b.stmt(s.Else)
			b.jump(done)
		}

		b.current = done

	case *ast.SwitchStmt:
		b.switchStmt(s, label)

	case *ast.TypeSwitchStmt:
		b.typeSwitchStmt(s, label)

	case *ast.SelectStmt:
		b.selectStmt(s, label)

	case *ast.ForStmt:
		b.forStmt(s, label)

	case *ast.RangeStmt:
		b.rangeStmt(s, label)

	default:
		panic(fmt.Sprintf("unexpected statement kind: %T", s))
	}
}

		return invalid
	}
	return nil
}

// targets describes the target statements within which break
// or continue statements are valid.
type targets struct {
	breaks    Stmt     // *ForStmt, *SwitchStmt, *SelectStmt, or nil
	continues *ForStmt // or nil
	caseIndex int      // case index of immediately enclosing switch statement, or < 0
}

// blockBranches processes a block's body starting at start and returns the

		Comm  Stmt      // send or receive statement; nil means default case
		Colon token.Pos // position of ":"
		Body  []Stmt    // statement list; or nil
	}

	// A SelectStmt node represents a select statement.
	SelectStmt struct {
		Select token.Pos  // position of "select" keyword
		Body   *BlockStmt // CommClauses only
	}

	// A ForStmt represents a for statement.
	ForStmt struct {

		children = append(children,
			tok(n.For, len("for")),
			tok(n.TokPos, len(n.Tok.String())))

	case *ast.ReturnStmt:
		children = append(children,
			tok(n.Return, len("return")))

	case *ast.SelectStmt:
		children = append(children,
			tok(n.Select, len("select")))

	case *ast.SelectorExpr:
		// nop

	case *ast.SendStmt:
		children = append(children,
			tok(n.Arrow, len("<-")))

				Rbrace: stmt.End(),
			}
			n.Else = block
		case *ast.BlockStmt:
			stmt.Lbrace = pos
		default:
			panic("unexpected node type in if")
		}
		ast.Walk(f, n.Else)
		return nil
	case *ast.SelectStmt:
		// Don't annotate an empty select - creates a syntax error.
		if n.Body == nil || len(n.Body.List) == 0 {
			return nil
		}
	case *ast.SwitchStmt:
		// Don't annotate an empty switch - creates a syntax error.

			forEachLastStmt(cc.Body, onLast)
		}
	case *ast.TypeSwitchStmt:
		for _, c := range s.Body.List {
			cc := c.(*ast.CaseClause)
			forEachLastStmt(cc.Body, onLast)
		}
	case *ast.SelectStmt:
		for _, c := range s.Body.List {
			cc := c.(*ast.CommClause)
			forEachLastStmt(cc.Body, onLast)
		}
	default:
		onLast(s)
	}
}

		f.walk(n.Init, ctxStmt, visit)
		f.walk(n.Assign, ctxStmt, visit)
		f.walk(n.Body, ctxTypeSwitch, visit)
	case *ast.CommClause:
		f.walk(n.Comm, ctxStmt, visit)
		f.walk(n.Body, ctxStmt, visit)
	case *ast.SelectStmt:
		f.walk(n.Body, ctxStmt, visit)
	case *ast.ForStmt:
		f.walk(n.Init, ctxStmt, visit)
		f.walk(&n.Cond, ctxExpr, visit)
		f.walk(n.Post, ctxStmt, visit)
		f.walk(n.Body, ctxStmt, visit)
	case *ast.RangeStmt:

		a.apply(n, "Init", nil, n.Init)
		a.apply(n, "Assign", nil, n.Assign)
		a.apply(n, "Body", nil, n.Body)

	case *ast.CommClause:
		a.apply(n, "Comm", nil, n.Comm)
		a.applyList(n, "Body")

	case *ast.SelectStmt:
		a.apply(n, "Body", nil, n.Body)

	case *ast.ForStmt:
		a.apply(n, "Init", nil, n.Init)
		a.apply(n, "Cond", nil, n.Cond)
		a.apply(n, "Post", nil, n.Post)
		a.apply(n, "Body", nil, n.Body)

		walkBeforeAfter(&n.Assign, before, after)
		walkBeforeAfter(&n.Body, before, after)
	case *ast.CommClause:
		walkBeforeAfter(&n.Comm, before, after)
		walkBeforeAfter(&n.Body, before, after)
	case *ast.SelectStmt:
		walkBeforeAfter(&n.Body, before, after)
	case *ast.ForStmt:
		walkBeforeAfter(&n.Init, before, after)
		walkBeforeAfter(&n.Cond, before, after)
		walkBeforeAfter(&n.Post, before, after)

			r.walkStmts(n.Body.List)
		}

	case *ast.CommClause:
		r.openScope(n.Pos())
		defer r.closeScope()
		if n.Comm != nil {
			ast.Walk(r, n.Comm)
		}
		r.walkStmts(n.Body)

	case *ast.SelectStmt:
		// as for switch statements, select statement bodies don't get their own
		// scope.
		if n.Body != nil {
			r.walkStmts(n.Body.List)
		}

	case *ast.ForStmt:
		r.openScope(n.Pos())