false assertion apparently undetected in the presence of overloaded virtual functions
ID0001975: This issue was created automatically from Mantis Issue 1975. Further discussion may take place here.
| Id | Project | Category | View | Due Date | Updated |
|---|---|---|---|---|---|
| ID0001975 | Frama-Clang | Plug-in > clang | public | 2014-11-20 | 2015-02-23 |
| Reporter | Jochen | Assigned To | virgile | Resolution | open |
| Priority | normal | Severity | minor | Reproducibility | always |
| Platform | frama-c-Neon-20140301+dev-stance | OS | - | OS Version | xubuntu-cfe13.10 |
| Product Version | - | Target Version | - | Fixed in Version | - |
Description :
Running "frama-c -wp -wp-rte" on the attached file generates 117 proof obligations of which 43 can be proven. I suppose that the obligation for the false assertion from line 19 is also proven, by qed; probably it has the name "typed_main_assert".
My reasons are:
If the assertion wasn't proven, an .mlw file for Alt-Ergo should appear in the wp-out directory which should contain the string "333"; however, no that string couldn't be found there, nor could "111"; while "222" occurs (in many/all .mlw files) only as value of the global variable "G__ZN6SquareE12_frama_c_vmt_221" which, in turn, is used only as index to an int array "t" and as an argument to "region" in global variables axioms, i.e. "222" doesn't occur in a goal.
If the value "333" in line 19 of file 139.cpp is changed to "222", i.e. if the assertion is made true, then the very same proof goal names and Valid/Unknown/Timeout results appear in the verification log. Similarly, if the value is changed to "111". All three log differ only in prover timings and obligation order, as can be seen by applying the shell-script "normalizeVerificationLog.sh" to the 117 obligation log lines in each of the log files "139_111orig.txt", "139_222orig.txt", and "139_333orig.txt" (all files attached).
Possibly, some precondition equivalent to \false is given to qed together with the goal for the line 19 assertion.