Given the following contract named `contract.jsligo`: ```js let recursion : ( xs : list<_a>) => option<_a> = (xs : list<_a>) : option<_a> => { return recursion(xs); }; export let main = ([parameter, storage] : [list<string>, int]) : [list<operation>, int] => { let _ = recursion(parameter); return [list([]) as list<operation>, storage] } ``` and the given test fragment: ```js #import "contract.jsligo" "Contract" let _ = Test.originate(Contract.main, 0, 0 as tez); ``` The test execution fails with the following message: ```sh ➤ ~/bin/ligo run test test.jsligo An internal error ocurred. Please, contact the developers. Corner case: recursion not found in env. ``` Note: This problem does not exist if I remove the polymorphic type replacing `_a` by `string` for instance.