diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-standard-types.h b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-standard-types.h
--- a/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-standard-types.h
+++ b/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-standard-types.h
@@ -9,7 +9,7 @@
 typedef unsigned short      uint16_t;   // NOLINT
 typedef unsigned long       uint32_t;   // NOLINT
 typedef unsigned long long  uint64_t;   // NOLINT
-#ifndef _WIN32
+#ifndef _MSC_VER
 typedef unsigned long long  size_t;     // NOLINT
 #endif
 typedef long                intptr_t;   // NOLINT