Estimated hours taken: 0.25
tests/hard_coded/bidirectional.m:
tests/hard_coded/cycles.m:
Add `import_module char', needed for type `char'.
(Previously, before Simon's changes to implement `:- use_module',
the compiler incorrectly allowed these illegal programs, because
types were imported transitively. That bug is not completely fixed,
but now such types are only imported as if by `:- use_module' rather
than `:- import_module', so the compiler now catches such errors
if the type name is not explicitly module-qualified.)
