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| ID | Project | Category | View Status | Date Submitted | Last Update |
| 0002394 | Frama-C | Plug-in > wp | public | 2018-08-23 14:12 | 2019-10-17 17:05 |
|
| Reporter | timourf | |
| Assigned To | correnson | |
| Priority | normal | Severity | major | Reproducibility | always |
| Status | resolved | Resolution | fixed | |
| Platform | x86_64 | OS | GNU/Linux | OS Version | Debian 9 |
| Product Version | Frama-C 17-Chlorine | |
| Target Version | | Fixed in Version | Frama-C 20-Calcium | |
|
| Summary | 0002394: conditional input annotations result in why3 type errors |
| Description | I am trying to put conditions on my function specification that specify return values conditioned on special input values. A minimal example is as follows:
/*@ requires 0 <= t <= 1;
@ ensures t == 1.f ==> \result == b;
@ assigns \nothing
*/
float interpolate(float a, float b, float t) { ... }
Why3 (stderr) reports:
===================================================================================
File "/tmp/wp0a3ed9.dir/typed/interpolate_Why3_ide.why", line 20, characters 11-26:
This term has type real -> real, but is expected to have type real
===================================================================================
The "problem line" is "ensures t == 1.f ==> \result == b;"
This seems to be a problem between wp and why3. The error persists with every external prover I use with why3. The list of provers I've tried is [Z3,CVC3,CVC4,Alt-Ergo,Gappa], and the only exception is why3:coq (see issue 0002389). |
| Steps To Reproduce | see attached file "buggy.c"
run:
> frama-c -wp -wp-prover "why3:XXX" buggy.c
where XXX is any prover installed with why3 |
| Additional Information | why3 0.88.3
frama-c chlorine 20180502 |
| Tags | No tags attached. |
|
| Attached Files |  buggy.c [^] (320 bytes) 2018-08-23 14:12 [Show Content] [Hide Content]/*@ requires 0 <= t <= 1;
@ ensures t == 1.f ==> \result == b;
@ ensures t == 0.f ==> \result == a;
@ ensures \min(a,b) <= \result <= \max(a,b);
@ assigns \nothing;
*/
float interpolate(float a, float b, float t) {
float t2 = 1.0f - t;
float left = a*t2;
float right = b*t;
return left+right;
}
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