From 5d5e73b14a46178a636b20f45ed8f8fae0177dee Mon Sep 17 00:00:00 2001
From: Rob Pike <r@golang.org>
Date: Mon, 22 Sep 2014 17:48:13 -0700
Subject: [PATCH] text/template: type-check chained node as argument Was just a
 missing case (literally) in the type checker.

Fixes #8473.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/142460043
---
 src/text/template/exec.go      | 2 ++
 src/text/template/exec_test.go | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/src/text/template/exec.go b/src/text/template/exec.go
index 8e155d478e..f6eed662b7 100644
--- a/src/text/template/exec.go
+++ b/src/text/template/exec.go
@@ -636,6 +636,8 @@ func (s *state) evalArg(dot reflect.Value, typ reflect.Type, n parse.Node) refle
 		return s.validateType(s.evalPipeline(dot, arg), typ)
 	case *parse.IdentifierNode:
 		return s.evalFunction(dot, arg, arg, nil, zero)
+	case *parse.ChainNode:
+		return s.validateType(s.evalChainNode(dot, arg, nil, zero), typ)
 	}
 	switch typ.Kind() {
 	case reflect.Bool:
diff --git a/src/text/template/exec_test.go b/src/text/template/exec_test.go
index 3bffcc1599..e2cf2d3705 100644
--- a/src/text/template/exec_test.go
+++ b/src/text/template/exec_test.go
@@ -176,6 +176,12 @@ func (t *T) Method3(v interface{}) string {
 	return fmt.Sprintf("Method3: %v", v)
 }
 
+func (t *T) Copy() *T {
+	n := new(T)
+	*n = *t
+	return n
+}
+
 func (t *T) MAdd(a int, b []int) []int {
 	v := make([]int, len(b))
 	for i, x := range b {
@@ -519,6 +525,8 @@ var execTests = []execTest{
 	{"bug12xE", "{{printf `%T` 0xEE}}", "int", T{}, true},
 	{"bug12Xe", "{{printf `%T` 0Xef}}", "int", T{}, true},
 	{"bug12XE", "{{printf `%T` 0XEE}}", "int", T{}, true},
+	// Chained nodes did not work as arguments. Issue 8473.
+	{"bug13", "{{print (.Copy).I}}", "17", tVal, true},
 }
 
 func zeroArgs() string {
-- 
2.50.0