to ignore ImplicitCastExpr when calling superclass method

Change-Id: I76a3068446acfee85aa1baeb216e57f63c7099c1
Reviewed-on: https://gerrit.libreoffice.org/27279Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>