legacy_warnings: bool)
608 -> PResult<'a, Expansion> {
610 ExpansionKind::Items => {
611 let mut items = SmallVector::new();
612 while let Some(item) = self.parse_item()? {
615 Expansion::Items(items)
617 ExpansionKind::TraitItems => {
618 let mut items = SmallVector::new();
619 while self.token != token::Eof {
620 items.push(self.parse_trait_item(&mut false)?);
622 Expansion::TraitItems(items)
624 ExpansionKind::ImplItems => {
625 let mut items = SmallVector::new();
626 while self.token != token::Eof {
627 items.push(self.parse_impl_item(&mut false)?);
629 Expansion::ImplItems(items)
631 ExpansionKind::Stmts => {
632 let mut stmts = SmallVector::new();
633 while self.token != token::Eof &&
634 // won't make progress on a `}`
635 self.token != token::CloseDelim(token::Brace) {
636 if let Some(stmt) = self.parse_full_stmt(macro_legacy_warnings)? {
640 Expansion::Stmts(stmts)
642 ExpansionKind::Expr => Expansion::Expr(self.parse_expr()?),
643 ExpansionKind::OptExpr => Expansion::OptExpr(Some(self.parse_expr()?)),
644 ExpansionKind::Ty => Expansion::Ty(self.parse_ty()?),
645 ExpansionKind::Pat => Expansion::Pat(self.parse_pat()?),
649 pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span: Span) {
650 if self.token != token::Eof {
651 let msg = format!("macro expansion ignores token `{}` and any following",
652 self.this_token_to_string());
653 let mut err = self.diagnostic().struct_span_err(self.span, &msg);
654 let msg = format!("caused by the macro expansion here; the usage \
655 of `{}!` is likely invalid in {} context",
656 macro_path, kind_name);
657 err.span_note(span, &msg).emit();
662 struct InvocationCollector<'a, 'b: 'a> {
663 cx: &'a mut ExtCtxt<'b>,
664 cfg: StripUnconfigured<'a>,
665 invocations: Vec<Invocation>,
669 macro_rules! fully_configure {
670 ($this:ident, $node:ident, $noop_fold:ident) => {
671 match $noop_fold($node, &mut $this.cfg).pop() {
673 None => return SmallVector::new(),
678 impl<'a, 'b> InvocationCollector<'a, 'b> {
679 fn collect(&mut self, expansion_kind: ExpansionKind, kind: InvocationKind) -> Expansion {
680 let mark = Mark::fresh();
681 self.invocations.push(Invocation {
683 expansion_kind: expansion_kind,
684 expansion_data: ExpansionData {
686 depth: self.cx.current_expansion.depth + 1,
687 ..self.cx.current_expansion.clone()
690 placeholder(expansion_kind, NodeId::placeholder_from_mark(mark))
693 fn collect_bang(&mut self, mac: ast::Mac, span: Span, kind: ExpansionKind) -> Expansion {
694 self.collect(kind, InvocationKind::Bang { mac: mac, ident: None, span: span })
697 fn collect_attr(&mut self,
698 attr: Option<ast::Attribute>,
703 if !traits.is_empty() &&
704 (kind == ExpansionKind::TraitItems || kind == ExpansionKind::ImplItems) {
705 self.cx.span_err(traits[0].span, "`derive` can be only be applied to items");
706 return kind.expect_from_annotatables(::std::iter::once(item));
708 self.collect(kind, InvocationKind::Attr { attr: attr, traits: traits, item: item })
711 // If `item` is an attr invocation, remove and return the macro attribute.
712 fn classify_item<T>(&mut self, mut item: T) -> (Option<ast::Attribute>, Vec<Path>, T)
715 let (mut attr, mut traits) = (None, Vec::new());
717 item = item.map_attrs(|mut attrs| {
718 if let Some(legacy_attr_invoc) = self.cx.resolver.find_legacy_attr_invoc(&mut attrs) {
719 attr = Some(legacy_attr_invoc);
723 if self.cx.ecfg.proc_macro_enabled() {
724 attr = find_attr_invoc(&mut attrs);
726 traits = collect_derives(&mut self.cx, &mut attrs);
733 fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
734 self.cfg.configure(node)
737 // Detect use of feature-gated or invalid attributes on macro invocations
738 // since they will not be detected after macro expansion.
739 fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
740 let features = self.cx.ecfg.features.unwrap();
741 for attr in attrs.iter() {
742 feature_gate::check_attribute(&attr, &self.cx.parse_sess, features);
747 pub fn find_attr_invoc(attrs: &mut Vec<ast::Attribute>) -> Option<ast::Attribute> {
748 for i in 0 .. attrs.len() {
749 if !attr::is_known(&attrs[i]) && !is_builtin_attr(&attrs[i]) {
750 return Some(attrs.remove(i));
757 // These are pretty nasty. Ideally, we would keep the tokens around, linked from
758 // the AST. However, we don't so we need to create new ones. Since the item might
759 // have come from a macro expansion (possibly only in part), we can't use the
762 // Therefore, we must use the pretty printer (yuck) to turn the AST node into a
763 // string, which we then re-tokenise (double yuck), but first we have to patch
764 // the pretty-printed string on to the end of the existing codemap (infinity-yuck).
765 fn stream_for_item(item: &Annotatable, parse_sess: &ParseSess) -> TokenStream {
766 let text = match *item {
767 Annotatable::Item(ref i) => pprust::item_to_string(i),
768 Annotatable::TraitItem(ref ti) => pprust::trait_item_to_string(ti),
769 Annotatable::ImplItem(ref ii) => pprust::impl_item_to_string(ii),
771 string_to_stream(text, parse_sess)
774 fn string_to_stream(text: String, parse_sess: &ParseSess) -> TokenStream {
775 let filename = String::from("<macro expansion>");
776 filemap_to_stream(parse_sess, parse_sess.codemap().new_filemap(filename, None, text))
779 impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
780 fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
781 let mut expr = self.cfg.configure_expr(expr).unwrap();
782 expr.node = self.cfg.configure_expr_kind(expr.node);
784 if let ast::ExprKind::Mac(mac) = expr.node {
785 self.check_attributes(&expr.attrs);
786 self.collect_bang(mac, expr.span, ExpansionKind::Expr).make_expr()
788 P(noop_fold_expr(expr, self))
792 fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
793 let mut expr = configure!(self, expr).unwrap();
794 expr.node = self.cfg.configure_expr_kind(expr.node);
796 if let ast::ExprKind::Mac(mac) = expr.node {
797 self.check_attributes(&expr.attrs);
798 self.collect_bang(mac, expr.span, ExpansionKind::OptExpr).make_opt_expr()
800 Some(P(noop_fold_expr(expr, self)))
804 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
805 let pat = self.cfg.configure_pat(pat);
807 PatKind::Mac(_) => {}
808 _ => return noop_fold_pat(pat, self),
811 pat.and_then(|pat| match pat.node {
812 PatKind::Mac(mac) => self.collect_bang(mac, pat.span, ExpansionKind::Pat).make_pat(),
817 fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
818 let stmt = match self.cfg.configure_stmt(stmt) {
820 None => return SmallVector::new(),
823 let (mac, style, attrs) = if let StmtKind::Mac(mac) = stmt.node {
826 // The placeholder expander gives ids to statements, so we avoid folding the id here.
827 let ast::Stmt { id, node, span } = stmt;
828 return noop_fold_stmt_kind(node, self).into_iter().map(|node| {
829 ast::Stmt { id: id, node: node, span: span }
833 self.check_attributes(&attrs);
834 let mut placeholder = self.collect_bang(mac, stmt.span, ExpansionKind::Stmts).make_stmts();
836 // If this is a macro invocation with a semicolon, then apply that
837 // semicolon to the final statement produced by expansion.
838 if style == MacStmtStyle::Semicolon {
839 if let Some(stmt) = placeholder.pop() {
840 placeholder.push(stmt.add_trailing_semicolon());
847 fn fold_block(&mut self, block: P<Block>) -> P<Block> {
848 let old_directory_ownership = self.cx.current_expansion.directory_ownership;
849 self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
850 let result = noop_fold_block(block, self);
851 self.cx.current_expansion.directory_ownership = old_directory_ownership;
855 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
856 let item = configure!(self, item);
858 let (attr, traits, mut item) = self.classify_item(item);
859 if attr.is_some() || !traits.is_empty() {
860 let item = Annotatable::Item(fully_configure!(self, item, noop_fold_item));
861 return self.collect_attr(attr, traits, item, ExpansionKind::Items).make_items();
865 ast::ItemKind::Mac(..) => {
866 self.check_attributes(&item.attrs);
867 item.and_then(|item| match item.node {
868 ItemKind::Mac(mac) => {
869 self.collect(ExpansionKind::Items, InvocationKind::Bang {
871 ident: Some(item.ident),
878 ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
879 if item.ident == keywords::Invalid.ident() {
880 return noop_fold_item(item, self);
883 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
884 let mut module = (*self.cx.current_expansion.module).clone();
885 module.mod_path.push(item.ident);
887 // Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
888 // In the non-inline case, `inner` is never the dummy span (c.f. `parse_item_mod`).
889 // Thus, if `inner` is the dummy span, we know the module is inline.
890 let inline_module = item.span.contains(inner) || inner == DUMMY_SP;
893 if let Some(path) = attr::first_attr_value_str_by_name(&item.attrs, "path") {
894 self.cx.current_expansion.directory_ownership = DirectoryOwnership::Owned;
895 module.directory.push(&*path.as_str());
897 module.directory.push(&*item.ident.name.as_str());
901 PathBuf::from(self.cx.parse_sess.codemap().span_to_filename(inner));
902 let directory_ownership = match path.file_name().unwrap().to_str() {
903 Some("mod.rs") => DirectoryOwnership::Owned,
904 _ => DirectoryOwnership::UnownedViaMod(false),
907 module.directory = path;
908 self.cx.current_expansion.directory_ownership = directory_ownership;
912 mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
913 let result = noop_fold_item(item, self);
914 self.cx.current_expansion.module = orig_module;
915 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
918 // Ensure that test functions are accessible from the test harness.
919 ast::ItemKind::Fn(..) if self.cx.ecfg.should_test => {
920 if item.attrs.iter().any(|attr| is_test_or_bench(attr)) {
921 item = item.map(|mut item| { item.vis = ast::Visibility::Public; item });
923 noop_fold_item(item, self)
925 _ => noop_fold_item(item, self),
929 fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
930 let item = configure!(self, item);
932 let (attr, traits, item) = self.classify_item(item);
933 if attr.is_some() || !traits.is_empty() {
935 Annotatable::TraitItem(P(fully_configure!(self, item, noop_fold_trait_item)));
936 return self.collect_attr(attr, traits, item, ExpansionKind::TraitItems)
941 ast::TraitItemKind::Macro(mac) => {
942 let ast::TraitItem { attrs, span, .. } = item;
943 self.check_attributes(&attrs);
944 self.collect_bang(mac, span, ExpansionKind::TraitItems).make_trait_items()
946 _ => fold::noop_fold_trait_item(item, self),
950 fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
951 let item = configure!(self, item);
953 let (attr, traits, item) = self.classify_item(item);
954 if attr.is_some() || !traits.is_empty() {
955 let item = Annotatable::ImplItem(P(fully_configure!(self, item, noop_fold_impl_item)));
956 return self.collect_attr(attr, traits, item, ExpansionKind::ImplItems)
961 ast::ImplItemKind::Macro(mac) => {
962 let ast::ImplItem { attrs, span, .. } = item;
963 self.check_attributes(&attrs);
964 self.collect_bang(mac, span, ExpansionKind::ImplItems).make_impl_items()
966 _ => fold::noop_fold_impl_item(item, self),
970 fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
971 let ty = match ty.node {
972 ast::TyKind::Mac(_) => ty.unwrap(),
973 _ => return fold::noop_fold_ty(ty, self),
977 ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, ExpansionKind::Ty).make_ty(),
982 fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
983 noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
986 fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
988 ast::ItemKind::MacroDef(..) => item,
989 _ => noop_fold_item_kind(self.cfg.configure_item_kind(item), self),
993 fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
995 assert_eq!(id, ast::DUMMY_NODE_ID);
996 self.cx.resolver.next_node_id()
1003 pub struct ExpansionConfig<'feat> {
1004 pub crate_name: String,
1005 pub features: Option<&'feat Features>,
1006 pub recursion_limit: usize,
1007 pub trace_mac: bool,
1008 pub should_test: bool, // If false, strip `#[test]` nodes
1009 pub single_step: bool,
1010 pub keep_macs: bool,
1013 macro_rules! feature_tests {
1014 ($( fn $getter:ident = $field:ident, )*) => {
1016 pub fn $getter(&self) -> bool {
1017 match self.features {
1018 Some(&Features { $field: true, .. }) => true,
1026 impl<'feat> ExpansionConfig<'feat> {
1027 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1029 crate_name: crate_name,
1031 recursion_limit: 64,
1040 fn enable_quotes = quote,
1041 fn enable_asm = asm,
1042 fn enable_global_asm = global_asm,
1043 fn enable_log_syntax = log_syntax,
1044 fn enable_concat_idents = concat_idents,
1045 fn enable_trace_macros = trace_macros,
1046 fn enable_allow_internal_unstable = allow_internal_unstable,
1047 fn enable_custom_derive = custom_derive,
1048 fn proc_macro_enabled = proc_macro,
1052 // A Marker adds the given mark to the syntax context.
1053 struct Marker(Mark);
1055 impl Folder for Marker {
1056 fn fold_ident(&mut self, mut ident: Ident) -> Ident {
1057 ident.ctxt = ident.ctxt.apply_mark(self.0);
1061 fn new_span(&mut self, mut span: Span) -> Span {
1062 span.ctxt = span.ctxt.apply_mark(self.0);
1066 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1067 noop_fold_mac(mac, self)