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From: "dcb314 at hotmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/109056] New: cppcheck: no warning for suspicious return type
Date: Tue, 07 Mar 2023 16:50:14 +0000
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X-Bugzilla-Version: 13.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109056

            Bug ID: 109056
           Summary: cppcheck: no warning for suspicious return type
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For the following C code:

unsigned long f( int n)
{
        return n * 1000;
}

where the programmer may have intended using an unsigned long constant
like 1000UL, then static analyser cppcheck can be made to say:

mar7b.cc:4:2: style: int result is returned as long value. If the return va=
lue
is long to avoid loss of information, then you have loss of information.
[truncLongCastReturn]
 return n * 1000;

gcc says nothing:

$ ~/gcc/results/bin/gcc -c -g  -O2 -Wall -Wextra mar7b.cc
$=20

The example code is derived from 10 examples in the source code of
linux-6.3-rc1, so the problem does really occur in practice.=