tests/cases/compiler/inheritSameNamePropertiesWithDifferentVisibility.ts(9,11): error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'. Named property 'x' of types 'C' and 'C2' are not identical. ==== tests/cases/compiler/inheritSameNamePropertiesWithDifferentVisibility.ts (1 errors) ==== class C { public x: number; } class C2 { private x: number; } interface A extends C, C2 { // error ~ !!! error TS2320: Interface 'A' cannot simultaneously extend types 'C' and 'C2'. !!! error TS2320: Named property 'x' of types 'C' and 'C2' are not identical. y: string; }