diff --git a/cpp/ql/test/library-tests/regex/Consistency.expected b/cpp/ql/test/library-tests/regex/Consistency.expected
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/cpp/ql/test/library-tests/regex/Consistency.ql b/cpp/ql/test/library-tests/regex/Consistency.ql
new file mode 100644
index 00000000000..c99a56fb90b
--- /dev/null
+++ b/cpp/ql/test/library-tests/regex/Consistency.ql
@@ -0,0 +1,11 @@
+/**
+ * Regression guard: every corpus regex must parse without leaving any
+ * character unaccounted for. Expected output is empty.
+ */
+
+import cpp
+import semmle.code.cpp.regex.internal.ParseRegExp
+
+from RegExp re, int i
+where re.failedToParse(i)
+select re, i, re.getChar(i)