SOURCE_FILE
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "a"
    PARAM_LIST
      L_PAREN "("
      R_PAREN ")"
    WHITESPACE " "
    RET_TYPE
      THIN_ARROW "->"
      WHITESPACE " "
      PATH_TYPE
        PATH
          PATH_SEGMENT
            NAME_REF
              IDENT "Foo"
            GENERIC_ARG_LIST
              L_ANGLE "<"
              TYPE_ARG
                PATH_TYPE
                  PATH
                    PATH
                      PATH_SEGMENT
                        NAME_REF
                          IDENT "bar"
                    COLON2 "::"
                    PATH_SEGMENT
                      NAME_REF
                        IDENT "Baz"
              R_ANGLE ">"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n\n"
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "b"
    PARAM_LIST
      L_PAREN "("
      PARAM
        WILDCARD_PAT
          UNDERSCORE "_"
        COLON ":"
        WHITESPACE " "
        IMPL_TRAIT_TYPE
          IMPL_KW "impl"
          WHITESPACE " "
          TYPE_BOUND_LIST
            TYPE_BOUND
              PATH_TYPE
                PATH
                  PATH_SEGMENT
                    NAME_REF
                      IDENT "FnMut"
                    PARAM_LIST
                      L_PAREN "("
                      PARAM
                        PATH_TYPE
                          PATH
                            PATH
                              PATH_SEGMENT
                                NAME_REF
                                  IDENT "x"
                            COLON2 "::"
                            PATH_SEGMENT
                              NAME_REF
                                IDENT "Y"
                      R_PAREN ")"
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n\n"
  FN
    FN_KW "fn"
    WHITESPACE " "
    NAME
      IDENT "c"
    PARAM_LIST
      L_PAREN "("
      PARAM
        WILDCARD_PAT
          UNDERSCORE "_"
        COLON ":"
        WHITESPACE " "
        IMPL_TRAIT_TYPE
          IMPL_KW "impl"
          WHITESPACE " "
          TYPE_BOUND_LIST
            TYPE_BOUND
              PATH_TYPE
                PATH
                  PATH_SEGMENT
                    NAME_REF
                      IDENT "FnMut"
                    PARAM_LIST
                      L_PAREN "("
                      PARAM
                        REF_TYPE
                          AMP "&"
                          PATH_TYPE
                            PATH
                              PATH
                                PATH_SEGMENT
                                  NAME_REF
                                    IDENT "x"
                              COLON2 "::"
                              PATH_SEGMENT
                                NAME_REF
                                  IDENT "Y"
                      R_PAREN ")"
      R_PAREN ")"
    WHITESPACE " "
    BLOCK_EXPR
      STMT_LIST
        L_CURLY "{"
        R_CURLY "}"
  WHITESPACE "\n"