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::{Block, Crate, DeclLocal, ExprMac, PatMac};
12 use ast::{Local, Ident, MacInvocTT};
13 use ast::{ItemMac, MacStmtWithSemicolon, Mrk, Stmt, StmtDecl, StmtMac};
14 use ast::{StmtExpr, StmtSemi};
18 use ext::build::AstBuilder;
20 use attr::AttrMetaMethods;
22 use codemap::{Span, Spanned, ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
24 use feature_gate::{self, Features};
28 use parse::token::{fresh_mark, fresh_name, intern};
31 use util::small_vector::SmallVector;
36 pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
37 e.and_then(|ast::Expr {id, node, span}| match node {
38 // expr_mac should really be expr_ext or something; it's the
39 // entry-point for all syntax extensions.
40 ast::ExprMac(mac) => {
41 let expanded_expr = match expand_mac_invoc(mac, span,
46 return DummyResult::raw_expr(span);
50 // Keep going, outside-in.
52 let fully_expanded = fld.fold_expr(expanded_expr);
55 fully_expanded.map(|e| ast::Expr {
56 id: ast::DUMMY_NODE_ID,
58 span: fld.new_span(span),
62 ast::ExprWhile(cond, body, opt_ident) => {
63 let cond = fld.fold_expr(cond);
64 let (body, opt_ident) = expand_loop_block(body, opt_ident, fld);
65 fld.cx.expr(span, ast::ExprWhile(cond, body, opt_ident))
68 // Desugar ExprWhileLet
69 // From: `[opt_ident]: while let <pat> = <expr> <body>`
70 ast::ExprWhileLet(pat, expr, body, opt_ident) => {
73 // [opt_ident]: loop {
82 let body_expr = fld.cx.expr_block(body);
83 fld.cx.arm(pat.span, vec![pat], body_expr)
88 let pat_under = fld.cx.pat_wild(span);
89 let break_expr = fld.cx.expr_break(span);
90 fld.cx.arm(span, vec![pat_under], break_expr)
93 // `match <expr> { ... }`
94 let arms = vec![pat_arm, break_arm];
95 let match_expr = fld.cx.expr(span,
96 ast::ExprMatch(expr, arms, ast::MatchSource::WhileLetDesugar));
98 // `[opt_ident]: loop { ... }`
99 let loop_block = fld.cx.block_expr(match_expr);
100 let (loop_block, opt_ident) = expand_loop_block(loop_block, opt_ident, fld);
101 fld.cx.expr(span, ast::ExprLoop(loop_block, opt_ident))
105 // From: `if let <pat> = <expr> <body> [<elseopt>]`
106 ast::ExprIfLet(pat, expr, body, mut elseopt) => {
111 // [_ if <elseopt_if_cond> => <elseopt_if_body>,]
112 // _ => [<elseopt> | ()]
117 let body_expr = fld.cx.expr_block(body);
118 fld.cx.arm(pat.span, vec![pat], body_expr)
121 // `[_ if <elseopt_if_cond> => <elseopt_if_body>,]`
123 let mut arms = vec![];
125 let elseopt_continue = elseopt
126 .and_then(|els| els.and_then(|els| match els.node {
128 ast::ExprIf(cond, then, elseopt) => {
129 let pat_under = fld.cx.pat_wild(span);
132 pats: vec![pat_under],
134 body: fld.cx.expr_block(then)
136 elseopt.map(|elseopt| (elseopt, true))
138 _ => Some((P(els), false))
140 match elseopt_continue {
144 Some((e, false)) => {
157 let contains_else_clause = elseopt.is_some();
159 // `_ => [<elseopt> | ()]`
161 let pat_under = fld.cx.pat_wild(span);
162 let else_expr = elseopt.unwrap_or_else(|| fld.cx.expr_tuple(span, vec![]));
163 fld.cx.arm(span, vec![pat_under], else_expr)
166 let mut arms = Vec::with_capacity(else_if_arms.len() + 2);
168 arms.extend(else_if_arms.into_iter());
171 let match_expr = fld.cx.expr(span,
172 ast::ExprMatch(expr, arms,
173 ast::MatchSource::IfLetDesugar {
174 contains_else_clause: contains_else_clause,
176 fld.fold_expr(match_expr)
179 // Desugar support for ExprIfLet in the ExprIf else position
180 ast::ExprIf(cond, blk, elseopt) => {
181 let elseopt = elseopt.map(|els| els.and_then(|els| match els.node {
182 ast::ExprIfLet(..) => {
183 // wrap the if-let expr in a block
185 let blk = P(ast::Block {
188 id: ast::DUMMY_NODE_ID,
189 rules: ast::DefaultBlock,
192 fld.cx.expr_block(blk)
196 let if_expr = fld.cx.expr(span, ast::ExprIf(cond, blk, elseopt));
197 if_expr.map(|e| noop_fold_expr(e, fld))
200 ast::ExprLoop(loop_block, opt_ident) => {
201 let (loop_block, opt_ident) = expand_loop_block(loop_block, opt_ident, fld);
202 fld.cx.expr(span, ast::ExprLoop(loop_block, opt_ident))
205 // Desugar ExprForLoop
206 // From: `[opt_ident]: for <pat> in <head> <body>`
207 ast::ExprForLoop(pat, head, body, opt_ident) => {
211 // let result = match ::std::iter::IntoIterator::into_iter(<head>) {
213 // [opt_ident]: loop {
214 // match ::std::iter::Iterator::next(&mut iter) {
215 // ::std::option::Option::Some(<pat>) => <body>,
216 // ::std::option::Option::None => break
225 let head = fld.fold_expr(head);
227 // create an hygienic ident
229 let ident = fld.cx.ident_of("iter");
230 let new_ident = fresh_name(&ident);
231 let rename = (ident, new_ident);
232 let mut rename_list = vec![rename];
233 let mut rename_fld = IdentRenamer{ renames: &mut rename_list };
235 rename_fld.fold_ident(ident)
238 let pat_span = pat.span;
239 // `:;std::option::Option::Some(<pat>) => <body>`
241 let body_expr = fld.cx.expr_block(body);
242 let some_pat = fld.cx.pat_some(pat_span, pat);
244 fld.cx.arm(pat_span, vec![some_pat], body_expr)
247 // `::std::option::Option::None => break`
249 let break_expr = fld.cx.expr_break(span);
251 fld.cx.arm(span, vec![fld.cx.pat_none(span)], break_expr)
254 // `match ::std::iter::Iterator::next(&mut iter) { ... }`
258 fld.cx.ident_of_std("core"),
259 fld.cx.ident_of("iter"),
260 fld.cx.ident_of("Iterator"),
261 fld.cx.ident_of("next"),
264 fld.cx.path_global(span, strs)
266 let ref_mut_iter = fld.cx.expr_mut_addr_of(span, fld.cx.expr_ident(span, iter));
268 fld.cx.expr_call(span, fld.cx.expr_path(next_path), vec![ref_mut_iter]);
269 let arms = vec![pat_arm, break_arm];
271 fld.cx.expr(pat_span,
272 ast::ExprMatch(next_expr, arms, ast::MatchSource::ForLoopDesugar))
275 // `[opt_ident]: loop { ... }`
276 let loop_block = fld.cx.block_expr(match_expr);
277 let (loop_block, opt_ident) = expand_loop_block(loop_block, opt_ident, fld);
278 let loop_expr = fld.cx.expr(span, ast::ExprLoop(loop_block, opt_ident));
280 // `mut iter => { ... }`
283 fld.cx.pat_ident_binding_mode(span, iter, ast::BindByValue(ast::MutMutable));
284 fld.cx.arm(span, vec![iter_pat], loop_expr)
287 // `match ::std::iter::IntoIterator::into_iter(<head>) { ... }`
288 let into_iter_expr = {
289 let into_iter_path = {
291 fld.cx.ident_of_std("core"),
292 fld.cx.ident_of("iter"),
293 fld.cx.ident_of("IntoIterator"),
294 fld.cx.ident_of("into_iter"),
297 fld.cx.path_global(span, strs)
300 fld.cx.expr_call(span, fld.cx.expr_path(into_iter_path), vec![head])
303 let match_expr = fld.cx.expr_match(span, into_iter_expr, vec![iter_arm]);
305 // `{ let result = ...; result }`
306 let result_ident = token::gensym_ident("result");
310 vec![fld.cx.stmt_let(span, false, result_ident, match_expr)],
311 Some(fld.cx.expr_ident(span, result_ident))))
314 ast::ExprClosure(capture_clause, fn_decl, block) => {
315 let (rewritten_fn_decl, rewritten_block)
316 = expand_and_rename_fn_decl_and_block(fn_decl, block, fld);
317 let new_node = ast::ExprClosure(capture_clause,
320 P(ast::Expr{id:id, node: new_node, span: fld.new_span(span)})
324 P(noop_fold_expr(ast::Expr {
333 /// Expand a (not-ident-style) macro invocation. Returns the result
334 /// of expansion and the mark which must be applied to the result.
335 /// Our current interface doesn't allow us to apply the mark to the
336 /// result until after calling make_expr, make_items, etc.
337 fn expand_mac_invoc<T, F, G>(mac: ast::Mac, span: codemap::Span,
340 fld: &mut MacroExpander)
342 F: for<'a> FnOnce(Box<MacResult+'a>) -> Option<T>,
343 G: FnOnce(T, Mrk) -> T,
346 // it would almost certainly be cleaner to pass the whole
347 // macro invocation in, rather than pulling it apart and
348 // marking the tts and the ctxt separately. This also goes
349 // for the other three macro invocation chunks of code
351 // Token-tree macros:
352 MacInvocTT(pth, tts, _) => {
353 if pth.segments.len() > 1 {
354 fld.cx.span_err(pth.span,
355 "expected macro name without module \
357 // let compilation continue
360 let extname = pth.segments[0].identifier;
361 let extnamestr = token::get_ident(extname);
362 match fld.cx.syntax_env.find(&extname.name) {
366 &format!("macro undefined: '{}!'",
369 // let compilation continue
372 Some(rc) => match *rc {
373 NormalTT(ref expandfun, exp_span, allow_internal_unstable) => {
374 fld.cx.bt_push(ExpnInfo {
376 callee: NameAndSpan {
377 name: extnamestr.to_string(),
380 allow_internal_unstable: allow_internal_unstable,
383 let fm = fresh_mark();
384 let marked_before = mark_tts(&tts[..], fm);
386 // The span that we pass to the expanders we want to
387 // be the root of the call stack. That's the most
388 // relevant span and it's the actual invocation of
390 let mac_span = fld.cx.original_span();
393 let expanded = expandfun.expand(fld.cx,
396 parse_thunk(expanded)
398 let parsed = match opt_parsed {
403 &format!("non-expression macro in expression position: {}",
409 Some(mark_thunk(parsed,fm))
414 &format!("'{}' is not a tt-style macro",
424 /// Rename loop label and expand its loop body
426 /// The renaming procedure for loop is different in the sense that the loop
427 /// body is in a block enclosed by loop head so the renaming of loop label
428 /// must be propagated to the enclosed context.
429 fn expand_loop_block(loop_block: P<Block>,
430 opt_ident: Option<Ident>,
431 fld: &mut MacroExpander) -> (P<Block>, Option<Ident>) {
434 let new_label = fresh_name(&label);
435 let rename = (label, new_label);
437 // The rename *must not* be added to the pending list of current
438 // syntax context otherwise an unrelated `break` or `continue` in
439 // the same context will pick that up in the deferred renaming pass
440 // and be renamed incorrectly.
441 let mut rename_list = vec!(rename);
442 let mut rename_fld = IdentRenamer{renames: &mut rename_list};
443 let renamed_ident = rename_fld.fold_ident(label);
445 // The rename *must* be added to the enclosed syntax context for
446 // `break` or `continue` to pick up because by definition they are
447 // in a block enclosed by loop head.
448 fld.cx.syntax_env.push_frame();
449 fld.cx.syntax_env.info().pending_renames.push(rename);
450 let expanded_block = expand_block_elts(loop_block, fld);
451 fld.cx.syntax_env.pop_frame();
453 (expanded_block, Some(renamed_ident))
455 None => (fld.fold_block(loop_block), opt_ident)
459 // eval $e with a new exts frame.
460 // must be a macro so that $e isn't evaluated too early.
461 macro_rules! with_exts_frame {
462 ($extsboxexpr:expr,$macros_escape:expr,$e:expr) =>
463 ({$extsboxexpr.push_frame();
464 $extsboxexpr.info().macros_escape = $macros_escape;
466 $extsboxexpr.pop_frame();
471 // When we enter a module, record it, for the sake of `module!`
472 pub fn expand_item(it: P<ast::Item>, fld: &mut MacroExpander)
473 -> SmallVector<P<ast::Item>> {
474 let it = expand_item_modifiers(it, fld);
476 expand_annotatable(Annotatable::Item(it), fld)
477 .into_iter().map(|i| i.expect_item()).collect()
480 fn expand_item_modifiers(mut it: P<ast::Item>, fld: &mut MacroExpander)
482 // partition the attributes into ItemModifiers and others
483 let (modifiers, other_attrs) = modifiers(&it.attrs, fld);
485 // update the attrs, leave everything else alone. Is this mutation really a good idea?
491 if modifiers.is_empty() {
492 let it = expand_item_multi_modifier(Annotatable::Item(it), fld);
493 return it.expect_item();
496 for attr in &modifiers {
497 let mname = attr.name();
499 match fld.cx.syntax_env.find(&intern(&mname)) {
500 Some(rc) => match *rc {
501 Modifier(ref mac) => {
502 attr::mark_used(attr);
503 fld.cx.bt_push(ExpnInfo {
504 call_site: attr.span,
505 callee: NameAndSpan {
506 name: mname.to_string(),
507 format: MacroAttribute,
509 // attributes can do whatever they like,
511 allow_internal_unstable: true,
514 it = mac.expand(fld.cx, attr.span, &*attr.node.value, it);
523 // Expansion may have added new ItemModifiers.
524 // It is possible, that an item modifier could expand to a multi-modifier or
525 // vice versa. In this case we will expand all modifiers before multi-modifiers,
526 // which might give an odd ordering. However, I think it is unlikely that the
527 // two kinds will be mixed, and I old-style multi-modifiers should be deprecated
529 expand_item_modifiers(it, fld)
532 /// Expand item_underscore
533 fn expand_item_underscore(item: ast::Item_, fld: &mut MacroExpander) -> ast::Item_ {
535 ast::ItemFn(decl, fn_style, abi, generics, body) => {
536 let (rewritten_fn_decl, rewritten_body)
537 = expand_and_rename_fn_decl_and_block(decl, body, fld);
538 let expanded_generics = fold::noop_fold_generics(generics,fld);
539 ast::ItemFn(rewritten_fn_decl, fn_style, abi, expanded_generics, rewritten_body)
541 _ => noop_fold_item_underscore(item, fld)
545 // does this attribute list contain "macro_use" ?
546 fn contains_macro_use(fld: &mut MacroExpander, attrs: &[ast::Attribute]) -> bool {
548 let mut is_use = attr.check_name("macro_use");
549 if attr.check_name("macro_escape") {
550 fld.cx.span_warn(attr.span, "macro_escape is a deprecated synonym for macro_use");
552 if let ast::AttrInner = attr.node.style {
553 fld.cx.fileline_help(attr.span, "consider an outer attribute, \
554 #[macro_use] mod ...");
559 match attr.node.value.node {
560 ast::MetaWord(..) => (),
561 _ => fld.cx.span_err(attr.span, "arguments to macro_use are not allowed here"),
569 // Support for item-position macro invocations, exactly the same
570 // logic as for expression-position macro invocations.
571 pub fn expand_item_mac(it: P<ast::Item>,
572 fld: &mut MacroExpander) -> SmallVector<P<ast::Item>> {
573 let (extname, path_span, tts) = match it.node {
574 ItemMac(codemap::Spanned {
575 node: MacInvocTT(ref pth, ref tts, _),
578 (pth.segments[0].identifier, pth.span, (*tts).clone())
580 _ => fld.cx.span_bug(it.span, "invalid item macro invocation")
583 let extnamestr = token::get_ident(extname);
584 let fm = fresh_mark();
586 let expanded = match fld.cx.syntax_env.find(&extname.name) {
588 fld.cx.span_err(path_span,
589 &format!("macro undefined: '{}!'",
591 // let compilation continue
592 return SmallVector::zero();
595 Some(rc) => match *rc {
596 NormalTT(ref expander, span, allow_internal_unstable) => {
597 if it.ident.name != parse::token::special_idents::invalid.name {
600 &format!("macro {}! expects no ident argument, given '{}'",
602 token::get_ident(it.ident)));
603 return SmallVector::zero();
605 fld.cx.bt_push(ExpnInfo {
607 callee: NameAndSpan {
608 name: extnamestr.to_string(),
611 allow_internal_unstable: allow_internal_unstable,
614 // mark before expansion:
615 let marked_before = mark_tts(&tts[..], fm);
616 expander.expand(fld.cx, it.span, &marked_before[..])
618 IdentTT(ref expander, span, allow_internal_unstable) => {
619 if it.ident.name == parse::token::special_idents::invalid.name {
620 fld.cx.span_err(path_span,
621 &format!("macro {}! expects an ident argument",
623 return SmallVector::zero();
625 fld.cx.bt_push(ExpnInfo {
627 callee: NameAndSpan {
628 name: extnamestr.to_string(),
631 allow_internal_unstable: allow_internal_unstable,
634 // mark before expansion:
635 let marked_tts = mark_tts(&tts[..], fm);
636 expander.expand(fld.cx, it.span, it.ident, marked_tts)
639 if it.ident.name == parse::token::special_idents::invalid.name {
640 fld.cx.span_err(path_span,
641 &format!("macro_rules! expects an ident argument")
643 return SmallVector::zero();
646 fld.cx.bt_push(ExpnInfo {
648 callee: NameAndSpan {
649 name: extnamestr.to_string(),
652 // `macro_rules!` doesn't directly allow
653 // unstable (this is orthogonal to whether
654 // the macro it creates allows it)
655 allow_internal_unstable: false,
658 // DON'T mark before expansion.
660 let allow_internal_unstable = attr::contains_name(&it.attrs,
661 "allow_internal_unstable");
663 // ensure any #[allow_internal_unstable]s are
664 // detected (including nested macro definitions
666 if allow_internal_unstable && !fld.cx.ecfg.enable_allow_internal_unstable() {
667 feature_gate::emit_feature_err(
668 &fld.cx.parse_sess.span_diagnostic,
669 "allow_internal_unstable",
671 feature_gate::EXPLAIN_ALLOW_INTERNAL_UNSTABLE)
674 let def = ast::MacroDef {
676 attrs: it.attrs.clone(),
677 id: ast::DUMMY_NODE_ID,
680 export: attr::contains_name(&it.attrs, "macro_export"),
682 allow_internal_unstable: allow_internal_unstable,
685 fld.cx.insert_macro(def);
687 // macro_rules! has a side effect but expands to nothing.
689 return SmallVector::zero();
692 fld.cx.span_err(it.span,
693 &format!("{}! is not legal in item position",
695 return SmallVector::zero();
700 expanded.make_items()
703 let items = match items {
706 .map(|i| mark_item(i, fm))
707 .flat_map(|i| fld.fold_item(i).into_iter())
711 fld.cx.span_err(path_span,
712 &format!("non-item macro in item position: {}",
714 return SmallVector::zero();
723 fn expand_stmt(stmt: P<Stmt>, fld: &mut MacroExpander) -> SmallVector<P<Stmt>> {
724 let stmt = stmt.and_then(|stmt| stmt);
725 let (mac, style) = match stmt.node {
726 StmtMac(mac, style) => (mac, style),
727 _ => return expand_non_macro_stmt(stmt, fld)
730 let maybe_new_items =
731 expand_mac_invoc(mac.and_then(|m| m), stmt.span,
733 |stmts, mark| stmts.move_map(|m| mark_stmt(m, mark)),
736 let mut fully_expanded = match maybe_new_items {
738 // Keep going, outside-in.
739 let new_items = stmts.into_iter().flat_map(|s| {
740 fld.fold_stmt(s).into_iter()
745 None => SmallVector::zero()
748 // If this is a macro invocation with a semicolon, then apply that
749 // semicolon to the final statement produced by expansion.
750 if style == MacStmtWithSemicolon {
751 if let Some(stmt) = fully_expanded.pop() {
752 let new_stmt = stmt.map(|Spanned {node, span}| {
755 StmtExpr(e, stmt_id) => StmtSemi(e, stmt_id),
756 _ => node /* might already have a semi */
761 fully_expanded.push(new_stmt);
768 // expand a non-macro stmt. this is essentially the fallthrough for
769 // expand_stmt, above.
770 fn expand_non_macro_stmt(Spanned {node, span: stmt_span}: Stmt, fld: &mut MacroExpander)
771 -> SmallVector<P<Stmt>> {
774 StmtDecl(decl, node_id) => decl.and_then(|Spanned {node: decl, span}| match decl {
775 DeclLocal(local) => {
777 let rewritten_local = local.map(|Local {id, pat, ty, init, source, span}| {
778 // expand the ty since TyFixedLengthVec contains an Expr
779 // and thus may have a macro use
780 let expanded_ty = ty.map(|t| fld.fold_ty(t));
781 // expand the pat (it might contain macro uses):
782 let expanded_pat = fld.fold_pat(pat);
783 // find the PatIdents in the pattern:
784 // oh dear heaven... this is going to include the enum
785 // names, as well... but that should be okay, as long as
786 // the new names are gensyms for the old ones.
787 // generate fresh names, push them to a new pending list
788 let idents = pattern_bindings(&*expanded_pat);
789 let mut new_pending_renames =
790 idents.iter().map(|ident| (*ident, fresh_name(ident))).collect();
791 // rewrite the pattern using the new names (the old
792 // ones have already been applied):
793 let rewritten_pat = {
794 // nested binding to allow borrow to expire:
795 let mut rename_fld = IdentRenamer{renames: &mut new_pending_renames};
796 rename_fld.fold_pat(expanded_pat)
798 // add them to the existing pending renames:
799 fld.cx.syntax_env.info().pending_renames
800 .extend(new_pending_renames.into_iter());
805 // also, don't forget to expand the init:
806 init: init.map(|e| fld.fold_expr(e)),
811 SmallVector::one(P(Spanned {
812 node: StmtDecl(P(Spanned {
813 node: DeclLocal(rewritten_local),
821 noop_fold_stmt(Spanned {
822 node: StmtDecl(P(Spanned {
832 noop_fold_stmt(Spanned {
840 // expand the arm of a 'match', renaming for macro hygiene
841 fn expand_arm(arm: ast::Arm, fld: &mut MacroExpander) -> ast::Arm {
842 // expand pats... they might contain macro uses:
843 let expanded_pats = arm.pats.move_map(|pat| fld.fold_pat(pat));
844 if expanded_pats.is_empty() {
845 panic!("encountered match arm with 0 patterns");
847 // all of the pats must have the same set of bindings, so use the
848 // first one to extract them and generate new names:
849 let idents = pattern_bindings(&*expanded_pats[0]);
850 let new_renames = idents.into_iter().map(|id| (id, fresh_name(&id))).collect();
851 // apply the renaming, but only to the PatIdents:
852 let mut rename_pats_fld = PatIdentRenamer{renames:&new_renames};
853 let rewritten_pats = expanded_pats.move_map(|pat| rename_pats_fld.fold_pat(pat));
854 // apply renaming and then expansion to the guard and the body:
855 let mut rename_fld = IdentRenamer{renames:&new_renames};
856 let rewritten_guard =
857 arm.guard.map(|g| fld.fold_expr(rename_fld.fold_expr(g)));
858 let rewritten_body = fld.fold_expr(rename_fld.fold_expr(arm.body));
860 attrs: fold::fold_attrs(arm.attrs, fld),
861 pats: rewritten_pats,
862 guard: rewritten_guard,
863 body: rewritten_body,
867 /// A visitor that extracts the PatIdent (binding) paths
868 /// from a given thingy and puts them in a mutable
871 struct PatIdentFinder {
872 ident_accumulator: Vec<ast::Ident>
875 impl<'v> Visitor<'v> for PatIdentFinder {
876 fn visit_pat(&mut self, pattern: &ast::Pat) {
878 ast::Pat { id: _, node: ast::PatIdent(_, ref path1, ref inner), span: _ } => {
879 self.ident_accumulator.push(path1.node);
880 // visit optional subpattern of PatIdent:
881 if let Some(ref subpat) = *inner {
882 self.visit_pat(&**subpat)
885 // use the default traversal for non-PatIdents
886 _ => visit::walk_pat(self, pattern)
891 /// find the PatIdent paths in a pattern
892 fn pattern_bindings(pat: &ast::Pat) -> Vec<ast::Ident> {
893 let mut name_finder = PatIdentFinder{ident_accumulator:Vec::new()};
894 name_finder.visit_pat(pat);
895 name_finder.ident_accumulator
898 /// find the PatIdent paths in a
899 fn fn_decl_arg_bindings(fn_decl: &ast::FnDecl) -> Vec<ast::Ident> {
900 let mut pat_idents = PatIdentFinder{ident_accumulator:Vec::new()};
901 for arg in &fn_decl.inputs {
902 pat_idents.visit_pat(&*arg.pat);
904 pat_idents.ident_accumulator
907 // expand a block. pushes a new exts_frame, then calls expand_block_elts
908 pub fn expand_block(blk: P<Block>, fld: &mut MacroExpander) -> P<Block> {
909 // see note below about treatment of exts table
910 with_exts_frame!(fld.cx.syntax_env,false,
911 expand_block_elts(blk, fld))
914 // expand the elements of a block.
915 pub fn expand_block_elts(b: P<Block>, fld: &mut MacroExpander) -> P<Block> {
916 b.map(|Block {id, stmts, expr, rules, span}| {
917 let new_stmts = stmts.into_iter().flat_map(|x| {
918 // perform all pending renames
920 let pending_renames = &mut fld.cx.syntax_env.info().pending_renames;
921 let mut rename_fld = IdentRenamer{renames:pending_renames};
922 rename_fld.fold_stmt(x).expect_one("rename_fold didn't return one value")
924 // expand macros in the statement
925 fld.fold_stmt(renamed_stmt).into_iter()
927 let new_expr = expr.map(|x| {
929 let pending_renames = &mut fld.cx.syntax_env.info().pending_renames;
930 let mut rename_fld = IdentRenamer{renames:pending_renames};
931 rename_fld.fold_expr(x)
945 fn expand_pat(p: P<ast::Pat>, fld: &mut MacroExpander) -> P<ast::Pat> {
948 _ => return noop_fold_pat(p, fld)
950 p.map(|ast::Pat {node, span, ..}| {
951 let (pth, tts) = match node {
952 PatMac(mac) => match mac.node {
953 MacInvocTT(pth, tts, _) => {
959 if pth.segments.len() > 1 {
960 fld.cx.span_err(pth.span, "expected macro name without module separators");
961 return DummyResult::raw_pat(span);
963 let extname = pth.segments[0].identifier;
964 let extnamestr = token::get_ident(extname);
965 let marked_after = match fld.cx.syntax_env.find(&extname.name) {
967 fld.cx.span_err(pth.span,
968 &format!("macro undefined: '{}!'",
970 // let compilation continue
971 return DummyResult::raw_pat(span);
974 Some(rc) => match *rc {
975 NormalTT(ref expander, tt_span, allow_internal_unstable) => {
976 fld.cx.bt_push(ExpnInfo {
978 callee: NameAndSpan {
979 name: extnamestr.to_string(),
982 allow_internal_unstable: allow_internal_unstable,
986 let fm = fresh_mark();
987 let marked_before = mark_tts(&tts[..], fm);
988 let mac_span = fld.cx.original_span();
989 let expanded = match expander.expand(fld.cx,
991 &marked_before[..]).make_pat() {
997 "non-pattern macro in pattern position: {}",
1001 return DummyResult::raw_pat(span);
1006 mark_pat(expanded,fm)
1009 fld.cx.span_err(span,
1010 &format!("{}! is not legal in pattern position",
1012 return DummyResult::raw_pat(span);
1017 let fully_expanded =
1018 fld.fold_pat(marked_after).node.clone();
1022 id: ast::DUMMY_NODE_ID,
1023 node: fully_expanded,
1029 /// A tree-folder that applies every rename in its (mutable) list
1030 /// to every identifier, including both bindings and varrefs
1031 /// (and lots of things that will turn out to be neither)
1032 pub struct IdentRenamer<'a> {
1033 renames: &'a mtwt::RenameList,
1036 impl<'a> Folder for IdentRenamer<'a> {
1037 fn fold_ident(&mut self, id: Ident) -> Ident {
1040 ctxt: mtwt::apply_renames(self.renames, id.ctxt),
1043 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1044 fold::noop_fold_mac(mac, self)
1048 /// A tree-folder that applies every rename in its list to
1049 /// the idents that are in PatIdent patterns. This is more narrowly
1050 /// focused than IdentRenamer, and is needed for FnDecl,
1051 /// where we want to rename the args but not the fn name or the generics etc.
1052 pub struct PatIdentRenamer<'a> {
1053 renames: &'a mtwt::RenameList,
1056 impl<'a> Folder for PatIdentRenamer<'a> {
1057 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
1059 ast::PatIdent(..) => {},
1060 _ => return noop_fold_pat(pat, self)
1063 pat.map(|ast::Pat {id, node, span}| match node {
1064 ast::PatIdent(binding_mode, Spanned{span: sp, node: ident}, sub) => {
1065 let new_ident = Ident{name: ident.name,
1066 ctxt: mtwt::apply_renames(self.renames, ident.ctxt)};
1068 ast::PatIdent(binding_mode,
1069 Spanned{span: self.new_span(sp), node: new_ident},
1070 sub.map(|p| self.fold_pat(p)));
1074 span: self.new_span(span)
1080 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1081 fold::noop_fold_mac(mac, self)
1085 fn expand_annotatable(a: Annotatable,
1086 fld: &mut MacroExpander)
1087 -> SmallVector<Annotatable> {
1088 let a = expand_item_multi_modifier(a, fld);
1090 let mut decorator_items = SmallVector::zero();
1091 let mut new_attrs = Vec::new();
1092 for attr in a.attrs() {
1093 let mname = attr.name();
1095 match fld.cx.syntax_env.find(&intern(&mname)) {
1096 Some(rc) => match *rc {
1097 Decorator(ref dec) => {
1099 Annotatable::Item(ref it) => it,
1100 // ItemDecorators are only implemented for Items.
1104 attr::mark_used(attr);
1106 fld.cx.bt_push(ExpnInfo {
1107 call_site: attr.span,
1108 callee: NameAndSpan {
1109 name: mname.to_string(),
1110 format: MacroAttribute,
1111 span: Some(attr.span),
1112 // attributes can do whatever they like,
1114 allow_internal_unstable: true,
1118 // we'd ideally decorator_items.push_all(expand_item(item, fld)),
1119 // but that double-mut-borrows fld
1120 let mut items: SmallVector<P<ast::Item>> = SmallVector::zero();
1121 dec.expand(fld.cx, attr.span, &*attr.node.value, &**it,
1122 &mut |item| items.push(item));
1123 decorator_items.extend(
1125 .flat_map(|item| expand_item(item, fld).into_iter()));
1129 _ => new_attrs.push((*attr).clone()),
1131 _ => new_attrs.push((*attr).clone()),
1135 let mut new_items: SmallVector<Annotatable> = match a {
1136 Annotatable::Item(it) => match it.node {
1137 ast::ItemMac(..) => {
1138 expand_item_mac(it, fld).into_iter().map(|i| Annotatable::Item(i)).collect()
1140 ast::ItemMod(_) | ast::ItemForeignMod(_) => {
1142 it.ident.name != parse::token::special_idents::invalid.name;
1145 fld.cx.mod_push(it.ident);
1147 let macro_use = contains_macro_use(fld, &new_attrs[..]);
1148 let result = with_exts_frame!(fld.cx.syntax_env,
1150 noop_fold_item(it, fld));
1154 result.into_iter().map(|i| Annotatable::Item(i)).collect()
1157 let it = P(ast::Item {
1161 noop_fold_item(it, fld).into_iter().map(|i| Annotatable::Item(i)).collect()
1165 Annotatable::TraitItem(it) => match it.node {
1166 ast::MethodTraitItem(_, Some(_)) => SmallVector::one(it.map(|ti| ast::TraitItem {
1170 node: match ti.node {
1171 ast::MethodTraitItem(sig, Some(body)) => {
1172 let (sig, body) = expand_and_rename_method(sig, body, fld);
1173 ast::MethodTraitItem(sig, Some(body))
1177 span: fld.new_span(ti.span)
1179 _ => fold::noop_fold_trait_item(it, fld)
1180 }.into_iter().map(Annotatable::TraitItem).collect(),
1182 Annotatable::ImplItem(ii) => {
1183 expand_impl_item(ii, fld).into_iter().map(Annotatable::ImplItem).collect()
1187 new_items.push_all(decorator_items.into_iter().map(|i| Annotatable::Item(i)).collect());
1191 // partition the attributes into ItemModifiers and others
1192 fn modifiers(attrs: &Vec<ast::Attribute>,
1193 fld: &MacroExpander)
1194 -> (Vec<ast::Attribute>, Vec<ast::Attribute>) {
1195 attrs.iter().cloned().partition(|attr| {
1196 match fld.cx.syntax_env.find(&intern(&attr.name())) {
1197 Some(rc) => match *rc {
1198 Modifier(_) => true,
1206 // partition the attributes into MultiModifiers and others
1207 fn multi_modifiers(attrs: &[ast::Attribute],
1208 fld: &MacroExpander)
1209 -> (Vec<ast::Attribute>, Vec<ast::Attribute>) {
1210 attrs.iter().cloned().partition(|attr| {
1211 match fld.cx.syntax_env.find(&intern(&attr.name())) {
1212 Some(rc) => match *rc {
1213 MultiModifier(_) => true,
1221 fn expand_item_multi_modifier(mut it: Annotatable,
1222 fld: &mut MacroExpander)
1224 let (modifiers, other_attrs) = multi_modifiers(it.attrs(), fld);
1226 // Update the attrs, leave everything else alone. Is this mutation really a good idea?
1227 it = it.fold_attrs(other_attrs);
1229 if modifiers.is_empty() {
1233 for attr in &modifiers {
1234 let mname = attr.name();
1236 match fld.cx.syntax_env.find(&intern(&mname)) {
1237 Some(rc) => match *rc {
1238 MultiModifier(ref mac) => {
1239 attr::mark_used(attr);
1240 fld.cx.bt_push(ExpnInfo {
1241 call_site: attr.span,
1242 callee: NameAndSpan {
1243 name: mname.to_string(),
1244 format: MacroAttribute,
1246 // attributes can do whatever they like,
1248 allow_internal_unstable: true,
1251 it = mac.expand(fld.cx, attr.span, &*attr.node.value, it);
1260 // Expansion may have added new ItemModifiers.
1261 expand_item_multi_modifier(it, fld)
1264 fn expand_impl_item(ii: P<ast::ImplItem>, fld: &mut MacroExpander)
1265 -> SmallVector<P<ast::ImplItem>> {
1267 ast::MethodImplItem(..) => SmallVector::one(ii.map(|ii| ast::ImplItem {
1272 node: match ii.node {
1273 ast::MethodImplItem(sig, body) => {
1274 let (sig, body) = expand_and_rename_method(sig, body, fld);
1275 ast::MethodImplItem(sig, body)
1279 span: fld.new_span(ii.span)
1281 ast::MacImplItem(_) => {
1282 let (span, mac) = ii.and_then(|ii| match ii.node {
1283 ast::MacImplItem(mac) => (ii.span, mac),
1286 let maybe_new_items =
1287 expand_mac_invoc(mac, span,
1288 |r| r.make_impl_items(),
1289 |meths, mark| meths.move_map(|m| mark_impl_item(m, mark)),
1292 match maybe_new_items {
1293 Some(impl_items) => {
1294 // expand again if necessary
1295 let new_items = impl_items.into_iter().flat_map(|ii| {
1296 expand_impl_item(ii, fld).into_iter()
1301 None => SmallVector::zero()
1304 _ => fold::noop_fold_impl_item(ii, fld)
1308 /// Given a fn_decl and a block and a MacroExpander, expand the fn_decl, then use the
1309 /// PatIdents in its arguments to perform renaming in the FnDecl and
1310 /// the block, returning both the new FnDecl and the new Block.
1311 fn expand_and_rename_fn_decl_and_block(fn_decl: P<ast::FnDecl>, block: P<ast::Block>,
1312 fld: &mut MacroExpander)
1313 -> (P<ast::FnDecl>, P<ast::Block>) {
1314 let expanded_decl = fld.fold_fn_decl(fn_decl);
1315 let idents = fn_decl_arg_bindings(&*expanded_decl);
1317 idents.iter().map(|id : &ast::Ident| (*id,fresh_name(id))).collect();
1318 // first, a renamer for the PatIdents, for the fn_decl:
1319 let mut rename_pat_fld = PatIdentRenamer{renames: &renames};
1320 let rewritten_fn_decl = rename_pat_fld.fold_fn_decl(expanded_decl);
1321 // now, a renamer for *all* idents, for the body:
1322 let mut rename_fld = IdentRenamer{renames: &renames};
1323 let rewritten_body = fld.fold_block(rename_fld.fold_block(block));
1324 (rewritten_fn_decl,rewritten_body)
1327 fn expand_and_rename_method(sig: ast::MethodSig, body: P<ast::Block>,
1328 fld: &mut MacroExpander)
1329 -> (ast::MethodSig, P<ast::Block>) {
1330 let (rewritten_fn_decl, rewritten_body)
1331 = expand_and_rename_fn_decl_and_block(sig.decl, body, fld);
1333 generics: fld.fold_generics(sig.generics),
1335 explicit_self: fld.fold_explicit_self(sig.explicit_self),
1336 unsafety: sig.unsafety,
1337 decl: rewritten_fn_decl
1341 /// A tree-folder that performs macro expansion
1342 pub struct MacroExpander<'a, 'b:'a> {
1343 pub cx: &'a mut ExtCtxt<'b>,
1346 impl<'a, 'b> MacroExpander<'a, 'b> {
1347 pub fn new(cx: &'a mut ExtCtxt<'b>) -> MacroExpander<'a, 'b> {
1348 MacroExpander { cx: cx }
1352 impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
1353 fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
1354 expand_expr(expr, self)
1357 fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
1358 expand_pat(pat, self)
1361 fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
1362 expand_item(item, self)
1365 fn fold_item_underscore(&mut self, item: ast::Item_) -> ast::Item_ {
1366 expand_item_underscore(item, self)
1369 fn fold_stmt(&mut self, stmt: P<ast::Stmt>) -> SmallVector<P<ast::Stmt>> {
1370 expand_stmt(stmt, self)
1373 fn fold_block(&mut self, block: P<Block>) -> P<Block> {
1374 expand_block(block, self)
1377 fn fold_arm(&mut self, arm: ast::Arm) -> ast::Arm {
1378 expand_arm(arm, self)
1381 fn fold_trait_item(&mut self, i: P<ast::TraitItem>) -> SmallVector<P<ast::TraitItem>> {
1382 expand_annotatable(Annotatable::TraitItem(i), self)
1383 .into_iter().map(|i| i.expect_trait_item()).collect()
1386 fn fold_impl_item(&mut self, i: P<ast::ImplItem>) -> SmallVector<P<ast::ImplItem>> {
1387 expand_annotatable(Annotatable::ImplItem(i), self)
1388 .into_iter().map(|i| i.expect_impl_item()).collect()
1391 fn new_span(&mut self, span: Span) -> Span {
1392 new_span(self.cx, span)
1396 fn new_span(cx: &ExtCtxt, sp: Span) -> Span {
1397 /* this discards information in the case of macro-defining macros */
1401 expn_id: cx.backtrace(),
1405 pub struct ExpansionConfig<'feat> {
1406 pub crate_name: String,
1407 pub features: Option<&'feat Features>,
1408 pub recursion_limit: usize,
1409 pub trace_mac: bool,
1412 macro_rules! feature_tests {
1413 ($( fn $getter:ident = $field:ident, )*) => {
1415 pub fn $getter(&self) -> bool {
1416 match self.features {
1417 Some(&Features { $field: true, .. }) => true,
1425 impl<'feat> ExpansionConfig<'feat> {
1426 pub fn default(crate_name: String) -> ExpansionConfig<'static> {
1428 crate_name: crate_name,
1430 recursion_limit: 64,
1436 fn enable_quotes = allow_quote,
1437 fn enable_asm = allow_asm,
1438 fn enable_log_syntax = allow_log_syntax,
1439 fn enable_concat_idents = allow_concat_idents,
1440 fn enable_trace_macros = allow_trace_macros,
1441 fn enable_allow_internal_unstable = allow_internal_unstable,
1442 fn enable_custom_derive = allow_custom_derive,
1446 pub fn expand_crate<'feat>(parse_sess: &parse::ParseSess,
1447 cfg: ExpansionConfig<'feat>,
1448 // these are the macros being imported to this crate:
1449 imported_macros: Vec<ast::MacroDef>,
1450 user_exts: Vec<NamedSyntaxExtension>,
1451 c: Crate) -> Crate {
1452 let mut cx = ExtCtxt::new(parse_sess, c.config.clone(), cfg);
1453 cx.use_std = std_inject::use_std(&c);
1455 let mut expander = MacroExpander::new(&mut cx);
1457 for def in imported_macros {
1458 expander.cx.insert_macro(def);
1461 for (name, extension) in user_exts {
1462 expander.cx.syntax_env.insert(name, extension);
1465 let mut ret = expander.fold_crate(c);
1466 ret.exported_macros = expander.cx.exported_macros.clone();
1467 parse_sess.span_diagnostic.handler().abort_if_errors();
1471 // HYGIENIC CONTEXT EXTENSION:
1472 // all of these functions are for walking over
1473 // ASTs and making some change to the context of every
1474 // element that has one. a CtxtFn is a trait-ified
1475 // version of a closure in (SyntaxContext -> SyntaxContext).
1476 // the ones defined here include:
1477 // Marker - add a mark to a context
1479 // A Marker adds the given mark to the syntax context
1480 struct Marker { mark: Mrk }
1482 impl Folder for Marker {
1483 fn fold_ident(&mut self, id: Ident) -> Ident {
1486 ctxt: mtwt::apply_mark(self.mark, id.ctxt)
1489 fn fold_mac(&mut self, Spanned {node, span}: ast::Mac) -> ast::Mac {
1492 MacInvocTT(path, tts, ctxt) => {
1493 MacInvocTT(self.fold_path(path),
1494 self.fold_tts(&tts[..]),
1495 mtwt::apply_mark(self.mark, ctxt))
1503 // apply a given mark to the given token trees. Used prior to expansion of a macro.
1504 fn mark_tts(tts: &[TokenTree], m: Mrk) -> Vec<TokenTree> {
1505 noop_fold_tts(tts, &mut Marker{mark:m})
1508 // apply a given mark to the given expr. Used following the expansion of a macro.
1509 fn mark_expr(expr: P<ast::Expr>, m: Mrk) -> P<ast::Expr> {
1510 Marker{mark:m}.fold_expr(expr)
1513 // apply a given mark to the given pattern. Used following the expansion of a macro.
1514 fn mark_pat(pat: P<ast::Pat>, m: Mrk) -> P<ast::Pat> {
1515 Marker{mark:m}.fold_pat(pat)
1518 // apply a given mark to the given stmt. Used following the expansion of a macro.
1519 fn mark_stmt(stmt: P<ast::Stmt>, m: Mrk) -> P<ast::Stmt> {
1520 Marker{mark:m}.fold_stmt(stmt)
1521 .expect_one("marking a stmt didn't return exactly one stmt")
1524 // apply a given mark to the given item. Used following the expansion of a macro.
1525 fn mark_item(expr: P<ast::Item>, m: Mrk) -> P<ast::Item> {
1526 Marker{mark:m}.fold_item(expr)
1527 .expect_one("marking an item didn't return exactly one item")
1530 // apply a given mark to the given item. Used following the expansion of a macro.
1531 fn mark_impl_item(ii: P<ast::ImplItem>, m: Mrk) -> P<ast::ImplItem> {
1532 Marker{mark:m}.fold_impl_item(ii)
1533 .expect_one("marking an impl item didn't return exactly one impl item")
1536 /// Check that there are no macro invocations left in the AST:
1537 pub fn check_for_macros(sess: &parse::ParseSess, krate: &ast::Crate) {
1538 visit::walk_crate(&mut MacroExterminator{sess:sess}, krate);
1541 /// A visitor that ensures that no macro invocations remain in an AST.
1542 struct MacroExterminator<'a>{
1543 sess: &'a parse::ParseSess
1546 impl<'a, 'v> Visitor<'v> for MacroExterminator<'a> {
1547 fn visit_mac(&mut self, mac: &ast::Mac) {
1548 self.sess.span_diagnostic.span_bug(mac.span,
1549 "macro exterminator: expected AST \
1550 with no macro invocations");
1557 use super::{pattern_bindings, expand_crate};
1558 use super::{PatIdentFinder, IdentRenamer, PatIdentRenamer, ExpansionConfig};
1566 use util::parser_testing::{string_to_parser};
1567 use util::parser_testing::{string_to_pat, string_to_crate, strs_to_idents};
1571 // a visitor that extracts the paths
1572 // from a given thingy and puts them in a mutable
1573 // array (passed in to the traversal)
1575 struct PathExprFinderContext {
1576 path_accumulator: Vec<ast::Path> ,
1579 impl<'v> Visitor<'v> for PathExprFinderContext {
1580 fn visit_expr(&mut self, expr: &ast::Expr) {
1581 if let ast::ExprPath(None, ref p) = expr.node {
1582 self.path_accumulator.push(p.clone());
1584 visit::walk_expr(self, expr);
1588 // find the variable references in a crate
1589 fn crate_varrefs(the_crate : &ast::Crate) -> Vec<ast::Path> {
1590 let mut path_finder = PathExprFinderContext{path_accumulator:Vec::new()};
1591 visit::walk_crate(&mut path_finder, the_crate);
1592 path_finder.path_accumulator
1595 /// A Visitor that extracts the identifiers from a thingy.
1596 // as a side note, I'm starting to want to abstract over these....
1597 struct IdentFinder {
1598 ident_accumulator: Vec<ast::Ident>
1601 impl<'v> Visitor<'v> for IdentFinder {
1602 fn visit_ident(&mut self, _: codemap::Span, id: ast::Ident){
1603 self.ident_accumulator.push(id);
1607 /// Find the idents in a crate
1608 fn crate_idents(the_crate: &ast::Crate) -> Vec<ast::Ident> {
1609 let mut ident_finder = IdentFinder{ident_accumulator: Vec::new()};
1610 visit::walk_crate(&mut ident_finder, the_crate);
1611 ident_finder.ident_accumulator
1614 // these following tests are quite fragile, in that they don't test what
1615 // *kind* of failure occurs.
1617 fn test_ecfg() -> ExpansionConfig<'static> {
1618 ExpansionConfig::default("test".to_string())
1621 // make sure that macros can't escape fns
1623 #[test] fn macros_cant_escape_fns_test () {
1624 let src = "fn bogus() {macro_rules! z (() => (3+4));}\
1625 fn inty() -> i32 { z!() }".to_string();
1626 let sess = parse::new_parse_sess();
1627 let crate_ast = parse::parse_crate_from_source_str(
1628 "<test>".to_string(),
1632 expand_crate(&sess,test_ecfg(),vec!(),vec!(),crate_ast);
1635 // make sure that macros can't escape modules
1637 #[test] fn macros_cant_escape_mods_test () {
1638 let src = "mod foo {macro_rules! z (() => (3+4));}\
1639 fn inty() -> i32 { z!() }".to_string();
1640 let sess = parse::new_parse_sess();
1641 let crate_ast = parse::parse_crate_from_source_str(
1642 "<test>".to_string(),
1645 expand_crate(&sess,test_ecfg(),vec!(),vec!(),crate_ast);
1648 // macro_use modules should allow macros to escape
1649 #[test] fn macros_can_escape_flattened_mods_test () {
1650 let src = "#[macro_use] mod foo {macro_rules! z (() => (3+4));}\
1651 fn inty() -> i32 { z!() }".to_string();
1652 let sess = parse::new_parse_sess();
1653 let crate_ast = parse::parse_crate_from_source_str(
1654 "<test>".to_string(),
1657 expand_crate(&sess, test_ecfg(), vec!(), vec!(), crate_ast);
1660 fn expand_crate_str(crate_str: String) -> ast::Crate {
1661 let ps = parse::new_parse_sess();
1662 let crate_ast = panictry!(string_to_parser(&ps, crate_str).parse_crate_mod());
1663 // the cfg argument actually does matter, here...
1664 expand_crate(&ps,test_ecfg(),vec!(),vec!(),crate_ast)
1667 // find the pat_ident paths in a crate
1668 fn crate_bindings(the_crate : &ast::Crate) -> Vec<ast::Ident> {
1669 let mut name_finder = PatIdentFinder{ident_accumulator:Vec::new()};
1670 visit::walk_crate(&mut name_finder, the_crate);
1671 name_finder.ident_accumulator
1674 #[test] fn macro_tokens_should_match(){
1676 "macro_rules! m((a)=>(13)) ;fn main(){m!(a);}".to_string());
1679 // should be able to use a bound identifier as a literal in a macro definition:
1680 #[test] fn self_macro_parsing(){
1682 "macro_rules! foo ((zz) => (287;));
1683 fn f(zz: i32) {foo!(zz);}".to_string()
1687 // renaming tests expand a crate and then check that the bindings match
1688 // the right varrefs. The specification of the test case includes the
1689 // text of the crate, and also an array of arrays. Each element in the
1690 // outer array corresponds to a binding in the traversal of the AST
1691 // induced by visit. Each of these arrays contains a list of indexes,
1692 // interpreted as the varrefs in the varref traversal that this binding
1693 // should match. So, for instance, in a program with two bindings and
1694 // three varrefs, the array ~[~[1,2],~[0]] would indicate that the first
1695 // binding should match the second two varrefs, and the second binding
1696 // should match the first varref.
1698 // Put differently; this is a sparse representation of a boolean matrix
1699 // indicating which bindings capture which identifiers.
1701 // Note also that this matrix is dependent on the implicit ordering of
1702 // the bindings and the varrefs discovered by the name-finder and the path-finder.
1704 // The comparisons are done post-mtwt-resolve, so we're comparing renamed
1705 // names; differences in marks don't matter any more.
1707 // oog... I also want tests that check "bound-identifier-=?". That is,
1708 // not just "do these have the same name", but "do they have the same
1709 // name *and* the same marks"? Understanding this is really pretty painful.
1710 // in principle, you might want to control this boolean on a per-varref basis,
1711 // but that would make things even harder to understand, and might not be
1712 // necessary for thorough testing.
1713 type RenamingTest = (&'static str, Vec<Vec<usize>>, bool);
1716 fn automatic_renaming () {
1717 let tests: Vec<RenamingTest> =
1718 vec!(// b & c should get new names throughout, in the expr too:
1719 ("fn a() -> i32 { let b = 13; let c = b; b+c }",
1720 vec!(vec!(0,1),vec!(2)), false),
1721 // both x's should be renamed (how is this causing a bug?)
1722 ("fn main () {let x: i32 = 13;x;}",
1723 vec!(vec!(0)), false),
1724 // the use of b after the + should be renamed, the other one not:
1725 ("macro_rules! f (($x:ident) => (b + $x)); fn a() -> i32 { let b = 13; f!(b)}",
1726 vec!(vec!(1)), false),
1727 // the b before the plus should not be renamed (requires marks)
1728 ("macro_rules! f (($x:ident) => ({let b=9; ($x + b)})); fn a() -> i32 { f!(b)}",
1729 vec!(vec!(1)), false),
1730 // the marks going in and out of letty should cancel, allowing that $x to
1731 // capture the one following the semicolon.
1732 // this was an awesome test case, and caught a *lot* of bugs.
1733 ("macro_rules! letty(($x:ident) => (let $x = 15;));
1734 macro_rules! user(($x:ident) => ({letty!($x); $x}));
1735 fn main() -> i32 {user!(z)}",
1736 vec!(vec!(0)), false)
1738 for (idx,s) in tests.iter().enumerate() {
1739 run_renaming_test(s,idx);
1743 // no longer a fixme #8062: this test exposes a *potential* bug; our system does
1744 // not behave exactly like MTWT, but a conversation with Matthew Flatt
1745 // suggests that this can only occur in the presence of local-expand, which
1746 // we have no plans to support. ... unless it's needed for item hygiene....
1751 &("fn main() {let hrcoo = 19; macro_rules! getx(()=>(hrcoo)); getx!();}",
1752 vec!(vec!(0)), true), 0)
1756 // the z flows into and out of two macros (g & f) along one path, and one
1757 // (just g) along the other, so the result of the whole thing should
1758 // be "let z_123 = 3; z_123"
1763 &("macro_rules! g (($x:ident) =>
1764 ({macro_rules! f(($y:ident)=>({let $y=3;$x}));f!($x)}));
1766 vec!(vec!(0)),false),
1770 // match variable hygiene. Should expand into
1771 // fn z() {match 8 {x_1 => {match 9 {x_2 | x_2 if x_2 == x_1 => x_2 + x_1}}}}
1775 &("macro_rules! bad_macro (($ex:expr) => ({match 9 {x | x if x == $ex => x + $ex}}));
1776 fn z() {match 8 {x => bad_macro!(x)}}",
1777 // NB: the third "binding" is the repeat of the second one.
1778 vec!(vec!(1,3),vec!(0,2),vec!(0,2)),
1783 // interpolated nodes weren't getting labeled.
1784 // should expand into
1785 // fn main(){let g1_1 = 13; g1_1}}
1787 fn pat_expand_issue_15221(){
1789 &("macro_rules! inner ( ($e:pat ) => ($e));
1790 macro_rules! outer ( ($e:pat ) => (inner!($e)));
1791 fn main() { let outer!(g) = 13; g;}",
1797 // create a really evil test case where a $x appears inside a binding of $x
1798 // but *shouldn't* bind because it was inserted by a different macro....
1799 // can't write this test case until we have macro-generating macros.
1801 // method arg hygiene
1802 // method expands to fn get_x(&self_0, x_1: i32) {self_0 + self_2 + x_3 + x_1}
1804 fn method_arg_hygiene(){
1806 &("macro_rules! inject_x (()=>(x));
1807 macro_rules! inject_self (()=>(self));
1809 impl A{fn get_x(&self, x: i32) {self + inject_self!() + inject_x!() + x;} }",
1810 vec!(vec!(0),vec!(3)),
1815 // ooh, got another bite?
1816 // expands to struct A; impl A {fn thingy(&self_1) {self_1;}}
1818 fn method_arg_hygiene_2(){
1821 macro_rules! add_method (($T:ty) =>
1822 (impl $T { fn thingy(&self) {self;} }));
1830 // expands to fn q(x_1: i32){fn g(x_2: i32){x_2 + x_1};}
1834 &("macro_rules! bad_macro (($ex:expr) => (fn g(x: i32){ x + $ex }));
1835 fn q(x: i32) { bad_macro!(x); }",
1836 vec!(vec!(1),vec!(0)),true),
1840 // closure arg hygiene (ExprClosure)
1841 // expands to fn f(){(|x_1 : i32| {(x_2 + x_1)})(3);}
1843 fn closure_arg_hygiene(){
1845 &("macro_rules! inject_x (()=>(x));
1846 fn f(){(|x : i32| {(inject_x!() + x)})(3);}",
1852 // macro_rules in method position. Sadly, unimplemented.
1854 fn macro_in_method_posn(){
1856 "macro_rules! my_method (() => (fn thirteen(&self) -> i32 {13}));
1858 impl A{ my_method!(); }
1859 fn f(){A.thirteen;}".to_string());
1862 // another nested macro
1863 // expands to impl Entries {fn size_hint(&self_1) {self_1;}
1865 fn item_macro_workaround(){
1867 &("macro_rules! item { ($i:item) => {$i}}
1869 macro_rules! iterator_impl {
1870 () => { item!( impl Entries { fn size_hint(&self) { self;}});}}
1871 iterator_impl! { }",
1872 vec!(vec!(0)), true),
1876 // run one of the renaming tests
1877 fn run_renaming_test(t: &RenamingTest, test_idx: usize) {
1878 let invalid_name = token::special_idents::invalid.name;
1879 let (teststr, bound_connections, bound_ident_check) = match *t {
1880 (ref str,ref conns, bic) => (str.to_string(), conns.clone(), bic)
1882 let cr = expand_crate_str(teststr.to_string());
1883 let bindings = crate_bindings(&cr);
1884 let varrefs = crate_varrefs(&cr);
1886 // must be one check clause for each binding:
1887 assert_eq!(bindings.len(),bound_connections.len());
1888 for (binding_idx,shouldmatch) in bound_connections.iter().enumerate() {
1889 let binding_name = mtwt::resolve(bindings[binding_idx]);
1890 let binding_marks = mtwt::marksof(bindings[binding_idx].ctxt, invalid_name);
1891 // shouldmatch can't name varrefs that don't exist:
1892 assert!((shouldmatch.is_empty()) ||
1893 (varrefs.len() > *shouldmatch.iter().max().unwrap()));
1894 for (idx,varref) in varrefs.iter().enumerate() {
1895 let print_hygiene_debug_info = || {
1896 // good lord, you can't make a path with 0 segments, can you?
1897 let final_varref_ident = match varref.segments.last() {
1898 Some(pathsegment) => pathsegment.identifier,
1899 None => panic!("varref with 0 path segments?")
1901 let varref_name = mtwt::resolve(final_varref_ident);
1902 let varref_idents : Vec<ast::Ident>
1903 = varref.segments.iter().map(|s| s.identifier)
1905 println!("varref #{}: {:?}, resolves to {}",idx, varref_idents, varref_name);
1906 let string = token::get_ident(final_varref_ident);
1907 println!("varref's first segment's string: \"{}\"", &string[..]);
1908 println!("binding #{}: {}, resolves to {}",
1909 binding_idx, bindings[binding_idx], binding_name);
1910 mtwt::with_sctable(|x| mtwt::display_sctable(x));
1912 if shouldmatch.contains(&idx) {
1913 // it should be a path of length 1, and it should
1914 // be free-identifier=? or bound-identifier=? to the given binding
1915 assert_eq!(varref.segments.len(),1);
1916 let varref_name = mtwt::resolve(varref.segments[0].identifier);
1917 let varref_marks = mtwt::marksof(varref.segments[0]
1921 if !(varref_name==binding_name) {
1922 println!("uh oh, should match but doesn't:");
1923 print_hygiene_debug_info();
1925 assert_eq!(varref_name,binding_name);
1926 if bound_ident_check {
1927 // we're checking bound-identifier=?, and the marks
1928 // should be the same, too:
1929 assert_eq!(varref_marks,binding_marks.clone());
1932 let varref_name = mtwt::resolve(varref.segments[0].identifier);
1933 let fail = (varref.segments.len() == 1)
1934 && (varref_name == binding_name);
1937 println!("failure on test {}",test_idx);
1938 println!("text of test case: \"{}\"", teststr);
1940 println!("uh oh, matches but shouldn't:");
1941 print_hygiene_debug_info();
1950 fn fmt_in_macro_used_inside_module_macro() {
1951 let crate_str = "macro_rules! fmt_wrap(($b:expr)=>($b.to_string()));
1952 macro_rules! foo_module (() => (mod generated { fn a() { let xx = 147; fmt_wrap!(xx);}}));
1955 let cr = expand_crate_str(crate_str);
1956 // find the xx binding
1957 let bindings = crate_bindings(&cr);
1958 let cxbinds: Vec<&ast::Ident> =
1959 bindings.iter().filter(|b| {
1960 let ident = token::get_ident(**b);
1961 let string = &ident[..];
1964 let cxbinds: &[&ast::Ident] = &cxbinds[..];
1965 let cxbind = match (cxbinds.len(), cxbinds.get(0)) {
1967 _ => panic!("expected just one binding for ext_cx")
1969 let resolved_binding = mtwt::resolve(*cxbind);
1970 let varrefs = crate_varrefs(&cr);
1972 // the xx binding should bind all of the xx varrefs:
1973 for (idx,v) in varrefs.iter().filter(|p| {
1974 p.segments.len() == 1
1975 && "xx" == &*token::get_ident(p.segments[0].identifier)
1977 if mtwt::resolve(v.segments[0].identifier) != resolved_binding {
1978 println!("uh oh, xx binding didn't match xx varref:");
1979 println!("this is xx varref \\# {}", idx);
1980 println!("binding: {}", cxbind);
1981 println!("resolves to: {}", resolved_binding);
1982 println!("varref: {}", v.segments[0].identifier);
1983 println!("resolves to: {}",
1984 mtwt::resolve(v.segments[0].identifier));
1985 mtwt::with_sctable(|x| mtwt::display_sctable(x));
1987 assert_eq!(mtwt::resolve(v.segments[0].identifier),
1994 let pat = string_to_pat(
1995 "(a,Foo{x:c @ (b,9),y:Bar(4,d)})".to_string());
1996 let idents = pattern_bindings(&*pat);
1997 assert_eq!(idents, strs_to_idents(vec!("a","c","b","d")));
2000 // test the list of identifier patterns gathered by the visitor. Note that
2001 // 'None' is listed as an identifier pattern because we don't yet know that
2002 // it's the name of a 0-ary variant, and that 'i' appears twice in succession.
2004 fn crate_bindings_test(){
2005 let the_crate = string_to_crate("fn main (a: i32) -> i32 {|b| {
2006 match 34 {None => 3, Some(i) | i => j, Foo{k:z,l:y} => \"banana\"}} }".to_string());
2007 let idents = crate_bindings(&the_crate);
2008 assert_eq!(idents, strs_to_idents(vec!("a","b","None","i","i","z","y")));
2011 // test the IdentRenamer directly
2013 fn ident_renamer_test () {
2014 let the_crate = string_to_crate("fn f(x: i32){let x = x; x}".to_string());
2015 let f_ident = token::str_to_ident("f");
2016 let x_ident = token::str_to_ident("x");
2017 let int_ident = token::str_to_ident("i32");
2018 let renames = vec!((x_ident,Name(16)));
2019 let mut renamer = IdentRenamer{renames: &renames};
2020 let renamed_crate = renamer.fold_crate(the_crate);
2021 let idents = crate_idents(&renamed_crate);
2022 let resolved : Vec<ast::Name> = idents.iter().map(|id| mtwt::resolve(*id)).collect();
2023 assert_eq!(resolved, [f_ident.name,Name(16),int_ident.name,Name(16),Name(16),Name(16)]);
2026 // test the PatIdentRenamer; only PatIdents get renamed
2028 fn pat_ident_renamer_test () {
2029 let the_crate = string_to_crate("fn f(x: i32){let x = x; x}".to_string());
2030 let f_ident = token::str_to_ident("f");
2031 let x_ident = token::str_to_ident("x");
2032 let int_ident = token::str_to_ident("i32");
2033 let renames = vec!((x_ident,Name(16)));
2034 let mut renamer = PatIdentRenamer{renames: &renames};
2035 let renamed_crate = renamer.fold_crate(the_crate);
2036 let idents = crate_idents(&renamed_crate);
2037 let resolved : Vec<ast::Name> = idents.iter().map(|id| mtwt::resolve(*id)).collect();
2038 let x_name = x_ident.name;
2039 assert_eq!(resolved, [f_ident.name,Name(16),int_ident.name,Name(16),x_name,x_name]);