ReErased regions are local

Author: Lukas Markeffsky

compiler/rustc_type_ir/src/lib.rs

@@ -220,7 +220,8 @@ bitflags! {
                                           // which is different from how types/const are freshened.
                                           | TypeFlags::HAS_TY_FRESH.bits
                                           | TypeFlags::HAS_CT_FRESH.bits
-                                          | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits;
+                                          | TypeFlags::HAS_FREE_LOCAL_REGIONS.bits
+                                          | TypeFlags::HAS_RE_ERASED.bits;
 
         /// Does this have `Projection`?
         const HAS_TY_PROJECTION           = 1 << 10;

tests/ui/mir/issue-107678-projection-with-lifetime.rs

@@ -0,0 +1,20 @@
+// build-pass
+
+#![crate_type = "lib"]
+
+pub trait StreamOnce {
+    type Error;
+}
+
+pub trait ResetStream: StreamOnce {
+    fn reset(&mut self) -> Result<(), Self::Error>;
+}
+
+impl<'a> ResetStream for &'a str
+    where Self: StreamOnce
+{
+    #[inline]
+    fn reset(&mut self) -> Result<(), Self::Error> {
+        Ok(())
+    }
+}

tests/ui/recursion/issue-83150.stderr

@@ -9,9 +9,11 @@ LL |     func(&mut iter.map(|x| x + 1))
    = help: a `loop` may express intention better if this is on purpose
    = note: `#[warn(unconditional_recursion)]` on by default
 
-error[E0275]: overflow evaluating the requirement `Map<&mut Map<&mut Map<&mut Map<..., ...>, ...>, ...>, ...>: Iterator`
+error[E0275]: overflow evaluating the requirement `Map<&mut std::ops::Range<u8>, [closure@$DIR/issue-83150.rs:12:24: 12:27]>: Iterator`
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_83150`)
+   = note: required for `&mut Map<&mut std::ops::Range<u8>, [closure@$DIR/issue-83150.rs:12:24: 12:27]>` to implement `Iterator`
+   = note: 65 redundant requirements hidden
    = note: required for `&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<..., ...>, ...>, ...>, ...>, ...>, ...>, ...>` to implement `Iterator`
    = note: the full type name has been written to '$TEST_BUILD_DIR/recursion/issue-83150/issue-83150.long-type-hash.txt'