Aliases provide a way to refer to a value by a different identifier. They are declared using an equals sign (=).

An alias is typically used to access a field in an outer scope that has been made inaccessible, or shadowed.
Some of their other uses are also demonstrated in the example below.

Aliases are not members of a struct.
They do not appear in output, and can only be referenced within the scope in which they are defined.

// Alias A provides access to a top-level field
// with a name that is not a valid identifier.
A="a top level field": 1

// Alias B provides access to a dynamic field.
#b:     "a dynamic field"
B=(#b): 2

a: A
b: B

// Alias C provides access to a field that's
// shadowed in c's innermost scope.
c: C={
	field: value: 3
	d: {
		field: C.field.value
$ cue export file.cue
    "a top level field": 1,
    "a": 1,
    "b": 2,
    "a dynamic field": 2,
    "c": {
        "field": {
            "value": 3
        "d": {
            "field": 3

The CUE language specification defines the full list of positions where an alias can be declared.