Cannot use as on anything unioned with a pointer type

[icy-arctic-fox]

The as method can't be used on a union when one of the types is a pointer.

The following doesn't compile:

a = Pointer(UInt8).new(1) || 2
p! typeof(a), a
b = a.as(Pointer(UInt8))
p! typeof(b), b

Gives the error:

 3 | b = a.as(Pointer(UInt8))
         ^
Error: can't cast (Int32 | Pointer(UInt8)) to Pointer(UInt8)

Crystal 1.7.2

[Blacksmoke16]

Related to/duplicate of #9281?

[beta-ziliani]

Definitively a duplicate