SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "func"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        WHITESPACE " "
        LET_STMT
          LET_KW "let"
          WHITESPACE " "
          TUPLE_STRUCT_PAT
            PATH
              PATH_SEGMENT
                NAME_REF
                  IDENT "Some"
            L_PAREN "("
            WILDCARD_PAT
              UNDERSCORE "_"
            R_PAREN ")"
          WHITESPACE " "
          EQ "="
          WHITESPACE " "
          BLOCK_EXPR
            STMT_LIST
              L_CURLY "{"
              CALL_EXPR
                PATH_EXPR
                  PATH
                    PATH_SEGMENT
                      NAME_REF
                        IDENT "Some"
                ARG_LIST
                  L_PAREN "("
                  LITERAL
                    INT_NUMBER "1"
                  R_PAREN ")"
              R_CURLY "}"
          WHITESPACE " "
          LET_ELSE
            ELSE_KW "else"
            WHITESPACE " "
            BLOCK_EXPR
              STMT_LIST
                L_CURLY "{"
                WHITESPACE " "
                MACRO_EXPR
                  MACRO_CALL
                    PATH
                      PATH_SEGMENT
                        NAME_REF
                          IDENT "panic"
                    BANG "!"
                    TOKEN_TREE
                      L_PAREN "("
                      STRING "\"h\""
                      R_PAREN ")"
                WHITESPACE " "
                R_CURLY "}"
          SEMICOLON ";"
        R_CURLY "}"
  WHITESPACE "\n"
error 35: right curly brace `}` before `else` in a `let...else` statement not allowed
