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Diffstat (limited to 'compiler/rustc_resolve/src/macros.rs')
| -rw-r--r-- | compiler/rustc_resolve/src/macros.rs | 921 |
1 files changed, 921 insertions, 0 deletions
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs new file mode 100644 index 000000000..070fb9c72 --- /dev/null +++ b/compiler/rustc_resolve/src/macros.rs @@ -0,0 +1,921 @@ +//! 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::{BuiltinMacroState, Determinacy}; +use crate::{DeriveData, Finalize, ParentScope, ResolutionError, Resolver, ScopeSet}; +use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment}; +use rustc_ast::{self as ast, Inline, ItemKind, ModKind, NodeId}; +use rustc_ast_pretty::pprust; +use rustc_attr::StabilityLevel; +use rustc_data_structures::fx::FxHashSet; +use rustc_data_structures::intern::Interned; +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_hir::def::{self, DefKind, NonMacroAttrKind}; +use rustc_hir::def_id::{CrateNum, LocalDefId}; +use rustc_middle::middle::stability; +use rustc_middle::ty::RegisteredTools; +use rustc_session::lint::builtin::{LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE}; +use rustc_session::lint::builtin::{UNUSED_MACROS, UNUSED_MACRO_RULES}; +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; + +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> { + pub(crate) binding: &'a NameBinding<'a>, + /// `macro_rules` scope into which the `macro_rules` item was planted. + pub(crate) parent_macro_rules_scope: MacroRulesScopeRef<'a>, + 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 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 linearly with the number of macro invocations +/// in a module (including derives) and hurt performance. +pub(crate) type MacroRulesScopeRef<'a> = Interned<'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. +pub(crate) 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 +} + +pub(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 invocation_parent(&self, id: LocalExpnId) -> LocalDefId { + self.invocation_parents[&id].0 + } + + 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).to_def_id()); + let expn_id = LocalExpnId::fresh( + ExpnData::allow_unstable( + ExpnKind::AstPass(pass), + call_site, + self.session.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) { + 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(); + let def_id = 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); + self.unused_macro_rules.remove(&(did, rule_i)); + } + + fn check_unused_macros(&mut self) { + for (_, &(node_id, ident)) in self.unused_macros.iter() { + self.lint_buffer.buffer_lint( + UNUSED_MACROS, + node_id, + ident.span, + &format!("unused macro definition: `{}`", ident.name), + ); + } + for (&(def_id, arm_i), &(ident, rule_span)) in self.unused_macro_rules.iter() { + 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, + &format!( + "{} rule of macro `{}` is never used", + crate::diagnostics::ordinalize(arm_i + 1), + 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() -> 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.maybe_resolve_path(path, Some(ns), &parent_scope) { + 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.session + .struct_span_err(span, "not sure whether the path is accessible or not") + .note("the type may have associated items, but we are currently not checking them") + .emit(); + + // 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 + // posibilities, only at that time we can return false. + PathResult::Failed { .. } => {} + PathResult::Module(_) => panic!("unexpected path resolution"), + } + } + + if indeterminate { + return Err(Indeterminate); + } + + 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) + } + + fn declare_proc_macro(&mut self, id: NodeId) { + self.proc_macros.push(id) + } + + fn registered_tools(&self) -> &RegisteredTools { + &self.registered_tools + } +} + +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.maybe_resolve_path(&path, Some(MacroNS), parent_scope) { + 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, + None, + force, + 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); + res + }; + + res.map(|res| (self.get_macro(res).map(|macro_data| macro_data.ext), res)) + } + + pub(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, + Some(Finalize::new(ast::CRATE_NODE_ID, path_span)), + None, + ) { + 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, + Some(Finalize::new(ast::CRATE_NODE_ID, ident.span)), + true, + None, + ) { + Ok(binding) => { + let initial_res = initial_binding.map(|initial_binding| { + self.record_use(ident, 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, + Some(Finalize::new(ast::CRATE_NODE_ID, ident.span)), + true, + 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.active_features.contains(&feature) || span.allows_unstable(feature) + }; + let allowed_by_implication = + implied_by.map(|feature| is_allowed(feature)).unwrap_or(false); + if !is_allowed(feature) && !allowed_by_implication { + 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.to_opt_reason(), + issue, + None, + is_soft, + span, + soft_handler, + ); + } + } + } + if let Some(depr) = &ext.deprecation { + let path = pprust::path_to_string(&path); + let (message, lint) = stability::deprecation_message_and_lint(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(); + } + } + } + + 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.session.span_err( + ident.span, + &format!("name `{}` is reserved in attribute namespace", 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, + item: &ast::Item, + edition: Edition, + ) -> (SyntaxExtension, Vec<(usize, Span)>) { + let (mut result, mut rule_spans) = 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; + rule_spans = Vec::new(); + if item.id != ast::DUMMY_NODE_ID { + self.builtin_macro_kinds + .insert(self.local_def_id(item.id), result.macro_kind()); + } + } + 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, rule_spans) + } +} |