Auto merge of #87287 - oli-obk:fixup_fixup_fixup_opaque_types, r=spastorino

 Make mir borrowck's use of opaque types independent of the typeck query's result

fixes #87218
fixes #86465

we used to use the typeck results only to generate an obligation for the mir borrowck type to be equal to the typeck result.

When i removed the `fixup_opaque_types` function in #87200, I exposed a bug that showed that mir borrowck can't doesn't get enough information from typeck in order to build the correct lifetime mapping from opaque type usage to the actual concrete type. We therefor now fully compute the information within mir borrowck (we already did that, but we only used it to verify the typeck result) and stop using the typeck information.

We will likely be able to remove most opaque type information from the borrowck results in the future and just have all current callers use the mir borrowck result instead.

r? `@spastorino`

2 files changed, 10 insertions, 5 deletions

diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index 16151e9dca5..4467980054f 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -24,6 +24,7 @@
 #![feature(new_uninit)]
 #![feature(once_cell)]
 #![feature(maybe_uninit_uninit_array)]
+#![feature(min_type_alias_impl_trait)]
 #![allow(rustc::default_hash_types)]
 #![deny(unaligned_references)]
 
diff --git a/compiler/rustc_data_structures/src/vec_map.rs b/compiler/rustc_data_structures/src/vec_map.rs
index 1786fa340cc..e3fa587985d 100644
--- a/compiler/rustc_data_structures/src/vec_map.rs
+++ b/compiler/rustc_data_structures/src/vec_map.rs
@@ -1,6 +1,6 @@
 use std::borrow::Borrow;
 use std::iter::FromIterator;
-use std::slice::{Iter, IterMut};
+use std::slice::Iter;
 use std::vec::IntoIter;
 
 use crate::stable_hasher::{HashStable, StableHasher};
@@ -67,9 +67,13 @@ where
         self.into_iter()
     }
 
-    pub fn iter_mut(&mut self) -> IterMut<'_, (K, V)> {
+    pub fn iter_mut(&mut self) -> impl Iterator<Item = (&K, &mut V)> {
         self.into_iter()
     }
+
+    pub fn retain(&mut self, f: impl Fn(&(K, V)) -> bool) {
+        self.0.retain(f)
+    }
 }
 
 impl<K, V> Default for VecMap<K, V> {
@@ -108,12 +112,12 @@ impl<'a, K, V> IntoIterator for &'a VecMap<K, V> {
 }
 
 impl<'a, K, V> IntoIterator for &'a mut VecMap<K, V> {
-    type Item = &'a mut (K, V);
-    type IntoIter = IterMut<'a, (K, V)>;
+    type Item = (&'a K, &'a mut V);
+    type IntoIter = impl Iterator<Item = Self::Item>;
 
     #[inline]
     fn into_iter(self) -> Self::IntoIter {
-        self.0.iter_mut()
+        self.0.iter_mut().map(|(k, v)| (&*k, v))
     }
 }