Re: pushing the JLS envelope... (6.4.2. Obscuring)

From:
Lew <lewbloch@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 19 Oct 2013 14:41:58 -0700 (PDT)
Message-ID:
<2070fb43-7040-45a4-bb2b-cd69c86e40cf@googlegroups.com>
Daniele Futtorovic wrote:

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 (=A714.3).
("bad_name" isn't a local class, so the "unless"-part doesn't apply.)
 
Even if the field was non-static, the compiler still doesn't use
the type but rather complains about unavailability of the field,
even with the fqn.
 
PS: suggesting "rename the field or (better) the type" as a solution
    is really missing the point of this post.
 


Great question.

The FQN is ambiguous. According to [6.5.2. Reclassification of


Great answer.

Contextually Ambiguous Names]:

  If the name to the left of the "." is reclassified as a TypeName, then:
 
    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 TypeNam=

e.

<<<<<<
 
Ergo, foo.Foo.bad_name refers to foo's the member of type String,
bad_name (great name btw.).


"bad_name" == great name.

... At least that's how I'd interpret it.


Makes sense to me, both question and answer.

I shall rethink it a couple or few more times, but so far you seem to have =
it aright.
If so, then

foo.Foo.bad_name.foo(); // fqn doesn't work, either, but shouldn't it?

would fail to compile because 'String' doesn't have a method 'foo()'.

--
Lew

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