From 9b67b272baf204550613dbd00c8057a3c6d13dfa Mon Sep 17 00:00:00 2001
From: Dale Wijnand <dale.wijnand@gmail.com>
Date: Thu, 6 Sep 2018 00:26:29 +0100
Subject: [PATCH] Don't use an empty RUSTC_WRAPPER

---
 src/cargo/util/rustc.rs  | 13 +++++++------
 tests/testsuite/check.rs |  6 ++++++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/cargo/util/rustc.rs b/src/cargo/util/rustc.rs
index 1c25a79bef1..af6d6312131 100644
--- a/src/cargo/util/rustc.rs
+++ b/src/cargo/util/rustc.rs
@@ -66,12 +66,13 @@ impl Rustc {
 
     /// Get a process builder set up to use the found rustc version, with a wrapper if Some
     pub fn process(&self) -> ProcessBuilder {
-        if let Some(ref wrapper) = self.wrapper {
-            let mut cmd = util::process(wrapper);
-            cmd.arg(&self.path);
-            cmd
-        } else {
-            self.process_no_wrapper()
+        match self.wrapper {
+            Some(ref wrapper) if !wrapper.as_os_str().is_empty() => {
+                let mut cmd = util::process(wrapper);
+                cmd.arg(&self.path);
+                cmd
+            }
+            _ => self.process_no_wrapper()
         }
     }
 
diff --git a/tests/testsuite/check.rs b/tests/testsuite/check.rs
index 0468f6a830c..a0984950361 100644
--- a/tests/testsuite/check.rs
+++ b/tests/testsuite/check.rs
@@ -684,3 +684,9 @@ fn proc_macro() {
         ).build();
     p.cargo("check -v").env("RUST_LOG", "cargo=trace").run();
 }
+
+#[test]
+fn does_not_use_empty_rustc_wrapper() {
+    let p = project().file("src/lib.rs", "").build();
+    p.cargo("check").env("RUSTC_WRAPPER", "").run();
+}