1 use {AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
2 use {CrateLint, Resolver, ResolutionError, ScopeSet, Weak};
3 use {Module, ModuleKind, NameBinding, NameBindingKind, PathResult, Segment, ToNameBinding};
4 use {is_known_tool, resolve_error};
5 use ModuleOrUniformRoot;
7 use build_reduced_graph::{BuildReducedGraphVisitor, IsMacroExport};
8 use resolve_imports::ImportResolver;
9 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, DefIndex,
10 CrateNum, DefIndexAddressSpace};
11 use rustc::hir::def::{Def, NonMacroAttrKind};
12 use rustc::hir::map::{self, DefCollector};
13 use rustc::{ty, lint};
14 use syntax::ast::{self, Ident};
16 use syntax::errors::DiagnosticBuilder;
17 use syntax::ext::base::{self, Determinacy};
18 use syntax::ext::base::{Annotatable, MacroKind, SyntaxExtension};
19 use syntax::ext::expand::{AstFragment, Invocation, InvocationKind};
20 use syntax::ext::hygiene::{self, Mark};
21 use syntax::ext::tt::macro_rules;
22 use syntax::feature_gate::{feature_err, is_builtin_attr_name, GateIssue};
23 use syntax::symbol::{Symbol, keywords};
24 use syntax::visit::Visitor;
25 use syntax::util::lev_distance::find_best_match_for_name;
26 use syntax_pos::{Span, DUMMY_SP};
27 use errors::Applicability;
31 use rustc_data_structures::sync::Lrc;
33 #[derive(Clone, Debug)]
34 pub struct InvocationData<'a> {
36 /// Module in which the macro was invoked.
37 crate module: Cell<Module<'a>>,
38 /// Legacy scope in which the macro was invoked.
39 /// The invocation path is resolved in this scope.
40 crate parent_legacy_scope: Cell<LegacyScope<'a>>,
41 /// Legacy scope *produced* by expanding this macro invocation,
42 /// includes all the macro_rules items, other invocations, etc generated by it.
43 /// `None` if the macro is not expanded yet.
44 crate output_legacy_scope: Cell<Option<LegacyScope<'a>>>,
47 impl<'a> InvocationData<'a> {
48 pub fn root(graph_root: Module<'a>) -> Self {
50 module: Cell::new(graph_root),
51 def_index: CRATE_DEF_INDEX,
52 parent_legacy_scope: Cell::new(LegacyScope::Empty),
53 output_legacy_scope: Cell::new(Some(LegacyScope::Empty)),
58 /// Binding produced by a `macro_rules` item.
59 /// Not modularized, can shadow previous legacy bindings, etc.
61 pub struct LegacyBinding<'a> {
62 binding: &'a NameBinding<'a>,
63 /// Legacy scope into which the `macro_rules` item was planted.
64 parent_legacy_scope: LegacyScope<'a>,
68 /// Scope introduced by a `macro_rules!` macro.
69 /// Starts at the macro's definition and ends at the end of the macro's parent module
70 /// (named or unnamed), or even further if it escapes with `#[macro_use]`.
71 /// Some macro invocations need to introduce legacy scopes too because they
72 /// potentially can expand into macro definitions.
73 #[derive(Copy, Clone, Debug)]
74 pub enum LegacyScope<'a> {
75 /// Created when invocation data is allocated in the arena,
76 /// must be replaced with a proper scope later.
78 /// Empty "root" scope at the crate start containing no names.
80 /// Scope introduced by a `macro_rules!` macro definition.
81 Binding(&'a LegacyBinding<'a>),
82 /// Scope introduced by a macro invocation that can potentially
83 /// create a `macro_rules!` macro definition.
84 Invocation(&'a InvocationData<'a>),
87 /// Everything you need to resolve a macro or import path.
88 #[derive(Clone, Debug)]
89 pub struct ParentScope<'a> {
90 crate module: Module<'a>,
91 crate expansion: Mark,
92 crate legacy: LegacyScope<'a>,
93 crate derives: Vec<ast::Path>,
96 // Macro namespace is separated into two sub-namespaces, one for bang macros and
97 // one for attribute-like macros (attributes, derives).
98 // We ignore resolutions from one sub-namespace when searching names in scope for another.
99 fn sub_namespace_match(candidate: Option<MacroKind>, requirement: Option<MacroKind>) -> bool {
101 enum SubNS { Bang, AttrLike }
102 let sub_ns = |kind| match kind {
103 MacroKind::Bang => Some(SubNS::Bang),
104 MacroKind::Attr | MacroKind::Derive => Some(SubNS::AttrLike),
105 MacroKind::ProcMacroStub => None,
107 let requirement = requirement.and_then(|kind| sub_ns(kind));
108 let candidate = candidate.and_then(|kind| sub_ns(kind));
109 // "No specific sub-namespace" means "matches anything" for both requirements and candidates.
110 candidate.is_none() || requirement.is_none() || candidate == requirement
113 impl<'a> base::Resolver for Resolver<'a> {
114 fn next_node_id(&mut self) -> ast::NodeId {
115 self.session.next_node_id()
118 fn get_module_scope(&mut self, id: ast::NodeId) -> Mark {
119 let mark = Mark::fresh(Mark::root());
120 let module = self.module_map[&self.definitions.local_def_id(id)];
121 self.invocations.insert(mark, self.arenas.alloc_invocation_data(InvocationData {
122 module: Cell::new(module),
123 def_index: module.def_id().unwrap().index,
124 parent_legacy_scope: Cell::new(LegacyScope::Empty),
125 output_legacy_scope: Cell::new(Some(LegacyScope::Empty)),
130 fn resolve_dollar_crates(&mut self, annotatable: &Annotatable) {
131 pub struct ResolveDollarCrates<'a, 'b: 'a> {
132 pub resolver: &'a mut Resolver<'b>,
134 impl<'a> Visitor<'a> for ResolveDollarCrates<'a, '_> {
135 fn visit_ident(&mut self, ident: Ident) {
136 if ident.name == keywords::DollarCrate.name() {
137 let name = match self.resolver.resolve_crate_root(ident).kind {
138 ModuleKind::Def(_, name) if name != keywords::Invalid.name() => name,
139 _ => keywords::Crate.name(),
141 ident.span.ctxt().set_dollar_crate_name(name);
144 fn visit_mac(&mut self, _: &ast::Mac) {}
147 annotatable.visit_with(&mut ResolveDollarCrates { resolver: self });
150 fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
152 let invocation = self.invocations[&mark];
153 self.collect_def_ids(mark, invocation, fragment);
155 self.current_module = invocation.module.get();
156 self.current_module.unresolved_invocations.borrow_mut().remove(&mark);
157 self.current_module.unresolved_invocations.borrow_mut().extend(derives);
158 self.invocations.extend(derives.iter().map(|&derive| (derive, invocation)));
159 let mut visitor = BuildReducedGraphVisitor {
161 current_legacy_scope: invocation.parent_legacy_scope.get(),
164 fragment.visit_with(&mut visitor);
165 invocation.output_legacy_scope.set(Some(visitor.current_legacy_scope));
168 fn add_builtin(&mut self, ident: ast::Ident, ext: Lrc<SyntaxExtension>) {
170 krate: CrateNum::BuiltinMacros,
171 index: DefIndex::from_array_index(self.macro_map.len(),
172 DefIndexAddressSpace::Low),
174 let kind = ext.kind();
175 self.macro_map.insert(def_id, ext);
176 let binding = self.arenas.alloc_name_binding(NameBinding {
177 kind: NameBindingKind::Def(Def::Macro(def_id, kind), false),
180 vis: ty::Visibility::Public,
181 expansion: Mark::root(),
183 if self.builtin_macros.insert(ident.name, binding).is_some() {
184 self.session.span_err(ident.span,
185 &format!("built-in macro `{}` was already defined", ident));
189 fn resolve_imports(&mut self) {
190 ImportResolver { resolver: self }.resolve_imports()
193 fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: Mark, force: bool)
194 -> Result<Option<Lrc<SyntaxExtension>>, Determinacy> {
195 let (path, kind, derives_in_scope, after_derive) = match invoc.kind {
196 InvocationKind::Attr { attr: None, .. } =>
198 InvocationKind::Attr { attr: Some(ref attr), ref traits, after_derive, .. } =>
199 (&attr.path, MacroKind::Attr, traits.clone(), after_derive),
200 InvocationKind::Bang { ref mac, .. } =>
201 (&mac.node.path, MacroKind::Bang, Vec::new(), false),
202 InvocationKind::Derive { ref path, .. } =>
203 (path, MacroKind::Derive, Vec::new(), false),
206 let parent_scope = self.invoc_parent_scope(invoc_id, derives_in_scope);
207 let (def, ext) = match self.resolve_macro_to_def(path, kind, &parent_scope, true, force) {
208 Ok((def, ext)) => (def, ext),
209 Err(Determinacy::Determined) if kind == MacroKind::Attr => {
210 // Replace unresolved attributes with used inert attributes for better recovery.
211 return Ok(Some(Lrc::new(SyntaxExtension::NonMacroAttr { mark_used: true })));
213 Err(determinacy) => return Err(determinacy),
216 if let Def::Macro(def_id, _) = def {
218 self.session.span_err(invoc.span(),
219 "macro attributes must be placed before `#[derive]`");
221 self.macro_defs.insert(invoc.expansion_data.mark, def_id);
222 let normal_module_def_id =
223 self.macro_def_scope(invoc.expansion_data.mark).normal_ancestor_id;
224 self.definitions.add_parent_module_of_macro_def(invoc.expansion_data.mark,
225 normal_module_def_id);
226 invoc.expansion_data.mark.set_default_transparency(ext.default_transparency());
232 fn resolve_macro_path(&mut self, path: &ast::Path, kind: MacroKind, invoc_id: Mark,
233 derives_in_scope: Vec<ast::Path>, force: bool)
234 -> Result<Lrc<SyntaxExtension>, Determinacy> {
235 let parent_scope = self.invoc_parent_scope(invoc_id, derives_in_scope);
236 Ok(self.resolve_macro_to_def(path, kind, &parent_scope, false, force)?.1)
239 fn check_unused_macros(&self) {
240 for did in self.unused_macros.iter() {
241 let id_span = match *self.macro_map[did] {
242 SyntaxExtension::NormalTT { def_info, .. } |
243 SyntaxExtension::DeclMacro { def_info, .. } => def_info,
246 if let Some((id, span)) = id_span {
247 let lint = lint::builtin::UNUSED_MACROS;
248 let msg = "unused macro definition";
249 self.session.buffer_lint(lint, id, span, msg);
251 bug!("attempted to create unused macro error, but span not available");
257 impl<'a> Resolver<'a> {
258 pub fn dummy_parent_scope(&self) -> ParentScope<'a> {
259 self.invoc_parent_scope(Mark::root(), Vec::new())
262 fn invoc_parent_scope(&self, invoc_id: Mark, derives: Vec<ast::Path>) -> ParentScope<'a> {
263 let invoc = self.invocations[&invoc_id];
265 module: invoc.module.get().nearest_item_scope(),
266 expansion: invoc_id.parent(),
267 legacy: invoc.parent_legacy_scope.get(),
272 fn resolve_macro_to_def(
276 parent_scope: &ParentScope<'a>,
279 ) -> Result<(Def, Lrc<SyntaxExtension>), Determinacy> {
280 let def = self.resolve_macro_to_def_inner(path, kind, parent_scope, trace, force);
282 // Report errors and enforce feature gates for the resolved macro.
283 if def != Err(Determinacy::Undetermined) {
284 // Do not report duplicated errors on every undetermined resolution.
285 for segment in &path.segments {
286 if let Some(args) = &segment.args {
287 self.session.span_err(args.span(), "generic arguments in macro path");
295 Def::Macro(def_id, macro_kind) => {
296 self.unused_macros.remove(&def_id);
297 if macro_kind == MacroKind::ProcMacroStub {
298 let msg = "can't use a procedural macro from the same crate that defines it";
299 self.session.span_err(path.span, msg);
300 return Err(Determinacy::Determined);
303 Def::NonMacroAttr(attr_kind) => {
304 if kind == MacroKind::Attr {
305 let features = self.session.features_untracked();
306 if attr_kind == NonMacroAttrKind::Custom {
307 assert!(path.segments.len() == 1);
308 let name = path.segments[0].ident.as_str();
309 if name.starts_with("rustc_") {
310 if !features.rustc_attrs {
311 let msg = "unless otherwise specified, attributes with the prefix \
312 `rustc_` are reserved for internal compiler diagnostics";
313 feature_err(&self.session.parse_sess, "rustc_attrs", path.span,
314 GateIssue::Language, &msg).emit();
316 } else if !features.custom_attribute {
317 let msg = format!("The attribute `{}` is currently unknown to the \
318 compiler and may have meaning added to it in the \
320 feature_err(&self.session.parse_sess, "custom_attribute", path.span,
321 GateIssue::Language, &msg).emit();
325 // Not only attributes, but anything in macro namespace can result in
326 // `Def::NonMacroAttr` definition (e.g., `inline!()`), so we must report
327 // an error for those cases.
328 let msg = format!("expected a macro, found {}", def.kind_name());
329 self.session.span_err(path.span, &msg);
330 return Err(Determinacy::Determined);
334 return Err(Determinacy::Determined);
336 _ => panic!("expected `Def::Macro` or `Def::NonMacroAttr`"),
339 Ok((def, self.get_macro(def)))
342 pub fn resolve_macro_to_def_inner(
346 parent_scope: &ParentScope<'a>,
349 ) -> Result<Def, Determinacy> {
350 let path_span = path.span;
351 let mut path = Segment::from_path(path);
353 // Possibly apply the macro helper hack
354 if kind == MacroKind::Bang && path.len() == 1 &&
355 path[0].ident.span.ctxt().outer().expn_info()
356 .map_or(false, |info| info.local_inner_macros) {
357 let root = Ident::new(keywords::DollarCrate.name(), path[0].ident.span);
358 path.insert(0, Segment::from_ident(root));
362 let def = match self.resolve_path(&path, Some(MacroNS), parent_scope,
363 false, path_span, CrateLint::No) {
364 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
365 Ok(path_res.base_def())
367 PathResult::Indeterminate if !force => return Err(Determinacy::Undetermined),
368 PathResult::NonModule(..) | PathResult::Indeterminate | PathResult::Failed(..) => {
369 Err(Determinacy::Determined)
371 PathResult::Module(..) => unreachable!(),
375 parent_scope.module.multi_segment_macro_resolutions.borrow_mut()
376 .push((path, path_span, kind, parent_scope.clone(), def.ok()));
381 let binding = self.early_resolve_ident_in_lexical_scope(
382 path[0].ident, ScopeSet::Macro(kind), parent_scope, false, force, path_span
384 if let Err(Determinacy::Undetermined) = binding {
385 return Err(Determinacy::Undetermined);
389 parent_scope.module.single_segment_macro_resolutions.borrow_mut()
390 .push((path[0].ident, kind, parent_scope.clone(), binding.ok()));
393 binding.map(|binding| binding.def())
397 // Resolve an identifier in lexical scope.
398 // This is a variation of `fn resolve_ident_in_lexical_scope` that can be run during
399 // expansion and import resolution (perhaps they can be merged in the future).
400 // The function is used for resolving initial segments of macro paths (e.g., `foo` in
401 // `foo::bar!(); or `foo!();`) and also for import paths on 2018 edition.
402 crate fn early_resolve_ident_in_lexical_scope(
406 parent_scope: &ParentScope<'a>,
410 ) -> Result<&'a NameBinding<'a>, Determinacy> {
411 // General principles:
412 // 1. Not controlled (user-defined) names should have higher priority than controlled names
413 // built into the language or standard library. This way we can add new names into the
414 // language or standard library without breaking user code.
415 // 2. "Closed set" below means new names cannot appear after the current resolution attempt.
416 // Places to search (in order of decreasing priority):
418 // 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
419 // (open set, not controlled).
420 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
421 // (open, not controlled).
422 // 3. Extern prelude (closed, not controlled).
423 // 4. Tool modules (closed, controlled right now, but not in the future).
424 // 5. Standard library prelude (de-facto closed, controlled).
425 // 6. Language prelude (closed, controlled).
427 // 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
428 // (open set, not controlled).
429 // 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
430 // (open, not controlled).
431 // 3. Standard library prelude (de-facto closed, controlled).
433 // 1-3. Derive helpers (open, not controlled). All ambiguities with other names
434 // are currently reported as errors. They should be higher in priority than preludes
435 // and probably even names in modules according to the "general principles" above. They
436 // also should be subject to restricted shadowing because are effectively produced by
437 // derives (you need to resolve the derive first to add helpers into scope), but they
438 // should be available before the derive is expanded for compatibility.
439 // It's mess in general, so we are being conservative for now.
440 // 1-3. `macro_rules` (open, not controlled), loop through legacy scopes. Have higher
441 // priority than prelude macros, but create ambiguities with macros in modules.
442 // 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
443 // (open, not controlled). Have higher priority than prelude macros, but create
444 // ambiguities with `macro_rules`.
445 // 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
446 // 4a. User-defined prelude from macro-use
447 // (open, the open part is from macro expansions, not controlled).
448 // 4b. Standard library prelude is currently implemented as `macro-use` (closed, controlled)
449 // 5. Language prelude: builtin macros (closed, controlled, except for legacy plugins).
450 // 6. Language prelude: builtin attributes (closed, controlled).
451 // 4-6. Legacy plugin helpers (open, not controlled). Similar to derive helpers,
452 // but introduced by legacy plugins using `register_attribute`. Priority is somewhere
453 // in prelude, not sure where exactly (creates ambiguities with any other prelude names).
455 enum WhereToResolve<'a> {
457 MacroRules(LegacyScope<'a>),
472 const MACRO_RULES = 1 << 0;
473 const MODULE = 1 << 1;
474 const PRELUDE = 1 << 2;
475 const MISC_SUGGEST_CRATE = 1 << 3;
476 const MISC_SUGGEST_SELF = 1 << 4;
477 const MISC_FROM_PRELUDE = 1 << 5;
481 assert!(force || !record_used); // `record_used` implies `force`
482 let mut ident = orig_ident.modern();
484 // Make sure `self`, `super` etc produce an error when passed to here.
485 if ident.is_path_segment_keyword() {
486 return Err(Determinacy::Determined);
489 // This is *the* result, resolution from the scope closest to the resolved identifier.
490 // However, sometimes this result is "weak" because it comes from a glob import or
491 // a macro expansion, and in this case it cannot shadow names from outer scopes, e.g.
492 // mod m { ... } // solution in outer scope
494 // use prefix::*; // imports another `m` - innermost solution
495 // // weak, cannot shadow the outer `m`, need to report ambiguity error
498 // So we have to save the innermost solution and continue searching in outer scopes
499 // to detect potential ambiguities.
500 let mut innermost_result: Option<(&NameBinding, Flags)> = None;
502 // Go through all the scopes and try to resolve the name.
503 let rust_2015 = orig_ident.span.rust_2015();
504 let (ns, macro_kind, is_import, is_absolute_path) = match scope_set {
505 ScopeSet::Import(ns) => (ns, None, true, false),
506 ScopeSet::AbsolutePath(ns) => (ns, None, false, true),
507 ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false, false),
508 ScopeSet::Module => (TypeNS, None, false, false),
510 let mut where_to_resolve = match ns {
511 _ if is_absolute_path || is_import && rust_2015 => WhereToResolve::CrateRoot,
512 TypeNS | ValueNS => WhereToResolve::Module(parent_scope.module),
513 MacroNS => WhereToResolve::DeriveHelpers,
515 let mut use_prelude = !parent_scope.module.no_implicit_prelude;
516 let mut determinacy = Determinacy::Determined;
518 let result = match where_to_resolve {
519 WhereToResolve::DeriveHelpers => {
520 let mut result = Err(Determinacy::Determined);
521 for derive in &parent_scope.derives {
522 let parent_scope = ParentScope { derives: Vec::new(), ..*parent_scope };
523 match self.resolve_macro_to_def(derive, MacroKind::Derive,
524 &parent_scope, true, force) {
526 if let SyntaxExtension::ProcMacroDerive(_, helpers, _) = &*ext {
527 if helpers.contains(&ident.name) {
529 (Def::NonMacroAttr(NonMacroAttrKind::DeriveHelper),
530 ty::Visibility::Public, derive.span, Mark::root())
531 .to_name_binding(self.arenas);
532 result = Ok((binding, Flags::empty()));
537 Err(Determinacy::Determined) => {}
538 Err(Determinacy::Undetermined) =>
539 result = Err(Determinacy::Undetermined),
544 WhereToResolve::MacroRules(legacy_scope) => match legacy_scope {
545 LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident =>
546 Ok((legacy_binding.binding, Flags::MACRO_RULES)),
547 LegacyScope::Invocation(invoc) if invoc.output_legacy_scope.get().is_none() =>
548 Err(Determinacy::Undetermined),
549 _ => Err(Determinacy::Determined),
551 WhereToResolve::CrateRoot => {
552 let root_ident = Ident::new(keywords::PathRoot.name(), orig_ident.span);
553 let root_module = self.resolve_crate_root(root_ident);
554 let binding = self.resolve_ident_in_module_ext(
555 ModuleOrUniformRoot::Module(root_module),
563 Ok(binding) => Ok((binding, Flags::MODULE | Flags::MISC_SUGGEST_CRATE)),
564 Err((Determinacy::Undetermined, Weak::No)) =>
565 return Err(Determinacy::determined(force)),
566 Err((Determinacy::Undetermined, Weak::Yes)) =>
567 Err(Determinacy::Undetermined),
568 Err((Determinacy::Determined, _)) => Err(Determinacy::Determined),
571 WhereToResolve::Module(module) => {
572 let orig_current_module = mem::replace(&mut self.current_module, module);
573 let binding = self.resolve_ident_in_module_unadjusted_ext(
574 ModuleOrUniformRoot::Module(module),
582 self.current_module = orig_current_module;
585 let misc_flags = if ptr::eq(module, self.graph_root) {
586 Flags::MISC_SUGGEST_CRATE
587 } else if module.is_normal() {
588 Flags::MISC_SUGGEST_SELF
592 Ok((binding, Flags::MODULE | misc_flags))
594 Err((Determinacy::Undetermined, Weak::No)) =>
595 return Err(Determinacy::determined(force)),
596 Err((Determinacy::Undetermined, Weak::Yes)) =>
597 Err(Determinacy::Undetermined),
598 Err((Determinacy::Determined, _)) => Err(Determinacy::Determined),
601 WhereToResolve::MacroUsePrelude => {
602 if use_prelude || rust_2015 {
603 match self.macro_use_prelude.get(&ident.name).cloned() {
605 Ok((binding, Flags::PRELUDE | Flags::MISC_FROM_PRELUDE)),
606 None => Err(Determinacy::determined(
607 self.graph_root.unresolved_invocations.borrow().is_empty()
611 Err(Determinacy::Determined)
614 WhereToResolve::BuiltinMacros => {
615 match self.builtin_macros.get(&ident.name).cloned() {
616 Some(binding) => Ok((binding, Flags::PRELUDE)),
617 None => Err(Determinacy::Determined),
620 WhereToResolve::BuiltinAttrs => {
621 if is_builtin_attr_name(ident.name) {
622 let binding = (Def::NonMacroAttr(NonMacroAttrKind::Builtin),
623 ty::Visibility::Public, DUMMY_SP, Mark::root())
624 .to_name_binding(self.arenas);
625 Ok((binding, Flags::PRELUDE))
627 Err(Determinacy::Determined)
630 WhereToResolve::LegacyPluginHelpers => {
631 if (use_prelude || rust_2015) &&
632 self.session.plugin_attributes.borrow().iter()
633 .any(|(name, _)| ident.name == &**name) {
634 let binding = (Def::NonMacroAttr(NonMacroAttrKind::LegacyPluginHelper),
635 ty::Visibility::Public, DUMMY_SP, Mark::root())
636 .to_name_binding(self.arenas);
637 Ok((binding, Flags::PRELUDE))
639 Err(Determinacy::Determined)
642 WhereToResolve::ExternPrelude => {
643 if use_prelude || is_absolute_path {
644 match self.extern_prelude_get(ident, !record_used) {
645 Some(binding) => Ok((binding, Flags::PRELUDE)),
646 None => Err(Determinacy::determined(
647 self.graph_root.unresolved_invocations.borrow().is_empty()
651 Err(Determinacy::Determined)
654 WhereToResolve::ToolPrelude => {
655 if use_prelude && is_known_tool(ident.name) {
656 let binding = (Def::ToolMod, ty::Visibility::Public,
657 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
658 Ok((binding, Flags::PRELUDE))
660 Err(Determinacy::Determined)
663 WhereToResolve::StdLibPrelude => {
664 let mut result = Err(Determinacy::Determined);
666 if let Some(prelude) = self.prelude {
667 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
668 ModuleOrUniformRoot::Module(prelude),
674 result = Ok((binding, Flags::PRELUDE | Flags::MISC_FROM_PRELUDE));
680 WhereToResolve::BuiltinTypes => {
681 match self.primitive_type_table.primitive_types.get(&ident.name).cloned() {
683 let binding = (Def::PrimTy(prim_ty), ty::Visibility::Public,
684 DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
685 Ok((binding, Flags::PRELUDE))
687 None => Err(Determinacy::Determined)
693 Ok((binding, flags)) if sub_namespace_match(binding.macro_kind(), macro_kind) => {
698 if let Some((innermost_binding, innermost_flags)) = innermost_result {
699 // Found another solution, if the first one was "weak", report an error.
700 let (def, innermost_def) = (binding.def(), innermost_binding.def());
701 if def != innermost_def {
702 let builtin = Def::NonMacroAttr(NonMacroAttrKind::Builtin);
703 let derive_helper = Def::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
705 Def::NonMacroAttr(NonMacroAttrKind::LegacyPluginHelper);
707 let ambiguity_error_kind = if is_import {
708 Some(AmbiguityKind::Import)
709 } else if is_absolute_path {
710 Some(AmbiguityKind::AbsolutePath)
711 } else if innermost_def == builtin || def == builtin {
712 Some(AmbiguityKind::BuiltinAttr)
713 } else if innermost_def == derive_helper || def == derive_helper {
714 Some(AmbiguityKind::DeriveHelper)
715 } else if innermost_def == legacy_helper &&
716 flags.contains(Flags::PRELUDE) ||
717 def == legacy_helper &&
718 innermost_flags.contains(Flags::PRELUDE) {
719 Some(AmbiguityKind::LegacyHelperVsPrelude)
720 } else if innermost_flags.contains(Flags::MACRO_RULES) &&
721 flags.contains(Flags::MODULE) &&
722 !self.disambiguate_legacy_vs_modern(innermost_binding,
724 flags.contains(Flags::MACRO_RULES) &&
725 innermost_flags.contains(Flags::MODULE) &&
726 !self.disambiguate_legacy_vs_modern(binding,
728 Some(AmbiguityKind::LegacyVsModern)
729 } else if innermost_binding.is_glob_import() {
730 Some(AmbiguityKind::GlobVsOuter)
731 } else if innermost_binding.may_appear_after(parent_scope.expansion,
733 Some(AmbiguityKind::MoreExpandedVsOuter)
737 if let Some(kind) = ambiguity_error_kind {
738 let misc = |f: Flags| if f.contains(Flags::MISC_SUGGEST_CRATE) {
739 AmbiguityErrorMisc::SuggestCrate
740 } else if f.contains(Flags::MISC_SUGGEST_SELF) {
741 AmbiguityErrorMisc::SuggestSelf
742 } else if f.contains(Flags::MISC_FROM_PRELUDE) {
743 AmbiguityErrorMisc::FromPrelude
745 AmbiguityErrorMisc::None
747 self.ambiguity_errors.push(AmbiguityError {
750 b1: innermost_binding,
752 misc1: misc(innermost_flags),
755 return Ok(innermost_binding);
759 // Found the first solution.
760 innermost_result = Some((binding, flags));
763 Ok(..) | Err(Determinacy::Determined) => {}
764 Err(Determinacy::Undetermined) => determinacy = Determinacy::Undetermined
767 where_to_resolve = match where_to_resolve {
768 WhereToResolve::DeriveHelpers =>
769 WhereToResolve::MacroRules(parent_scope.legacy),
770 WhereToResolve::MacroRules(legacy_scope) => match legacy_scope {
771 LegacyScope::Binding(binding) => WhereToResolve::MacroRules(
772 binding.parent_legacy_scope
774 LegacyScope::Invocation(invoc) => WhereToResolve::MacroRules(
775 invoc.output_legacy_scope.get().unwrap_or(invoc.parent_legacy_scope.get())
777 LegacyScope::Empty => WhereToResolve::Module(parent_scope.module),
778 LegacyScope::Uninitialized => unreachable!(),
780 WhereToResolve::CrateRoot if is_import => match ns {
781 TypeNS | ValueNS => WhereToResolve::Module(parent_scope.module),
782 MacroNS => WhereToResolve::DeriveHelpers,
784 WhereToResolve::CrateRoot if is_absolute_path => match ns {
786 ident.span.adjust(Mark::root());
787 WhereToResolve::ExternPrelude
789 ValueNS | MacroNS => break,
791 WhereToResolve::CrateRoot => unreachable!(),
792 WhereToResolve::Module(module) => {
793 match self.hygienic_lexical_parent(module, &mut ident.span) {
794 Some(parent_module) => WhereToResolve::Module(parent_module),
796 use_prelude = !module.no_implicit_prelude;
798 TypeNS => WhereToResolve::ExternPrelude,
799 ValueNS => WhereToResolve::StdLibPrelude,
800 MacroNS => WhereToResolve::MacroUsePrelude,
805 WhereToResolve::MacroUsePrelude => WhereToResolve::BuiltinMacros,
806 WhereToResolve::BuiltinMacros => WhereToResolve::BuiltinAttrs,
807 WhereToResolve::BuiltinAttrs => WhereToResolve::LegacyPluginHelpers,
808 WhereToResolve::LegacyPluginHelpers => break, // nowhere else to search
809 WhereToResolve::ExternPrelude if is_absolute_path => break,
810 WhereToResolve::ExternPrelude => WhereToResolve::ToolPrelude,
811 WhereToResolve::ToolPrelude => WhereToResolve::StdLibPrelude,
812 WhereToResolve::StdLibPrelude => match ns {
813 TypeNS => WhereToResolve::BuiltinTypes,
814 ValueNS => break, // nowhere else to search
815 MacroNS => unreachable!(),
817 WhereToResolve::BuiltinTypes => break, // nowhere else to search
823 // The first found solution was the only one, return it.
824 if let Some((binding, flags)) = innermost_result {
825 // We get to here only if there's no ambiguity, in ambiguous cases an error will
826 // be reported anyway, so there's no reason to report an additional feature error.
827 // The `binding` can actually be introduced by something other than `--extern`,
828 // but its `Def` should coincide with a crate passed with `--extern`
829 // (otherwise there would be ambiguity) and we can skip feature error in this case.
831 if !is_import || self.session.features_untracked().uniform_paths {
834 if ns == TypeNS && use_prelude && self.extern_prelude_get(ident, true).is_some() {
838 let root_ident = Ident::new(keywords::PathRoot.name(), orig_ident.span);
839 let root_module = self.resolve_crate_root(root_ident);
840 if self.resolve_ident_in_module_ext(ModuleOrUniformRoot::Module(root_module),
841 orig_ident, ns, None, false, path_span)
847 let msg = "imports can only refer to extern crate names \
848 passed with `--extern` on stable channel";
849 let mut err = feature_err(&self.session.parse_sess, "uniform_paths",
850 ident.span, GateIssue::Language, msg);
852 let what = self.binding_description(binding, ident,
853 flags.contains(Flags::MISC_FROM_PRELUDE));
854 let note_msg = format!("this import refers to {what}", what = what);
855 let label_span = if binding.span.is_dummy() {
859 err.span_note(binding.span, ¬e_msg);
862 err.span_label(label_span, "not an extern crate passed with `--extern`");
869 let determinacy = Determinacy::determined(determinacy == Determinacy::Determined || force);
870 if determinacy == Determinacy::Determined && macro_kind == Some(MacroKind::Attr) {
871 // For single-segment attributes interpret determinate "no resolution" as a custom
872 // attribute. (Lexical resolution implies the first segment and attr kind should imply
873 // the last segment, so we are certainly working with a single-segment attribute here.)
874 assert!(ns == MacroNS);
875 let binding = (Def::NonMacroAttr(NonMacroAttrKind::Custom),
876 ty::Visibility::Public, ident.span, Mark::root())
877 .to_name_binding(self.arenas);
884 pub fn finalize_current_module_macro_resolutions(&mut self) {
885 let module = self.current_module;
887 let check_consistency = |this: &mut Self, path: &[Segment], span, kind: MacroKind,
888 initial_def: Option<Def>, def: Def| {
889 if let Some(initial_def) = initial_def {
890 if def != initial_def && def != Def::Err && this.ambiguity_errors.is_empty() {
891 // Make sure compilation does not succeed if preferred macro resolution
892 // has changed after the macro had been expanded. In theory all such
893 // situations should be reported as ambiguity errors, so this is a bug.
894 if initial_def == Def::NonMacroAttr(NonMacroAttrKind::Custom) {
895 // Yeah, legacy custom attributes are implemented using forced resolution
896 // (which is a best effort error recovery tool, basically), so we can't
897 // promise their resolution won't change later.
898 let msg = format!("inconsistent resolution for a macro: first {}, then {}",
899 initial_def.kind_name(), def.kind_name());
900 this.session.span_err(span, &msg);
902 span_bug!(span, "inconsistent resolution for a macro");
906 // It's possible that the macro was unresolved (indeterminate) and silently
907 // expanded into a dummy fragment for recovery during expansion.
908 // Now, post-expansion, the resolution may succeed, but we can't change the
909 // past and need to report an error.
910 // However, non-speculative `resolve_path` can successfully return private items
911 // even if speculative `resolve_path` returned nothing previously, so we skip this
912 // less informative error if the privacy error is reported elsewhere.
913 if this.privacy_errors.is_empty() {
914 let msg = format!("cannot determine resolution for the {} `{}`",
915 kind.descr(), Segment::names_to_string(path));
916 let msg_note = "import resolution is stuck, try simplifying macro imports";
917 this.session.struct_span_err(span, &msg).note(msg_note).emit();
922 let macro_resolutions =
923 mem::replace(&mut *module.multi_segment_macro_resolutions.borrow_mut(), Vec::new());
924 for (mut path, path_span, kind, parent_scope, initial_def) in macro_resolutions {
925 // FIXME: Path resolution will ICE if segment IDs present.
926 for seg in &mut path { seg.id = None; }
927 match self.resolve_path(&path, Some(MacroNS), &parent_scope,
928 true, path_span, CrateLint::No) {
929 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => {
930 let def = path_res.base_def();
931 check_consistency(self, &path, path_span, kind, initial_def, def);
933 path_res @ PathResult::NonModule(..) | path_res @ PathResult::Failed(..) => {
934 let (span, msg) = if let PathResult::Failed(span, msg, ..) = path_res {
937 (path_span, format!("partially resolved path in {} {}",
938 kind.article(), kind.descr()))
940 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
942 PathResult::Module(..) | PathResult::Indeterminate => unreachable!(),
946 let macro_resolutions =
947 mem::replace(&mut *module.single_segment_macro_resolutions.borrow_mut(), Vec::new());
948 for (ident, kind, parent_scope, initial_binding) in macro_resolutions {
949 match self.early_resolve_ident_in_lexical_scope(ident, ScopeSet::Macro(kind),
950 &parent_scope, true, true, ident.span) {
952 let initial_def = initial_binding.map(|initial_binding| {
953 self.record_use(ident, MacroNS, initial_binding, false);
954 initial_binding.def()
956 let def = binding.def();
957 let seg = Segment::from_ident(ident);
958 check_consistency(self, &[seg], ident.span, kind, initial_def, def);
961 assert!(initial_binding.is_none());
962 let bang = if kind == MacroKind::Bang { "!" } else { "" };
964 format!("cannot find {} `{}{}` in this scope", kind.descr(), ident, bang);
965 let mut err = self.session.struct_span_err(ident.span, &msg);
966 self.suggest_macro_name(&ident.as_str(), kind, &mut err, ident.span);
972 let builtin_attrs = mem::replace(&mut *module.builtin_attrs.borrow_mut(), Vec::new());
973 for (ident, parent_scope) in builtin_attrs {
974 let _ = self.early_resolve_ident_in_lexical_scope(
975 ident, ScopeSet::Macro(MacroKind::Attr), &parent_scope, true, true, ident.span
980 fn suggest_macro_name(&mut self, name: &str, kind: MacroKind,
981 err: &mut DiagnosticBuilder<'a>, span: Span) {
982 // First check if this is a locally-defined bang macro.
983 let suggestion = if let MacroKind::Bang = kind {
984 find_best_match_for_name(self.macro_names.iter().map(|ident| &ident.name), name, None)
987 // Then check global macros.
989 let names = self.builtin_macros.iter().chain(self.macro_use_prelude.iter())
990 .filter_map(|(name, binding)| {
991 if binding.macro_kind() == Some(kind) { Some(name) } else { None }
993 find_best_match_for_name(names, name, None)
994 // Then check modules.
996 let is_macro = |def| {
997 if let Def::Macro(_, def_kind) = def {
1003 let ident = Ident::new(Symbol::intern(name), span);
1004 self.lookup_typo_candidate(&[Segment::from_ident(ident)], MacroNS, is_macro, span)
1007 if let Some(suggestion) = suggestion {
1008 if suggestion != name {
1009 if let MacroKind::Bang = kind {
1010 err.span_suggestion_with_applicability(
1012 "you could try the macro",
1013 suggestion.to_string(),
1014 Applicability::MaybeIncorrect
1017 err.span_suggestion_with_applicability(
1020 suggestion.to_string(),
1021 Applicability::MaybeIncorrect
1025 err.help("have you added the `#[macro_use]` on the module/import?");
1030 fn collect_def_ids(&mut self,
1032 invocation: &'a InvocationData<'a>,
1033 fragment: &AstFragment) {
1034 let Resolver { ref mut invocations, arenas, graph_root, .. } = *self;
1035 let InvocationData { def_index, .. } = *invocation;
1037 let visit_macro_invoc = &mut |invoc: map::MacroInvocationData| {
1038 invocations.entry(invoc.mark).or_insert_with(|| {
1039 arenas.alloc_invocation_data(InvocationData {
1040 def_index: invoc.def_index,
1041 module: Cell::new(graph_root),
1042 parent_legacy_scope: Cell::new(LegacyScope::Uninitialized),
1043 output_legacy_scope: Cell::new(None),
1048 let mut def_collector = DefCollector::new(&mut self.definitions, mark);
1049 def_collector.visit_macro_invoc = Some(visit_macro_invoc);
1050 def_collector.with_parent(def_index, |def_collector| {
1051 fragment.visit_with(def_collector)
1055 pub fn define_macro(&mut self,
1058 current_legacy_scope: &mut LegacyScope<'a>) {
1059 self.local_macro_def_scopes.insert(item.id, self.current_module);
1060 let ident = item.ident;
1061 if ident.name == "macro_rules" {
1062 self.session.span_err(item.span, "user-defined macros may not be named `macro_rules`");
1065 let def_id = self.definitions.local_def_id(item.id);
1066 let ext = Lrc::new(macro_rules::compile(&self.session.parse_sess,
1067 &self.session.features_untracked(),
1068 item, hygiene::default_edition()));
1069 self.macro_map.insert(def_id, ext);
1071 let def = match item.node { ast::ItemKind::MacroDef(ref def) => def, _ => unreachable!() };
1073 let ident = ident.modern();
1074 self.macro_names.insert(ident);
1075 let def = Def::Macro(def_id, MacroKind::Bang);
1076 let vis = ty::Visibility::Invisible; // Doesn't matter for legacy bindings
1077 let binding = (def, vis, item.span, expansion).to_name_binding(self.arenas);
1078 self.set_binding_parent_module(binding, self.current_module);
1079 let legacy_binding = self.arenas.alloc_legacy_binding(LegacyBinding {
1080 parent_legacy_scope: *current_legacy_scope, binding, ident
1082 *current_legacy_scope = LegacyScope::Binding(legacy_binding);
1083 self.all_macros.insert(ident.name, def);
1084 if attr::contains_name(&item.attrs, "macro_export") {
1085 let module = self.graph_root;
1086 let vis = ty::Visibility::Public;
1087 self.define(module, ident, MacroNS,
1088 (def, vis, item.span, expansion, IsMacroExport));
1090 if !attr::contains_name(&item.attrs, "rustc_doc_only_macro") {
1091 self.check_reserved_macro_name(ident, MacroNS);
1093 self.unused_macros.insert(def_id);
1096 let module = self.current_module;
1097 let def = Def::Macro(def_id, MacroKind::Bang);
1098 let vis = self.resolve_visibility(&item.vis);
1099 if vis != ty::Visibility::Public {
1100 self.unused_macros.insert(def_id);
1102 self.define(module, ident, MacroNS, (def, vis, item.span, expansion));