foo(
a=
, 3)
-----
Groovy script
  Method call
    Reference expression
      PsiElement(identifier)('foo')
    Arguments
      PsiElement(()('(')
      PsiWhiteSpace('\n')
      Assignment expression
        Reference expression
          PsiElement(identifier)('a')
        PsiElement(=)('=')
        PsiErrorElement:Expression expected
          <empty list>
      PsiWhiteSpace('\n')
      PsiElement(,)(',')
      PsiWhiteSpace(' ')
      Literal
        PsiElement(Integer)('3')
      PsiElement())(')')