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Do anonymous lifetimes remapping correctly for nested rpits

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This commit is contained in:
Santiago Pastorino
2022-10-18 14:05:17 -03:00
parent fb5475887f
commit 49ce8a22b0
2 changed files with 34 additions and 16 deletions
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27
compiler/rustc_ast_lowering/src/lib.rs
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@@ -540,9 +540,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
/// Get the previously recorded `to` local def id given the `from` local def id, obtained using
/// `generics_def_id_map` field.
fn get_remapped_def_id(&self, mut local_def_id: LocalDefId) -> LocalDefId {
fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId {
// `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
// push new mappings so we need to try first the latest mappings, hence `iter().rev()`.
// push new mappings, so we first need to get the latest (innermost) mappings, hence `iter().rev()`.
//
// Consider:
//
@@ -552,18 +552,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
//
// `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
//
// for the opaque type generated on `impl Sized + 'b`, We want the result to be:
// impl_sized#'b, so iterating forward is the wrong thing to do.
for map in self.generics_def_id_map.iter().rev() {
if let Some(r) = map.get(&local_def_id) {
debug!("def_id_remapper: remapping from `{local_def_id:?}` to `{r:?}`");
local_def_id = *r;
} else {
debug!("def_id_remapper: no remapping for `{local_def_id:?}` found in map");
}
}
local_def_id
// for the opaque type generated on `impl Sized + 'b`, we want the result to be: impl_sized#'b.
// So, if we were trying to find first from the start (outermost) would give the wrong result, impl_trait#'b.
self.generics_def_id_map
.iter()
.rev()
.find_map(|map| map.get(&local_def_id).map(|local_def_id| *local_def_id))
.unwrap_or(local_def_id)
}
/// Freshen the `LoweringContext` and ready it to lower a nested item.
@@ -1641,7 +1636,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
LifetimeRes::Fresh { param, binder: _ } => {
debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
if let Some(old_def_id) = self.opt_local_def_id(param) && remapping.get(&old_def_id).is_none() {
if let Some(old_def_id) = self.orig_opt_local_def_id(param) && remapping.get(&old_def_id).is_none() {
let node_id = self.next_node_id();
let new_def_id = self.create_def(
@@ -1886,7 +1881,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let extra_lifetime_params = self.resolver.take_extra_lifetime_params(opaque_ty_node_id);
debug!(?extra_lifetime_params);
for (ident, outer_node_id, outer_res) in extra_lifetime_params {
let outer_def_id = self.local_def_id(outer_node_id);
let outer_def_id = self.orig_local_def_id(outer_node_id);
let inner_node_id = self.next_node_id();
// Add a definition for the in scope lifetime def.