["abc", , 3, 4+8]
-----
Groovy script
  Generalized list
    PsiElement([)('[')
    Literal
      PsiElement(Gstring)('"abc"')
    PsiElement(,)(',')
    PsiErrorElement:Expression expected
      <empty list>
    PsiWhiteSpace(' ')
    PsiElement(,)(',')
    PsiWhiteSpace(' ')
    Literal
      PsiElement(Integer)('3')
    PsiElement(,)(',')
    PsiWhiteSpace(' ')
    Additive expression
      Literal
        PsiElement(Integer)('4')
      PsiElement(+)('+')
      Literal
        PsiElement(Integer)('8')
    PsiElement(])(']')