cppcheck 2.10: false positive [knownConditionTrueFalse]

[Sylvain Joubert]

The following code:

#include <string>

void test(std::string const& a, std::string const& b)
{

  if (a.empty() && b.empty())
  {
  }
  else if (a.empty() == false && b.empty() == false) // False positives
  {
  }

  if (a.empty() && b.empty())
  {
  }
  else if (!a.empty() && !b.empty()) // This is fine
  {
  }
}

produces the following warnings:

Checking test.cpp ...
test.cpp:8:22: style: Condition 'a.empty()==false' is always true [knownConditionTrueFalse]
  else if (a.empty() == false && b.empty() == false)
                     ^
test.cpp:5:14: note: Assuming that condition 'a.empty()' is not redundant
  if (a.empty() && b.empty())
             ^
test.cpp:8:22: note: Condition 'a.empty()==false' is always true
  else if (a.empty() == false && b.empty() == false)
                     ^
test.cpp:8:44: style: Condition 'b.empty()==false' is always true [knownConditionTrueFalse]
  else if (a.empty() == false && b.empty() == false)
                                           ^
test.cpp:5:27: note: Assuming that condition 'b.empty()' is not redundant
  if (a.empty() && b.empty())
                          ^
test.cpp:8:44: note: Condition 'b.empty()==false' is always true
  else if (a.empty() == false && b.empty() == false)
                                           ^

Note that turning the .empty() == false calls into using the not operator like !a.empty() does not produce the warnings.

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/11548