SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "foo"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          IDENT_PAT
            NAME
              IDENT "x"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          BOX_EXPR
            BOX_KW "box"
            WHITESPACE " "
            LITERAL
              INT_NUMBER "1i32"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          IDENT_PAT
            NAME
              IDENT "y"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          TUPLE_EXPR
            L_PAREN "("
            BOX_EXPR
              BOX_KW "box"
              WHITESPACE " "
              LITERAL
                INT_NUMBER "1i32"
            COMMA ","
            WHITESPACE " "
            BOX_EXPR
              BOX_KW "box"
              WHITESPACE " "
              LITERAL
                INT_NUMBER "2i32"
            R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE "\n    "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          IDENT_PAT
            NAME
              IDENT "z"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          CALL_EXPR
            PATH_EXPR
              PATH
                PATH_SEGMENT
                  NAME_REF
                    IDENT "Foo"
            ARG_LIST
              L_PAREN "("
              BOX_EXPR
                BOX_KW "box"
                WHITESPACE " "
                LITERAL
                  INT_NUMBER "1i32"
              COMMA ","
              WHITESPACE " "
              BOX_EXPR
                BOX_KW "box"
                WHITESPACE " "
                LITERAL
                  INT_NUMBER "2i32"
              R_PAREN ")"
          SEMICOLON ";"
        WHITESPACE "\n"
        R_CURLY "}"
  WHITESPACE "\n"
