Added test.

Author: DanielRosenwasser

tests/cases/compiler/errorMessageOnIntersectionsWithDiscriminants01.ts

@@ -0,0 +1,10 @@
+// @noEmit: true
+
+export type Common = { test: true } | { test: false };
+export type A = Common & { foo: 1 };
+export type B = Common & { bar: 1 };
+
+declare const a: A;
+declare let b: B;
+
+b = a;