Warnings on disabled code

[Dennis Mierke]

Hello,
I get unmatched suppression warnings by cppcheck 1.90 on inline suppressions in disabled code.
For example:

#if FOO

void foo()
{
    static constexpr bool enabled = true;

    // cppcheck-suppress knownConditionTrueFalse
    if(enabled) std::cout << "Hello World"  << std::endl;
}

#endif // FOO

With enabled code:

$ cppcheck --enable=all --inline-suppr -DFOO=1 foo.cpp 
Checking foo.cpp ...
Checking foo.cpp: FOO_ENABLED=1...

That was to be expected.
But if I disable the code, I get this warning:

$ cppcheck --enable=all --inline-suppr -DFOO=0 foo.cpp
Checking foo.cpp ...
Checking foo.cpp: FOO_ENABLED=0...
test.cpp:8:0: information: Unmatched suppression: knownConditionTrueFalse [unmatchedSuppression]
    if(enabled) std::cout << "Hello World"  << std::endl;
^

Is this behaviour intended?

[Daniel Marjamäki]

It is not intended. There is a ticket: https://trac.cppcheck.net/ticket/5704

It's not very straightforward to fix this unfortunately. The suppressions are extracted from the "raw tokens" as far as I remember and that contains all code, even code that is defined out. Well maybe we can add a pass after preprocessing that removes inline suppressions that don't "have code".

If you have time to look at this.. feel free to submit a PR at github.