Pros & cons of Erlang single assignment and type checking

[Sheheryar Qadir]

Being new to Erlang i was reading about the language from whatever source
that i could find however i was unable to find essential features of
Erlang's non destructive assignment statement plus where can i find up to
date information about the work thats been done or is going on to
incorporate static type checking in Erlang and the consequences of not
accomodating type checking.