diff --git a/ucl/eval.go b/ucl/eval.go
index 4f6894f..ae71896 100644
--- a/ucl/eval.go
+++ b/ucl/eval.go
@@ -79,7 +79,7 @@ func (e evaluator) evalCmd(ctx context.Context, ec *evalCtx, currentPipe Object,
 			return nil, err
 		}
 
-		return e.assignDot(ctx, ec, ast.Assign, assignVal)
+		return e.assignDot(ctx, ec, ast.Name, assignVal)
 	case (ast.Name.Arg.Ident != nil) && len(ast.Name.DotSuffix) == 0:
 		name := ast.Name.Arg.Ident.String()
 
@@ -184,12 +184,12 @@ func (e evaluator) evalDot(ctx context.Context, ec *evalCtx, n astDot) (Object,
 	return res, nil
 }
 
-func (e evaluator) assignDot(ctx context.Context, ec *evalCtx, n *astDot, toVal Object) (Object, error) {
+func (e evaluator) assignDot(ctx context.Context, ec *evalCtx, n astDot, toVal Object) (Object, error) {
 	if len(n.DotSuffix) == 0 {
 		return e.assignArg(ctx, ec, n.Arg, toVal)
 	}
 
-	panic("TODO")
+	return nil, errors.New("TODO")
 }
 
 func (e evaluator) evalArg(ctx context.Context, ec *evalCtx, n astCmdArg) (Object, error) {