More precisely, you need to wrap the two expressions in curly braces to forge them into a single block expression - see the language spec, in particular §6, §6.11, §6.25. The first is parsed as a block statement, the second as a result expression.
The key takeaway is that the more important concept here is expressions. Statements are required to account for imports and definitions/templates, but these don’t occur in this example at all. Where statements are used, they are just a step on the way to arrive at a proper expression in the end.
Theoretically you could use mechanisms other than a block to combine the two (side-effecting) expressions into one - silly example:
def chain[A, B](a: => A)(b: => B): B = ((x: A) => b)(a)