FALSE NEGATIVE: `unreadVariable` misses an initialization in an unevaluated short-circuit RHS

[Rodri]

Hi, I found a false negative in Cppcheck 2.21.0 when a local variable is used only on the unevaluated right-hand side of a short-circuit expression.

Affected tool

Cppcheck 2.21.0

Affected checker

unreadVariable

Minimal reproducer

int test() {
  int source = 0;
  int divisor = source;
  return true || divisor;
}

Reproduction command

cppcheck --version
cppcheck --enable=all --inconclusive --check-level=exhaustive --std=c++17 --output-format=xmlv2 mutant-cppcheck-unreadvariable-fn-short-circuit-rhs.cpp

Current behavior

Cppcheck produces no unreadVariable diagnostic for divisor.

Expected behavior

The right-hand side of true || divisor is not evaluated, so the value stored in divisor is never read. Cppcheck should report the unused initialization.

[CHR]

We don't warn about the expression return true || divisor;, which is arguably dubious, but may be intentional, similar to if (false) etc. So we won't report the induced unreadVariable either.