[LLVMbugs] [Bug 20950] New: variable reassignment in switch not detected ?

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=20950

            Bug ID: 20950
           Summary: variable reassignment in switch not detected ?
           Product: new-bugs
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: dcb314 at hotmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

Given the following source code

void f(int n)
{
    int m;

    switch (n)
    {
    case 1: m = 2;
    case 2: m = 3;
    case 3: m = 4;
    case 4: m = 5;
    }
}

Here is trunk clang++:

$ ~/llvm/results/bin/clang++ -c -g -O2 -Wall jun23b.cc
$

Here is trunk gcc warning about something else:

$ ~/gcc/results/bin/g++ -c -g -O2 -Wall jun23b.cc
jun23b.cc: In function ‘void f(int)’:
jun23b.cc:4:6: warning: variable ‘m’ set but not used
[-Wunused-but-set-variable]
  int m;
      ^
$

And here is trunk cppcheck finding the problem

$ ~/cppcheck/trunk/cppcheck --enable=all jun23b.cc
Checking jun23b.cc...
[jun23b.cc:8] -> [jun23b.cc:9]: (warning) Variable 'm' is reassigned a value
before the old one has been used. 'break;' missing?
[jun23b.cc:9] -> [jun23b.cc:10]: (warning) Variable 'm' is reassigned a value
before the old one has been used. 'break;' missing?
[jun23b.cc:10] -> [jun23b.cc:11]: (warning) Variable 'm' is reassigned a value
before the old one has been used. 'break;' missing?
$

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