tests/cases/conformance/es6/computedProperties/computedPropertyNames43_ES5.ts(10,5): error TS2411: Property '["get1"]' of type 'Foo' is not assignable to string index type 'Foo2'. ==== tests/cases/conformance/es6/computedProperties/computedPropertyNames43_ES5.ts (1 errors) ==== class Foo { x } class Foo2 { x; y } class C { [s: string]: Foo2; } class D extends C { // Computed properties get ["get1"]() { return new Foo } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ !!! error TS2411: Property '["get1"]' of type 'Foo' is not assignable to string index type 'Foo2'. set ["set1"](p: Foo2) { } }