-Wimplicit-fallthrough

Author: vinay-deshmukh

libc/cmake/modules/LLVMLibCTestRules.cmake

@@ -33,7 +33,7 @@ function(_get_common_test_compile_options output_var c_test flags)
     endif()
     # list(APPEND compile_options "-Wconversion")
     # list(APPEND compile_options "-Wno-sign-conversion")
-    # list(APPEND compile_options "-Wimplicit-fallthrough")
+    list(APPEND compile_options "-Wimplicit-fallthrough")
     list(APPEND compile_options "-Wwrite-strings")
     list(APPEND compile_options "-Wextra-semi")
     # Silence this warning because _Complex is a part of C99.