patch 8.0.0655: not easy to make sure a function does not exist commit https://github.com/vim/vim/commit/d6abcd154cdc6a8dd4b7c6ccad37617ea8a1b4aa Author: Bram Moolenaar <Bram@vim.org> Date: Thu Jun 22 19:15:24 2017 +0200 patch 8.0.0655: not easy to make sure a function does not exist Problem: Not easy to make sure a function does not exist. Solution: Add ! as an optional argument to :delfunc.

TYPEMAP
VIWIN	T_VIOBJNOMUNGE
VIBUF	T_VIOBJNOMUNGE

INPUT
T_VIOBJNOMUNGE
	if (sv_isa($arg, \"${ntype}\")) {
	    IV tmp = SvIV((SV*)SvRV($arg));
	    $var = INT2PTR($type, tmp);
	    if (!tmp)
		croak(\"$ntype no longer exists\");
	}
	else
	    croak(\"$var is not of type ${ntype}\")