An ActionContainer array should itself be an ActionContainer

[a2]

This would alleviate the need for the + operator.

Before:

let shortcut = buildShortcut(
    foo() +
    bar() +
    baz()
)

After:

let shortcut = buildShortcut([
    foo(),
    bar(),
    baz()
])

[a2]

Not sure if this is actually even possible due to type constraint limitations.