406 lines
16 KiB
Rust
406 lines
16 KiB
Rust
// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use {Module, ModuleKind, NameBinding, NameBindingKind, Resolver, AmbiguityError};
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use Namespace::{self, MacroNS};
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use build_reduced_graph::BuildReducedGraphVisitor;
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use resolve_imports::ImportResolver;
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use rustc::hir::def_id::{DefId, BUILTIN_MACROS_CRATE, CRATE_DEF_INDEX, DefIndex};
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use rustc::hir::def::{Def, Export};
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use rustc::hir::map::{self, DefCollector};
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use rustc::ty;
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use std::cell::Cell;
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use std::rc::Rc;
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use syntax::ast::{self, Name};
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use syntax::errors::DiagnosticBuilder;
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use syntax::ext::base::{self, Determinacy, MultiModifier, MultiDecorator};
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use syntax::ext::base::{NormalTT, SyntaxExtension};
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use syntax::ext::expand::Expansion;
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use syntax::ext::hygiene::Mark;
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use syntax::ext::tt::macro_rules;
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use syntax::fold::Folder;
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use syntax::ptr::P;
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use syntax::util::lev_distance::find_best_match_for_name;
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use syntax::visit::Visitor;
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use syntax_pos::{Span, DUMMY_SP};
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#[derive(Clone)]
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pub struct InvocationData<'a> {
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pub module: Cell<Module<'a>>,
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pub def_index: DefIndex,
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// True if this expansion is in a `const_integer` position, for example `[u32; m!()]`.
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// c.f. `DefCollector::visit_ast_const_integer`.
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pub const_integer: bool,
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// The scope in which the invocation path is resolved.
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pub legacy_scope: Cell<LegacyScope<'a>>,
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// The smallest scope that includes this invocation's expansion,
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// or `Empty` if this invocation has not been expanded yet.
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pub expansion: Cell<LegacyScope<'a>>,
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}
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impl<'a> InvocationData<'a> {
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pub fn root(graph_root: Module<'a>) -> Self {
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InvocationData {
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module: Cell::new(graph_root),
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def_index: CRATE_DEF_INDEX,
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const_integer: false,
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legacy_scope: Cell::new(LegacyScope::Empty),
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expansion: Cell::new(LegacyScope::Empty),
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}
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}
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}
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#[derive(Copy, Clone)]
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pub enum LegacyScope<'a> {
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Empty,
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Invocation(&'a InvocationData<'a>), // The scope of the invocation, not including its expansion
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Expansion(&'a InvocationData<'a>), // The scope of the invocation, including its expansion
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Binding(&'a LegacyBinding<'a>),
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}
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pub struct LegacyBinding<'a> {
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pub parent: Cell<LegacyScope<'a>>,
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pub name: ast::Name,
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ext: Rc<SyntaxExtension>,
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pub span: Span,
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}
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pub enum MacroBinding<'a> {
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Legacy(&'a LegacyBinding<'a>),
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Modern(&'a NameBinding<'a>),
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}
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impl<'a> base::Resolver for Resolver<'a> {
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fn next_node_id(&mut self) -> ast::NodeId {
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self.session.next_node_id()
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}
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fn get_module_scope(&mut self, id: ast::NodeId) -> Mark {
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let mark = Mark::fresh();
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let module = self.module_map[&id];
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self.invocations.insert(mark, self.arenas.alloc_invocation_data(InvocationData {
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module: Cell::new(module),
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def_index: module.def_id().unwrap().index,
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const_integer: false,
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legacy_scope: Cell::new(LegacyScope::Empty),
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expansion: Cell::new(LegacyScope::Empty),
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}));
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mark
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}
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fn eliminate_crate_var(&mut self, item: P<ast::Item>) -> P<ast::Item> {
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struct EliminateCrateVar<'b, 'a: 'b>(&'b mut Resolver<'a>);
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impl<'a, 'b> Folder for EliminateCrateVar<'a, 'b> {
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fn fold_path(&mut self, mut path: ast::Path) -> ast::Path {
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let ident = path.segments[0].identifier;
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if ident.name == "$crate" {
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path.global = true;
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let module = self.0.resolve_crate_var(ident.ctxt);
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if module.is_local() {
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path.segments.remove(0);
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} else {
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path.segments[0].identifier = match module.kind {
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ModuleKind::Def(_, name) => ast::Ident::with_empty_ctxt(name),
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_ => unreachable!(),
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};
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}
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}
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path
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}
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}
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EliminateCrateVar(self).fold_item(item).expect_one("")
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}
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fn visit_expansion(&mut self, mark: Mark, expansion: &Expansion) {
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let invocation = self.invocations[&mark];
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self.collect_def_ids(invocation, expansion);
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self.current_module = invocation.module.get();
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self.current_module.unresolved_invocations.borrow_mut().remove(&mark);
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let mut visitor = BuildReducedGraphVisitor {
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resolver: self,
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legacy_scope: LegacyScope::Invocation(invocation),
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expansion: mark,
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};
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expansion.visit_with(&mut visitor);
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self.current_module.unresolved_invocations.borrow_mut().remove(&mark);
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invocation.expansion.set(visitor.legacy_scope);
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}
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fn add_macro(&mut self, scope: Mark, mut def: ast::MacroDef, export: bool) {
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if def.ident.name == "macro_rules" {
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self.session.span_err(def.span, "user-defined macros may not be named `macro_rules`");
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}
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let invocation = self.invocations[&scope];
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let binding = self.arenas.alloc_legacy_binding(LegacyBinding {
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parent: Cell::new(invocation.legacy_scope.get()),
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name: def.ident.name,
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ext: Rc::new(macro_rules::compile(&self.session.parse_sess, &def)),
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span: def.span,
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});
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invocation.legacy_scope.set(LegacyScope::Binding(binding));
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self.macro_names.insert(def.ident.name);
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if export {
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def.id = self.next_node_id();
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DefCollector::new(&mut self.definitions).with_parent(CRATE_DEF_INDEX, |collector| {
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collector.visit_macro_def(&def)
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});
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self.macro_exports.push(Export {
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name: def.ident.name,
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def: Def::Macro(self.definitions.local_def_id(def.id)),
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});
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self.exported_macros.push(def);
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}
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}
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fn add_ext(&mut self, ident: ast::Ident, ext: Rc<SyntaxExtension>) {
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if let NormalTT(..) = *ext {
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self.macro_names.insert(ident.name);
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}
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let def_id = DefId {
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krate: BUILTIN_MACROS_CRATE,
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index: DefIndex::new(self.macro_map.len()),
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};
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self.macro_map.insert(def_id, ext);
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let binding = self.arenas.alloc_name_binding(NameBinding {
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kind: NameBindingKind::Def(Def::Macro(def_id)),
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span: DUMMY_SP,
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vis: ty::Visibility::PrivateExternal,
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expansion: Mark::root(),
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});
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self.builtin_macros.insert(ident.name, binding);
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}
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fn add_expansions_at_stmt(&mut self, id: ast::NodeId, macros: Vec<Mark>) {
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self.macros_at_scope.insert(id, macros);
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}
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fn resolve_imports(&mut self) {
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ImportResolver { resolver: self }.resolve_imports()
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}
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fn find_attr_invoc(&mut self, attrs: &mut Vec<ast::Attribute>) -> Option<ast::Attribute> {
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for i in 0..attrs.len() {
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match self.builtin_macros.get(&attrs[i].name()).cloned() {
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Some(binding) => match *binding.get_macro(self) {
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MultiModifier(..) | MultiDecorator(..) | SyntaxExtension::AttrProcMacro(..) => {
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return Some(attrs.remove(i))
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}
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_ => {}
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},
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None => {}
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}
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}
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None
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}
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fn resolve_macro(&mut self, scope: Mark, path: &ast::Path, force: bool)
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-> Result<Rc<SyntaxExtension>, Determinacy> {
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if path.segments.len() > 1 || path.global || !path.segments[0].parameters.is_empty() {
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self.session.span_err(path.span, "expected macro name without module separators");
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return Err(Determinacy::Determined);
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}
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let name = path.segments[0].identifier.name;
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let invocation = self.invocations[&scope];
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self.current_module = invocation.module.get();
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let ext = match self.resolve_legacy_scope(&invocation.legacy_scope, name, false) {
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Some(MacroBinding::Legacy(binding)) => binding.ext.clone(),
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Some(MacroBinding::Modern(binding)) => binding.get_macro(self),
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None => match self.resolve_in_item_lexical_scope(name, MacroNS, None) {
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Some(binding) => binding.get_macro(self),
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None => return Err(if force {
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let msg = format!("macro undefined: '{}!'", name);
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let mut err = self.session.struct_span_err(path.span, &msg);
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self.suggest_macro_name(&name.as_str(), &mut err);
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err.emit();
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Determinacy::Determined
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} else {
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Determinacy::Undetermined
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}),
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},
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};
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if self.use_extern_macros {
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self.current_module.legacy_macro_resolutions.borrow_mut()
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.push((scope, name, path.span));
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}
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Ok(ext)
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}
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}
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impl<'a> Resolver<'a> {
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// Resolve the name in the module's lexical scope, excluding non-items.
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fn resolve_in_item_lexical_scope(&mut self,
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name: Name,
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ns: Namespace,
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record_used: Option<Span>)
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-> Option<&'a NameBinding<'a>> {
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let mut module = self.current_module;
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let mut potential_expanded_shadower = None;
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loop {
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// Since expanded macros may not shadow the lexical scope (enforced below),
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// we can ignore unresolved invocations (indicated by the penultimate argument).
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match self.resolve_name_in_module(module, name, ns, true, record_used) {
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Ok(binding) => {
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let span = match record_used {
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Some(span) => span,
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None => return Some(binding),
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};
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if let Some(shadower) = potential_expanded_shadower {
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self.ambiguity_errors.push(AmbiguityError {
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span: span, name: name, b1: shadower, b2: binding, lexical: true,
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});
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return Some(shadower);
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} else if binding.expansion == Mark::root() {
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return Some(binding);
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} else {
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potential_expanded_shadower = Some(binding);
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}
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},
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Err(Determinacy::Undetermined) => return None,
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Err(Determinacy::Determined) => {}
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}
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match module.kind {
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ModuleKind::Block(..) => module = module.parent.unwrap(),
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ModuleKind::Def(..) => return potential_expanded_shadower,
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}
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}
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}
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pub fn resolve_legacy_scope(&mut self,
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mut scope: &'a Cell<LegacyScope<'a>>,
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name: Name,
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record_used: bool)
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-> Option<MacroBinding<'a>> {
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let mut possible_time_travel = None;
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let mut relative_depth: u32 = 0;
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let mut binding = None;
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loop {
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match scope.get() {
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LegacyScope::Empty => break,
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LegacyScope::Expansion(invocation) => {
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match invocation.expansion.get() {
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LegacyScope::Invocation(_) => scope.set(invocation.legacy_scope.get()),
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LegacyScope::Empty => {
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if possible_time_travel.is_none() {
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possible_time_travel = Some(scope);
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}
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scope = &invocation.legacy_scope;
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}
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_ => {
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relative_depth += 1;
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scope = &invocation.expansion;
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}
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}
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}
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LegacyScope::Invocation(invocation) => {
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relative_depth = relative_depth.saturating_sub(1);
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scope = &invocation.legacy_scope;
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}
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LegacyScope::Binding(potential_binding) => {
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if potential_binding.name == name {
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if (!self.use_extern_macros || record_used) && relative_depth > 0 {
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self.disallowed_shadowing.push(potential_binding);
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}
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binding = Some(potential_binding);
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break
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}
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scope = &potential_binding.parent;
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}
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};
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}
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let binding = match binding {
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Some(binding) => MacroBinding::Legacy(binding),
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None => match self.builtin_macros.get(&name).cloned() {
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Some(binding) => MacroBinding::Modern(binding),
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None => return None,
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},
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};
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if !self.use_extern_macros {
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if let Some(scope) = possible_time_travel {
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// Check for disallowed shadowing later
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self.lexical_macro_resolutions.push((name, scope));
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}
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}
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Some(binding)
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}
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pub fn finalize_current_module_macro_resolutions(&mut self) {
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let module = self.current_module;
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for &(mark, name, span) in module.legacy_macro_resolutions.borrow().iter() {
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let legacy_scope = &self.invocations[&mark].legacy_scope;
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let legacy_resolution = self.resolve_legacy_scope(legacy_scope, name, true);
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let resolution = self.resolve_in_item_lexical_scope(name, MacroNS, Some(span));
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let (legacy_resolution, resolution) = match (legacy_resolution, resolution) {
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(Some(legacy_resolution), Some(resolution)) => (legacy_resolution, resolution),
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_ => continue,
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};
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let (legacy_span, participle) = match legacy_resolution {
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MacroBinding::Modern(binding) if binding.def() == resolution.def() => continue,
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MacroBinding::Modern(binding) => (binding.span, "imported"),
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MacroBinding::Legacy(binding) => (binding.span, "defined"),
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};
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let msg1 = format!("`{}` could resolve to the macro {} here", name, participle);
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let msg2 = format!("`{}` could also resolve to the macro imported here", name);
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self.session.struct_span_err(span, &format!("`{}` is ambiguous", name))
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.span_note(legacy_span, &msg1)
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.span_note(resolution.span, &msg2)
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.emit();
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}
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}
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fn suggest_macro_name(&mut self, name: &str, err: &mut DiagnosticBuilder<'a>) {
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if let Some(suggestion) = find_best_match_for_name(self.macro_names.iter(), name, None) {
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if suggestion != name {
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err.help(&format!("did you mean `{}!`?", suggestion));
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} else {
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err.help(&format!("have you added the `#[macro_use]` on the module/import?"));
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}
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}
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}
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fn collect_def_ids(&mut self, invocation: &'a InvocationData<'a>, expansion: &Expansion) {
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let Resolver { ref mut invocations, arenas, graph_root, .. } = *self;
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let InvocationData { def_index, const_integer, .. } = *invocation;
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let visit_macro_invoc = &mut |invoc: map::MacroInvocationData| {
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invocations.entry(invoc.mark).or_insert_with(|| {
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arenas.alloc_invocation_data(InvocationData {
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def_index: invoc.def_index,
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const_integer: invoc.const_integer,
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module: Cell::new(graph_root),
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expansion: Cell::new(LegacyScope::Empty),
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legacy_scope: Cell::new(LegacyScope::Empty),
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})
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});
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};
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let mut def_collector = DefCollector::new(&mut self.definitions);
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def_collector.visit_macro_invoc = Some(visit_macro_invoc);
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def_collector.with_parent(def_index, |def_collector| {
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if const_integer {
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if let Expansion::Expr(ref expr) = *expansion {
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def_collector.visit_ast_const_integer(expr);
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}
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}
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expansion.visit_with(def_collector)
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});
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}
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}
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