<div dir="ltr">Actually, it seems <font face="courier new, monospace">M#{a := b}</font> always work when M is an empty map:<div><br></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div><div><font face="courier new, monospace">-module(foo).</font></div>
</div><div><div><font face="courier new, monospace">-compile(export_all).</font></div></div><div><div><font face="courier new, monospace"><br></font></div></div><div><div><font face="courier new, monospace">bat(M) -></font></div>
</div><div><div><font face="courier new, monospace"> M#{a := b}.</font></div></div></blockquote><div><div><br></div><div>Here is my session:</div></div><div><br></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px">
<div><div><div><font face="courier new, monospace">1> foo:bat(#{a => b}).</font></div></div></div><div><div><font face="courier new, monospace">#{a => b}</font></div></div><div><div><font face="courier new, monospace">2> foo:bat(#{b => b}).</font></div>
</div><div><div><font face="courier new, monospace">** exception error: bad argument</font></div></div><div><div><font face="courier new, monospace"> in function foo:bat/1 (foo.erl, line 5)</font></div></div><div><div>
<font face="courier new, monospace">3> foo:bat(#{}).</font></div></div><div><div><font face="courier new, monospace">#{a => b}</font></div></div></blockquote><font face="courier new, monospace"><br></font><div>3> was supposed to fail. Note <font face="courier new, monospace">(#{})#{a := b} </font>works in the shell (eval).</div>
</div><div class="gmail_extra"><br clear="all"><div><div><br></div><div><br></div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><b><span style="border-collapse:separate;font-family:arial;font-weight:normal"><div>
<span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><b>José Valim</b></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><div><span style="font-family:verdana,sans-serif;font-size:x-small"><a href="http://www.plataformatec.com.br/" style="color:rgb(42,93,176)" target="_blank">www.plataformatec.com.br</a></span></div>
<div><span style="font-family:verdana,sans-serif;font-size:x-small">Founder and Lead Developer</span></div></span></div></span></b></span></div>
<br><br><div class="gmail_quote">On Wed, Feb 5, 2014 at 6:16 PM, José Valim <span dir="ltr"><<a href="mailto:jose.valim@gmail.com" target="_blank">jose.valim@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Hello folks,<div><br></div><div>Maps are not working properly on update with a literal (via a var):</div><div><br></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font face="courier new, monospace">-module(foo).</font></div>
</div><div><div><font face="courier new, monospace">-compile(export_all).</font></div></div><div><div><font face="courier new, monospace"><br></font></div></div><div><div><font face="courier new, monospace">%% This function does not fail (and it should)</font></div>
</div><div><div><font face="courier new, monospace">bar() -></font></div></div><div><div><font face="courier new, monospace"> M = #{},</font></div></div><div><div><font face="courier new, monospace"> M#{a := b}.</font></div>
</div><div><div><font face="courier new, monospace"><br></font></div></div><div><div><font face="courier new, monospace">%% This function fails horribly</font></div></div><div><div><font face="courier new, monospace">%%</font></div>
</div><div><div><font face="courier new, monospace">%% =ERROR REPORT==== 5-Feb-2014::18:10:18 ===</font></div></div><div><div><font face="courier new, monospace">%% beam/beam_load.c(2065): Error loading function foo:baz/0: op update_map_exact p a r u u a a:</font></div>
</div><div><div><font face="courier new, monospace">%% no specific operation found</font></div></div><div><div><font face="courier new, monospace">baz() -></font></div></div><div><div><font face="courier new, monospace"> M = nil,</font></div>
</div><div><div><font face="courier new, monospace"> M#{a := b}.</font></div></div></blockquote><div><div><div><br></div><div>I assume there is some sort of inlining happening and discarding useful information.</div><div>
As far as I can see, the Erlang Abstract Format is correct.</div><div><br></div><div>Thank you!</div><span class="HOEnZb"><font color="#888888"><div><br></div><div><br></div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><b><span style="border-collapse:separate;font-family:arial;font-weight:normal"><div>
<span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><b>José Valim</b></span></div><div><span style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse"><div><span style="font-family:verdana,sans-serif;font-size:x-small"><a href="http://www.plataformatec.com.br/" style="color:rgb(42,93,176)" target="_blank">www.plataformatec.com.br</a></span></div>
<div><span style="font-family:verdana,sans-serif;font-size:x-small">Founder and Lead Developer</span></div></span></div></span></b></span></font></span></div>
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