diff --git a/src/vim9expr.c b/src/vim9expr.c
index 41ed7e7..c001d9e 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -238,6 +238,7 @@
 	    case VAR_INSTR:
 	    case VAR_CLASS:
 	    case VAR_OBJECT:
+	    case VAR_TYPEALIAS:
 	    case VAR_UNKNOWN:
 	    case VAR_ANY:
 	    case VAR_VOID:
@@ -529,6 +530,13 @@
     {
 	svar_T		*sv = ((svar_T *)si->sn_var_vals.ga_data) + idx;
 
+	if (sv->sv_tv->v_type == VAR_TYPEALIAS)
+	{
+	    semsg(_(e_using_typealias_as_variable),
+				sv->sv_tv->vval.v_typealias->ta_name);
+	    return FAIL;
+	}
+
 	generate_VIM9SCRIPT(cctx, ISN_LOADSCRIPT,
 					current_sctx.sc_sid, idx, sv->sv_type);
 	return OK;