9.3.4 Implementation bugs and limitations

The current implementation of submodules has a couple of minor limitations.

• The compiler sometimes reports spurious errors if you define an equivalence type in a submodule and export it as an abstract type.
• Using ‘mmake’ to do parallel makes (e.g. ‘mmake --jobs 2’) doesn’t always work correctly if you are using nested submodules. (The work-around is to use separate submodules instead of nested submodules, i.e. to put the submodules in separate source files.)