List<?> is not equivalent to List<? extends Object>
Alex.Buckley at Sun.COM
Mon Apr 21 12:35:46 PDT 2008
Please don't bring JLS changes to compiler-dev. OpenJDK is about the
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// Whatever you like
See also bug 6480391.
Rémi Forax wrote:
> Hi all,
> the JLS currently considers that List<? extends Object> is not
> equivalent to List<?>.
> List<?> is reified but not List<? extends Object> so they behave
> It's not a big problem in general, if you want a List<?>, you declare a
> But (there is always a but), when the compiler infers a type argument
> it's more problematic, by example,
> HashSet<Class<?>> constantClassSet=new HashSet<Class<?>>();
> String.class, Object.class
> emits a warning because the second line creates an array of
> Class<? extends Object> which is not safe.
> I think it's stupid, i propose to modify section 22.214.171.124 (JLS3) to
> add a line saying that if an inferred type argument is Type<? extends
> with Bound the bound of the type varaible of Type, it is inferred Type<?>.
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