A reference refers to the value of the field defined within the nearest enclosing scope.

If a reference doesn’t match a field within the same file, then it may match a top-level field defined in any other file making up the same CUE package.

If there is still no match then it may match a predefined value, such as a predefined bound.

val: 1

A: {
	val: 2
	B:   val // Matches the inner val
}

A: {
	C: val // Matches the top-level val
}

B: val // Matches the top-level val

$ cue eval file.cue
val: 1
A: {
    val: 2
    C:   1
    B:   2
}
B: 1