FALSE NEGATIVE: `unreadVariable` misses an unused range-for variable

[Rodri]

Hi, I found a false negative in Cppcheck 2.21.0 and 2.22 dev when a range-based for loop initializes its loop variable but the body never reads it.

Affected tool

Cppcheck 2.21.0; also reproduced with Cppcheck 2.22 dev

Affected checker

Cppcheck unreadVariable

Minimal reproducer

void test(int (&values)[3]) {
  for (int value : values) {
  }
}

Reproduction command

cppcheck --version
cppcheck --enable=style --inconclusive --std=c++17 --checkers-report=checkers.txt --template='{file}:{line}:{column}: [{id}] {message}' cppcheck-unreadvariable-fn-range-for.cpp

Current behavior

Cppcheck produces no unreadVariable or unusedVariable diagnostic.

Expected behavior

Cppcheck should report line 2 because each value assigned to the loop variable is never read.

[CHR]

This seems like a bad fit for unreadVariable/unusedVariable because there would be no loop without declaring the variable. Currently we don't flag empty loop/if/... scopes.