Add tests

tests/cases/conformance/types/keyof/keyofIntersection.ts

@@ -0,0 +1,29 @@
+// @strict: true
+// @declaration: true
+
+type A = { a: string };
+type B = { b: string };
+
+type T01 = keyof (A & B);  // "a" | "b"
+type T02<T> = keyof (T & B);  // "b" | keyof T
+type T03<U> = keyof (A & U);  // "a" | keyof U
+type T04<T, U> = keyof (T & U);  // keyof T | keyof U
+type T05 = T02<A>;  // "a" | "b"
+type T06 = T03<B>;  // "a" | "b"
+type T07 = T04<A, B>;  // "a" | "b"
+
+// Repros from #22291
+
+type Example1<T extends string, U extends string> = keyof (Record<T, any> & Record<U, any>);
+type Result1 = Example1<'x', 'y'>;  // "x" | "y"
+
+type Result2 = keyof (Record<'x', any> & Record<'y', any>);  // "x" | "y"
+
+type Example3<T extends string> = keyof (Record<T, any>);
+type Result3 = Example3<'x' | 'y'>;  // "x" | "y"
+
+type Example4<T extends string, U extends string> = (Record<T, any> & Record<U, any>);
+type Result4 = keyof Example4<'x', 'y'>;  // "x" | "y"
+
+type Example5<T, U> = keyof (T & U);
+type Result5 = Example5<Record<'x', any>, Record<'y', any>>;  // "x" | "y"