Internal error when type checking Real -> Int assignment

[leonardoalt]

constructor of LValue
interface constructor()

creates
	uint x := 2.5

->

act: internal error: infer type of:Zoom (AlexPn 67 5 20) (IntLit 2) (IntLit 5)
CallStack (from HasCallStack):
  error, called at Type.hs:363:10 in main:Type

[d-xo]

I think the error message will get nicer here once we implement support for the "zoom" dot syntax (e.g. LValue.x) for storage reads, we're running into the internal error here because some of the typechecking machinery around that language feature doesn't exist yet...