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When invoking code completion in an example like the following (caret represented by "<|>"): private void foo() { Collection<?> c = new ArrayLis<|>; } The result is this: private void foo() { Collection<?> c = new ArrayList<E>(); } This doesn't compile. With the target language level being Java 7+ I think it would actually make sense to complete with the diamond operator. Alternatively one might here as well use "Object" instead of "E".
I assume this example has been simplified from smth more meaningful? There doesn't seem to be much that you can do with 'c' :) More to the point: why would you invoke completion in this position at Java 7+? With a little less typing, completion would have offered exactly what you expect.
> I assume this example has been simplified from smth more meaningful? There doesn't seem to be much that you can do with 'c' :) Not that much simplified really. Would also apply to e.g. `Map<String, ?>`. > With a little less typing, completion would have offered exactly what you expect. Can you elaborate on this? What would I have to type? If I use code completion after typing "List<?> l = new " it doesn't offer "ArrayList()", which surprises me, because if I type "Map<String, ?> = new " it offers "HashMap()".
(In reply to Knut Wannheden from comment #2) > > I assume this example has been simplified from smth more meaningful? There doesn't seem to be much that you can do with 'c' :) > > Not that much simplified really. Would also apply to e.g. `Map<String, ?>`. In both cases you have an empty collection into which you cannot add any element. Am I missing anything? > > With a little less typing, completion would have offered exactly what you expect. > > Can you elaborate on this? What would I have to type? If I use code > completion after typing "List<?> l = new " it doesn't offer "ArrayList()", > which surprises me, because if I type "Map<String, ?> = new " it offers > "HashMap()". In both cases, I need to type at least one character of the type name and then the diamond constructor is offered: Map<String, ?> = new | <- does not offer diamond Map<String, ?> = new H| <- offers "HashMap<>()" The same for Collection<?> & ArrayList<>(). If you see different, we'll need to do the typical walk through all preference options & plugins installed to find out why you see different results than I do.
> In both cases you have an empty collection into which you cannot add any element. Am I missing anything? Yes, I would only be able to add "null", unless the object is first cast (which I think is a valid and not too uncommon use case). But I think this is still somewhat beside the point. The same problem is also present if I for example substitute "?" with "? super Integer" as in "List<? super Integer>". > In both cases, I need to type at least one character of the type name and then > the diamond constructor is offered I only see proposals like "ArrayList()" which, when selected, get expanded to "ArrayList<E>()". I can't get content assist to insert "ArrayList<>()", which is what I would really want. > If you see different, we'll need to do the typical walk through all preference > options & plugins installed to find out why you see different results than I do. I am using Eclipse 2020-03 and do my testing in a Java 11 project (I have checked that the JDK compliance is properly set for this project).
(In reply to Knut Wannheden from comment #4) > > If you see different, we'll need to do the typical walk through all preference > > options & plugins installed to find out why you see different results than I do. > > I am using Eclipse 2020-03 and do my testing in a Java 11 project (I have > checked that the JDK compliance is properly set for this project). Which package (e.g. "IDE for Java Developers")? Any additional plugins? Which options are enabled at Preferences > Java > Editor > Content Assist > Advanced (upper box)?
> Which package (e.g. "IDE for Java Developers")? Yes, IDE for Java Developers. > Any additional plugins? None. > Which options are enabled at Preferences > Java > Editor > Content Assist > Advanced (upper box)? Standard settings with "Java Proposals (Task-Focused)", "SWT Template Proposals", and "Template Proposals". Changing from the default "Java Proposals (Task-Focused)" to plain "Java Proposals" (or alternatively to "Java Non-Type Proposals") resolved the issue. So it seems like the "Java Proposals (Task-Focused)" is broken. (I even wonder how many people use Mylyn these days and if it should be part of this distro, but that's a separate topic.) Further investigation shows that somehow the defaults for content assist settings are behaving very oddly. When I create a new workspace and check the preferences I can see the following being selected: "Java Proposals", "Java Proposals (Task-Focused)", "SWT Template Proposals", and "Template Proposals". But as soon as I create a Java project, create a Java class and start using content assist in there (Ctrl+Space), the preference has changed to show only "Java Proposals (Task-Focused)", "SWT Template Proposals", and "Template Proposals" (i.e. no more "Java Proposals"). If I now in the Preferences dialog click on "Restore Defaults" the selection changes to "Java Proposals", "SWT Template Proposals", and "Template Proposals"! Do "Java Proposals" and "Java Proposals (Task-Focused)" possibly use the same ID? In addition to "Java Proposals (Task-Focused)" not inserting the diamond operator it also seems like it interferes with the standard "Java Proposals" somehow.
(In reply to Knut Wannheden from comment #6) > > Which package (e.g. "IDE for Java Developers")? > > Yes, IDE for Java Developers. > > > Any additional plugins? > > None. > > > Which options are enabled at Preferences > Java > Editor > Content Assist > Advanced (upper box)? > > Standard settings with "Java Proposals (Task-Focused)", "SWT Template > Proposals", and "Template Proposals". > > Changing from the default "Java Proposals (Task-Focused)" to plain "Java > Proposals" (or alternatively to "Java Non-Type Proposals") resolved the > issue. So it seems like the "Java Proposals (Task-Focused)" is broken. (I > even wonder how many people use Mylyn these days and if it should be part of > this distro, but that's a separate topic.) This is bug 461809 (where we currently think that a JDT bug is exposed by enabling Mylyn). > Further investigation shows that somehow the defaults for content assist > settings are behaving very oddly. [...] I can't say much about these. Could be a bug in JDT/UI or in Mylyn. Once completion is fixed (by workaround or by code fix) for Map<String, ?> = new H| <- offers "HashMap<>()" do you still think the original request for completion between < and > is necessary?
> This is bug 461809 (where we currently think that a JDT bug is exposed > by enabling Mylyn). Yes, looks like it. > Once completion is fixed (by workaround or by code fix) for > Map<String, ?> = new H| <- offers "HashMap<>()" > do you still think the original request for completion between < and > is necessary? No, I think that corner case can be ignored, as the diamond operator is nicer anyway. I assume 461809 will fix the issue so that the diamond operator completion works out of the box, without any custom settings required.
(In reply to Knut Wannheden from comment #8) > > This is bug 461809 (where we currently think that a JDT bug is exposed > > by enabling Mylyn). > > Yes, looks like it. > > > Once completion is fixed (by workaround or by code fix) for > > Map<String, ?> = new H| <- offers "HashMap<>()" > > do you still think the original request for completion between < and > is necessary? > > No, I think that corner case can be ignored, as the diamond operator is > nicer anyway. > > I assume 461809 will fix the issue so that the diamond operator completion > works out of the box, without any custom settings required. Thanks, closing. *** This bug has been marked as a duplicate of bug 461809 ***
