Missing parentheses around SELECT as expressions

[cpg314]

local u = import 'sqlsonnet.libsonnet';

 local x = u.select({
   fields: [1.5],
});

u.select({
    fields: [
        u.fn('round', [
        x
        ])
    ],
})

generates

SELECT
  round(
    SELECT
      1.5
  )

which is not valid in Clickhouse's dialect.

On the other hand,

SELECT
  round(
    (SELECT
      1.5)
  )

is fine, so we are just missing parentheses.