Test coupling of type parameters

src/harness/unittests/extractMethods.ts

@@ -600,6 +600,11 @@ namespace A {
     M<T1, T2>(t1: T1, t2: T2) {
         [#|t1.toString()|];
     }
+}`);
+        // Coupled constraints
+        testExtractMethod("extractMethod19",
+            `function F<T, U extends T[], V extends U[]>(v: V) {
+    [#|v.toString()|];
 }`);
     });