staticFunction ignores an external function-address comparison

[Long Huang]

Reproduction

handler.c:

void DefaultHandler(void)
{
}

void (*const Handlers[])(void) = { DefaultHandler };

compare.c:

extern void DefaultHandler(void);
extern void (*const Handlers[])(void);

int HasHandler(int index)
{
   return Handlers[index] != DefaultHandler;
}

Run both translation units together:

cppcheck --enable=all --inline-suppr --template=gcc \
  --suppress=checkersReport --suppress=unusedFunction --quiet \
  handler.c compare.c

Cppcheck 2.22.0

Actual:

handler.c:1:6: warning: The function 'DefaultHandler' should have static linkage since it is not used outside of its translation unit. [staticFunction]

Expected:

No warning for DefaultHandler. compare.c takes its address to
compare against the exported table. Giving the definition internal linkage
would leave that external symbol reference unresolved. The function need not
be called directly to require external linkage.

[CHR]

Thanks for reporting, ticket is here: https://trac.cppcheck.net/ticket/15189