False negative: file resource leak with a local pointer alias

[Rodri]

Hi, I found a false negative regarding the rule resourceLeak.

Cppcheck misses the resource leak when the null check uses a local alias of the file pointer.

#include <cstdio>

int f() {
  const FILE *a = fopen("input.txt", "r");
  const FILE *b = a;
  if (!b)
    return 0;
  return 0;
}

Actual result

Cppcheck does not report resourceLeak. Removing b and changing the condition to if (!a) produces the warning.

Expected result

Cppcheck should report the missing fclose in both forms.

Verification

The issue was reproduced with:

cppcheck --output-format=xmlv2 --enable=all file_alias.cpp

Version: 2.21.0

[CHR]

See https://trac.cppcheck.net/ticket/2853