diff --git a/mypy.ini b/mypy.ini
index 886b254744..eb98e38e4a 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -35,6 +35,8 @@ follow_imports = error
 # This doesn't get in the way of using the stubs we *do* have.
 ignore_missing_imports = True
 
+# Warn of unreachable or redundant code.
+warn_unreachable = True
 
 #
 #
diff --git a/tools/run-mypy b/tools/run-mypy
index 0a4f6f3708..1284e3f346 100755
--- a/tools/run-mypy
+++ b/tools/run-mypy
@@ -36,10 +36,6 @@ parser.add_argument('-a', '--all', action='store_true',
                     help="check all files, bypassing the default exclude list")
 parser.add_argument('--force', action="store_true",
                     help="run tests despite possible provisioning problems")
-parser.add_argument('--warn-unreachable',
-                    action='store_false',
-                    default=True,
-                    help="warn of unreachable or redundant code; defaults to true")
 args = parser.parse_args()
 
 assert_provisioning_status_ok(args.force)
@@ -77,8 +73,6 @@ if not python_files and not pyi_files:
 extra_args = []
 if args.quick:
     extra_args.append("--quick")
-elif args.warn_unreachable:
-    extra_args.append("--warn-unreachable")
 
 mypy_args = extra_args + python_files + pyi_files
 if args.no_daemon: