<p dir="ltr">I can see this both ways (bug and not a bug), so let's err on the side of bug and see if we can make the behaviour match C#.</p>
<br><div class="gmail_quote"><div dir="ltr">On Mon, Aug 29, 2016, 23:53 Markus Schaber <<a href="mailto:m.schaber@codesys.com">m.schaber@codesys.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">





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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi, Slide,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Using a public abstract base class produces the same result: If the derived class is internal, the call works fine, if the derived class is public, the call does
 not work.<u></u><u></u></span></p></div></div><div lang="DE" link="blue" vlink="purple"><div>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Best regards<br>
<br>
Markus Schaber</span><span lang="EN-US"><br>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Slide [mailto:<a href="mailto:slide.o.mix@gmail.com" target="_blank">slide.o.mix@gmail.com</a>]
<br>
<b>Sent:</b> Monday, August 29, 2016 4:24 PM<br>
<b>To:</b> Markus Schaber; Discussion of IronPython<br>
<b>Subject:</b> Re: [Ironpython-users] Binding problem with default parameters in public classes<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
<p>What happens if it's an abstract base class instead of an interface?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<div>
<p class="MsoNormal">On Mon, Aug 29, 2016, 03:25 Markus Schaber <<a href="mailto:m.schaber@codesys.com" target="_blank">m.schaber@codesys.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Our tests recently caught a strange regression in our application. One can make existing scripts fail
 by changing an internal class to public.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">The attached program reproduces the issue. The problem is that the method has optional parameters, but
 those are only declared at the interface.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Now, when the class changes from “internal” to “public”, IronPython binds directly to the public methods
 without considering the interfaces any more, and thus does not recognize the optional parameters.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Now, the question is whether this could be considered a bug in IronPython, or whether it should be considered
 a bug to implement an interface method without replicating the default parameter values…</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Best regards<br>
<br>
Markus Schaber</span><span lang="EN-US"><br>
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