segmentation fault from grompp with non-existing atomtype in *.top
When generating input for free-energy perturbation I set the B atomtype to DUM in my topology file. However DUM does not exist in the force field I wanted to use. In version 3.3.3 this resulted in an error message (as expected).
In version 4.0.4 I got a segmentation fault (which should be an error message).