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spec: type assertions and switches don't operate on type parameters 

Change-Id: I11111b3617673be94508128489aed6488d518537
Reviewed-on: https://go-review.googlesource.com/c/go/+/366834
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Robert Griesemer 2021-11-23 20:56:33 -08:00
parent 6ea17aa52c
commit 696515ee39
1 changed files with 5 additions and 3 deletions
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8
doc/go_spec.html
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@ -3884,8 +3884,9 @@ If the indices are out of range at run time, a <a href="#Run_time_panics">run-ti
<h3 id="Type_assertions">Type assertions</h3> <h3 id="Type_assertions">Type assertions</h3>
<p> <p>
For an expression <code>x</code> of <a href="#Interface_types">interface type</a> For an expression <code>x</code> of <a href="#Interface_types">interface type</a>,
and a type <code>T</code>, the primary expression but not a <a href="#Type_parameters">type parameter</a>, and a type <code>T</code>,
the primary expression
</p> </p>
<pre> <pre>
@ -5677,7 +5678,8 @@ switch x.(type) {
<p> <p>
Cases then match actual types <code>T</code> against the dynamic type of the Cases then match actual types <code>T</code> against the dynamic type of the
expression <code>x</code>. As with type assertions, <code>x</code> must be of expression <code>x</code>. As with type assertions, <code>x</code> must be of
<a href="#Interface_types">interface type</a>, and each non-interface type <a href="#Interface_types">interface type</a>, but not a
<a href="#Type_parameters">type parameter</a>, and each non-interface type
<code>T</code> listed in a case must implement the type of <code>x</code>. <code>T</code> listed in a case must implement the type of <code>x</code>.
The types listed in the cases of a type switch must all be The types listed in the cases of a type switch must all be
<a href="#Type_identity">different</a>. <a href="#Type_identity">different</a>.