diff --git a/CMakeLists.txt b/CMakeLists.txt
index c1e0ea56..f9d40a29 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -109,7 +109,7 @@ if (NOT FMT_VARIADIC_TEMPLATES)
 endif ()
 
 # GTest doesn't detect <tuple> with clang.
-if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   target_compile_definitions(gmock PUBLIC GTEST_USE_OWN_TR1_TUPLE=1)
 endif ()