Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Daniele Futtorovic Newsgroups: comp.lang.java.programmer Subject: Re: pushing the JLS envelope... (6.4.2. Obscuring) Date: Tue, 22 Oct 2013 12:27:51 +0200 Organization: A noiseless patient Spider Lines: 64 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Injection-Date: Tue, 22 Oct 2013 10:27:52 +0000 (UTC) Injection-Info: mx05.eternal-september.org; posting-host="953b16a53032f86ce9f7e118c805bb98"; logging-data="16207"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19L/ChQDOwMfD/MQN3MwlyG" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 In-Reply-To: Cancel-Lock: sha1:3U6eWgiZReGYwZqSlB6S11teCRw= Xref: csiph.com comp.lang.java.programmer:26402 On 2013-10-20 23:33, Andreas Leitgeb allegedly wrote: > Daniele Futtorovic wrote: >> On 2013-10-19 01:48, Andreas Leitgeb allegedly wrote: >>> Ok, I know that this breaks conventions and common sense, but >>> just for the sake of understanding the JLS... >>> --- snip foo/Foo.java --- >>> package foo; >>> public class Foo { >>> public static String bad_name = "boo!"; // bad name for a field >>> public static class bad_name { // even worse, because lower case >>> public static void foo() { } >>> } >>> static { >>> bad_name.foo(); // doesn't work, because field obscures type - Ok. >>> foo.Foo.bad_name.foo(); // fqn doesn't work, either, but shouldn't it? >>> } >>> } >>> --- end snip --- >>> JLS (6.4.2. Obscuring) has to say about this case: >>> - If a field name obscures a type name, then a >>> fully qualified name for the type can be used >>> unless the type name denotes a local class (§14.3). >>> ("bad_name" isn't a local class, so the "unless"-part doesn't apply.) > > My fault for stopping reading at (6.4.2) in the JLS... > > It seems that "Obscuring" is really only meant between some > visible field and some visible type which however stem from > different qualifying paths (or local versus qualifyable). > >> The FQN is ambiguous. According to [6.5.2. Reclassification of >> Contextually Ambiguous Names]: > > Thanks for pointing that out (although I had to read all the > 6.5 and 6.5.1 to make any sense of the quoted part of 6.5.2 :-) ! > > After having determined "foo.Foo" as a Type and considering > Identifier "bad_name": > >> If the Identifier is the name of a method or field of the type >> denoted by TypeName, this AmbiguousName is reclassified as an >> ExpressionName. >> >> *Otherwise*, if the Identifier is the name of a member type of the >> type denoted by TypeName, this AmbiguousName is reclassified as a TypeName. > > So, this is, where field "bad_name" wins over type "bad_name" and > that is regardless that the next identifier is not a member of that > field's type. > > Now, I'm going to be (unsolicitedly) sadistic, maybe causing some cringe... > In my example, if I rewrote the static initializer block as follows: > static { bad_name bad_name = null; bad_name.foo(); } > then it becomes "correct" w.r.t. the JLS, because the name now first > appears in a context that infers a type name, then as a local variable > that beats the field ;-) You're such a dirty man, you know that? ;P > Thanks, Daniele, for pointing out, that "Obscuring" wasn't the case. Thank you for giving me the opportunity to find out what was happening there.