==== tests/cases/compiler/declareClassInterfaceImplementation.ts (1 errors) ====
    interface IBuffer {
        [index: number]: number;
    }
    
    declare class Buffer implements IBuffer {
                  ~~~~~~
!!! declareClassInterfaceImplementation.ts(5,15): error TS2137: Class Buffer declares interface IBuffer but does not implement it:
!!! 	Index signatures of types 'Buffer' and 'IBuffer' are incompatible.
    
    }
    