v.ast.walker: pass nodes by reference

vlib/v/ast/walker/walker.v

@@ -4,10 +4,10 @@ import v.ast
 
 // Visitor defines a visit method which is invoked by the walker in each node it encounters.
 pub interface Visitor {
-	visit(node ast.Node) ?
+	visit(node &ast.Node) ?
 }
 
-pub type InspectorFn = fn (node ast.Node, data voidptr) bool
+pub type InspectorFn = fn (node &ast.Node, data voidptr) bool
 
 struct Inspector {
 	inspector_callback InspectorFn
@@ -15,7 +15,7 @@ mut:
 	data voidptr
 }
 
-pub fn (i &Inspector) visit(node ast.Node) ? {
+pub fn (i &Inspector) visit(node &ast.Node) ? {
 	if i.inspector_callback(node, i.data) {
 		return
 	}
@@ -23,12 +23,12 @@ pub fn (i &Inspector) visit(node ast.Node) ? {
 }
 
 // inspect traverses and checks the AST node on a depth-first order and based on the data given
-pub fn inspect(node ast.Node, data voidptr, inspector_callback InspectorFn) {
+pub fn inspect(node &ast.Node, data voidptr, inspector_callback InspectorFn) {
 	walk(Inspector{inspector_callback, data}, node)
 }
 
 // walk traverses the AST using the given visitor
-pub fn walk(visitor Visitor, node ast.Node) {
+pub fn walk(visitor Visitor, node &ast.Node) {
 	visitor.visit(node) or { return }
 	children := node.children()
 	for child_node in children {

vlib/v/ast/walker/walker_test.v

@@ -15,7 +15,7 @@ mut:
 	node ast.Node
 }
 
-fn (mut n NodeByOffset) visit(node ast.Node) ? {
+fn (mut n NodeByOffset) visit(node &ast.Node) ? {
 	node_pos := node.position()
 	if n.pos >= node_pos.pos && n.pos <= node_pos.pos + node_pos.len && node !is ast.File {
 		n.node = node
@@ -46,7 +46,7 @@ fn test_inspect() {
 module main
 	'
 	file := parse_text(source)
-	walker.inspect(file, voidptr(0), fn (node ast.Node, data voidptr) bool {
+	walker.inspect(file, voidptr(0), fn (node &ast.Node, data voidptr) bool {
 		// Second visit must be ast.Stmt
 		if node is ast.Stmt {
 			if node !is ast.Module {