Declaring a variable with AS clause does not assign any type to it in VFP.
Only assigning a value would actually change variable type

LOCAL test1 AS Number
? TYPE("test1")    && L
test1 = 0
? TYPE("test1")    && N
test1 = Null
? TYPE("test1")    && still N

>Ive also tried to define strong type variable without success e.g.
>
>LOCAL TEST1 AS NUMBER
>TEST1 = NULL
>
< snip >