patch 8.2.3186: Vim9: not all failures for import tested

Problem:    Vim9: not all failures for import tested
Solution:   Test more import failures
diff --git a/src/evalvars.c b/src/evalvars.c
index dcf1058..d0bbff7 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -3250,6 +3250,7 @@
 	{
 	    scriptitem_T    *si = SCRIPT_ITEM(import->imp_sid);
 	    svar_T	    *sv;
+	    where_T	    where;
 
 	    // imported variable from another script
 	    if ((flags & ASSIGN_NO_DECL) == 0)
@@ -3257,10 +3258,16 @@
 		semsg(_(e_redefining_imported_item_str), name);
 		goto failed;
 	    }
-	    sv = ((svar_T *)si->sn_var_vals.ga_data)
-						    + import->imp_var_vals_idx;
-	    // TODO: check the type
-	    // TODO: check for const and locked
+	    sv = ((svar_T *)si->sn_var_vals.ga_data) + import->imp_var_vals_idx;
+
+	    where.wt_index = 0;
+	    where.wt_variable = TRUE;
+	    if (check_typval_type(sv->sv_type, tv, where) == FAIL
+		    || value_check_lock(sv->sv_tv->v_lock, name, FALSE))
+	    {
+		goto failed;
+	    }
+
 	    dest_tv = sv->sv_tv;
 	    clear_tv(dest_tv);
 	}