SOURCE_FILE@0..52
  FN@0..51
    FN_KW@0..2 "fn"
    WHITESPACE@2..3 " "
    NAME@3..7
      IDENT@3..7 "main"
    PARAM_LIST@7..9
      L_PAREN@7..8 "("
      R_PAREN@8..9 ")"
    WHITESPACE@9..10 " "
    BLOCK_EXPR@10..51
      L_CURLY@10..11 "{"
      WHITESPACE@11..16 "\n    "
      LET_STMT@16..28
        LET_KW@16..19 "let"
        WHITESPACE@19..20 " "
        REF_PAT@20..22
          AMP@20..21 "&"
          IDENT_PAT@21..22
            NAME@21..22
              IDENT@21..22 "a"
        WHITESPACE@22..23 " "
        EQ@23..24 "="
        WHITESPACE@24..25 " "
        TUPLE_EXPR@25..27
          L_PAREN@25..26 "("
          R_PAREN@26..27 ")"
        SEMICOLON@27..28 ";"
      WHITESPACE@28..33 "\n    "
      LET_STMT@33..49
        LET_KW@33..36 "let"
        WHITESPACE@36..37 " "
        REF_PAT@37..43
          AMP@37..38 "&"
          MUT_KW@38..41 "mut"
          WHITESPACE@41..42 " "
          IDENT_PAT@42..43
            NAME@42..43
              IDENT@42..43 "b"
        WHITESPACE@43..44 " "
        EQ@44..45 "="
        WHITESPACE@45..46 " "
        TUPLE_EXPR@46..48
          L_PAREN@46..47 "("
          R_PAREN@47..48 ")"
        SEMICOLON@48..49 ";"
      WHITESPACE@49..50 "\n"
      R_CURLY@50..51 "}"
  WHITESPACE@51..52 "\n"