diff --git a/clang-tools-extra/test/clang-tidy/infrastructure/validate-check-names.cpp b/clang-tools-extra/test/clang-tidy/infrastructure/validate-check-names.cpp
--- a/clang-tools-extra/test/clang-tidy/infrastructure/validate-check-names.cpp
+++ b/clang-tools-extra/test/clang-tidy/infrastructure/validate-check-names.cpp
@@ -1,2 +1,6 @@
 // Check names may only contain alphanumeric characters, '-', '_', and '.'.
-// RUN: clang-tidy -checks=* -list-checks | grep '^    ' | cut -b5- | not grep -v '^[a-zA-Z0-9_.\-]\+$'
+// RUN: clang-tidy -checks=* -list-checks | grep '^    ' | cut -b5- | not grep -v '^[a-zA-Z0-9_.\-]*$'
+
+// Hack: The regex should ideally use \+ instead of * to require at least
+// one char, but if grep is a MSYS based tool, the command line argument
+// can end up misparsed by the MSYS runtime.