1 files changed, 28 insertions, 27 deletions

diff --git a/crates/ra_toolchain/src/lib.rs b/crates/ra_toolchain/src/lib.rs
index 110c92c88..afa76619d 100644
--- a/crates/ra_toolchain/src/lib.rs
+++ b/crates/ra_toolchain/src/lib.rs
@@ -14,7 +14,8 @@ use anyhow::{bail, Result};
 /// E.g., `get_path_for_executable("cargo")` may return just `cargo` if that
 /// gives a valid Cargo executable; or it may return a full path to a valid
 /// Cargo.
-pub fn get_path_for_executable(executable_name: impl AsRef<str>) -> Result<PathBuf> {
+pub fn get_path_for_executable(executable_name: &'static str) -> Result<PathBuf> {
+    assert!(executable_name == "rustc" || executable_name == "cargo");
     // The current implementation checks three places for an executable to use:
     // 1) Appropriate environment variable (erroring if this is set but not a usable executable)
     //      example: for cargo, this checks $CARGO environment variable; for rustc, $RUSTC; etc
@@ -23,46 +24,46 @@ pub fn get_path_for_executable(executable_name: impl AsRef<str>) -> Result<PathB
     // 3) `~/.cargo/bin/<executable_name>`
     //      example: for cargo, this tries ~/.cargo/bin/cargo
     //      It seems that this is a reasonable place to try for cargo, rustc, and rustup
-    let executable_name = executable_name.as_ref();
     let env_var = executable_name.to_ascii_uppercase();
     if let Ok(path) = env::var(&env_var) {
-        if is_valid_executable(&path) {
+        return if is_valid_executable(&path) {
             Ok(path.into())
         } else {
             bail!(
                 "`{}` environment variable points to something that's not a valid executable",
                 env_var
             )
+        };
+    }
+
+    if is_valid_executable(executable_name) {
+        return Ok(executable_name.into());
+    }
+
+    if let Some(mut path) = home::home_dir() {
+        path.push(".cargo");
+        path.push("bin");
+        path.push(executable_name);
+        if is_valid_executable(&path) {
+            return Ok(path);
         }
-    } else {
-        if is_valid_executable(executable_name) {
-            return Ok(executable_name.into());
-        }
-        if let Some(mut path) = ::home::home_dir() {
-            path.push(".cargo");
-            path.push("bin");
-            path.push(executable_name);
-            if is_valid_executable(&path) {
-                return Ok(path);
-            }
-        }
-        // This error message may also be caused by $PATH or $CARGO/$RUSTC/etc not being set correctly
-        // for VSCode, even if they are set correctly in a terminal.
-        // On macOS in particular, launching VSCode from terminal with `code <dirname>` causes VSCode
-        // to inherit environment variables including $PATH, $CARGO, $RUSTC, etc from that terminal;
-        // but launching VSCode from Dock does not inherit environment variables from a terminal.
-        // For more discussion, see #3118.
-        bail!(
-            "Failed to find `{}` executable. Make sure `{}` is in `$PATH`, or set `${}` to point to a valid executable.",
-            executable_name, executable_name, env_var
-        )
     }
+    // This error message may also be caused by $PATH or $CARGO/$RUSTC/etc not being set correctly
+    // for VSCode, even if they are set correctly in a terminal.
+    // On macOS in particular, launching VSCode from terminal with `code <dirname>` causes VSCode
+    // to inherit environment variables including $PATH, $CARGO, $RUSTC, etc from that terminal;
+    // but launching VSCode from Dock does not inherit environment variables from a terminal.
+    // For more discussion, see #3118.
+    bail!(
+        "Failed to find `{}` executable. Make sure `{}` is in `$PATH`, or set `${}` to point to a valid executable.",
+        executable_name, executable_name, env_var
+    )
 }
 
 /// Does the given `Path` point to a usable executable?
 ///
 /// (assumes the executable takes a `--version` switch and writes to stdout,
 /// which is true for `cargo`, `rustc`, and `rustup`)
-fn is_valid_executable(p: impl AsRef<Path>) -> bool {
-    Command::new(p.as_ref()).arg("--version").output().is_ok()
+fn is_valid_executable(p: &'static str) -> bool {
+    Command::new(p).arg("--version").output().is_ok()
 }