reject unsupported worker-wrapper source shapes

test/invariants.ml

@@ -13,6 +13,13 @@ let assert_target_invalid msg term =
   | Ok () -> failwith msg
   | Error _ -> ()
 
+let assert_invalid_arg msg f =
+  try
+    let _ = f () in
+    failwith msg
+  with
+  | Invalid_argument _ -> ()
+
 let find_case name =
   match List.find_opt (fun (case : Corpus.case) -> String.equal case.name name) Corpus.all with
   | Some case -> case
@@ -72,4 +79,15 @@ let () =
          wrap_body = Target.Tuple [Target.Int 0; Target.Bool true];
          worker_body = Target.Tuple [Target.Var "u0"; Target.Bool true];
          in_term = Target.Var "wrapper";
-       })
+       });
+  assert_invalid_arg
+    "expected unsupported worker-wrapper source shape to be rejected"
+    (fun () ->
+       Pipeline.compile
+         { Pipeline.default_flags with unsafe_repr_eq = false; unsafe_strict_unroll = false }
+         (Types.TArrow (Types.TPair (Types.TInt, Types.TBool), Types.TPair (Types.TInt, Types.TBool)))
+         (Source.Lam
+            ( "p",
+              Types.TPair (Types.TInt, Types.TBool),
+              Types.TPair (Types.TInt, Types.TBool),
+              Source.Pair (Source.Int 0, Source.Bool true) )))