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Reorganize opaque lowering code

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Santiago Pastorino 2023-06-22 17:56:46 -03:00
parent 33d21e62d0
commit 72a32583d1
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1 changed files with 51 additions and 44 deletions
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95
compiler/rustc_ast_lowering/src/lib.rs
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@ -1539,9 +1539,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
);
debug!(?opaque_ty_def_id);
// Contains the new lifetime definitions created for the TAIT (if any).
let mut collected_lifetimes = Vec::new();
// If this came from a TAIT (as opposed to a function that returns an RPIT), we only want
// to capture the lifetimes that appear in the bounds. So visit the bounds to find out
// exactly which ones those are.
@ -1558,20 +1555,29 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
};
debug!(?lifetimes_to_remap);
let mut new_remapping = FxHashMap::default();
// Contains the new lifetime definitions created for the TAIT (if any).
// If this opaque type is only capturing a subset of the lifetimes (those that appear in
// bounds), then create the new lifetime parameters required and create a mapping from the
// old `'a` (on the function) to the new `'a` (on the opaque type).
let collected_lifetimes =
self.create_lifetime_defs(opaque_ty_def_id, &lifetimes_to_remap, &mut new_remapping);
debug!(?collected_lifetimes);
debug!(?new_remapping);
// This creates HIR lifetime arguments as `hir::GenericArg`, in the given example `type
// TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing `&['x]`.
let lifetimes: Vec<_> = collected_lifetimes
.iter()
.map(|(_, lifetime)| {
let id = self.next_node_id();
self.new_named_lifetime(lifetime.id, id, lifetime.ident)
})
.collect();
debug!(?lifetimes);
self.with_hir_id_owner(opaque_ty_node_id, |lctx| {
let mut new_remapping = FxHashMap::default();
// If this opaque type is only capturing a subset of the lifetimes (those that appear
// in bounds), then create the new lifetime parameters required and create a mapping
// from the old `'a` (on the function) to the new `'a` (on the opaque type).
collected_lifetimes = lctx.create_lifetime_defs(
opaque_ty_def_id,
&lifetimes_to_remap,
&mut new_remapping,
);
debug!(?collected_lifetimes);
debug!(?new_remapping);
// Install the remapping from old to new (if any):
lctx.with_remapping(new_remapping, |lctx| {
// This creates HIR lifetime definitions as `hir::GenericParam`, in the given
@ -1630,12 +1636,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// This creates HIR lifetime arguments as `hir::GenericArg`, in the given example `type
// TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing `&['x]`.
let lifetimes =
self.arena.alloc_from_iter(collected_lifetimes.into_iter().map(|(_, lifetime)| {
let id = self.next_node_id();
let l = self.new_named_lifetime(lifetime.id, id, lifetime.ident);
hir::GenericArg::Lifetime(l)
}));
let lifetimes = self.arena.alloc_from_iter(
lifetimes.into_iter().map(|lifetime| hir::GenericArg::Lifetime(lifetime)),
);
debug!(?lifetimes);
// `impl Trait` now just becomes `Foo<'a, 'b, ..>`.
@ -1993,22 +1996,32 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let lifetimes_to_remap = lifetime_collector::lifetimes_in_ret_ty(&self.resolver, output);
debug!(?lifetimes_to_remap);
self.with_hir_id_owner(opaque_ty_node_id, |this| {
// If this opaque type is only capturing a subset of the lifetimes (those that appear
// in bounds), then create the new lifetime parameters required and create a mapping
// from the old `'a` (on the function) to the new `'a` (on the opaque type).
collected_lifetimes.extend(
this.create_lifetime_defs(
opaque_ty_def_id,
&lifetimes_to_remap,
&mut new_remapping,
)
// If this opaque type is only capturing a subset of the lifetimes (those that appear in
// bounds), then create the new lifetime parameters required and create a mapping from the
// old `'a` (on the function) to the new `'a` (on the opaque type).
collected_lifetimes.extend(
self.create_lifetime_defs(opaque_ty_def_id, &lifetimes_to_remap, &mut new_remapping)
.into_iter()
.map(|(new_node_id, lifetime)| (new_node_id, lifetime, None)),
);
debug!(?collected_lifetimes);
debug!(?new_remapping);
);
debug!(?collected_lifetimes);
debug!(?new_remapping);
// This creates HIR lifetime arguments as `hir::GenericArg`, in the given example `type
// TestReturn<'a, T, 'x> = impl Debug + 'x`, it creates a collection containing `&['x]`.
let lifetimes: Vec<_> = collected_lifetimes
.iter()
.map(|(_, lifetime, res)| {
let id = self.next_node_id();
let res = res.unwrap_or(
self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error),
);
self.new_named_lifetime_with_res(id, lifetime.ident, res)
})
.collect();
debug!(?lifetimes);
self.with_hir_id_owner(opaque_ty_node_id, |this| {
// Install the remapping from old to new (if any):
this.with_remapping(new_remapping, |this| {
// We have to be careful to get elision right here. The
@ -2096,15 +2109,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
//
// For the "output" lifetime parameters, we just want to
// generate `'_`.
let generic_args = self.arena.alloc_from_iter(collected_lifetimes.into_iter().map(
|(_, lifetime, res)| {
let id = self.next_node_id();
let res = res.unwrap_or(
self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error),
);
hir::GenericArg::Lifetime(self.new_named_lifetime_with_res(id, lifetime.ident, res))
},
));
let generic_args = self
.arena
.alloc_from_iter(lifetimes.iter().map(|lifetime| hir::GenericArg::Lifetime(*lifetime)));
// Create the `Foo<...>` reference itself. Note that the `type
// Foo = impl Trait` is, internally, created as a child of the