alias between int* and uint* handled incorrectly
ID0000829: This issue was created automatically from Mantis Issue 829. Further discussion may take place here.
| Id | Project | Category | View | Due Date | Updated |
|---|---|---|---|---|---|
| ID0000829 | Frama-C | Plug-in > jessie | public | 2011-05-18 | 2011-05-24 |
| Reporter | Jochen | Assigned To | cmarche | Resolution | open |
| Priority | normal | Severity | minor | Reproducibility | always |
| Platform | - | OS | - | OS Version | - |
| Product Version | Frama-C Carbon-20110201 | Target Version | - | Fixed in Version | - |
Description :
The manual "jessie-tutorial-Carbon-beta.pdf" allows casts between pointer types (p.22). However, in the attached program, the property "*x == \old(*x)" of the function ftest() can be verified under SeparationPolicy(none), although ftest() modifies *x via its (possible) alias *y. A reason for this behavior is that x and y point to different types, viz. int and uint (if y is made an int, too, the bug vanishes).
As a consequence, "p == \old(p)" can be proven for main(), although running the program reveals that p changes from 0 to 123. A side remark: type incompatibility uint* vs. int* seems to be unchecked in the initialization in line 14; no cast was needed there.