Merge pull request #18944 from WaffleLapkin/trait_upcast_chalk

update chalk, fixing trait upcasting

Author: lnicola

Cargo.lock

@@ -106,10 +106,10 @@ arrayvec = "0.7.4"
 bitflags = "2.4.1"
 cargo_metadata = "0.18.1"
 camino = "1.1.6"
-chalk-solve = { version = "0.98.0", default-features = false }
-chalk-ir = "0.98.0"
-chalk-recursive = { version = "0.98.0", default-features = false }
-chalk-derive = "0.98.0"
+chalk-solve = { version = "0.99.0", default-features = false }
+chalk-ir = "0.99.0"
+chalk-recursive = { version = "0.99.0", default-features = false }
+chalk-derive = "0.99.0"
 crossbeam-channel = "0.5.8"
 dissimilar = "1.0.7"
 dot = "0.1.4"

Cargo.toml

@@ -1163,6 +1163,37 @@ struct Bar {
         );
     }
 
+    #[test]
+    fn trait_upcast_ok() {
+        check_diagnostics(
+            r#"
+//- minicore: coerce_unsized
+trait A: B {}
+trait B {}
+
+fn test(a: &dyn A) -> &dyn B {
+    a
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn trait_upcast_err() {
+        check_diagnostics(
+            r#"
+//- minicore: coerce_unsized
+trait A {} // `A` does not have `B` as a supertrait, so no upcast :c
+trait B {}
+
+fn test(a: &dyn A) -> &dyn B {
+    a
+  //^ error: expected &dyn B, found &dyn A
+}
+"#,
+        );
+    }
+
     #[test]
     fn return_no_value() {
         check_diagnostics_with_disabled(