Classes cannot be specified in implements clause

Rule arkts-implements-only-iface

Severity: error

ArkTS does not allow to specify a class in implements clause. Only interfaces may be specified.

TypeScript

    class C {
      foo() {}
    }

    class C1 implements C {
      foo() {}
    }

ArkTS

    interface C {
      foo(): void
    }

    class C1 implements C {
      foo() {}
    }