Redefintion of variables in same scope is allowed in annotations
ID0002125: This issue was created automatically from Mantis Issue 2125. Further discussion may take place here.
| Id | Project | Category | View | Due Date | Updated |
|---|---|---|---|---|---|
| ID0002125 | Frama-C | Kernel > ACSL implementation | public | 2015-06-01 | 2015-06-02 |
| Reporter | gaggarwal | Assigned To | virgile | Resolution | open |
| Priority | normal | Severity | minor | Reproducibility | always |
| Platform | - | OS | - | OS Version | - |
| Product Version | Frama-C Neon-20140301 | Target Version | - | Fixed in Version | - |
Description :
Consider an example:
/@ predicate is_valid(int n, int n) = (0 <= n) ; */
Frama-C doesn't throw any exception for the above predicate, even though variable "n" is defined twice in the same scope and it uses n as of Type int and allows comparison 0 <= n.
If I change the above predicate to following: /@ predicate is_valid_int_range(int n, int n) = (0 <= n) ; / Frama-c complains "[kernel] user error: comparison of incompatible types: ℤ and int * in annotation" for comparison 0 <= n in above example, which means that it treats n of type int.
Similarly, redefinition of variable in same scope is allowed in quantifier expressions like: loop invariant \forall int k, char k; 0 <= k && k< i ==> a[k] == b[k];
In C language it is not allowed to redefine variable in same scope. Is this an intentional behavior? And if so that is the purpose behind it? I don't see this matter is discussed in ACSL document.