Type equations
Simple case: inference rule for a constant; type of concept instance always equals some concrete type
Example 1: type of instance of integer literal is always instance of IntegerType (int)
Another simple case: inference rule for variable reference; type of concept instance equals to the type of some other node
Example 2
Subtyping
checking, inference,
Example. conditional ternary operator
Example for each loop
Subtyping
defining