SOURCE_FILE@0..24
  FN@0..23
    FN_KW@0..2 "fn"
    WHITESPACE@2..3 " "
    NAME@3..6
      IDENT@3..6 "foo"
    PARAM_LIST@6..12
      L_PAREN@6..7 "("
      PARAM@7..11
        IDENT_PAT@7..8
          NAME@7..8
            IDENT@7..8 "a"
        COLON@8..9 ":"
        WHITESPACE@9..10 " "
        PATH_TYPE@10..11
          PATH@10..11
            PATH_SEGMENT@10..11
              NAME_REF@10..11
                IDENT@10..11 "A"
      R_PAREN@11..12 ")"
    WHITESPACE@12..13 " "
    BLOCK_EXPR@13..23
      L_CURLY@13..14 "{"
      WHITESPACE@14..19 "\n    "
      FIELD_EXPR@19..21
        PATH_EXPR@19..20
          PATH@19..20
            PATH_SEGMENT@19..20
              NAME_REF@19..20
                IDENT@19..20 "a"
        DOT@20..21 "."
      WHITESPACE@21..22 "\n"
      R_CURLY@22..23 "}"
  WHITESPACE@23..24 "\n"
error 21..21: expected field name or number