tests/cases/compiler/moduleAssignmentCompat4.ts(12,8): error TS2304: Cannot find name 'A'. tests/cases/compiler/moduleAssignmentCompat4.ts(13,8): error TS2304: Cannot find name 'B'. ==== tests/cases/compiler/moduleAssignmentCompat4.ts (2 errors) ==== module A { export module M { class C { } } } module B { export module M { export class D { } } } var a: A; ~ !!! error TS2304: Cannot find name 'A'. var b: B; ~ !!! error TS2304: Cannot find name 'B'. a = b; b = a; // error