Cyclic bounds generate stack overflow error

[Erik Hogeman]

When a bound extends itself, a stack overflow error occurs instead of a normal error message. For example, the code below will generate a stack overflow error when compiled with JastAddJ:

interface Y { <S extends S> void execute(S s); }

[Jesper Öqvist]

Fix stack overflow for cyclic bounds erasure

This fixes a stack overflow in the erasure() attribute when there is a cyclic bound in a type variable.

There needs to be an error check added for cyclic bounds now that the compiler no longer crashes whenever there is a cyclic bound.

fixes #65 (bitbucket)

→ <<cset c635f52a0b20>>