KtFile: TypeConstraints.kt
  PACKAGE_DIRECTIVE
    <empty list>
  IMPORT_LIST
    <empty list>
  CLASS
    PsiElement(class)('class')
    PsiWhiteSpace(' ')
    PsiElement(IDENTIFIER)('foo')
    TYPE_PARAMETER_LIST
      PsiElement(LT)('<')
      TYPE_PARAMETER
        PsiElement(IDENTIFIER)('T')
      PsiElement(GT)('>')
    PsiWhiteSpace(' ')
    PsiElement(where)('where')
    PsiWhiteSpace(' ')
    TYPE_CONSTRAINT_LIST
      TYPE_CONSTRAINT
        REFERENCE_EXPRESSION
          PsiElement(IDENTIFIER)('T')
        PsiWhiteSpace(' ')
        PsiElement(COLON)(':')
        PsiWhiteSpace(' ')
        TYPE_REFERENCE
          USER_TYPE
            REFERENCE_EXPRESSION
              PsiElement(IDENTIFIER)('T')
    PsiWhiteSpace(' ')
    CLASS_BODY
      PsiElement(LBRACE)('{')
      PsiWhiteSpace('\n\n')
      PsiElement(RBRACE)('}')