[cfe-dev] [clang-tidy] Issues with C++17 structured bindings

[Benics Balázs via cfe-dev]

Hi,
It seems like its a Clang Static Analyzer checker warns about something.

Could you please send the complete reproducer?
I failed reproducing this.

Regards,
Balazs


________________________________
From: cfe-dev <cfe-dev-bounces at lists.llvm.org> on behalf of Tamir Zahavi-Brunner via cfe-dev <cfe-dev at lists.llvm.org>
Sent: Tuesday, July 6, 2021 1:25:12 PM
To: cfe-dev at lists.llvm.org <cfe-dev at lists.llvm.org>
Subject: [cfe-dev] [clang-tidy] Issues with C++17 structured bindings

Hello,

Using clang-tidy-12, I'm getting false warnings when using structured bindings. There can actually be a variety of issues, but here is a very small example I've narrowed it down to:

auto [ptr, num] = std::make_tuple(malloc(1), 1);
free(ptr);

For which I get the following warning:

/tmp/test.cpp:7:5: warning: Potential leak of memory pointed to by '._M_head_impl' [clang-analyzer-unix.Malloc]
    free(ptr);
    ^
/tmp/test.cpp:6:39: note: Memory is allocated
    auto [ptr, num] = std::make_tuple(malloc(1), 1);
                                      ^
/tmp/test.cpp:7:5: note: Potential leak of memory pointed to by '._M_head_impl'
    free(ptr);
    ^

Searching online, I saw that I'm not the first person to encounter such issues (https://stackoverflow.com/questions/62706928/clang-tidy-vs-structured-bindings) but I couldn't find any solution.

Is this a bug in clang-tidy or am I missing something? Is there anything I can do to solve this other than stopping using structured bindings?

Thanks,
Tamir
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