required newline for local definitions in ZF expressions

It seems that a local definition in a ZF expression with let always requires a newline. I would expect this to work:

Start = [x\\x<-[],let y=1]

But a newline is required (even when another generator is placed after the let)

Start = [x\\x<-[],let y=1
]

A newline is also required when the let is followed by another generator. Is this by design?