Auto merge of #6582 - rail-rain:ice_6539, r=flip1995

Fix the ICE 6539

Fixes #6539

It happened because `zero_sized_map_values` used `layout_of` with types from type aliases, which is essentially the same as the ICE 4968.

---

changelog: Fix an ICE in `zero_sized_map_values`

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/ui/crashes/ice-6539.rs b/tests/ui/crashes/ice-6539.rs
new file mode 100644
index 00000000000..ac6c3e4aba0
--- /dev/null
+++ b/tests/ui/crashes/ice-6539.rs
@@ -0,0 +1,16 @@
+// The test for the ICE 6539: https://github.com/rust-lang/rust-clippy/issues/6539.
+// The cause is that `zero_sized_map_values` used `layout_of` with types from type aliases,
+// which is essentially the same as the ICE 4968.
+// Note that only type aliases with associated types caused the crash this time,
+// not others such as trait impls.
+
+use std::collections::{BTreeMap, HashMap};
+
+pub trait Trait {
+    type Assoc;
+}
+
+type TypeAlias<T> = HashMap<(), <T as Trait>::Assoc>;
+type TypeAlias2<T> = BTreeMap<(), <T as Trait>::Assoc>;
+
+fn main() {}