Correctly instantiate recursion variables under nested aliases

Like we instantiate nested lambda set variables and nested OIOP
variables for aliases, we need to do the same for recursion variables.

crates/compiler/can/src/scope.rs

@@ -463,6 +463,7 @@ pub fn create_alias(
         let mut hidden = type_variables;
 
         for var in (vars.iter().map(|lv| lv.value.var))
+            .chain(recursion_variables.iter().copied())
             .chain(infer_ext_in_output_variables.iter().copied())
         {
             hidden.remove(&var);