Error with matrix addition in PETSc

Dear Freefem community,

I have an issue with the addition of two matrices of type Mat. I read in the Forum that it should work since v4.9, however I receive the following error message :

Bmat = Amat + Tmat2; error operator + <N5PETSc14DistributedCSRIN5HPDDM7SchwarzINSt3__17complexIdEEEEEE>, <N5PETSc14DistributedCSRIN5HPDDM7SchwarzINSt3__17complexIdEEEEEE>
List of choices

Can you help me understand ?

Best,

Mayeul