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From: "cuzdav at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug analyzer/107725] New: Spurious warning: use of uninitialized
 value with std::any
Date: Wed, 16 Nov 2022 20:33:53 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107725

            Bug ID: 107725
           Summary: Spurious warning: use of uninitialized value with
                    std::any
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: cuzdav at gmail dot com
  Target Milestone: ---

Created attachment 53914
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D53914&action=3Dedit
preprocessed code

With the analyzer (-fanalyzer), this built cleanly with GCC10 and GCC11, but
starting with GCC 12 (still occurring in trunk) in either C++17 or c++20 mo=
de,
I see this warning (x86 linux):

<source>:4:13: warning: use of uninitialized value '<unknown>' [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
    4 |     return {};
      |             ^
  'std::any create()': events 1-2
    |
    |    3 | std::any create() {
    |      |                 ^
    |      |                 |
    |      |                 (1) region created on stack here
    |    4 |     return {};
    |      |             ~=20=20=20=20
    |      |             |
    |      |             (2) use of uninitialized value '<unknown>' here
    |
Compiler returned: 0


This is the code in its entirety:

    #include <any>
    std::any create() {
        return {};
    }

https://godbolt.org/z/TWPcaW4Kn=