This could be fixed in Java by two simple changes. x = func(null); // func is ignored and x is null proc(null); // proc is ignored and an NPE is thrown. and

This could be fixed in Java by two simple changes. x = func(null); // func is ignored and x is null proc(null); // proc is ignored and an NPE is thrown. and so implicitly y = a(b(c(d(null)))); // a b c d are ignored and y == null This would mean you could treat null like Nothing, threading it through non side effecting functions and only testing the result. If you tried to use it with a side effect, it would halt. The compiler would be free to omit these checks where x is provably not null. For example: foo (x); y = bar(x); The assignment to y does not need a null check, because a null would have thrown NPE in foo. Side effect of this design: code will never receive a null in parameters. Parameter values can be assumed to be definitely not-null by coder and compiler alike. EDIT: one more change would be needed: prim = func(ref) is illegal unless ref can be proved not null. Also, add a no-op built-in, notnull(x) that does nothing except NPE if x is null. That could be used as proof to the compiler.