Build Failed

[takakawa]

It occurs to me when i cargo-build the grpc in my MacBookPro

error[E0658]: `impl Trait` in return position is experimental (see issue #34511)
   --> /Users/gaochuan/.cargo/registry/src/github.com-1ecc6299db9ec823/httpbis-0.6.1/src/common/conn.rs:988:33
    |
988 |     fn recv_http_frame(self) -> impl Future<Item=(Self, HttpFrame), Error=error::Error> {
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: `impl Trait` in argument position is experimental (see issue #34511)
  --> /Users/gaochuan/.cargo/registry/src/github.com-1ecc6299db9ec823/httpbis-0.6.1/src/client_died_error_holder.rs:32:39
   |
32 |     pub fn wrap_future(&self, future: impl Future<Item=(), Error=error::Error>)
   |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: `impl Trait` in return position is experimental (see issue #34511)
  --> /Users/gaochuan/.cargo/registry/src/github.com-1ecc6299db9ec823/httpbis-0.6.1/src/client_died_error_holder.rs:33:12
   |
33 |         -> impl Future<Item=(), Error=()>
   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   Compiling protobuf-codegen v1.6.0
error[E0658]: non-reference pattern used to match a reference (see issue #42640)
  --> /Users/gaochuan/.cargo/registry/src/github.com-1ecc6299db9ec823/httpbis-0.6.1/src/req_resp.rs:10:13
   |
10 |             RequestOrResponse::Request => RequestOrResponse::Response,
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a reference: `&RequestOrResponse::Request`

error[E0658]: non-reference pattern used to match a reference (see issue #42640)
  --> /Users/gaochuan/.cargo/registry/src/github.com-1ecc6299db9ec823/httpbis-0.6.1/src/req_resp.rs:11:13
   |
11 |             RequestOrResponse::Response => RequestOrResponse::Request,
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using a reference: `&RequestOrResponse::Response`

error: aborting due to 5 previous errors

error: Could not compile `httpbis`.
warning: build failed, waiting for other jobs to finish...
error: build failed

[stepancheg]

I think upgrading to the latest stable rust will fix the issue.