diff --git a/tests/cases/conformance/controlFlow/assertionTypePredicates1.ts b/tests/cases/conformance/controlFlow/assertionTypePredicates1.ts
index 53d400ed91b..1b7db7affaa 100644
--- a/tests/cases/conformance/controlFlow/assertionTypePredicates1.ts
+++ b/tests/cases/conformance/controlFlow/assertionTypePredicates1.ts
@@ -1,4 +1,5 @@
 // @strict: true
+// @allowUnreachableCode: false
 // @declaration: true
 
 declare function isString(value: unknown): value is string;