tests/cases/compiler/assignmentCompatability31.ts(9,1): error TS2322: Type 'interfaceWithPublicAndOptional' is not assignable to type '{ one: string[]; }'. Types of property 'one' are incompatible. Type 'number' is not assignable to type 'string[]'. Property 'length' is missing in type 'Number'. ==== tests/cases/compiler/assignmentCompatability31.ts (1 errors) ==== module __test1__ { export interface interfaceWithPublicAndOptional { one: T; two?: U; }; var obj4: interfaceWithPublicAndOptional = { one: 1 };; export var __val__obj4 = obj4; } module __test2__ { export var aa:{one:string[];};; export var __val__aa = aa; } __test2__.__val__aa = __test1__.__val__obj4 ~~~~~~~~~~~~~~~~~~~ !!! error TS2322: Type 'interfaceWithPublicAndOptional' is not assignable to type '{ one: string[]; }'. !!! error TS2322: Types of property 'one' are incompatible. !!! error TS2322: Type 'number' is not assignable to type 'string[]'. !!! error TS2322: Property 'length' is missing in type 'Number'.