| //! A bunch of methods and structures more or less related to resolving macros and |
| //! interface provided by `Resolver` to macro expander. |
| |
| use crate::imports::ImportResolver; |
| use crate::Namespace::*; |
| use crate::{AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BuiltinMacroState, Determinacy}; |
| use crate::{CrateLint, DeriveData, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Weak}; |
| use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment, ToNameBinding}; |
| use rustc_ast::{self as ast, Inline, ItemKind, ModKind, NodeId}; |
| use rustc_ast_lowering::ResolverAstLowering; |
| use rustc_ast_pretty::pprust; |
| use rustc_attr::StabilityLevel; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_data_structures::ptr_key::PtrKey; |
| use rustc_data_structures::sync::Lrc; |
| use rustc_errors::struct_span_err; |
| use rustc_expand::base::{Annotatable, DeriveResolutions, Indeterminate, ResolverExpand}; |
| use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind}; |
| use rustc_expand::compile_declarative_macro; |
| use rustc_expand::expand::{AstFragment, Invocation, InvocationKind, SupportsMacroExpansion}; |
| use rustc_feature::is_builtin_attr_name; |
| use rustc_hir::def::{self, DefKind, NonMacroAttrKind}; |
| use rustc_hir::def_id::{CrateNum, LocalDefId}; |
| use rustc_hir::PrimTy; |
| use rustc_middle::middle::stability; |
| use rustc_middle::ty; |
| use rustc_session::lint::builtin::{LEGACY_DERIVE_HELPERS, PROC_MACRO_DERIVE_RESOLUTION_FALLBACK}; |
| use rustc_session::lint::builtin::{SOFT_UNSTABLE, UNUSED_MACROS}; |
| use rustc_session::lint::BuiltinLintDiagnostics; |
| use rustc_session::parse::feature_err; |
| use rustc_session::Session; |
| use rustc_span::edition::Edition; |
| use rustc_span::hygiene::{self, ExpnData, ExpnKind, LocalExpnId}; |
| use rustc_span::hygiene::{AstPass, MacroKind}; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::{Span, DUMMY_SP}; |
| use std::cell::Cell; |
| use std::{mem, ptr}; |
| |
| type Res = def::Res<NodeId>; |
| |
| /// Binding produced by a `macro_rules` item. |
| /// Not modularized, can shadow previous `macro_rules` bindings, etc. |
| #[derive(Debug)] |
| pub struct MacroRulesBinding<'a> { |
| crate binding: &'a NameBinding<'a>, |
| /// `macro_rules` scope into which the `macro_rules` item was planted. |
| crate parent_macro_rules_scope: MacroRulesScopeRef<'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 `macro_rules` scopes too because they |
| /// can potentially expand into macro definitions. |
| #[derive(Copy, Clone, Debug)] |
| pub enum MacroRulesScope<'a> { |
| /// Empty "root" scope at the crate start containing no names. |
| Empty, |
| /// The scope introduced by a `macro_rules!` macro definition. |
| Binding(&'a MacroRulesBinding<'a>), |
| /// The scope introduced by a macro invocation that can potentially |
| /// create a `macro_rules!` macro definition. |
| Invocation(LocalExpnId), |
| } |
| |
| /// `macro_rules!` scopes are always kept by reference and inside a cell. |
| /// The reason is that we update scopes with value `MacroRulesScope::Invocation(invoc_id)` |
| /// in-place after `invoc_id` gets expanded. |
| /// This helps to avoid uncontrollable growth of `macro_rules!` scope chains, |
| /// which usually grow lineraly with the number of macro invocations |
| /// in a module (including derives) and hurt performance. |
| pub(crate) type MacroRulesScopeRef<'a> = PtrKey<'a, Cell<MacroRulesScope<'a>>>; |
| |
| // 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 { |
| 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) |
| } |
| } |
| |
| /// The code common between processing `#![register_tool]` and `#![register_attr]`. |
| fn registered_idents( |
| sess: &Session, |
| attrs: &[ast::Attribute], |
| attr_name: Symbol, |
| descr: &str, |
| ) -> FxHashSet<Ident> { |
| let mut registered = FxHashSet::default(); |
| for attr in sess.filter_by_name(attrs, attr_name) { |
| for nested_meta in attr.meta_item_list().unwrap_or_default() { |
| match nested_meta.ident() { |
| Some(ident) => { |
| if let Some(old_ident) = registered.replace(ident) { |
| let msg = format!("{} `{}` was already registered", descr, ident); |
| sess.struct_span_err(ident.span, &msg) |
| .span_label(old_ident.span, "already registered here") |
| .emit(); |
| } |
| } |
| None => { |
| let msg = format!("`{}` only accepts identifiers", attr_name); |
| let span = nested_meta.span(); |
| sess.struct_span_err(span, &msg).span_label(span, "not an identifier").emit(); |
| } |
| } |
| } |
| } |
| registered |
| } |
| |
| crate fn registered_attrs_and_tools( |
| sess: &Session, |
| attrs: &[ast::Attribute], |
| ) -> (FxHashSet<Ident>, FxHashSet<Ident>) { |
| let registered_attrs = registered_idents(sess, attrs, sym::register_attr, "attribute"); |
| let mut registered_tools = registered_idents(sess, attrs, sym::register_tool, "tool"); |
| // We implicitly add `rustfmt` and `clippy` to known tools, |
| // but it's not an error to register them explicitly. |
| let predefined_tools = [sym::clippy, sym::rustfmt]; |
| registered_tools.extend(predefined_tools.iter().cloned().map(Ident::with_dummy_span)); |
| (registered_attrs, registered_tools) |
| } |
| |
| // Some feature gates for inner attributes are reported as lints for backward compatibility. |
| fn soft_custom_inner_attributes_gate(path: &ast::Path, invoc: &Invocation) -> bool { |
| match &path.segments[..] { |
| // `#![test]` |
| [seg] if seg.ident.name == sym::test => return true, |
| // `#![rustfmt::skip]` on out-of-line modules |
| [seg1, seg2] if seg1.ident.name == sym::rustfmt && seg2.ident.name == sym::skip => { |
| if let InvocationKind::Attr { item, .. } = &invoc.kind { |
| if let Annotatable::Item(item) = item { |
| if let ItemKind::Mod(_, ModKind::Loaded(_, Inline::No, _)) = item.kind { |
| return true; |
| } |
| } |
| } |
| } |
| _ => {} |
| } |
| false |
| } |
| |
| impl<'a> ResolverExpand for Resolver<'a> { |
| fn next_node_id(&mut self) -> NodeId { |
| self.next_node_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::Empty => name, |
| _ => kw::Crate, |
| } |
| }); |
| } |
| |
| fn visit_ast_fragment_with_placeholders( |
| &mut self, |
| expansion: LocalExpnId, |
| fragment: &AstFragment, |
| ) { |
| // Integrate the new AST fragment into all the definition and module structures. |
| // 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 output_macro_rules_scope = self.build_reduced_graph(fragment, parent_scope); |
| self.output_macro_rules_scopes.insert(expansion, output_macro_rules_scope); |
| |
| parent_scope.module.unexpanded_invocations.borrow_mut().remove(&expansion); |
| } |
| |
| fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind) { |
| if self.builtin_macros.insert(name, BuiltinMacroState::NotYetSeen(ext)).is_some() { |
| self.session |
| .diagnostic() |
| .bug(&format!("built-in macro `{}` was already registered", name)); |
| } |
| } |
| |
| // Create a new Expansion with a definition site of the provided module, or |
| // a fake empty `#[no_implicit_prelude]` module if no module is provided. |
| fn expansion_for_ast_pass( |
| &mut self, |
| call_site: Span, |
| pass: AstPass, |
| features: &[Symbol], |
| parent_module_id: Option<NodeId>, |
| ) -> LocalExpnId { |
| let parent_module = parent_module_id.map(|module_id| self.local_def_id(module_id)); |
| let expn_id = LocalExpnId::fresh( |
| ExpnData::allow_unstable( |
| ExpnKind::AstPass(pass), |
| call_site, |
| self.session.edition(), |
| features.into(), |
| None, |
| parent_module.map(LocalDefId::to_def_id), |
| ), |
| self.create_stable_hashing_context(), |
| ); |
| |
| let parent_scope = parent_module |
| .map_or(self.empty_module, |parent_def_id| self.module_map[&parent_def_id]); |
| self.ast_transform_scopes.insert(expn_id, parent_scope); |
| |
| expn_id |
| } |
| |
| fn resolve_imports(&mut self) { |
| ImportResolver { r: self }.resolve_imports() |
| } |
| |
| fn resolve_macro_invocation( |
| &mut self, |
| invoc: &Invocation, |
| eager_expansion_root: LocalExpnId, |
| force: bool, |
| ) -> Result<Lrc<SyntaxExtension>, Indeterminate> { |
| let invoc_id = invoc.expansion_data.id; |
| let parent_scope = match self.invocation_parent_scopes.get(&invoc_id) { |
| Some(parent_scope) => *parent_scope, |
| None => { |
| // If there's no entry in the table, then we are resolving an eagerly expanded |
| // macro, which should inherit its parent scope from its eager expansion root - |
| // the macro that requested this eager expansion. |
| let parent_scope = *self |
| .invocation_parent_scopes |
| .get(&eager_expansion_root) |
| .expect("non-eager expansion without a parent scope"); |
| self.invocation_parent_scopes.insert(invoc_id, parent_scope); |
| parent_scope |
| } |
| }; |
| |
| let (path, kind, inner_attr, derives) = match invoc.kind { |
| InvocationKind::Attr { ref attr, ref derives, .. } => ( |
| &attr.get_normal_item().path, |
| MacroKind::Attr, |
| attr.style == ast::AttrStyle::Inner, |
| self.arenas.alloc_ast_paths(derives), |
| ), |
| InvocationKind::Bang { ref mac, .. } => (&mac.path, MacroKind::Bang, false, &[][..]), |
| InvocationKind::Derive { ref path, .. } => (path, MacroKind::Derive, false, &[][..]), |
| }; |
| |
| // Derives are not included when `invocations` are collected, so we have to add them here. |
| let parent_scope = &ParentScope { derives, ..parent_scope }; |
| let supports_macro_expansion = invoc.fragment_kind.supports_macro_expansion(); |
| let node_id = invoc.expansion_data.lint_node_id; |
| let (ext, res) = self.smart_resolve_macro_path( |
| path, |
| kind, |
| supports_macro_expansion, |
| inner_attr, |
| parent_scope, |
| node_id, |
| force, |
| soft_custom_inner_attributes_gate(path, invoc), |
| )?; |
| |
| let span = invoc.span(); |
| invoc_id.set_expn_data( |
| ext.expn_data( |
| parent_scope.expansion, |
| span, |
| fast_print_path(path), |
| res.opt_def_id(), |
| res.opt_def_id().map(|macro_def_id| { |
| self.macro_def_scope_from_def_id(macro_def_id).nearest_parent_mod |
| }), |
| ), |
| self.create_stable_hashing_context(), |
| ); |
| |
| if let Res::Def(_, _) = res { |
| // Gate macro attributes in `#[derive]` output. |
| if !self.session.features_untracked().macro_attributes_in_derive_output |
| && kind == MacroKind::Attr |
| && ext.builtin_name != Some(sym::derive) |
| { |
| let mut expn_id = parent_scope.expansion; |
| loop { |
| // Helper attr table is a quick way to determine whether the attr is `derive`. |
| if self.helper_attrs.contains_key(&expn_id) { |
| feature_err( |
| &self.session.parse_sess, |
| sym::macro_attributes_in_derive_output, |
| path.span, |
| "macro attributes in `#[derive]` output are unstable", |
| ) |
| .emit(); |
| break; |
| } else { |
| let expn_data = expn_id.expn_data(); |
| match expn_data.kind { |
| ExpnKind::Root |
| | ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => { |
| break; |
| } |
| _ => expn_id = expn_data.parent.expect_local(), |
| } |
| } |
| } |
| } |
| } |
| |
| Ok(ext) |
| } |
| |
| fn check_unused_macros(&mut self) { |
| for (_, &(node_id, span)) in self.unused_macros.iter() { |
| self.lint_buffer.buffer_lint(UNUSED_MACROS, node_id, span, "unused macro definition"); |
| } |
| } |
| |
| fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool { |
| self.containers_deriving_copy.contains(&expn_id) |
| } |
| |
| fn resolve_derives( |
| &mut self, |
| expn_id: LocalExpnId, |
| force: bool, |
| derive_paths: &dyn Fn() -> DeriveResolutions, |
| ) -> Result<(), Indeterminate> { |
| // Block expansion of the container until we resolve all derives in it. |
| // This is required for two reasons: |
| // - Derive helper attributes are in scope for the item to which the `#[derive]` |
| // is applied, so they have to be produced by the container's expansion rather |
| // than by individual derives. |
| // - Derives in the container need to know whether one of them is a built-in `Copy`. |
| // Temporarily take the data to avoid borrow checker conflicts. |
| let mut derive_data = mem::take(&mut self.derive_data); |
| let entry = derive_data.entry(expn_id).or_insert_with(|| DeriveData { |
| resolutions: derive_paths(), |
| helper_attrs: Vec::new(), |
| has_derive_copy: false, |
| }); |
| let parent_scope = self.invocation_parent_scopes[&expn_id]; |
| for (i, (path, _, opt_ext)) in entry.resolutions.iter_mut().enumerate() { |
| if opt_ext.is_none() { |
| *opt_ext = Some( |
| match self.resolve_macro_path( |
| &path, |
| Some(MacroKind::Derive), |
| &parent_scope, |
| true, |
| force, |
| ) { |
| Ok((Some(ext), _)) => { |
| if !ext.helper_attrs.is_empty() { |
| let last_seg = path.segments.last().unwrap(); |
| let span = last_seg.ident.span.normalize_to_macros_2_0(); |
| entry.helper_attrs.extend( |
| ext.helper_attrs |
| .iter() |
| .map(|name| (i, Ident::new(*name, span))), |
| ); |
| } |
| entry.has_derive_copy |= ext.builtin_name == Some(sym::Copy); |
| ext |
| } |
| Ok(_) | Err(Determinacy::Determined) => self.dummy_ext(MacroKind::Derive), |
| Err(Determinacy::Undetermined) => { |
| assert!(self.derive_data.is_empty()); |
| self.derive_data = derive_data; |
| return Err(Indeterminate); |
| } |
| }, |
| ); |
| } |
| } |
| // Sort helpers in a stable way independent from the derive resolution order. |
| entry.helper_attrs.sort_by_key(|(i, _)| *i); |
| self.helper_attrs |
| .insert(expn_id, entry.helper_attrs.iter().map(|(_, ident)| *ident).collect()); |
| // Mark this derive as having `Copy` either if it has `Copy` itself or if its parent derive |
| // has `Copy`, to support cases like `#[derive(Clone, Copy)] #[derive(Debug)]`. |
| if entry.has_derive_copy || self.has_derive_copy(parent_scope.expansion) { |
| self.containers_deriving_copy.insert(expn_id); |
| } |
| assert!(self.derive_data.is_empty()); |
| self.derive_data = derive_data; |
| Ok(()) |
| } |
| |
| fn take_derive_resolutions(&mut self, expn_id: LocalExpnId) -> Option<DeriveResolutions> { |
| self.derive_data.remove(&expn_id).map(|data| data.resolutions) |
| } |
| |
| // The function that implements the resolution logic of `#[cfg_accessible(path)]`. |
| // Returns true if the path can certainly be resolved in one of three namespaces, |
| // returns false if the path certainly cannot be resolved in any of the three namespaces. |
| // Returns `Indeterminate` if we cannot give a certain answer yet. |
| fn cfg_accessible( |
| &mut self, |
| expn_id: LocalExpnId, |
| path: &ast::Path, |
| ) -> Result<bool, Indeterminate> { |
| let span = path.span; |
| let path = &Segment::from_path(path); |
| let parent_scope = self.invocation_parent_scopes[&expn_id]; |
| |
| let mut indeterminate = false; |
| for ns in [TypeNS, ValueNS, MacroNS].iter().copied() { |
| match self.resolve_path(path, Some(ns), &parent_scope, false, span, CrateLint::No) { |
| PathResult::Module(ModuleOrUniformRoot::Module(_)) => return Ok(true), |
| PathResult::NonModule(partial_res) if partial_res.unresolved_segments() == 0 => { |
| return Ok(true); |
| } |
| PathResult::Indeterminate => indeterminate = true, |
| // FIXME: `resolve_path` is not ready to report partially resolved paths |
| // correctly, so we just report an error if the path was reported as unresolved. |
| // This needs to be fixed for `cfg_accessible` to be useful. |
| PathResult::NonModule(..) | PathResult::Failed { .. } => {} |
| PathResult::Module(_) => panic!("unexpected path resolution"), |
| } |
| } |
| |
| if indeterminate { |
| return Err(Indeterminate); |
| } |
| |
| self.session |
| .struct_span_err(span, "not sure whether the path is accessible or not") |
| .span_note(span, "`cfg_accessible` is not fully implemented") |
| .emit(); |
| Ok(false) |
| } |
| |
| fn get_proc_macro_quoted_span(&self, krate: CrateNum, id: usize) -> Span { |
| self.crate_loader.cstore().get_proc_macro_quoted_span_untracked(krate, id, self.session) |
| } |
| } |
| |
| impl<'a> Resolver<'a> { |
| /// Resolve macro path with error reporting and recovery. |
| /// Uses dummy syntax extensions for unresolved macros or macros with unexpected resolutions |
| /// for better error recovery. |
| fn smart_resolve_macro_path( |
| &mut self, |
| path: &ast::Path, |
| kind: MacroKind, |
| supports_macro_expansion: SupportsMacroExpansion, |
| inner_attr: bool, |
| parent_scope: &ParentScope<'a>, |
| node_id: NodeId, |
| force: bool, |
| soft_custom_inner_attributes_gate: 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), |
| 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 for the resolved macro. |
| 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 && segment.ident.as_str().starts_with("rustc") { |
| self.session.span_err( |
| segment.ident.span, |
| "attributes starting with `rustc` are reserved for use by the `rustc` compiler", |
| ); |
| } |
| } |
| |
| match res { |
| Res::Def(DefKind::Macro(_), def_id) => { |
| if let Some(def_id) = def_id.as_local() { |
| self.unused_macros.remove(&def_id); |
| if self.proc_macro_stubs.contains(&def_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, node_id); |
| |
| let unexpected_res = if ext.macro_kind() != kind { |
| Some((kind.article(), kind.descr_expected())) |
| } else if matches!(res, Res::Def(..)) { |
| match supports_macro_expansion { |
| SupportsMacroExpansion::No => Some(("a", "non-macro attribute")), |
| SupportsMacroExpansion::Yes { supports_inner_attrs } => { |
| if inner_attr && !supports_inner_attrs { |
| Some(("a", "non-macro inner attribute")) |
| } else { |
| None |
| } |
| } |
| } |
| } else { |
| None |
| }; |
| if let Some((article, expected)) = unexpected_res { |
| let path_str = pprust::path_to_string(path); |
| let msg = format!("expected {}, found {} `{}`", expected, res.descr(), path_str); |
| self.session |
| .struct_span_err(path.span, &msg) |
| .span_label(path.span, format!("not {} {}", article, expected)) |
| .emit(); |
| return Ok((self.dummy_ext(kind), Res::Err)); |
| } |
| |
| // We are trying to avoid reporting this error if other related errors were reported. |
| if res != Res::Err |
| && inner_attr |
| && !self.session.features_untracked().custom_inner_attributes |
| { |
| let msg = match res { |
| Res::Def(..) => "inner macro attributes are unstable", |
| Res::NonMacroAttr(..) => "custom inner attributes are unstable", |
| _ => unreachable!(), |
| }; |
| if soft_custom_inner_attributes_gate { |
| self.session.parse_sess.buffer_lint(SOFT_UNSTABLE, path.span, node_id, msg); |
| } else { |
| feature_err(&self.session.parse_sess, sym::custom_inner_attributes, path.span, msg) |
| .emit(); |
| } |
| } |
| |
| Ok((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<'a>, |
| 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 MISC_SUGGEST_CRATE = 1 << 2; |
| const MISC_SUGGEST_SELF = 1 << 3; |
| const MISC_FROM_PRELUDE = 1 << 4; |
| } |
| } |
| |
| 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), |
| ScopeSet::Late(ns, ..) => (ns, None, 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.span.ctxt(), |
| |this, scope, use_prelude, ctxt| { |
| let ident = Ident::new(orig_ident.name, orig_ident.span.with_ctxt(ctxt)); |
| let ok = |res, span, arenas| { |
| Ok(( |
| (res, ty::Visibility::Public, span, LocalExpnId::ROOT) |
| .to_name_binding(arenas), |
| Flags::empty(), |
| )) |
| }; |
| let result = match scope { |
| Scope::DeriveHelpers(expn_id) => { |
| if let Some(attr) = this |
| .helper_attrs |
| .get(&expn_id) |
| .and_then(|attrs| attrs.iter().rfind(|i| ident == **i)) |
| { |
| let binding = ( |
| Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper), |
| ty::Visibility::Public, |
| attr.span, |
| expn_id, |
| ) |
| .to_name_binding(this.arenas); |
| Ok((binding, Flags::empty())) |
| } else { |
| Err(Determinacy::Determined) |
| } |
| } |
| Scope::DeriveHelpersCompat => { |
| 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) { |
| result = ok( |
| Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat), |
| derive.span, |
| this.arenas, |
| ); |
| break; |
| } |
| } |
| Ok(_) | Err(Determinacy::Determined) => {} |
| Err(Determinacy::Undetermined) => { |
| result = Err(Determinacy::Undetermined) |
| } |
| } |
| } |
| result |
| } |
| Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() { |
| MacroRulesScope::Binding(macro_rules_binding) |
| if ident == macro_rules_binding.ident => |
| { |
| Ok((macro_rules_binding.binding, Flags::MACRO_RULES)) |
| } |
| MacroRulesScope::Invocation(_) => 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, derive_fallback_lint_id) => { |
| 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, |
| !matches!(scope_set, ScopeSet::Late(..)), |
| record_used, |
| path_span, |
| ); |
| match binding { |
| Ok(binding) => { |
| if let Some(lint_id) = derive_fallback_lint_id { |
| this.lint_buffer.buffer_lint_with_diagnostic( |
| PROC_MACRO_DERIVE_RESOLUTION_FALLBACK, |
| lint_id, |
| orig_ident.span, |
| &format!( |
| "cannot find {} `{}` in this scope", |
| ns.descr(), |
| ident |
| ), |
| BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback( |
| orig_ident.span, |
| ), |
| ); |
| } |
| 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::RegisteredAttrs => match this.registered_attrs.get(&ident).cloned() { |
| Some(ident) => ok( |
| Res::NonMacroAttr(NonMacroAttrKind::Registered), |
| ident.span, |
| this.arenas, |
| ), |
| None => Err(Determinacy::Determined), |
| }, |
| Scope::MacroUsePrelude => { |
| match this.macro_use_prelude.get(&ident.name).cloned() { |
| Some(binding) => Ok((binding, Flags::MISC_FROM_PRELUDE)), |
| None => Err(Determinacy::determined( |
| this.graph_root.unexpanded_invocations.borrow().is_empty(), |
| )), |
| } |
| } |
| Scope::BuiltinAttrs => { |
| if is_builtin_attr_name(ident.name) { |
| ok( |
| Res::NonMacroAttr(NonMacroAttrKind::Builtin(ident.name)), |
| DUMMY_SP, |
| this.arenas, |
| ) |
| } else { |
| Err(Determinacy::Determined) |
| } |
| } |
| Scope::ExternPrelude => match this.extern_prelude_get(ident, !record_used) { |
| Some(binding) => Ok((binding, Flags::empty())), |
| None => Err(Determinacy::determined( |
| this.graph_root.unexpanded_invocations.borrow().is_empty(), |
| )), |
| }, |
| Scope::ToolPrelude => match this.registered_tools.get(&ident).cloned() { |
| Some(ident) => ok(Res::ToolMod, ident.span, this.arenas), |
| None => 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::MISC_FROM_PRELUDE)); |
| } |
| } |
| } |
| result |
| } |
| Scope::BuiltinTypes => match PrimTy::from_name(ident.name) { |
| Some(prim_ty) => ok(Res::PrimTy(prim_ty), DUMMY_SP, this.arenas), |
| None => Err(Determinacy::Determined), |
| }, |
| }; |
| |
| match result { |
| Ok((binding, flags)) |
| if sub_namespace_match(binding.macro_kind(), macro_kind) => |
| { |
| if !record_used || matches!(scope_set, ScopeSet::Late(..)) { |
| 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 is_builtin = |res| { |
| matches!(res, Res::NonMacroAttr(NonMacroAttrKind::Builtin(..))) |
| }; |
| let derive_helper = |
| Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper); |
| let derive_helper_compat = |
| Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat); |
| |
| let ambiguity_error_kind = if is_import { |
| Some(AmbiguityKind::Import) |
| } else if is_builtin(innermost_res) || is_builtin(res) { |
| Some(AmbiguityKind::BuiltinAttr) |
| } else if innermost_res == derive_helper_compat |
| || res == derive_helper_compat && innermost_res != derive_helper |
| { |
| Some(AmbiguityKind::DeriveHelper) |
| } else if innermost_flags.contains(Flags::MACRO_RULES) |
| && flags.contains(Flags::MODULE) |
| && !this.disambiguate_macro_rules_vs_modularized( |
| innermost_binding, |
| binding, |
| ) |
| || flags.contains(Flags::MACRO_RULES) |
| && innermost_flags.contains(Flags::MODULE) |
| && !this.disambiguate_macro_rules_vs_modularized( |
| binding, |
| innermost_binding, |
| ) |
| { |
| Some(AmbiguityKind::MacroRulesVsModularized) |
| } 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); |
| } |
| |
| Err(Determinacy::determined(determinacy == Determinacy::Determined || force)) |
| } |
| |
| 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 { |
| // 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 errors, so this is a bug. |
| this.session.delay_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); |
| if res == Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat) { |
| let node_id = self |
| .invocation_parents |
| .get(&parent_scope.expansion) |
| .map_or(ast::CRATE_NODE_ID, |id| self.def_id_to_node_id[id.0]); |
| self.lint_buffer.buffer_lint_with_diagnostic( |
| LEGACY_DERIVE_HELPERS, |
| node_id, |
| ident.span, |
| "derive helper attribute is used before it is introduced", |
| BuiltinLintDiagnostics::LegacyDeriveHelpers(binding.span), |
| ); |
| } |
| } |
| Err(..) => { |
| let expected = kind.descr_expected(); |
| let msg = format!("cannot find {} `{}` in this scope", expected, ident); |
| 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( |
| &mut self, |
| ext: &SyntaxExtension, |
| path: &ast::Path, |
| node_id: NodeId, |
| ) { |
| let span = path.span; |
| if let Some(stability) = &ext.stability { |
| if let StabilityLevel::Unstable { reason, issue, is_soft } = stability.level { |
| let feature = stability.feature; |
| if !self.active_features.contains(&feature) && !span.allows_unstable(feature) { |
| let lint_buffer = &mut self.lint_buffer; |
| let soft_handler = |
| |lint, span, msg: &_| lint_buffer.buffer_lint(lint, node_id, span, msg); |
| stability::report_unstable( |
| self.session, |
| feature, |
| reason, |
| issue, |
| is_soft, |
| span, |
| soft_handler, |
| ); |
| } |
| } |
| } |
| if let Some(depr) = &ext.deprecation { |
| let path = pprust::path_to_string(&path); |
| let (message, lint) = stability::deprecation_message(depr, "macro", &path); |
| stability::early_report_deprecation( |
| &mut self.lint_buffer, |
| &message, |
| depr.suggestion, |
| lint, |
| span, |
| node_id, |
| ); |
| } |
| } |
| |
| 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 {} {} through an import", kind.article(), 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 { |
| 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 |
| /// its expander to a pre-defined one for built-in macros. |
| crate fn compile_macro(&mut self, item: &ast::Item, edition: Edition) -> SyntaxExtension { |
| let mut result = compile_declarative_macro( |
| &self.session, |
| self.session.features_untracked(), |
| item, |
| edition, |
| ); |
| |
| if let Some(builtin_name) = result.builtin_name { |
| // The macro was marked with `#[rustc_builtin_macro]`. |
| if let Some(builtin_macro) = self.builtin_macros.get_mut(&builtin_name) { |
| // The macro is a built-in, replace its expander function |
| // while still taking everything else from the source code. |
| // If we already loaded this builtin macro, give a better error message than 'no such builtin macro'. |
| match mem::replace(builtin_macro, BuiltinMacroState::AlreadySeen(item.span)) { |
| BuiltinMacroState::NotYetSeen(ext) => result.kind = ext, |
| BuiltinMacroState::AlreadySeen(span) => { |
| struct_span_err!( |
| self.session, |
| item.span, |
| E0773, |
| "attempted to define built-in macro more than once" |
| ) |
| .span_note(span, "previously defined here") |
| .emit(); |
| } |
| } |
| } else { |
| let msg = format!("cannot find a built-in macro with name `{}`", item.ident); |
| self.session.span_err(item.span, &msg); |
| } |
| } |
| |
| result |
| } |
| } |
