How to have strongly typed numerical values?

[anonymous]

On Thursday, 6 September 2012 at 12:22:08 UTC, David Nadlinger 
wrote:
> Can you elaborate on that? I must admit that I didn't actively 
> work on std.units for quite some while now, as general interest 
> in it seemed to have faded (I'm glad to be proven wrong, 
> though), but adding quantities of the same type should 
> definitely work.

Maybe I'm missing something fundamental, but this little test 
fails:
---
auto foo = baseUnit!"foo";
auto foo2 = foo + foo;
---
Error: incompatible types for ((foo) + (foo)): 
'BaseUnit!("foo",null)' and 'BaseUnit!("foo",null)'

> And what do you mean by "different scopes"? If the unit types 
> are different, the quantity types should be different as well.

In the following, S1.foo and S2.foo are of the same type. I think 
they shouldn't be; just like S1.Bar and S2.Bar are different 
types.
---
struct S1 {enum foo = baseUnit!"foo"; struct Bar {}}
struct S2 {enum foo = baseUnit!"foo"; struct Bar {}}
---