DML Type System

[JonatanWaern]

Currently the server only tracks the locations of type references, and does not attempt to construct semantic descriptions of types, as a result we cannot currently:

• Got ref/def on types
• Detect assignments of incorrect type, including passing wrong type of argument
• Detect attempts to access non-shared methods from shared contexts
• Detect cyclic types, or conflicting type names
• Detect invalid layout or bitfield definitions
• Detect invalid usage of hook or saved types
• And probably more stuff