fix(build): Remove ambiguity in service method call

[yonran]

Motivation

I have an existing proto with a method that was unfortunately named Drop, and the tonic stub did not compile. When calling methods on Arc where the method is also defined on Arc (e.g. drop and clone), calling inner.#method_ident(request) will actually attempt to call the Arc method instead of the method on the service, resulting in a compile error when building the generated rust file.

Here is an excerpt from a test proto, which I have added as tests/ambiguous_methods/proto/ambiguous_methods.proto:

service HelloService {
    rpc Drop (DropReq) returns (DropResp);
    rpc Clone (DropReq) returns (DropResp);
}

Solution

This change removes the ambiguity by dereferencing the inner Arc.

An alternative fix would be to use the fully qualified syntax for method calls. I believe that this change should be good enough because #server_trait is only known to be #server_trait : Send + Sync + 'static, and Sync and Send define no other methods.

See also: my PR to grpc-rust for the exact same issue a year ago stepancheg/grpc-rust#142

[LucioFranco]

Great catch! and nice fix! I will get a bump release out.