foo -> UField (name = foo)
bar -> UField (name = bar)
baz -> UField (name = baz)
foobarbaz -> UField (name = foobarbaz)
foo -> USimpleNameReferenceExpression (identifier = foo)
bar -> USimpleNameReferenceExpression (identifier = bar)
baz -> USimpleNameReferenceExpression (identifier = baz)