Parsing Error templated constexpr member variable

[Mueller__Tobias]

Description:

When intializing a static constexpr class member variable using a brace-enclosed expression, compilation fails with error "expected a ")"".

Affected Versions:

icpc (ICC) 19.1.0.166 20191121

Minimal example:

class Test
{
template< typename Foo >
static constexpr bool UseSMPAssign_v =  (true) ;
};

int main(int argc, char** argv)
{
    return 0;
}

Expected Result:

Minimal example compiles without errors

Actual Result:

Compilation Fails with

testmain2.cpp(4): error: expected a ")"
  static constexpr bool UseSMPAssign_v =  (true) ;
                                                 ^

compilation aborted for testmain2.cpp (code 2)

Other Compilers:

GCC 8.3 and 9.2 are compiling the example

Note:

Omitting the Braces fixes the issue, but syntactically there should be nothing wrong adding them.

[PrasanthD_intel]

Hi,

We have also observed the error at our end. This seems to be a bug with the compiler.

Thanks for reporting. We will forward this issue to the respective engineering team.

Thanks 

Prasanth

[Viet_H_Intel]

I have submitted this bug to our FrontEnd (CMPLRIL0-32644). In the meantime, can you remove the () as a workaround?

[Mueller__Tobias]

Thank you for submitting the bug. Unfortunately, trying to implement the workaround, I found another one, which looks related, but prevents me from using templated static constexpr member variables for SFINAE (and therefore the blaze-library) with icpc.

It seems like any bracketed expression in the assignment will fail compiling with the above error.

Minimal example:

class Test
{
template< typename Foo >
static constexpr bool UseSMPAssign_v =  (true || false) && true ;
};

int main(int argc, char** argv)
{
    return 0;
}

Expected Result:

Minimal example compiles without errors

Actual Result:

Compilation Fails with

testmain2.cpp(4): error: expected a ")"
  static constexpr bool UseSMPAssign_v =  (true || false) && true ;
                                                 ^

compilation aborted for testmain2.cpp (code 2)

Other Compilers:

GCC 8.3 and 9.2 are compiling the example

Note:

() are needed here to logically structure the expression without relying on which order operators are executed according to the standard. Pretty sure, that there are cases constructible , which do not work without ().

[Viet_H_Intel]

I see. Hopefully, the fix will be in the next update compiler.

[Mueller__Tobias]

The fix apparently did not make it into the latest version (19.1.1.217)

[Viet_H_Intel]

Sorry for the inconvenient; 19.1.1.217 was built on Mar-6 (same day that this issue reported). Hence the fix couldn't be able to make it in.

[Mueller__Tobias]

Bug is still present in ICPC 19.1.2.254.

[Viet_H_Intel]

It will be fixed in the next major release compiler.

[Viet_H_Intel]

This issue is fixed in oneAPI2021.2.

$ icpc -V

Intel(R) C++ Intel(R) 64 Compiler Classic for applications running on Intel(R) 64, Version 2021.2.0 Build 20210228_000000

I am going to close this thread.