//! A bunch of methods and structures more or less related to resolving macros and //! interface provided by `Resolver` to macro expander. use std::cell::Cell; use std::mem; use std::sync::Arc; use rustc_ast::expand::StrippedCfgItem; use rustc_ast::{self as ast, Crate, NodeId, attr}; use rustc_ast_pretty::pprust; use rustc_attr_parsing::StabilityLevel; use rustc_data_structures::intern::Interned; use rustc_errors::{Applicability, StashKey}; use rustc_expand::base::{ DeriveResolution, Indeterminate, ResolverExpand, SyntaxExtension, SyntaxExtensionKind, }; use rustc_expand::compile_declarative_macro; use rustc_expand::expand::{ AstFragment, AstFragmentKind, Invocation, InvocationKind, SupportsMacroExpansion, }; use rustc_hir::def::{self, DefKind, Namespace, NonMacroAttrKind}; use rustc_hir::def_id::{CrateNum, DefId, LocalDefId}; use rustc_middle::middle::stability; use rustc_middle::ty::{RegisteredTools, TyCtxt, Visibility}; use rustc_session::lint::BuiltinLintDiag; use rustc_session::lint::builtin::{ LEGACY_DERIVE_HELPERS, OUT_OF_SCOPE_MACRO_CALLS, UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES, UNUSED_MACRO_RULES, UNUSED_MACROS, }; use rustc_session::parse::feature_err; use rustc_span::edit_distance::edit_distance; use rustc_span::edition::Edition; use rustc_span::hygiene::{self, AstPass, ExpnData, ExpnKind, LocalExpnId, MacroKind}; use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym}; use crate::Namespace::*; use crate::errors::{ self, AddAsNonDerive, CannotDetermineMacroResolution, CannotFindIdentInThisScope, MacroExpectedFound, RemoveSurroundingDerive, }; use crate::imports::Import; use crate::{ BindingKey, DeriveData, Determinacy, Finalize, InvocationParent, MacroData, ModuleKind, ModuleOrUniformRoot, NameBinding, NameBindingKind, ParentScope, PathResult, ResolutionError, Resolver, ScopeSet, Segment, ToNameBinding, Used, }; type Res = def::Res; /// Binding produced by a `macro_rules` item. /// Not modularized, can shadow previous `macro_rules` bindings, etc. #[derive(Debug)] pub(crate) struct MacroRulesBinding<'ra> { pub(crate) binding: NameBinding<'ra>, /// `macro_rules` scope into which the `macro_rules` item was planted. pub(crate) parent_macro_rules_scope: MacroRulesScopeRef<'ra>, pub(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(crate) enum MacroRulesScope<'ra> { /// Empty "root" scope at the crate start containing no names. Empty, /// The scope introduced by a `macro_rules!` macro definition. Binding(&'ra MacroRulesBinding<'ra>), /// 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 linearly with the number of macro invocations /// in a module (including derives) and hurt performance. pub(crate) type MacroRulesScopeRef<'ra> = Interned<'ra, Cell>>; /// 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. pub(crate) fn sub_namespace_match( candidate: Option, requirement: Option, ) -> 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 let [segment] = path.segments.as_slice() { segment.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) } } pub(crate) fn registered_tools(tcx: TyCtxt<'_>, (): ()) -> RegisteredTools { let mut registered_tools = RegisteredTools::default(); let (_, pre_configured_attrs) = &*tcx.crate_for_resolver(()).borrow(); for attr in attr::filter_by_name(pre_configured_attrs, sym::register_tool) { for meta_item_inner in attr.meta_item_list().unwrap_or_default() { match meta_item_inner.ident() { Some(ident) => { if let Some(old_ident) = registered_tools.replace(ident) { tcx.dcx().emit_err(errors::ToolWasAlreadyRegistered { span: ident.span, tool: ident, old_ident_span: old_ident.span, }); } } None => { tcx.dcx().emit_err(errors::ToolOnlyAcceptsIdentifiers { span: meta_item_inner.span(), tool: sym::register_tool, }); } } } } // We implicitly add `rustfmt`, `clippy`, `diagnostic`, `miri` and `rust_analyzer` to known // tools, but it's not an error to register them explicitly. let predefined_tools = [sym::clippy, sym::rustfmt, sym::diagnostic, sym::miri, sym::rust_analyzer]; registered_tools.extend(predefined_tools.iter().cloned().map(Ident::with_dummy_span)); registered_tools } impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> { fn next_node_id(&mut self) -> NodeId { self.next_node_id() } fn invocation_parent(&self, id: LocalExpnId) -> LocalDefId { self.invocation_parents[&id].parent_def } 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); if let Some(unexpanded_invocations) = self.impl_unexpanded_invocations.get_mut(&self.invocation_parent(expansion)) { unexpanded_invocations.remove(&expansion); } } fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind) { if self.builtin_macros.insert(name, ext).is_some() { self.dcx().bug(format!("built-in macro `{name}` was already registered")); } } // 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, ) -> LocalExpnId { let parent_module = parent_module_id.map(|module_id| self.local_def_id(module_id).to_def_id()); let expn_id = LocalExpnId::fresh( ExpnData::allow_unstable( ExpnKind::AstPass(pass), call_site, self.tcx.sess.edition(), features.into(), None, parent_module, ), self.create_stable_hashing_context(), ); let parent_scope = parent_module.map_or(self.empty_module, |def_id| self.expect_module(def_id)); self.ast_transform_scopes.insert(expn_id, parent_scope); expn_id } fn resolve_imports(&mut self) { self.resolve_imports() } fn resolve_macro_invocation( &mut self, invoc: &Invocation, eager_expansion_root: LocalExpnId, force: bool, ) -> Result, 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 (mut derives, mut inner_attr, mut deleg_impl) = (&[][..], false, None); let (path, kind) = match invoc.kind { InvocationKind::Attr { ref attr, derives: ref attr_derives, .. } => { derives = self.arenas.alloc_ast_paths(attr_derives); inner_attr = attr.style == ast::AttrStyle::Inner; (&attr.get_normal_item().path, MacroKind::Attr) } InvocationKind::Bang { ref mac, .. } => (&mac.path, MacroKind::Bang), InvocationKind::Derive { ref path, .. } => (path, MacroKind::Derive), InvocationKind::GlobDelegation { ref item } => { let ast::AssocItemKind::DelegationMac(deleg) = &item.kind else { unreachable!() }; deleg_impl = Some(self.invocation_parent(invoc_id)); // It is sufficient to consider glob delegation a bang macro for now. (&deleg.prefix, MacroKind::Bang) } }; // 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; // This is a heuristic, but it's good enough for the lint. let looks_like_invoc_in_mod_inert_attr = self .invocation_parents .get(&invoc_id) .or_else(|| self.invocation_parents.get(&eager_expansion_root)) .filter(|&&InvocationParent { parent_def: mod_def_id, in_attr, .. }| { in_attr && invoc.fragment_kind == AstFragmentKind::Expr && self.tcx.def_kind(mod_def_id) == DefKind::Mod }) .map(|&InvocationParent { parent_def: mod_def_id, .. }| mod_def_id); let (ext, res) = self.smart_resolve_macro_path( path, kind, supports_macro_expansion, inner_attr, parent_scope, node_id, force, deleg_impl, looks_like_invoc_in_mod_inert_attr, )?; let span = invoc.span(); let def_id = if deleg_impl.is_some() { None } else { res.opt_def_id() }; invoc_id.set_expn_data( ext.expn_data( parent_scope.expansion, span, fast_print_path(path), def_id, def_id.map(|def_id| self.macro_def_scope(def_id).nearest_parent_mod()), ), self.create_stable_hashing_context(), ); Ok(ext) } fn record_macro_rule_usage(&mut self, id: NodeId, rule_i: usize) { let did = self.local_def_id(id); if let Some(rules) = self.unused_macro_rules.get_mut(&did) { rules.remove(&rule_i); } } fn check_unused_macros(&mut self) { #[allow(rustc::potential_query_instability)] // FIXME for (_, &(node_id, ident)) in self.unused_macros.iter() { self.lint_buffer.buffer_lint( UNUSED_MACROS, node_id, ident.span, BuiltinLintDiag::UnusedMacroDefinition(ident.name), ); } for (&def_id, unused_arms) in self.unused_macro_rules.iter() { for (&arm_i, &(ident, rule_span)) in unused_arms.to_sorted_stable_ord() { if self.unused_macros.contains_key(&def_id) { // We already lint the entire macro as unused continue; } let node_id = self.def_id_to_node_id[def_id]; self.lint_buffer.buffer_lint( UNUSED_MACRO_RULES, node_id, rule_span, BuiltinLintDiag::MacroRuleNeverUsed(arm_i, ident.name), ); } } } 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() -> Vec, ) -> 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, resolution) in entry.resolutions.iter_mut().enumerate() { if resolution.exts.is_none() { resolution.exts = Some( match self.resolve_macro_path( &resolution.path, Some(MacroKind::Derive), &parent_scope, true, force, None, ) { Ok((Some(ext), _)) => { if !ext.helper_attrs.is_empty() { let last_seg = resolution.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); let helper_attrs = entry .helper_attrs .iter() .map(|(_, ident)| { let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper); let binding = (res, Visibility::::Public, ident.span, expn_id) .to_name_binding(self.arenas); (*ident, binding) }) .collect(); self.helper_attrs.insert(expn_id, helper_attrs); // 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> { 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 { self.path_accessible(expn_id, path, &[TypeNS, ValueNS, MacroNS]) } fn macro_accessible( &mut self, expn_id: LocalExpnId, path: &ast::Path, ) -> Result { self.path_accessible(expn_id, path, &[MacroNS]) } fn get_proc_macro_quoted_span(&self, krate: CrateNum, id: usize) -> Span { self.cstore().get_proc_macro_quoted_span_untracked(krate, id, self.tcx.sess) } fn declare_proc_macro(&mut self, id: NodeId) { self.proc_macros.push(id) } fn append_stripped_cfg_item(&mut self, parent_node: NodeId, name: Ident, cfg: ast::MetaItem) { self.stripped_cfg_items.push(StrippedCfgItem { parent_module: parent_node, name, cfg }); } fn registered_tools(&self) -> &RegisteredTools { self.registered_tools } fn register_glob_delegation(&mut self, invoc_id: LocalExpnId) { self.glob_delegation_invoc_ids.insert(invoc_id); } fn glob_delegation_suffixes( &mut self, trait_def_id: DefId, impl_def_id: LocalDefId, ) -> Result)>, Indeterminate> { let target_trait = self.expect_module(trait_def_id); if !target_trait.unexpanded_invocations.borrow().is_empty() { return Err(Indeterminate); } // FIXME: Instead of waiting try generating all trait methods, and pruning // the shadowed ones a bit later, e.g. when all macro expansion completes. // Pros: expansion will be stuck less (but only in exotic cases), the implementation may be // less hacky. // Cons: More code is generated just to be deleted later, deleting already created `DefId`s // may be nontrivial. if let Some(unexpanded_invocations) = self.impl_unexpanded_invocations.get(&impl_def_id) && !unexpanded_invocations.is_empty() { return Err(Indeterminate); } let mut idents = Vec::new(); target_trait.for_each_child(self, |this, ident, ns, _binding| { // FIXME: Adjust hygiene for idents from globs, like for glob imports. if let Some(overriding_keys) = this.impl_binding_keys.get(&impl_def_id) && overriding_keys.contains(&BindingKey::new(ident.normalize_to_macros_2_0(), ns)) { // The name is overridden, do not produce it from the glob delegation. } else { idents.push((ident, None)); } }); Ok(idents) } } impl<'ra, 'tcx> Resolver<'ra, 'tcx> { /// 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<'ra>, node_id: NodeId, force: bool, deleg_impl: Option, invoc_in_mod_inert_attr: Option, ) -> Result<(Arc, Res), Indeterminate> { let (ext, res) = match self.resolve_macro_or_delegation_path( path, Some(kind), parent_scope, true, force, deleg_impl, invoc_in_mod_inert_attr.map(|def_id| (def_id, node_id)), None, ) { 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), }; // Everything below is irrelevant to glob delegation, take a shortcut. if deleg_impl.is_some() { if !matches!(res, Res::Err | Res::Def(DefKind::Trait, _)) { self.dcx().emit_err(MacroExpectedFound { span: path.span, expected: "trait", article: "a", found: res.descr(), macro_path: &pprust::path_to_string(path), remove_surrounding_derive: None, add_as_non_derive: None, }); return Ok((self.dummy_ext(kind), Res::Err)); } return Ok((ext, res)); } // Report errors for the resolved macro. for segment in &path.segments { if let Some(args) = &segment.args { self.dcx().emit_err(errors::GenericArgumentsInMacroPath { span: args.span() }); } if kind == MacroKind::Attr && segment.ident.as_str().starts_with("rustc") { self.dcx().emit_err(errors::AttributesStartingWithRustcAreReserved { span: segment.ident.span, }); } } 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.dcx().emit_err(errors::ProcMacroSameCrate { span: path.span, is_test: self.tcx.sess.is_test_crate(), }); } } } 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 mut err = MacroExpectedFound { span: path.span, expected, article, found: res.descr(), macro_path: &path_str, remove_surrounding_derive: None, add_as_non_derive: None, }; // Suggest moving the macro out of the derive() if the macro isn't Derive if !path.span.from_expansion() && kind == MacroKind::Derive && ext.macro_kind() != MacroKind::Derive { err.remove_surrounding_derive = Some(RemoveSurroundingDerive { span: path.span }); err.add_as_non_derive = Some(AddAsNonDerive { macro_path: &path_str }); } self.dcx().emit_err(err); 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.tcx.features().custom_inner_attributes() { let is_macro = match res { Res::Def(..) => true, Res::NonMacroAttr(..) => false, _ => unreachable!(), }; let msg = if is_macro { "inner macro attributes are unstable" } else { "custom inner attributes are unstable" }; feature_err(&self.tcx.sess, sym::custom_inner_attributes, path.span, msg).emit(); } if res == Res::NonMacroAttr(NonMacroAttrKind::Tool) && let [namespace, attribute, ..] = &*path.segments && namespace.ident.name == sym::diagnostic && !(attribute.ident.name == sym::on_unimplemented || attribute.ident.name == sym::do_not_recommend) { let distance = edit_distance(attribute.ident.name.as_str(), sym::on_unimplemented.as_str(), 5); let typo_name = distance.map(|_| sym::on_unimplemented); self.tcx.sess.psess.buffer_lint( UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES, attribute.span(), node_id, BuiltinLintDiag::UnknownDiagnosticAttribute { span: attribute.span(), typo_name }, ); } Ok((ext, res)) } pub(crate) fn resolve_macro_path( &mut self, path: &ast::Path, kind: Option, parent_scope: &ParentScope<'ra>, trace: bool, force: bool, ignore_import: Option>, ) -> Result<(Option>, Res), Determinacy> { self.resolve_macro_or_delegation_path( path, kind, parent_scope, trace, force, None, None, ignore_import, ) } fn resolve_macro_or_delegation_path( &mut self, ast_path: &ast::Path, kind: Option, parent_scope: &ParentScope<'ra>, trace: bool, force: bool, deleg_impl: Option, invoc_in_mod_inert_attr: Option<(LocalDefId, NodeId)>, ignore_import: Option>, ) -> Result<(Option>, Res), Determinacy> { let path_span = ast_path.span; let mut path = Segment::from_path(ast_path); // Possibly apply the macro helper hack if deleg_impl.is_none() && kind == Some(MacroKind::Bang) && let [segment] = path.as_slice() && segment.ident.span.ctxt().outer_expn_data().local_inner_macros { let root = Ident::new(kw::DollarCrate, segment.ident.span); path.insert(0, Segment::from_ident(root)); } let res = if deleg_impl.is_some() || path.len() > 1 { let ns = if deleg_impl.is_some() { TypeNS } else { MacroNS }; let res = match self.maybe_resolve_path(&path, Some(ns), parent_scope, ignore_import) { PathResult::NonModule(path_res) if let Some(res) = path_res.full_res() => Ok(res), PathResult::Indeterminate if !force => return Err(Determinacy::Undetermined), PathResult::NonModule(..) | PathResult::Indeterminate | PathResult::Failed { .. } => Err(Determinacy::Determined), PathResult::Module(ModuleOrUniformRoot::Module(module)) => { Ok(module.res().unwrap()) } 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(), ns, )); } self.prohibit_imported_non_macro_attrs(None, res.ok(), path_span); res } else { let scope_set = kind.map_or(ScopeSet::All(MacroNS), ScopeSet::Macro); let binding = self.early_resolve_ident_in_lexical_scope( path[0].ident, scope_set, parent_scope, None, force, None, None, ); 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); self.report_out_of_scope_macro_calls( ast_path, parent_scope, invoc_in_mod_inert_attr, binding.ok(), ); res }; let res = res?; let ext = match deleg_impl { Some(impl_def_id) => match res { def::Res::Def(DefKind::Trait, def_id) => { let edition = self.tcx.sess.edition(); Some(Arc::new(SyntaxExtension::glob_delegation(def_id, impl_def_id, edition))) } _ => None, }, None => self.get_macro(res).map(|macro_data| Arc::clone(¯o_data.ext)), }; Ok((ext, res)) } pub(crate) fn finalize_macro_resolutions(&mut self, krate: &Crate) { let check_consistency = |this: &mut Self, path: &[Segment], span, kind: MacroKind, initial_res: Option, 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.dcx().span_delayed_bug(span, "inconsistent resolution for a macro"); } } else if this.tcx.dcx().has_errors().is_none() && this.privacy_errors.is_empty() { // 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 no other error is reported elsewhere. let err = this.dcx().create_err(CannotDetermineMacroResolution { span, kind: kind.descr(), path: Segment::names_to_string(path), }); err.stash(span, StashKey::UndeterminedMacroResolution); } }; let macro_resolutions = mem::take(&mut self.multi_segment_macro_resolutions); for (mut path, path_span, kind, parent_scope, initial_res, ns) 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(ns), &parent_scope, Some(Finalize::new(ast::CRATE_NODE_ID, path_span)), None, None, ) { PathResult::NonModule(path_res) if let Some(res) = path_res.full_res() => { check_consistency(self, &path, path_span, kind, initial_res, res) } // This may be a trait for glob delegation expansions. PathResult::Module(ModuleOrUniformRoot::Module(module)) => check_consistency( self, &path, path_span, kind, initial_res, module.res().unwrap(), ), path_res @ (PathResult::NonModule(..) | PathResult::Failed { .. }) => { let mut suggestion = None; let (span, label, module, segment) = if let PathResult::Failed { span, label, module, segment_name, .. } = path_res { // try to suggest if it's not a macro, maybe a function if let PathResult::NonModule(partial_res) = self.maybe_resolve_path(&path, Some(ValueNS), &parent_scope, None) && partial_res.unresolved_segments() == 0 { let sm = self.tcx.sess.source_map(); let exclamation_span = sm.next_point(span); suggestion = Some(( vec![(exclamation_span, "".to_string())], format!( "{} is not a macro, but a {}, try to remove `!`", Segment::names_to_string(&path), partial_res.base_res().descr() ), Applicability::MaybeIncorrect, )); } (span, label, module, segment_name) } else { ( path_span, format!( "partially resolved path in {} {}", kind.article(), kind.descr() ), None, path.last().map(|segment| segment.ident.name).unwrap(), ) }; self.report_error( span, ResolutionError::FailedToResolve { segment: Some(segment), label, suggestion, module, }, ); } 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, Some(Finalize::new(ast::CRATE_NODE_ID, ident.span)), true, None, None, ) { Ok(binding) => { let initial_res = initial_binding.map(|initial_binding| { self.record_use(ident, initial_binding, Used::Other); 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, |parent| { self.def_id_to_node_id[parent.parent_def] }); self.lint_buffer.buffer_lint( LEGACY_DERIVE_HELPERS, node_id, ident.span, BuiltinLintDiag::LegacyDeriveHelpers(binding.span), ); } } Err(..) => { let expected = kind.descr_expected(); let mut err = self.dcx().create_err(CannotFindIdentInThisScope { span: ident.span, expected, ident, }); self.unresolved_macro_suggestions(&mut err, kind, &parent_scope, ident, krate); 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, Some(Finalize::new(ast::CRATE_NODE_ID, ident.span)), true, None, None, ); } } 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, implied_by } = stability.level { let feature = stability.feature; let is_allowed = |feature| self.tcx.features().enabled(feature) || span.allows_unstable(feature); let allowed_by_implication = implied_by.is_some_and(|feature| is_allowed(feature)); if !is_allowed(feature) && !allowed_by_implication { let lint_buffer = &mut self.lint_buffer; let soft_handler = |lint, span, msg: String| { lint_buffer.buffer_lint( lint, node_id, span, BuiltinLintDiag::UnstableFeature( // FIXME make this translatable msg.into(), ), ) }; stability::report_unstable( self.tcx.sess, feature, reason.to_opt_reason(), issue, None, is_soft, span, soft_handler, stability::UnstableKind::Regular, ); } } } if let Some(depr) = &ext.deprecation { let path = pprust::path_to_string(path); stability::early_report_macro_deprecation( &mut self.lint_buffer, depr, span, node_id, path, ); } } fn prohibit_imported_non_macro_attrs( &self, binding: Option>, res: Option, span: Span, ) { if let Some(Res::NonMacroAttr(kind)) = res { if kind != NonMacroAttrKind::Tool && binding.is_none_or(|b| b.is_import()) { let binding_span = binding.map(|binding| binding.span); self.dcx().emit_err(errors::CannotUseThroughAnImport { span, article: kind.article(), descr: kind.descr(), binding_span, }); } } } fn report_out_of_scope_macro_calls( &mut self, path: &ast::Path, parent_scope: &ParentScope<'ra>, invoc_in_mod_inert_attr: Option<(LocalDefId, NodeId)>, binding: Option>, ) { if let Some((mod_def_id, node_id)) = invoc_in_mod_inert_attr && let Some(binding) = binding // This is a `macro_rules` itself, not some import. && let NameBindingKind::Res(res) = binding.kind && let Res::Def(DefKind::Macro(MacroKind::Bang), def_id) = res // And the `macro_rules` is defined inside the attribute's module, // so it cannot be in scope unless imported. && self.tcx.is_descendant_of(def_id, mod_def_id.to_def_id()) { // Try to resolve our ident ignoring `macro_rules` scopes. // If such resolution is successful and gives the same result // (e.g. if the macro is re-imported), then silence the lint. let no_macro_rules = self.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty); let fallback_binding = self.early_resolve_ident_in_lexical_scope( path.segments[0].ident, ScopeSet::Macro(MacroKind::Bang), &ParentScope { macro_rules: no_macro_rules, ..*parent_scope }, None, false, None, None, ); if fallback_binding.ok().and_then(|b| b.res().opt_def_id()) != Some(def_id) { let location = match parent_scope.module.kind { ModuleKind::Def(_, _, name) if name == kw::Empty => { "the crate root".to_string() } ModuleKind::Def(kind, def_id, name) => { format!("{} `{name}`", kind.descr(def_id)) } ModuleKind::Block => "this scope".to_string(), }; self.tcx.sess.psess.buffer_lint( OUT_OF_SCOPE_MACRO_CALLS, path.span, node_id, BuiltinLintDiag::OutOfScopeMacroCalls { span: path.span, path: pprust::path_to_string(path), location, }, ); } } } pub(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(|macro_data| macro_data.ext.macro_kind()); if macro_kind.is_some() && sub_namespace_match(macro_kind, Some(MacroKind::Attr)) { self.dcx() .emit_err(errors::NameReservedInAttributeNamespace { span: ident.span, ident }); } } } /// Compile the macro into a `SyntaxExtension` and its rule spans. /// /// Possibly replace its expander to a pre-defined one for built-in macros. pub(crate) fn compile_macro( &mut self, macro_def: &ast::MacroDef, ident: Ident, attrs: &[rustc_hir::Attribute], span: Span, node_id: NodeId, edition: Edition, ) -> MacroData { let (mut ext, mut rule_spans) = compile_declarative_macro( self.tcx.sess, self.tcx.features(), macro_def, ident, attrs, span, node_id, edition, ); if let Some(builtin_name) = ext.builtin_name { // The macro was marked with `#[rustc_builtin_macro]`. if let Some(builtin_ext_kind) = self.builtin_macros.get(&builtin_name) { // The macro is a built-in, replace its expander function // while still taking everything else from the source code. ext.kind = builtin_ext_kind.clone(); rule_spans = Vec::new(); } else { self.dcx().emit_err(errors::CannotFindBuiltinMacroWithName { span, ident }); } } MacroData { ext: Arc::new(ext), rule_spans, macro_rules: macro_def.macro_rules } } fn path_accessible( &mut self, expn_id: LocalExpnId, path: &ast::Path, namespaces: &[Namespace], ) -> Result { 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 namespaces { match self.maybe_resolve_path(path, Some(*ns), &parent_scope, None) { PathResult::Module(ModuleOrUniformRoot::Module(_)) => return Ok(true), PathResult::NonModule(partial_res) if partial_res.unresolved_segments() == 0 => { return Ok(true); } PathResult::NonModule(..) | // HACK(Urgau): This shouldn't be necessary PathResult::Failed { is_error_from_last_segment: false, .. } => { self.dcx() .emit_err(errors::CfgAccessibleUnsure { span }); // If we get a partially resolved NonModule in one namespace, we should get the // same result in any other namespaces, so we can return early. return Ok(false); } PathResult::Indeterminate => indeterminate = true, // We can only be sure that a path doesn't exist after having tested all the // possibilities, only at that time we can return false. PathResult::Failed { .. } => {} PathResult::Module(_) => panic!("unexpected path resolution"), } } if indeterminate { return Err(Indeterminate); } Ok(false) } }