bug in C++ compiler 14.0.0: nonvirtual function cannot be declared with "abstract" or "sealed" modifier

[Bocci__Andrea]

When:
 - a templated class inherits from one of the template arguments
 - a method overrides a (supposedly virtual) method of the base class, declarig it as "final", without declaring it "virtual" in the derived class
icpc comlains with

error: nonvirtual function cannot be declared with "abstract" or "sealed" modifier

while gcc (4.8.1) happily compiles the code.

How to reproduce:

class Base {
public:
  virtual const char * name() {
    return "Base";
  }
};
 

template <class B>
class Derived : public B {
public:
  const char * name() final {
    return "Derived";
  }
};

 Also, the error message is misleading, it should mention "override" or "final", not "abstract" or "sealed" (from C# ?).

[Bocci__Andrea]

And here is the actual error:

$ g++ -std=c++11 test.cpp -c -o test.o

$ icpc -std=c++11 test.cpp -c -o test.o
test.cpp(12): error: nonvirtual function cannot be declared with "abstract" or "sealed" modifier
const char * name() final {
^

compilation aborted for test.cpp (code 2)

[Georg_Z_Intel]

Hello, Thank you for reporting. I agree that this case should be allowed and the error message has to be rephrased. We'll track that as DPD200388855 and I'll inform you once implemented. The alternative is to apply the "virtual" keyword to the derived class' function as well. Best regards, Georg Zitzlsberger

[Bocci__Andrea]

Georg Zitzlsberger (Intel) wrote:
The alternative is to apply the "virtual" keyword to the derived class' function as well.

Yes, that's what we can do in the meantime.

Thanks,
.Andrea

[Bocci__Andrea]

For the record - this is still open with

$ icpc -v

icpc version 14.0.1 (gcc version 4.8.0 compatibility)

[Shahzad_Malik_MUZAFF]

and it is also open in 14.0.2

[Shahzad_Malik_MUZAFF]

and looks like it is still open in "Intel C++ Composer XE 2015 Pre-Release beta"

[Georg_Z_Intel]

Hello,

DPD200388855 is still at engineering. Once there's some progress I'll update this thread.

Best regards,

Georg Zitzlsberger

[Georg_Z_Intel]

Hello,

Intel(R) Parallel Studio XE 2015 Composer Edition contains the fix.

Best regards,

Georg Zitzlsberger