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ID0002428: This issue was created automatically from Mantis Issue 2428. Further discussion may take place here.

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Id	Project	Category	View	Due Date	Updated
ID0002428	Frama-C	Plug-in > wp	public	2019-02-17	2019-02-25

Reporter	evdenis	Assigned To	correnson	Resolution	no change required
Priority	normal	Severity	major	Reproducibility	always
Platform	-	OS	-	OS Version	-
Product Version	Frama-C 18-Argon	Target Version	-	Fixed in Version	-

Description :

Obvious division by zero doesn't increase the total number of proof obligations:

Test2:

/*@ assigns \nothing;
 */
int test2(int a)
{
	return a / 0;
}

Frama-C:

[kernel] Parsing test2.c (with preprocessing)
[rte] annotating function test2
[rte] test2.c:5:8: Warning: guaranteed RTE: assert division_by_zero: 0 ≢ 0;
[wp] 1 goal scheduled
[wp] Proved goals:    1 / 1
  Qed:             1

Proved goals line is the same as in the case without division: Test1:

/*@ assigns \nothing;
 */
int test1(int a)
{
	return a;
}

Frama-C output:

[kernel] Parsing test1.c (with preprocessing)
[rte] annotating function test1
[wp] 1 goal scheduled
[wp] Proved goals:    1 / 1
  Qed:             1

From my point of view this is an incorrect behavior and the proved goals like should be 'Proved goals: 1 / 2' as in this case: Test3:

/*@ assigns \nothing;
 */
int test3(int a)
{
	//@ assert 0 != 0;
	return a / 0;
}

Frama-C:

[kernel] Parsing test3.c (with preprocessing)
[rte] annotating function test3
[rte] test3.c:6:8: Warning: guaranteed RTE: assert division_by_zero: 0 ≢ 0;
[wp] 2 goals scheduled
[wp] [Alt-Ergo] Goal typed_test3_assert : Unknown (109ms)
[wp] Proved goals:    1 / 2
  Qed:             1
  Alt-Ergo:        0  (unknown: 1)

Attachments

• test2.c