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From: Thiago Adams <thiago.adams@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Fixing a sample from K&R book using cake static analyser
Date: Sat, 22 Jun 2024 17:32:36 -0300
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Link for the sample using GCC and CLANG (no warnings in both)

GCC https://godbolt.org/z/rGre3hbE1

CLANG https://godbolt.org/z/ez114sEMW

For this other sample, the compiler needs to track the state of p inside 
conditional expressions. This check is wrong (p || p->text) cake and GCC 
shows that.

#pragma safety enable

#include <stdlib.h>
#include <string.h>

struct X {
   char * _Owner _Opt text;
};

int main() {
    struct X * _Owner _Opt p = calloc(1, sizeof * p);
    if (p || p->text){
      p->text = strdup("a");
    }
    free(p->text);
    free(p);
}

cake

http://thradams.com/cake/playground.html?code=CiNwcmFnbWEgc2FmZXR5IGVuYWJsZSAKCiNpbmNsdWRlIDxzdGRsaWIuaD4KI2luY2x1ZGUgPHN0cmluZy5oPgoKc3RydWN0IFggewogIGNoYXIgKiBfT3duZXIgX09wdCB0ZXh0Owp9OwoKaW50IG1haW4oKSB7ICAgCiAgIHN0cnVjdCBYICogX093bmVyIF9PcHQgcCA9IGNhbGxvYygxLCBzaXplb2YgKiBwKTsKICAgaWYgKHAgfHwgcC0%2BdGV4dCl7ICAgCiAgICAgcC0%2BdGV4dCA9IHN0cmR1cCgiYSIpOyAgICAgCiAgIH0KICAgZnJlZShwLT50ZXh0KTsKICAgZnJlZShwKTsgIAp9CgoKCg%3D%3D&to=-1&options=

GCC
https://godbolt.org/z/4jdc7r9r3

GCC
does NOT detects this one

https://godbolt.org/z/T6GhfzrKT

and cake does

http://thradams.com/cake/playground.html?code=CiNwcmFnbWEgc2FmZXR5IGVuYWJsZSAKCiNpbmNsdWRlIDxzdGRsaWIuaD4KI2luY2x1ZGUgPHN0cmluZy5oPgoKc3RydWN0IFggewogIGNoYXIgKiBfT3duZXIgX09wdCB0ZXh0Owp9OwoKaW50IG1haW4oKSB7ICAgCiAgIHN0cnVjdCBYICogX093bmVyIF9PcHQgcCA9IGNhbGxvYygxLCBzaXplb2YgKiBwKTsKICAgaWYgKHAgKXsgICAKICAgICBwLT50ZXh0ID0gc3RyZHVwKCJhIik7ICAgICAKICAgfQogICAvL2ZyZWUocC0%2BdGV4dCk7CiAgIGZyZWUocCk7ICAKfQoKCgo%3D&to=-1&options=