Add regression test

Author: ahejlsberg

tests/cases/compiler/deeplyNestedConstraints.ts

@@ -0,0 +1,14 @@
+// @strict: true
+// @declaration: true
+
+// Repro from #41931
+
+type Enum = Record<string, string | number>;
+
+type TypeMap<E extends Enum> = { [key in E[keyof E]]: number | boolean | string | number[] };
+
+class BufferPool<E extends Enum, M extends TypeMap<E>> {
+    setArray2<K extends E[keyof E]>(_: K, array: Extract<M[K], ArrayLike<any>>) {
+        array.length; // Requires exploration of >5 levels of constraints
+    }
+}