3 ,---- Stack trace -- - - -
4 | base_attr_nullable_alt4::Foo::run_other (alt/base_attr_nullable_alt4.nit:42)
5 | base_attr_nullable_alt4::Bar::init (alt/base_attr_nullable_alt4.nit:69)
6 | base_attr_nullable_alt4::Sys::main (alt/base_attr_nullable_alt4.nit:81)
7 `------------------- - - -