2 files changed, 25 insertions, 6 deletions

diff --git a/crates/ra_proc_macro/src/lib.rs b/crates/ra_proc_macro/src/lib.rs
index 63da9f1b4..b200fd126 100644
--- a/crates/ra_proc_macro/src/lib.rs
+++ b/crates/ra_proc_macro/src/lib.rs
@@ -12,6 +12,7 @@ pub mod msg;
 use process::{ProcMacroProcessSrv, ProcMacroProcessThread};
 use ra_tt::{SmolStr, Subtree};
 use std::{
+    ffi::OsStr,
     path::{Path, PathBuf},
     sync::Arc,
 };
@@ -56,8 +57,15 @@ pub struct ProcMacroClient {
 }
 
 impl ProcMacroClient {
-    pub fn extern_process(process_path: &Path) -> Result<ProcMacroClient, std::io::Error> {
-        let (thread, process) = ProcMacroProcessSrv::run(process_path)?;
+    pub fn extern_process<I, S>(
+        process_path: &Path,
+        args: I,
+    ) -> Result<ProcMacroClient, std::io::Error>
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>,
+    {
+        let (thread, process) = ProcMacroProcessSrv::run(process_path, args)?;
         Ok(ProcMacroClient {
             kind: ProcMacroClientKind::Process { process: Arc::new(process), thread },
         })
diff --git a/crates/ra_proc_macro/src/process.rs b/crates/ra_proc_macro/src/process.rs
index e8c85be38..f851570bc 100644
--- a/crates/ra_proc_macro/src/process.rs
+++ b/crates/ra_proc_macro/src/process.rs
@@ -9,6 +9,7 @@ use crate::rpc::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTas
 use io::{BufRead, BufReader};
 use std::{
     convert::{TryFrom, TryInto},
+    ffi::OsStr,
     io::{self, Write},
     path::{Path, PathBuf},
     process::{Child, Command, Stdio},
@@ -44,8 +45,13 @@ impl Drop for Process {
 }
 
 impl Process {
-    fn run(process_path: &Path) -> Result<Process, io::Error> {
+    fn run<I, S>(process_path: &Path, args: I) -> Result<Process, io::Error>
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>,
+    {
         let child = Command::new(process_path.clone())
+            .args(args)
             .stdin(Stdio::piped())
             .stdout(Stdio::piped())
             .stderr(Stdio::null())
@@ -74,10 +80,15 @@ impl Process {
 }
 
 impl ProcMacroProcessSrv {
-    pub fn run(
+    pub fn run<I, S>(
         process_path: &Path,
-    ) -> Result<(ProcMacroProcessThread, ProcMacroProcessSrv), io::Error> {
-        let process = Process::run(process_path)?;
+        args: I,
+    ) -> Result<(ProcMacroProcessThread, ProcMacroProcessSrv), io::Error>
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<OsStr>,
+    {
+        let process = Process::run(process_path, args)?;
 
         let (task_tx, task_rx) = bounded(0);
         let handle = jod_thread::spawn(move || {