Globally enabling cargo pipelining seems to break RLS

[vi]

$ rls --version
rls 1.36.0 (9692ca8 2019-05-18)
$ cargo new --bin qwer
     Created binary (application) `qwer` package
$ cd qwer/
$ cargo add url
      Adding url v1.7.2 to dependencies
$ cargo add smart_default
WARN: Added `smart-default` instead of `smart_default`
      Adding smart-default v0.5.2 to dependencies
$ rls --cli
...
{"jsonrpc":"2.0","method":"window/progress","params":{"done":true,"id":"progress_0","message":null,"percentage":null,"title":"Indexing"}}
> quit
2: Ack

But if I uncomment pipelining = true in ~/.cargo/config:

$ rm -Rf target/rls/
$ rls --cli
...
error: Option 'error-format' given more than once

{"jsonrpc":"2.0","method":"window/progress","params":{"done":true,"id":"progress_1","message":null,"percentage":null,"title":"Building"}}
{"jsonrpc":"2.0","method":"window/progress","params":{"done":null,"id":"progress_0","message":null,"percentage":null,"title":"Indexing"}}
{"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"diagnostics":[{"message":"build failed","range":{"end":{"character":0,"line":9999},"start":{"character":0,"line":0}},"severity":1}],"uri":"file:///tmp/qwer/Cargo.toml"}}
{"jsonrpc":"2.0","method":"window/progress","params":{"done":true,"id":"progress_0","message":null,"percentage":null,"title":"Indexing"}}

[tesuji]

Did you use sccache? What is its version?

[vi]

I don't remember setting sccache up. Unless it is deployed by cargo/rustup by default it should be unused.

$ sccache
bash: sccache: command not found

[Xanewok]

Fixed with #1500