The 1st part of the PR adds missing visitor methods to Compiler and also adds examples for composite types to its spec.
And I also noticed in implication & intersection specs messing examples describing "#meta", probably were copy-pasted from sum_spec.rb and left as is. Sum#meta behaviour is defined explicitly and differs from the other composite types, so this PR fixes it.
The 1st part of the PR adds missing visitor methods to Compiler and also adds examples for composite types to its spec.
And I also noticed in implication & intersection specs messing examples describing "#meta", probably were copy-pasted from sum_spec.rb and left as is. Sum#meta behaviour is defined explicitly and differs from the other composite types, so this PR fixes it.