unikernel/duniverse/ppxlib/test/driver/error_embedding/raiser.ml

@@ -0,0 +1,13 @@
+open Ppxlib
+
+let rule =
+  let expand ~loc ~path:_ =
+    Location.raise_errorf ~loc "Raising inside the rewriter"
+  in
+  Extension.declare "raise" Extension.Context.expression
+    Ast_pattern.(pstr nil)
+    expand
+  |> Context_free.Rule.extension
+
+let () = Driver.register_transformation ~rules:[ rule ] "test"
+let () = Driver.standalone ()