rust/compiler/rustc_resolve/src/def_collector.rs
Maybe Waffle 40ae7b5b8e Parse closure binders
This is first step in implementing RFC 3216.
- Parse `for<'a>` before closures in ast
  - Error in lowering
- Add `closure_lifetime_binder` feature
2022-07-12 16:25:16 +04:00

355 lines
13 KiB
Rust

use crate::{ImplTraitContext, Resolver};
use rustc_ast::visit::{self, FnKind};
use rustc_ast::walk_list;
use rustc_ast::*;
use rustc_expand::expand::AstFragment;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::definitions::*;
use rustc_span::hygiene::LocalExpnId;
use rustc_span::symbol::sym;
use rustc_span::Span;
use tracing::debug;
pub(crate) fn collect_definitions(
resolver: &mut Resolver<'_>,
fragment: &AstFragment,
expansion: LocalExpnId,
) {
let (parent_def, impl_trait_context) = resolver.invocation_parents[&expansion];
fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion, impl_trait_context });
}
/// Creates `DefId`s for nodes in the AST.
struct DefCollector<'a, 'b> {
resolver: &'a mut Resolver<'b>,
parent_def: LocalDefId,
impl_trait_context: ImplTraitContext,
expansion: LocalExpnId,
}
impl<'a, 'b> DefCollector<'a, 'b> {
fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
let parent_def = self.parent_def;
debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
self.resolver.create_def(
parent_def,
node_id,
data,
self.expansion.to_expn_id(),
span.with_parent(None),
)
}
fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
f(self);
self.parent_def = orig_parent_def;
}
fn with_impl_trait<F: FnOnce(&mut Self)>(
&mut self,
impl_trait_context: ImplTraitContext,
f: F,
) {
let orig_itc = std::mem::replace(&mut self.impl_trait_context, impl_trait_context);
f(self);
self.impl_trait_context = orig_itc;
}
fn collect_field(&mut self, field: &'a FieldDef, index: Option<usize>) {
let index = |this: &Self| {
index.unwrap_or_else(|| {
let node_id = NodeId::placeholder_from_expn_id(this.expansion);
this.resolver.placeholder_field_indices[&node_id]
})
};
if field.is_placeholder {
let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
self.visit_macro_invoc(field.id);
} else {
let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
self.with_parent(def, |this| visit::walk_field_def(this, field));
}
}
fn visit_macro_invoc(&mut self, id: NodeId) {
let id = id.placeholder_to_expn_id();
let old_parent =
self.resolver.invocation_parents.insert(id, (self.parent_def, self.impl_trait_context));
assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
}
}
impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
fn visit_item(&mut self, i: &'a Item) {
debug!("visit_item: {:?}", i);
// Pick the def data. This need not be unique, but the more
// information we encapsulate into, the better
let def_data = match &i.kind {
ItemKind::Impl { .. } => DefPathData::Impl,
ItemKind::ForeignMod(..) => DefPathData::ForeignMod,
ItemKind::Mod(..)
| ItemKind::Trait(..)
| ItemKind::TraitAlias(..)
| ItemKind::Enum(..)
| ItemKind::Struct(..)
| ItemKind::Union(..)
| ItemKind::ExternCrate(..)
| ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) => {
DefPathData::ValueNs(i.ident.name)
}
ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
ItemKind::MacCall(..) => {
visit::walk_item(self, i);
return self.visit_macro_invoc(i.id);
}
ItemKind::GlobalAsm(..) => DefPathData::GlobalAsm,
ItemKind::Use(..) => {
return visit::walk_item(self, i);
}
};
let def = self.create_def(i.id, def_data, i.span);
self.with_parent(def, |this| {
this.with_impl_trait(ImplTraitContext::Existential, |this| {
match i.kind {
ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
// If this is a unit or tuple-like struct, register the constructor.
if let Some(ctor_hir_id) = struct_def.ctor_id() {
this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
}
}
_ => {}
}
visit::walk_item(this, i);
})
});
}
fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
if let FnKind::Fn(_, _, sig, _, generics, body) = fn_kind {
if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
self.visit_generics(generics);
let return_impl_trait_id =
self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);
// For async functions, we need to create their inner defs inside of a
// closure to match their desugared representation. Besides that,
// we must mirror everything that `visit::walk_fn` below does.
self.visit_fn_header(&sig.header);
for param in &sig.decl.inputs {
self.visit_param(param);
}
self.with_parent(return_impl_trait_id, |this| {
this.visit_fn_ret_ty(&sig.decl.output)
});
let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
return;
}
}
visit::walk_fn(self, fn_kind, span);
}
fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
self.create_def(id, DefPathData::Use, use_tree.span);
match use_tree.kind {
UseTreeKind::Simple(_, id1, id2) => {
self.create_def(id1, DefPathData::Use, use_tree.prefix.span);
self.create_def(id2, DefPathData::Use, use_tree.prefix.span);
}
UseTreeKind::Glob => (),
UseTreeKind::Nested(..) => {}
}
visit::walk_use_tree(self, use_tree, id);
}
fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
if let ForeignItemKind::MacCall(_) = foreign_item.kind {
return self.visit_macro_invoc(foreign_item.id);
}
let def = self.create_def(
foreign_item.id,
DefPathData::ValueNs(foreign_item.ident.name),
foreign_item.span,
);
self.with_parent(def, |this| {
visit::walk_foreign_item(this, foreign_item);
});
}
fn visit_variant(&mut self, v: &'a Variant) {
if v.is_placeholder {
return self.visit_macro_invoc(v.id);
}
let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
self.with_parent(def, |this| {
if let Some(ctor_hir_id) = v.data.ctor_id() {
this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
}
visit::walk_variant(this, v)
});
}
fn visit_variant_data(&mut self, data: &'a VariantData) {
// The assumption here is that non-`cfg` macro expansion cannot change field indices.
// It currently holds because only inert attributes are accepted on fields,
// and every such attribute expands into a single field after it's resolved.
for (index, field) in data.fields().iter().enumerate() {
self.collect_field(field, Some(index));
}
}
fn visit_generic_param(&mut self, param: &'a GenericParam) {
if param.is_placeholder {
self.visit_macro_invoc(param.id);
return;
}
let name = param.ident.name;
let def_path_data = match param.kind {
GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
};
self.create_def(param.id, def_path_data, param.ident.span);
// impl-Trait can happen inside generic parameters, like
// ```
// fn foo<U: Iterator<Item = impl Clone>>() {}
// ```
//
// In that case, the impl-trait is lowered as an additional generic parameter.
self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
visit::walk_generic_param(this, param)
});
}
fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
let def_data = match &i.kind {
AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
};
let def = self.create_def(i.id, def_data, i.span);
self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
}
fn visit_pat(&mut self, pat: &'a Pat) {
match pat.kind {
PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
_ => visit::walk_pat(self, pat),
}
}
fn visit_anon_const(&mut self, constant: &'a AnonConst) {
let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
self.with_parent(def, |this| visit::walk_anon_const(this, constant));
}
fn visit_expr(&mut self, expr: &'a Expr) {
let parent_def = match expr.kind {
ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
ExprKind::Closure(_, _, asyncness, ..) => {
// Async closures desugar to closures inside of closures, so
// we must create two defs.
let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
match asyncness {
Async::Yes { closure_id, .. } => {
self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
}
Async::No => closure_def,
}
}
ExprKind::Async(_, async_id, _) => {
self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
}
_ => self.parent_def,
};
self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
}
fn visit_ty(&mut self, ty: &'a Ty) {
match ty.kind {
TyKind::MacCall(..) => self.visit_macro_invoc(ty.id),
TyKind::ImplTrait(node_id, _) => {
let parent_def = match self.impl_trait_context {
ImplTraitContext::Universal(item_def) => self.resolver.create_def(
item_def,
node_id,
DefPathData::ImplTrait,
self.expansion.to_expn_id(),
ty.span,
),
ImplTraitContext::Existential => {
self.create_def(node_id, DefPathData::ImplTrait, ty.span)
}
};
self.with_parent(parent_def, |this| visit::walk_ty(this, ty))
}
_ => visit::walk_ty(self, ty),
}
}
fn visit_stmt(&mut self, stmt: &'a Stmt) {
match stmt.kind {
StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
_ => visit::walk_stmt(self, stmt),
}
}
fn visit_arm(&mut self, arm: &'a Arm) {
if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
}
fn visit_expr_field(&mut self, f: &'a ExprField) {
if f.is_placeholder {
self.visit_macro_invoc(f.id)
} else {
visit::walk_expr_field(self, f)
}
}
fn visit_pat_field(&mut self, fp: &'a PatField) {
if fp.is_placeholder {
self.visit_macro_invoc(fp.id)
} else {
visit::walk_pat_field(self, fp)
}
}
fn visit_param(&mut self, p: &'a Param) {
if p.is_placeholder {
self.visit_macro_invoc(p.id)
} else {
self.with_impl_trait(ImplTraitContext::Universal(self.parent_def), |this| {
visit::walk_param(this, p)
})
}
}
// This method is called only when we are visiting an individual field
// after expanding an attribute on it.
fn visit_field_def(&mut self, field: &'a FieldDef) {
self.collect_field(field, None);
}
fn visit_crate(&mut self, krate: &'a Crate) {
if krate.is_placeholder {
self.visit_macro_invoc(krate.id)
} else {
visit::walk_crate(self, krate)
}
}
}