diff --git a/.travis.yml b/.travis.yml
index 530ef434e..271673cbf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -216,6 +216,10 @@ matrix:
   - os: linux
     env: LLVM_VERSION=3.7.0
     compiler: clang
+    addons:
+      apt:
+        sources: ['ubuntu-toolchain-r-test']
+        packages: g++-7
 
   - os: linux
     env: LLVM_VERSION=3.7.1