References and Visibility
A reference refers to the value of the field defined within nearest enclosing scope.
If no field matches the reference within the file, it may match a top-level field defined in any other file of the same package.
If there is still no match, it may match a predefined value.
scopes.cue:
v: 1 a: { v: 2 b: v // matches the inner v } a: { c: v // matches the top-level v } b: v
$ cue eval scopes.cue
v: 1 a: { v: 2 b: 2 c: 1 } b: 1