From fbf92436b95d91151ce6717f40c46614ee68d487 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@golang.org>
Date: Wed, 16 Nov 2016 11:23:53 -0800
Subject: [PATCH] doc: add FAQ: why no conversion from []T1 to []T2?

Fixes #16934.

Change-Id: I725704e4c4aae7023fd89edc42af7ba0d242fec8
Reviewed-on: https://go-review.googlesource.com/33327
Reviewed-by: Rob Pike <r@golang.org>
---
 doc/go_faq.html | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/doc/go_faq.html b/doc/go_faq.html
index 37a31ae289..884d98ba6e 100644
--- a/doc/go_faq.html
+++ b/doc/go_faq.html
@@ -769,6 +769,29 @@ for i, v := range t {
 }
 </pre>
 
+<h3 id="convert_slice_with_same_underlying_type">
+Can I convert []T1 to []T2 if T1 and T2 have the same underlying type?</h3>
+
+This last line of this code sample does not compile.
+
+<pre>
+type T1 int
+type T2 int
+var t1 T1
+var x = T2(t1) // OK
+var st1 []T1
+var sx = ([]T2)(st1) // NOT OK
+</pre>
+
+<p>
+In Go, types are closely tied to methods, in that every named type has
+a (possibly empty) method set.
+The general rule is that you can change the name of the type being
+converted (and thus possibly change its method set) but you can't
+change the name (and method set) of elements of a composite type.
+Go requires you to be explicit about type conversions.
+</p>
+
 <h3 id="nil_error">
 Why is my nil error value not equal to nil?
 </h3>
-- 
2.50.0