some static analysis warning at line 11317

[ipodipad]

• What is the issue you have?

Firstly, thanks for making this great easy json utility!
I'm not sure this is false positive or something, but I just report this warning.
May this be helpful~

at line 11317 in json.hpp
const bool is_negative = std::is_same<NumberType, number_integer_t>::value and not (x >= 0);  // see issue #755

static analysis tool says (codesonar),
Redundant Condition
x >= 0 always evaluates to true.
The condition is testing whether an unsigned value is nonnegative, but unsigned values are always nonnegative.

• Please describe the steps to reproduce the issue. Can you provide a small but working code example?

• What is the expected behavior?

• And what is the actual behavior instead?

• Which compiler and operating system are you using? Is it a supported compiler?

arm-linux-gnueabihf-g++ (Linaro GCC 6.3-2017.05) 6.3.1 20170404

• Did you use a released version of the library or the version from the develop branch?

version: 3.4.0 from develop branch 

• If you experience a compilation error: can you compile and run the unit tests?

[nlohmann]

The function is templated for integer types. For signed integers, the line can become false, whereas it is always true for unsigned integer types. To "fix" this issue, I would need to artificially make two functions from it and remove some code from the unsigned version. Therefore, I would classify this as false positive. What do you think?

[mgerhardy]

This is not just static analysis - the compiler prints this, too. A proper fix is attached at #755

    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_unsigned_t>::value, int> = 0>
    bool is_negative_integer(NumberType x) { return false; }

    template<typename NumberType, detail::enable_if_t<
                 std::is_same<NumberType, number_integer_t>::value, int> = 0>
    bool is_negative_integer(NumberType x) { return x<0; }

and in dump_integer(NumberType x):
const bool is_negative = is_negative_integer(x); // see issue #755

[mgerhardy]

oh.. the compiler that reports this as a warning is clang-10 btw. and as we are compiling with -Werror - this is a problem for us

[t-b]

@mgerhardy Can you provide a PR?

[darkdragon-001]

This was fixed in c61a907.