From ae3c9992ae57a67629e884b8536aac17a56db414 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Mon, 26 Oct 2009 19:21:13 -0700
Subject: [PATCH] - gofmt-ify walk.go - fixed several bugs

R=rsc
http://go/go-review/1015015
---
 src/pkg/go/ast/walk.go | 111 +++++++++++++++++++++++++----------------
 1 file changed, 67 insertions(+), 44 deletions(-)

diff --git a/src/pkg/go/ast/walk.go b/src/pkg/go/ast/walk.go
index 472e6ea17b1..379cc901248 100644
--- a/src/pkg/go/ast/walk.go
+++ b/src/pkg/go/ast/walk.go
@@ -69,18 +69,28 @@ func walkBlockStmt(v Visitor, b *BlockStmt) {
 // Walk visits each of the children of n.
 //
 func Walk(v Visitor, node interface{}) {
-	if node != nil && !v.Visit(node) {
+	if node == nil || !v.Visit(node) {
 		return;
 	}
 
 	// walk children
+	// (the order of the cases matches the order
+	// of the corresponding declaration in ast.go)
 	switch n := node.(type) {
 	// Comments and fields
+	case *Comment:
+		// nothing to do
+
 	case *CommentGroup:
 		for _, c := range n.List {
 			Walk(v, c);
 		}
-		
+		// TODO(gri): Keep comments in a list/vector instead
+		// of linking them via Next. Following next will lead
+		// to multiple visits and potentially n^2 behavior
+		// since Doc and Comments fields point into the global
+		// comments list.
+
 	case *Field:
 		walkCommentGroup(v, n.Doc);
 		walkIdentList(v, n.Names);
@@ -91,51 +101,54 @@ func Walk(v Visitor, node interface{}) {
 		walkCommentGroup(v, n.Comment);
 
 	// Expressions
+	case *BadExpr, *Ident, *Ellipsis, *BasicLit:
+		// nothing to do
+
 	case *StringList:
 		for _, x := range n.Strings {
 			Walk(v, x);
 		}
-		
+
 	case *FuncLit:
-		Walk(v, n.Type);
+		if n != nil {
+			Walk(v, n.Type);
+		}
 		walkBlockStmt(v, n.Body);
-		
+
 	case *CompositeLit:
 		Walk(v, n.Type);
 		walkExprList(v, n.Elts);
-		
+
 	case *ParenExpr:
 		Walk(v, n.X);
-		
+
 	case *SelectorExpr:
 		Walk(v, n.X);
-		if n.Sel != nil {
-			Walk(v, n.Sel);
-		}
-		
+		walkIdent(v, n.Sel);
+
 	case *IndexExpr:
 		Walk(v, n.X);
 		Walk(v, n.Index);
 		Walk(v, n.End);
-		
+
 	case *TypeAssertExpr:
 		Walk(v, n.X);
 		Walk(v, n.Type);
-		
+
 	case *CallExpr:
 		Walk(v, n.Fun);
 		walkExprList(v, n.Args);
-		
+
 	case *StarExpr:
 		Walk(v, n.X);
-		
+
 	case *UnaryExpr:
 		Walk(v, n.X);
-		
+
 	case *BinaryExpr:
 		Walk(v, n.X);
 		Walk(v, n.Y);
-		
+
 	case *KeyValueExpr:
 		Walk(v, n.Key);
 		Walk(v, n.Value);
@@ -144,76 +157,82 @@ func Walk(v Visitor, node interface{}) {
 	case *ArrayType:
 		Walk(v, n.Len);
 		Walk(v, n.Elt);
-		
+
 	case *StructType:
 		walkFieldList(v, n.Fields);
-		
+
 	case *FuncType:
 		walkFieldList(v, n.Params);
 		walkFieldList(v, n.Results);
-		
+
 	case *InterfaceType:
 		walkFieldList(v, n.Methods);
-		
+
 	case *MapType:
 		Walk(v, n.Key);
 		Walk(v, n.Value);
-		
+
 	case *ChanType:
 		Walk(v, n.Value);
 
 	// Statements
+	case *BadStmt:
+		// nothing to do
+
 	case *DeclStmt:
 		Walk(v, n.Decl);
-		
+
+	case *EmptyStmt:
+		// nothing to do
+
 	case *LabeledStmt:
 		walkIdent(v, n.Label);
 		Walk(v, n.Stmt);
-		
+
 	case *ExprStmt:
 		Walk(v, n.X);
-		
+
 	case *IncDecStmt:
 		Walk(v, n.X);
-		
+
 	case *AssignStmt:
 		walkExprList(v, n.Lhs);
 		walkExprList(v, n.Rhs);
-		
+
 	case *GoStmt:
 		if n.Call != nil {
 			Walk(v, n.Call);
 		}
-		
+
 	case *DeferStmt:
 		if n.Call != nil {
 			Walk(v, n.Call);
 		}
-		
+
 	case *ReturnStmt:
 		walkExprList(v, n.Results);
-		
+
 	case *BranchStmt:
 		walkIdent(v, n.Label);
-		
+
 	case *BlockStmt:
 		walkStmtList(v, n.List);
-		
+
 	case *IfStmt:
 		Walk(v, n.Init);
 		Walk(v, n.Cond);
 		walkBlockStmt(v, n.Body);
 		Walk(v, n.Else);
-		
+
 	case *CaseClause:
 		walkExprList(v, n.Values);
 		walkStmtList(v, n.Body);
-		
+
 	case *SwitchStmt:
 		Walk(v, n.Init);
 		Walk(v, n.Tag);
 		walkBlockStmt(v, n.Body);
-		
+
 	case *TypeCaseClause:
 		walkExprList(v, n.Types);
 		walkStmtList(v, n.Body);
@@ -222,12 +241,12 @@ func Walk(v Visitor, node interface{}) {
 		Walk(v, n.Init);
 		Walk(v, n.Assign);
 		walkBlockStmt(v, n.Body);
-		
+
 	case *CommClause:
 		Walk(v, n.Lhs);
 		Walk(v, n.Rhs);
 		walkStmtList(v, n.Body);
-		
+
 	case *SelectStmt:
 		walkBlockStmt(v, n.Body);
 
@@ -236,13 +255,13 @@ func Walk(v Visitor, node interface{}) {
 		Walk(v, n.Cond);
 		Walk(v, n.Post);
 		walkBlockStmt(v, n.Body);
-		
+
 	case *RangeStmt:
 		Walk(v, n.Key);
 		Walk(v, n.Value);
 		Walk(v, n.X);
 		walkBlockStmt(v, n.Body);
-	
+
 	// Declarations
 	case *ImportSpec:
 		walkCommentGroup(v, n.Doc);
@@ -251,34 +270,38 @@ func Walk(v Visitor, node interface{}) {
 			Walk(v, x);
 		}
 		walkCommentGroup(v, n.Comment);
-		
-		
+
 	case *ValueSpec:
 		walkCommentGroup(v, n.Doc);
 		walkIdentList(v, n.Names);
 		Walk(v, n.Type);
 		walkExprList(v, n.Values);
 		walkCommentGroup(v, n.Comment);
-		
+
 	case *TypeSpec:
 		walkCommentGroup(v, n.Doc);
 		walkIdent(v, n.Name);
 		Walk(v, n.Type);
 		walkCommentGroup(v, n.Comment);
 
+	case *BadDecl:
+		// nothing to do
+
 	case *GenDecl:
 		walkCommentGroup(v, n.Doc);
 		for _, s := range n.Specs {
 			Walk(v, s);
 		}
-		
+
 	case *FuncDecl:
 		walkCommentGroup(v, n.Doc);
 		if n.Recv != nil {
 			Walk(v, n.Recv);
 		}
 		walkIdent(v, n.Name);
-		Walk(v, n.Type);
+		if n.Type != nil {
+			Walk(v, n.Type);
+		}
 		walkBlockStmt(v, n.Body);
 
 	// Files and packages