[llvm-bugs] [Bug 39884] New: Analyzer fails to recognize C-style union struct initialization

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=39884

            Bug ID: 39884
           Summary: Analyzer fails to recognize C-style union struct
                    initialization
           Product: clang
           Version: 7.0
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Static Analyzer
          Assignee: dcoughlin at apple.com
          Reporter: renat at idrisov.info
                CC: dcoughlin at apple.com, llvm-bugs at lists.llvm.org

Hi All,
I run analysis on a piece of code with:

$ clang-tidy tidy-minimal.c -checks=* --

Code:

#include <stdio.h>
#include <stdlib.h>

struct a {
  union {
    struct {
      void *b;
    };
  };
};

void *something();
void something_else(struct a *param);

void myfunction() {
  struct a c = { .b = malloc(256) };
  something_else(&c);
}

int main() {
  myfunction();
}

----------------
I get:
/.../tidy-minimal.c:18:1: warning: Potential memory leak
[clang-analyzer-unix.Malloc]
}
^
/.../tidy-minimal.c:21:3: note: Calling 'myfunction'
  myfunction();
  ^
/.../tidy-minimal.c:16:23: note: Memory is allocated
  struct a c = { .b = malloc(256) };
                      ^
/.../tidy-minimal.c:18:1: note: Potential memory leak
}
^
----------------

It looks like it is not handling struct initialization properly because if I
remove union -- it produces no warnings

The issue could be related to https://bugs.llvm.org/show_bug.cgi?id=35882
but in my case giving union a name does not resolve it.

Thanks!

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