--esModuleInterop: Strange incompatibility between correct and incorrect import of same type

**TypeScript Version:** master **Code** **b.d.ts** ```ts declare class C { f: this; } declare namespace C {} export = C; ``` **a.ts** ```ts import * as C1 from "./b"; import C2 = require("./b"); function f(t: (c: C1) => void): void { t(new C2()); } ``` **Expected behavior:** Error at `import * as C1`. **Actual behavior:** No error at the import declaration. Error at `new C2()`: ```ts src/a.ts(5,7): error TS2345: Argument of type 'C' is not assignable to parameter of type 'C'. Types of property 'f' are incompatible. Type 'C' is not assignable to type 'this'. ``` (possibly related: #20704)