[Bug c++/31545] New: No warning on missing return in if construct

[walter at schreppers dot com]

This happens on other gcc versions too. It seems the checks on whether the
necessary return statement is used fail when using an if statement.
I included a little code snippet here. It compiles without warnings or errors
(all optimizations and even with -Wall no warnings are given). When executed it
crashes ofcourse because a function is called and return value expected which
is never pushed onto stack:

walter-schreppers-computer:~/ClassGen wschrep$ cat cppbug.cpp 

#include <iostream>
using namespace std;

class Test{
  public:
    Test(){ fOk = false; }
    ~Test(){}

    string indent(){
      return " ";
    }

    string faultyReturn(){
      if( !fOk )  indent();  //forgot return here (but compiler does not warn
me!)
      else return indent();
    }

  private:
    bool fOk;
};

int main(){
  cout << "testing faulty class we forgot to return in member faultyReturn" <<
endl;
  cout << "this should not compile, but it does and then crashes on runtime!"
<< endl;

  Test t;
  cout << "'" << t.faultyReturn() << "'" << endl;

  return 0;
}



walter-schreppers-computer:~/ClassGen wschrep$ g++ --version   
i686-apple-darwin8-g++-4.0.1 (GCC) 4.0.1 (Apple Computer, Inc. build 5367)
Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO

warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

walter-schreppers-computer:~/ClassGen wschrep$ g++ -Wall -O2 cppbug.cpp -o
cppbug
walter-schreppers-computer:~/ClassGen wschrep$ ./cppbug 

testing faulty class we forgot to return in member faultyReturn
this should not compile, but it does and then crashes!

Bus error


-- 
           Summary: No warning on missing return in if construct
           Product: gcc
           Version: 4.0.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: walter at schreppers dot com
 GCC build triplet: 5367
  GCC host triplet: i686-apple-darwin8
GCC target triplet: i686-apple-darwin8


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31545