Description Henrik Lindberg 2010-10-19 19:32:57 EDT

Integer a = null;
Currently results in a type mismatch error "can not convert Object to Integer".
The evaluator already copes with null assignment, so this is only a validation issue.

Unfotunately, it is not enough to only check for direct assignment of null - null values can also be part of type inference in other situations:

var a = if wtf() then null else 2;

where the common type of null and 2 (Integer) is computed.

By introducing a NullType and modifying TypeUtils.isAssignableFrom(Type, Type), and other methods dealing with type compatibility to synthetically allow assignment of null the issue should be solved.