Fix compiling with 'ipc' feature enabled

Author: Xanewok

Cargo.lock

@@ -14,6 +14,7 @@ log = "0.4"
 rand = "0.7"
 clippy_lints = { git = "https://github.com/rust-lang/rust-clippy", rev = "8b7f7e667268921c278af94ae30a61e87a22b22b", optional = true }
 tokio = { version = "0.1", optional = true }
+failure = { version = "0.1" }
 futures = { version = "0.1", optional = true }
 serde = { version = "1", features = ["derive"], optional = true }
 rls-data = { version = "0.19", optional = true }

rls-rustc/Cargo.toml

@@ -2,6 +2,7 @@ use std::collections::{HashMap, HashSet};
 use std::io;
 use std::path::{Path, PathBuf};
 
+use failure::Fail;
 use futures::Future;
 
 use rls_ipc::client::{Client as JointClient, RpcChannel, RpcError};

rls-rustc/src/ipc.rs

@@ -126,7 +126,7 @@ pub struct CompilationResult {
 fn run_out_of_process(
     changed: HashMap<PathBuf, String>,
     args: &[String],
-    envs: &HashMap<String, Option<OsString>>,
+    envs: &BTreeMap<String, Option<OsString>>,
     clippy_preference: ClippyPreference,
 ) -> Result<CompilationResult, ()> {
     let analysis = Arc::default();