diff --git a/tests/cases/compiler/conditionalTypeSimplification.ts b/tests/cases/compiler/conditionalTypeSimplification.ts
new file mode 100644
index 00000000000..74c4d950451
--- /dev/null
+++ b/tests/cases/compiler/conditionalTypeSimplification.ts
@@ -0,0 +1,10 @@
+// Repro from #30794
+
+interface AbstractSchema<S, V> {
+  m1<T> (v: T): SchemaType<S, Exclude<V, T>>;
+  m2<T> (v: T): SchemaType<S, T>;
+}
+
+type SchemaType<S, V> = S extends object ? AnySchema<V> : never;
+interface AnySchema<V> extends AnySchemaType<AnySchema<undefined>, V> { }
+interface AnySchemaType<S extends AbstractSchema<any, any>, V> extends AbstractSchema<S, V> { }