Auto merge of #18162 - ChayimFriedman2:gat-object-safe, r=Veykril

fix: Consider lifetime GATs object unsafe

Fixes #18156.

Author: bors

crates/hir-ty/src/object_safety.rs

@@ -349,7 +349,7 @@ where
                 ControlFlow::Continue(())
             } else {
                 let generic_params = db.generic_params(item.into());
-                if generic_params.len_type_or_consts() > 0 {
+                if !generic_params.is_empty() {
                     cb(ObjectSafetyViolation::GAT(it))
                 } else {
                     ControlFlow::Continue(())

crates/hir-ty/src/object_safety/tests.rs

@@ -378,3 +378,16 @@ pub trait Error: core::fmt::Debug + core::fmt::Display {
         [("Error", vec![])],
     );
 }
+
+#[test]
+fn lifetime_gat_is_object_unsafe() {
+    check_object_safety(
+        r#"
+//- minicore: dispatch_from_dyn
+trait Foo {
+    type Bar<'a>;
+}
+"#,
+        [("Foo", vec![ObjectSafetyViolationKind::GAT])],
+    );
+}