| //! A bunch of methods and structures more or less related to resolving macros and |
| //! interface provided by `Resolver` to macro expander. |
| |
| use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc, Determinacy}; |
| use crate::{CrateLint, Resolver, ResolutionError, Scope, ScopeSet, ParentScope, Weak}; |
| use crate::{ModuleKind, NameBinding, PathResult, Segment, ToNameBinding}; |
| use crate::{ModuleOrUniformRoot, KNOWN_TOOLS}; |
| use crate::Namespace::*; |
| use crate::resolve_imports::ImportResolver; |
| use rustc::hir::def::{self, DefKind, NonMacroAttrKind}; |
| use rustc::middle::stability; |
| use rustc::{ty, lint, span_bug}; |
| use syntax::ast::{self, Ident}; |
| use syntax::attr::StabilityLevel; |
| use syntax::edition::Edition; |
| use syntax::ext::base::{self, Indeterminate, SpecialDerives}; |
| use syntax::ext::base::{MacroKind, SyntaxExtension}; |
| use syntax::ext::expand::{AstFragment, Invocation, InvocationKind}; |
| use syntax::ext::hygiene::{self, ExpnId, ExpnData, ExpnKind}; |
| use syntax::ext::tt::macro_rules; |
| use syntax::feature_gate::{emit_feature_err, is_builtin_attr_name}; |
| use syntax::feature_gate::GateIssue; |
| use syntax::symbol::{Symbol, kw, sym}; |
| use syntax_pos::{Span, DUMMY_SP}; |
| |
| use std::{mem, ptr}; |
| use rustc_data_structures::sync::Lrc; |
| |
| type Res = def::Res<ast::NodeId>; |
| |
| /// Binding produced by a `macro_rules` item. |
| /// Not modularized, can shadow previous legacy bindings, etc. |
| #[derive(Debug)] |
| pub struct LegacyBinding<'a> { |
| crate binding: &'a NameBinding<'a>, |
| /// Legacy scope into which the `macro_rules` item was planted. |
| crate parent_legacy_scope: LegacyScope<'a>, |
| crate ident: Ident, |
| } |
| |
| /// The scope introduced by a `macro_rules!` macro. |
| /// This starts at the macro's definition and ends at the end of the macro's parent |
| /// module (named or unnamed), or even further if it escapes with `#[macro_use]`. |
| /// Some macro invocations need to introduce legacy scopes too because they |
| /// can potentially expand into macro definitions. |
| #[derive(Copy, Clone, Debug)] |
| pub enum LegacyScope<'a> { |
| /// Empty "root" scope at the crate start containing no names. |
| Empty, |
| /// The scope introduced by a `macro_rules!` macro definition. |
| Binding(&'a LegacyBinding<'a>), |
| /// The scope introduced by a macro invocation that can potentially |
| /// create a `macro_rules!` macro definition. |
| Invocation(ExpnId), |
| } |
| |
| // Macro namespace is separated into two sub-namespaces, one for bang macros and |
| // one for attribute-like macros (attributes, derives). |
| // We ignore resolutions from one sub-namespace when searching names in scope for another. |
| fn sub_namespace_match(candidate: Option<MacroKind>, requirement: Option<MacroKind>) -> bool { |
| #[derive(PartialEq)] |
| enum SubNS { Bang, AttrLike } |
| let sub_ns = |kind| match kind { |
| MacroKind::Bang => SubNS::Bang, |
| MacroKind::Attr | MacroKind::Derive => SubNS::AttrLike, |
| }; |
| let candidate = candidate.map(sub_ns); |
| let requirement = requirement.map(sub_ns); |
| // "No specific sub-namespace" means "matches anything" for both requirements and candidates. |
| candidate.is_none() || requirement.is_none() || candidate == requirement |
| } |
| |
| // We don't want to format a path using pretty-printing, |
| // `format!("{}", path)`, because that tries to insert |
| // line-breaks and is slow. |
| fn fast_print_path(path: &ast::Path) -> Symbol { |
| if path.segments.len() == 1 { |
| return path.segments[0].ident.name |
| } else { |
| let mut path_str = String::with_capacity(64); |
| for (i, segment) in path.segments.iter().enumerate() { |
| if i != 0 { |
| path_str.push_str("::"); |
| } |
| if segment.ident.name != kw::PathRoot { |
| path_str.push_str(&segment.ident.as_str()) |
| } |
| } |
| Symbol::intern(&path_str) |
| } |
| } |
| |
| impl<'a> base::Resolver for Resolver<'a> { |
| fn next_node_id(&mut self) -> ast::NodeId { |
| self.session.next_node_id() |
| } |
| |
| fn get_module_scope(&mut self, id: ast::NodeId) -> ExpnId { |
| let expn_id = ExpnId::fresh(Some(ExpnData::default( |
| ExpnKind::Macro(MacroKind::Attr, sym::test_case), DUMMY_SP, self.session.edition() |
| ))); |
| let module = self.module_map[&self.definitions.local_def_id(id)]; |
| self.invocation_parent_scopes.insert(expn_id, ParentScope::module(module)); |
| self.definitions.set_invocation_parent(expn_id, module.def_id().unwrap().index); |
| expn_id |
| } |
| |
| fn resolve_dollar_crates(&mut self) { |
| hygiene::update_dollar_crate_names(|ctxt| { |
| let ident = Ident::new(kw::DollarCrate, DUMMY_SP.with_ctxt(ctxt)); |
| match self.resolve_crate_root(ident).kind { |
| ModuleKind::Def(.., name) if name != kw::Invalid => name, |
| _ => kw::Crate, |
| } |
| }); |
| } |
| |
| fn visit_ast_fragment_with_placeholders( |
| &mut self, expansion: ExpnId, fragment: &AstFragment, derives: &[ExpnId] |
| ) { |
| // Fill in some data for derives if the fragment is from a derive container. |
| // We are inside the `expansion` now, but other parent scope components are still the same. |
| let parent_scope = ParentScope { expansion, ..self.invocation_parent_scopes[&expansion] }; |
| let parent_def = self.definitions.invocation_parent(expansion); |
| self.invocation_parent_scopes.extend(derives.iter().map(|&derive| (derive, parent_scope))); |
| for &derive_invoc_id in derives { |
| self.definitions.set_invocation_parent(derive_invoc_id, parent_def); |
| } |
| parent_scope.module.unresolved_invocations.borrow_mut().remove(&expansion); |
| parent_scope.module.unresolved_invocations.borrow_mut().extend(derives); |
| |
| // Integrate the new AST fragment into all the definition and module structures. |
| let output_legacy_scope = self.build_reduced_graph(fragment, parent_scope); |
| self.output_legacy_scopes.insert(expansion, output_legacy_scope); |
| } |
| |
| fn register_builtin_macro(&mut self, ident: ast::Ident, ext: SyntaxExtension) { |
| if self.builtin_macros.insert(ident.name, ext).is_some() { |
| self.session.span_err(ident.span, |
| &format!("built-in macro `{}` was already defined", ident)); |
| } |
| } |
| |
| fn resolve_imports(&mut self) { |
| ImportResolver { r: self }.resolve_imports() |
| } |
| |
| fn resolve_macro_invocation(&mut self, invoc: &Invocation, invoc_id: ExpnId, force: bool) |
| -> Result<Option<Lrc<SyntaxExtension>>, Indeterminate> { |
| let parent_scope = self.invocation_parent_scopes[&invoc_id]; |
| let (path, kind, derives, after_derive) = match invoc.kind { |
| InvocationKind::Attr { ref attr, ref derives, after_derive, .. } => |
| (&attr.path, MacroKind::Attr, self.arenas.alloc_ast_paths(derives), after_derive), |
| InvocationKind::Bang { ref mac, .. } => |
| (&mac.path, MacroKind::Bang, &[][..], false), |
| InvocationKind::Derive { ref path, .. } => |
| (path, MacroKind::Derive, &[][..], false), |
| InvocationKind::DeriveContainer { ref derives, .. } => { |
| // Block expansion of derives in the container until we know whether one of them |
| // is a built-in `Copy`. Skip the resolution if there's only one derive - either |
| // it's not a `Copy` and we don't need to do anything, or it's a `Copy` and it |
| // will automatically knows about itself. |
| let mut result = Ok(None); |
| if derives.len() > 1 { |
| for path in derives { |
| match self.resolve_macro_path(path, Some(MacroKind::Derive), |
| &parent_scope, true, force) { |
| Ok((Some(ref ext), _)) if ext.is_derive_copy => { |
| self.add_derives(invoc.expansion_data.id, SpecialDerives::COPY); |
| return Ok(None); |
| } |
| Err(Determinacy::Undetermined) => result = Err(Indeterminate), |
| _ => {} |
| } |
| } |
| } |
| return result; |
| } |
| }; |
| |
| // Derives are not included when `invocations` are collected, so we have to add them here. |
| let parent_scope = &ParentScope { derives, ..parent_scope }; |
| let (ext, res) = self.smart_resolve_macro_path(path, kind, parent_scope, force)?; |
| |
| let span = invoc.span(); |
| invoc.expansion_data.id.set_expn_data( |
| ext.expn_data(parent_scope.expansion, span, fast_print_path(path)) |
| ); |
| |
| if let Res::Def(_, def_id) = res { |
| if after_derive { |
| self.session.span_err(span, "macro attributes must be placed before `#[derive]`"); |
| } |
| self.macro_defs.insert(invoc.expansion_data.id, def_id); |
| let normal_module_def_id = |
| self.macro_def_scope(invoc.expansion_data.id).normal_ancestor_id; |
| self.definitions.add_parent_module_of_macro_def(invoc.expansion_data.id, |
| normal_module_def_id); |
| } |
| |
| Ok(Some(ext)) |
| } |
| |
| fn check_unused_macros(&self) { |
| for (&node_id, &span) in self.unused_macros.iter() { |
| self.session.buffer_lint( |
| lint::builtin::UNUSED_MACROS, node_id, span, "unused macro definition" |
| ); |
| } |
| } |
| |
| fn has_derives(&self, expn_id: ExpnId, derives: SpecialDerives) -> bool { |
| self.has_derives(expn_id, derives) |
| } |
| |
| fn add_derives(&mut self, expn_id: ExpnId, derives: SpecialDerives) { |
| *self.special_derives.entry(expn_id).or_default() |= derives; |
| } |
| } |
| |
| impl<'a> Resolver<'a> { |
| /// Resolve macro path with error reporting and recovery. |
| fn smart_resolve_macro_path( |
| &mut self, |
| path: &ast::Path, |
| kind: MacroKind, |
| parent_scope: &ParentScope<'a>, |
| force: bool, |
| ) -> Result<(Lrc<SyntaxExtension>, Res), Indeterminate> { |
| let (ext, res) = match self.resolve_macro_path(path, Some(kind), parent_scope, |
| true, force) { |
| Ok((Some(ext), res)) => (ext, res), |
| // Use dummy syntax extensions for unresolved macros for better recovery. |
| Ok((None, res)) => (self.dummy_ext(kind), res), |
| Err(Determinacy::Determined) => (self.dummy_ext(kind), Res::Err), |
| Err(Determinacy::Undetermined) => return Err(Indeterminate), |
| }; |
| |
| // Report errors and enforce feature gates for the resolved macro. |
| let features = self.session.features_untracked(); |
| for segment in &path.segments { |
| if let Some(args) = &segment.args { |
| self.session.span_err(args.span(), "generic arguments in macro path"); |
| } |
| if kind == MacroKind::Attr && !features.rustc_attrs && |
| segment.ident.as_str().starts_with("rustc") { |
| let msg = |
| "attributes starting with `rustc` are reserved for use by the `rustc` compiler"; |
| emit_feature_err( |
| &self.session.parse_sess, |
| sym::rustc_attrs, |
| segment.ident.span, |
| GateIssue::Language, |
| msg, |
| ); |
| } |
| } |
| |
| match res { |
| Res::Def(DefKind::Macro(_), def_id) => { |
| if let Some(node_id) = self.definitions.as_local_node_id(def_id) { |
| self.unused_macros.remove(&node_id); |
| if self.proc_macro_stubs.contains(&node_id) { |
| self.session.span_err( |
| path.span, |
| "can't use a procedural macro from the same crate that defines it", |
| ); |
| } |
| } |
| } |
| Res::NonMacroAttr(..) | Res::Err => {} |
| _ => panic!("expected `DefKind::Macro` or `Res::NonMacroAttr`"), |
| }; |
| |
| self.check_stability_and_deprecation(&ext, path); |
| |
| Ok(if ext.macro_kind() != kind { |
| let expected = if kind == MacroKind::Attr { "attribute" } else { kind.descr() }; |
| let msg = format!("expected {}, found {} `{}`", expected, res.descr(), path); |
| self.session.struct_span_err(path.span, &msg) |
| .span_label(path.span, format!("not {} {}", kind.article(), expected)) |
| .emit(); |
| // Use dummy syntax extensions for unexpected macro kinds for better recovery. |
| (self.dummy_ext(kind), Res::Err) |
| } else { |
| (ext, res) |
| }) |
| } |
| |
| pub fn resolve_macro_path( |
| &mut self, |
| path: &ast::Path, |
| kind: Option<MacroKind>, |
| parent_scope: &ParentScope<'a>, |
| trace: bool, |
| force: bool, |
| ) -> Result<(Option<Lrc<SyntaxExtension>>, Res), Determinacy> { |
| let path_span = path.span; |
| let mut path = Segment::from_path(path); |
| |
| // Possibly apply the macro helper hack |
| if kind == Some(MacroKind::Bang) && path.len() == 1 && |
| path[0].ident.span.ctxt().outer_expn_data().local_inner_macros { |
| let root = Ident::new(kw::DollarCrate, path[0].ident.span); |
| path.insert(0, Segment::from_ident(root)); |
| } |
| |
| let res = if path.len() > 1 { |
| let res = match self.resolve_path(&path, Some(MacroNS), parent_scope, |
| false, path_span, CrateLint::No) { |
| PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => { |
| Ok(path_res.base_res()) |
| } |
| PathResult::Indeterminate if !force => return Err(Determinacy::Undetermined), |
| PathResult::NonModule(..) |
| | PathResult::Indeterminate |
| | PathResult::Failed { .. } => Err(Determinacy::Determined), |
| PathResult::Module(..) => unreachable!(), |
| }; |
| |
| if trace { |
| let kind = kind.expect("macro kind must be specified if tracing is enabled"); |
| self.multi_segment_macro_resolutions |
| .push((path, path_span, kind, *parent_scope, res.ok())); |
| } |
| |
| self.prohibit_imported_non_macro_attrs(None, res.ok(), path_span); |
| res |
| } else { |
| let scope_set = kind.map_or(ScopeSet::All(MacroNS, false), ScopeSet::Macro); |
| let binding = self.early_resolve_ident_in_lexical_scope( |
| path[0].ident, scope_set, parent_scope, false, force, path_span |
| ); |
| if let Err(Determinacy::Undetermined) = binding { |
| return Err(Determinacy::Undetermined); |
| } |
| |
| if trace { |
| let kind = kind.expect("macro kind must be specified if tracing is enabled"); |
| self.single_segment_macro_resolutions |
| .push((path[0].ident, kind, *parent_scope, binding.ok())); |
| } |
| |
| let res = binding.map(|binding| binding.res()); |
| self.prohibit_imported_non_macro_attrs(binding.ok(), res.ok(), path_span); |
| res |
| }; |
| |
| res.map(|res| (self.get_macro(res), res)) |
| } |
| |
| // Resolve an identifier in lexical scope. |
| // This is a variation of `fn resolve_ident_in_lexical_scope` that can be run during |
| // expansion and import resolution (perhaps they can be merged in the future). |
| // The function is used for resolving initial segments of macro paths (e.g., `foo` in |
| // `foo::bar!(); or `foo!();`) and also for import paths on 2018 edition. |
| crate fn early_resolve_ident_in_lexical_scope( |
| &mut self, |
| orig_ident: Ident, |
| scope_set: ScopeSet, |
| parent_scope: &ParentScope<'a>, |
| record_used: bool, |
| force: bool, |
| path_span: Span, |
| ) -> Result<&'a NameBinding<'a>, Determinacy> { |
| bitflags::bitflags! { |
| struct Flags: u8 { |
| const MACRO_RULES = 1 << 0; |
| const MODULE = 1 << 1; |
| const PRELUDE = 1 << 2; |
| const MISC_SUGGEST_CRATE = 1 << 3; |
| const MISC_SUGGEST_SELF = 1 << 4; |
| const MISC_FROM_PRELUDE = 1 << 5; |
| } |
| } |
| |
| assert!(force || !record_used); // `record_used` implies `force` |
| |
| // Make sure `self`, `super` etc produce an error when passed to here. |
| if orig_ident.is_path_segment_keyword() { |
| return Err(Determinacy::Determined); |
| } |
| |
| let (ns, macro_kind, is_import) = match scope_set { |
| ScopeSet::All(ns, is_import) => (ns, None, is_import), |
| ScopeSet::AbsolutePath(ns) => (ns, None, false), |
| ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false), |
| }; |
| |
| // This is *the* result, resolution from the scope closest to the resolved identifier. |
| // However, sometimes this result is "weak" because it comes from a glob import or |
| // a macro expansion, and in this case it cannot shadow names from outer scopes, e.g. |
| // mod m { ... } // solution in outer scope |
| // { |
| // use prefix::*; // imports another `m` - innermost solution |
| // // weak, cannot shadow the outer `m`, need to report ambiguity error |
| // m::mac!(); |
| // } |
| // So we have to save the innermost solution and continue searching in outer scopes |
| // to detect potential ambiguities. |
| let mut innermost_result: Option<(&NameBinding<'_>, Flags)> = None; |
| let mut determinacy = Determinacy::Determined; |
| |
| // Go through all the scopes and try to resolve the name. |
| let break_result = self.visit_scopes(scope_set, parent_scope, orig_ident, |
| |this, scope, use_prelude, ident| { |
| let result = match scope { |
| Scope::DeriveHelpers => { |
| let mut result = Err(Determinacy::Determined); |
| for derive in parent_scope.derives { |
| let parent_scope = &ParentScope { derives: &[], ..*parent_scope }; |
| match this.resolve_macro_path(derive, Some(MacroKind::Derive), |
| parent_scope, true, force) { |
| Ok((Some(ext), _)) => if ext.helper_attrs.contains(&ident.name) { |
| let binding = (Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper), |
| ty::Visibility::Public, derive.span, ExpnId::root()) |
| .to_name_binding(this.arenas); |
| result = Ok((binding, Flags::empty())); |
| break; |
| } |
| Ok(_) | Err(Determinacy::Determined) => {} |
| Err(Determinacy::Undetermined) => |
| result = Err(Determinacy::Undetermined), |
| } |
| } |
| result |
| } |
| Scope::MacroRules(legacy_scope) => match legacy_scope { |
| LegacyScope::Binding(legacy_binding) if ident == legacy_binding.ident => |
| Ok((legacy_binding.binding, Flags::MACRO_RULES)), |
| LegacyScope::Invocation(invoc_id) |
| if !this.output_legacy_scopes.contains_key(&invoc_id) => |
| Err(Determinacy::Undetermined), |
| _ => Err(Determinacy::Determined), |
| } |
| Scope::CrateRoot => { |
| let root_ident = Ident::new(kw::PathRoot, ident.span); |
| let root_module = this.resolve_crate_root(root_ident); |
| let binding = this.resolve_ident_in_module_ext( |
| ModuleOrUniformRoot::Module(root_module), |
| ident, |
| ns, |
| parent_scope, |
| record_used, |
| path_span, |
| ); |
| match binding { |
| Ok(binding) => Ok((binding, Flags::MODULE | Flags::MISC_SUGGEST_CRATE)), |
| Err((Determinacy::Undetermined, Weak::No)) => |
| return Some(Err(Determinacy::determined(force))), |
| Err((Determinacy::Undetermined, Weak::Yes)) => |
| Err(Determinacy::Undetermined), |
| Err((Determinacy::Determined, _)) => Err(Determinacy::Determined), |
| } |
| } |
| Scope::Module(module) => { |
| let adjusted_parent_scope = &ParentScope { module, ..*parent_scope }; |
| let binding = this.resolve_ident_in_module_unadjusted_ext( |
| ModuleOrUniformRoot::Module(module), |
| ident, |
| ns, |
| adjusted_parent_scope, |
| true, |
| record_used, |
| path_span, |
| ); |
| match binding { |
| Ok(binding) => { |
| let misc_flags = if ptr::eq(module, this.graph_root) { |
| Flags::MISC_SUGGEST_CRATE |
| } else if module.is_normal() { |
| Flags::MISC_SUGGEST_SELF |
| } else { |
| Flags::empty() |
| }; |
| Ok((binding, Flags::MODULE | misc_flags)) |
| } |
| Err((Determinacy::Undetermined, Weak::No)) => |
| return Some(Err(Determinacy::determined(force))), |
| Err((Determinacy::Undetermined, Weak::Yes)) => |
| Err(Determinacy::Undetermined), |
| Err((Determinacy::Determined, _)) => Err(Determinacy::Determined), |
| } |
| } |
| Scope::MacroUsePrelude => match this.macro_use_prelude.get(&ident.name).cloned() { |
| Some(binding) => Ok((binding, Flags::PRELUDE | Flags::MISC_FROM_PRELUDE)), |
| None => Err(Determinacy::determined( |
| this.graph_root.unresolved_invocations.borrow().is_empty() |
| )) |
| } |
| Scope::BuiltinAttrs => if is_builtin_attr_name(ident.name) { |
| let binding = (Res::NonMacroAttr(NonMacroAttrKind::Builtin), |
| ty::Visibility::Public, DUMMY_SP, ExpnId::root()) |
| .to_name_binding(this.arenas); |
| Ok((binding, Flags::PRELUDE)) |
| } else { |
| Err(Determinacy::Determined) |
| } |
| Scope::LegacyPluginHelpers => if this.session.plugin_attributes.borrow().iter() |
| .any(|(name, _)| ident.name == *name) { |
| let binding = (Res::NonMacroAttr(NonMacroAttrKind::LegacyPluginHelper), |
| ty::Visibility::Public, DUMMY_SP, ExpnId::root()) |
| .to_name_binding(this.arenas); |
| Ok((binding, Flags::PRELUDE)) |
| } else { |
| Err(Determinacy::Determined) |
| } |
| Scope::ExternPrelude => match this.extern_prelude_get(ident, !record_used) { |
| Some(binding) => Ok((binding, Flags::PRELUDE)), |
| None => Err(Determinacy::determined( |
| this.graph_root.unresolved_invocations.borrow().is_empty() |
| )), |
| } |
| Scope::ToolPrelude => if KNOWN_TOOLS.contains(&ident.name) { |
| let binding = (Res::ToolMod, ty::Visibility::Public, DUMMY_SP, ExpnId::root()) |
| .to_name_binding(this.arenas); |
| Ok((binding, Flags::PRELUDE)) |
| } else { |
| Err(Determinacy::Determined) |
| } |
| Scope::StdLibPrelude => { |
| let mut result = Err(Determinacy::Determined); |
| if let Some(prelude) = this.prelude { |
| if let Ok(binding) = this.resolve_ident_in_module_unadjusted( |
| ModuleOrUniformRoot::Module(prelude), |
| ident, |
| ns, |
| parent_scope, |
| false, |
| path_span, |
| ) { |
| if use_prelude || this.is_builtin_macro(binding.res()) { |
| result = Ok((binding, Flags::PRELUDE | Flags::MISC_FROM_PRELUDE)); |
| } |
| } |
| } |
| result |
| } |
| Scope::BuiltinTypes => match this.primitive_type_table.primitive_types |
| .get(&ident.name).cloned() { |
| Some(prim_ty) => { |
| let binding = (Res::PrimTy(prim_ty), ty::Visibility::Public, |
| DUMMY_SP, ExpnId::root()).to_name_binding(this.arenas); |
| Ok((binding, Flags::PRELUDE)) |
| } |
| None => Err(Determinacy::Determined) |
| } |
| }; |
| |
| match result { |
| Ok((binding, flags)) if sub_namespace_match(binding.macro_kind(), macro_kind) => { |
| if !record_used { |
| return Some(Ok(binding)); |
| } |
| |
| if let Some((innermost_binding, innermost_flags)) = innermost_result { |
| // Found another solution, if the first one was "weak", report an error. |
| let (res, innermost_res) = (binding.res(), innermost_binding.res()); |
| if res != innermost_res { |
| let builtin = Res::NonMacroAttr(NonMacroAttrKind::Builtin); |
| let derive_helper = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper); |
| let legacy_helper = |
| Res::NonMacroAttr(NonMacroAttrKind::LegacyPluginHelper); |
| |
| let ambiguity_error_kind = if is_import { |
| Some(AmbiguityKind::Import) |
| } else if innermost_res == builtin || res == builtin { |
| Some(AmbiguityKind::BuiltinAttr) |
| } else if innermost_res == derive_helper || res == derive_helper { |
| Some(AmbiguityKind::DeriveHelper) |
| } else if innermost_res == legacy_helper && |
| flags.contains(Flags::PRELUDE) || |
| res == legacy_helper && |
| innermost_flags.contains(Flags::PRELUDE) { |
| Some(AmbiguityKind::LegacyHelperVsPrelude) |
| } else if innermost_flags.contains(Flags::MACRO_RULES) && |
| flags.contains(Flags::MODULE) && |
| !this.disambiguate_legacy_vs_modern(innermost_binding, |
| binding) || |
| flags.contains(Flags::MACRO_RULES) && |
| innermost_flags.contains(Flags::MODULE) && |
| !this.disambiguate_legacy_vs_modern(binding, |
| innermost_binding) { |
| Some(AmbiguityKind::LegacyVsModern) |
| } else if innermost_binding.is_glob_import() { |
| Some(AmbiguityKind::GlobVsOuter) |
| } else if innermost_binding.may_appear_after(parent_scope.expansion, |
| binding) { |
| Some(AmbiguityKind::MoreExpandedVsOuter) |
| } else { |
| None |
| }; |
| if let Some(kind) = ambiguity_error_kind { |
| let misc = |f: Flags| if f.contains(Flags::MISC_SUGGEST_CRATE) { |
| AmbiguityErrorMisc::SuggestCrate |
| } else if f.contains(Flags::MISC_SUGGEST_SELF) { |
| AmbiguityErrorMisc::SuggestSelf |
| } else if f.contains(Flags::MISC_FROM_PRELUDE) { |
| AmbiguityErrorMisc::FromPrelude |
| } else { |
| AmbiguityErrorMisc::None |
| }; |
| this.ambiguity_errors.push(AmbiguityError { |
| kind, |
| ident: orig_ident, |
| b1: innermost_binding, |
| b2: binding, |
| misc1: misc(innermost_flags), |
| misc2: misc(flags), |
| }); |
| return Some(Ok(innermost_binding)); |
| } |
| } |
| } else { |
| // Found the first solution. |
| innermost_result = Some((binding, flags)); |
| } |
| } |
| Ok(..) | Err(Determinacy::Determined) => {} |
| Err(Determinacy::Undetermined) => determinacy = Determinacy::Undetermined |
| } |
| |
| None |
| }); |
| |
| if let Some(break_result) = break_result { |
| return break_result; |
| } |
| |
| // The first found solution was the only one, return it. |
| if let Some((binding, _)) = innermost_result { |
| return Ok(binding); |
| } |
| |
| let determinacy = Determinacy::determined(determinacy == Determinacy::Determined || force); |
| if determinacy == Determinacy::Determined && macro_kind == Some(MacroKind::Attr) && |
| self.session.features_untracked().custom_attribute { |
| // For single-segment attributes interpret determinate "no resolution" as a custom |
| // attribute. (Lexical resolution implies the first segment and attr kind should imply |
| // the last segment, so we are certainly working with a single-segment attribute here.) |
| assert!(ns == MacroNS); |
| let binding = (Res::NonMacroAttr(NonMacroAttrKind::Custom), |
| ty::Visibility::Public, orig_ident.span, ExpnId::root()) |
| .to_name_binding(self.arenas); |
| Ok(binding) |
| } else { |
| Err(determinacy) |
| } |
| } |
| |
| crate fn finalize_macro_resolutions(&mut self) { |
| let check_consistency = |this: &mut Self, path: &[Segment], span, kind: MacroKind, |
| initial_res: Option<Res>, res: Res| { |
| if let Some(initial_res) = initial_res { |
| if res != initial_res && res != Res::Err && this.ambiguity_errors.is_empty() { |
| // Make sure compilation does not succeed if preferred macro resolution |
| // has changed after the macro had been expanded. In theory all such |
| // situations should be reported as ambiguity errors, so this is a bug. |
| if initial_res == Res::NonMacroAttr(NonMacroAttrKind::Custom) { |
| // Yeah, legacy custom attributes are implemented using forced resolution |
| // (which is a best effort error recovery tool, basically), so we can't |
| // promise their resolution won't change later. |
| let msg = format!("inconsistent resolution for a macro: first {}, then {}", |
| initial_res.descr(), res.descr()); |
| this.session.span_err(span, &msg); |
| } else { |
| span_bug!(span, "inconsistent resolution for a macro"); |
| } |
| } |
| } else { |
| // It's possible that the macro was unresolved (indeterminate) and silently |
| // expanded into a dummy fragment for recovery during expansion. |
| // Now, post-expansion, the resolution may succeed, but we can't change the |
| // past and need to report an error. |
| // However, non-speculative `resolve_path` can successfully return private items |
| // even if speculative `resolve_path` returned nothing previously, so we skip this |
| // less informative error if the privacy error is reported elsewhere. |
| if this.privacy_errors.is_empty() { |
| let msg = format!("cannot determine resolution for the {} `{}`", |
| kind.descr(), Segment::names_to_string(path)); |
| let msg_note = "import resolution is stuck, try simplifying macro imports"; |
| this.session.struct_span_err(span, &msg).note(msg_note).emit(); |
| } |
| } |
| }; |
| |
| let macro_resolutions = mem::take(&mut self.multi_segment_macro_resolutions); |
| for (mut path, path_span, kind, parent_scope, initial_res) in macro_resolutions { |
| // FIXME: Path resolution will ICE if segment IDs present. |
| for seg in &mut path { seg.id = None; } |
| match self.resolve_path( |
| &path, Some(MacroNS), &parent_scope, true, path_span, CrateLint::No |
| ) { |
| PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 => { |
| let res = path_res.base_res(); |
| check_consistency(self, &path, path_span, kind, initial_res, res); |
| } |
| path_res @ PathResult::NonModule(..) | path_res @ PathResult::Failed { .. } => { |
| let (span, label) = if let PathResult::Failed { span, label, .. } = path_res { |
| (span, label) |
| } else { |
| (path_span, format!("partially resolved path in {} {}", |
| kind.article(), kind.descr())) |
| }; |
| self.report_error(span, ResolutionError::FailedToResolve { |
| label, |
| suggestion: None |
| }); |
| } |
| PathResult::Module(..) | PathResult::Indeterminate => unreachable!(), |
| } |
| } |
| |
| let macro_resolutions = mem::take(&mut self.single_segment_macro_resolutions); |
| for (ident, kind, parent_scope, initial_binding) in macro_resolutions { |
| match self.early_resolve_ident_in_lexical_scope(ident, ScopeSet::Macro(kind), |
| &parent_scope, true, true, ident.span) { |
| Ok(binding) => { |
| let initial_res = initial_binding.map(|initial_binding| { |
| self.record_use(ident, MacroNS, initial_binding, false); |
| initial_binding.res() |
| }); |
| let res = binding.res(); |
| let seg = Segment::from_ident(ident); |
| check_consistency(self, &[seg], ident.span, kind, initial_res, res); |
| } |
| Err(..) => { |
| assert!(initial_binding.is_none()); |
| let bang = if kind == MacroKind::Bang { "!" } else { "" }; |
| let msg = |
| format!("cannot find {} `{}{}` in this scope", kind.descr(), ident, bang); |
| let mut err = self.session.struct_span_err(ident.span, &msg); |
| self.unresolved_macro_suggestions(&mut err, kind, &parent_scope, ident); |
| err.emit(); |
| } |
| } |
| } |
| |
| let builtin_attrs = mem::take(&mut self.builtin_attrs); |
| for (ident, parent_scope) in builtin_attrs { |
| let _ = self.early_resolve_ident_in_lexical_scope( |
| ident, ScopeSet::Macro(MacroKind::Attr), &parent_scope, true, true, ident.span |
| ); |
| } |
| } |
| |
| fn check_stability_and_deprecation(&self, ext: &SyntaxExtension, path: &ast::Path) { |
| let span = path.span; |
| if let Some(stability) = &ext.stability { |
| if let StabilityLevel::Unstable { reason, issue } = stability.level { |
| let feature = stability.feature; |
| if !self.active_features.contains(&feature) && !span.allows_unstable(feature) { |
| stability::report_unstable(self.session, feature, reason, issue, span); |
| } |
| } |
| if let Some(depr) = &stability.rustc_depr { |
| let (message, lint) = stability::rustc_deprecation_message(depr, &path.to_string()); |
| stability::early_report_deprecation( |
| self.session, &message, depr.suggestion, lint, span |
| ); |
| } |
| } |
| if let Some(depr) = &ext.deprecation { |
| let (message, lint) = stability::deprecation_message(depr, &path.to_string()); |
| stability::early_report_deprecation(self.session, &message, None, lint, span); |
| } |
| } |
| |
| fn prohibit_imported_non_macro_attrs(&self, binding: Option<&'a NameBinding<'a>>, |
| res: Option<Res>, span: Span) { |
| if let Some(Res::NonMacroAttr(kind)) = res { |
| if kind != NonMacroAttrKind::Tool && binding.map_or(true, |b| b.is_import()) { |
| let msg = format!("cannot use a {} through an import", kind.descr()); |
| let mut err = self.session.struct_span_err(span, &msg); |
| if let Some(binding) = binding { |
| err.span_note(binding.span, &format!("the {} imported here", kind.descr())); |
| } |
| err.emit(); |
| } |
| } |
| } |
| |
| crate fn check_reserved_macro_name(&mut self, ident: Ident, res: Res) { |
| // Reserve some names that are not quite covered by the general check |
| // performed on `Resolver::builtin_attrs`. |
| if ident.name == sym::cfg || ident.name == sym::cfg_attr || ident.name == sym::derive { |
| let macro_kind = self.get_macro(res).map(|ext| ext.macro_kind()); |
| if macro_kind.is_some() && sub_namespace_match(macro_kind, Some(MacroKind::Attr)) { |
| self.session.span_err( |
| ident.span, &format!("name `{}` is reserved in attribute namespace", ident) |
| ); |
| } |
| } |
| } |
| |
| /// Compile the macro into a `SyntaxExtension` and possibly replace it with a pre-defined |
| /// extension partially or entirely for built-in macros and legacy plugin macros. |
| crate fn compile_macro(&mut self, item: &ast::Item, edition: Edition) -> Lrc<SyntaxExtension> { |
| let mut result = macro_rules::compile( |
| &self.session.parse_sess, self.session.features_untracked(), item, edition |
| ); |
| |
| if result.is_builtin { |
| // The macro was marked with `#[rustc_builtin_macro]`. |
| if let Some(ext) = self.builtin_macros.remove(&item.ident.name) { |
| if ext.is_builtin { |
| // The macro is a built-in, replace only the expander function. |
| result.kind = ext.kind; |
| } else { |
| // The macro is from a plugin, the in-source definition is dummy, |
| // take all the data from the resolver. |
| result = ext; |
| } |
| } else { |
| let msg = format!("cannot find a built-in macro with name `{}`", item.ident); |
| self.session.span_err(item.span, &msg); |
| } |
| } |
| |
| Lrc::new(result) |
| } |
| } |
