Cannot make a static reference to the non-static type T

[testforstephen]

import java.util.function.Consumer;

public class HelloWorld {
    public static <T> void build(T element) {
        new Thread(() -> {
            new Consumer<T>() {

                @Override
                public void accept(T t) {

                }
            };
        });
    }
}

Opening the sample code in VS Code, it reports "Cannot make a static reference to the non-static type T" error at the line of public void accept(T t). The same code doesn't have error in Eclipse and Intellij IDEA.

[snjeza]

This is an Eclipse regression issue. It can be reproduced in Eclipse 4.20M3 and Eclipse I20210526-2310.

[rgrunber]

Thanks for narrowing this down. Also seems to have been reported recently upstream as https://bugs.eclipse.org/bugs/show_bug.cgi?id=572873 .

[testforstephen]

I'm using Eclipse 2020-12. Yes, it's same as the upstream issue. If the generic method includes a lambda expression and use the generics inside the lambda expression, it will report this error.

[testforstephen]

This is a regression issue introduced by 2021-03 release. And the upstream issue has been fixed and targeted for 4.20 RC2. And the I-build for 4.20 RC2 is released at June 3, see https://download.eclipse.org/eclipse/downloads/. But the release download page (https://download.eclipse.org/releases/2021-06/) didn't include RC2 yet. The release link is what we used in target platform definition.

@rgrunber Do you know what's the status of 4.20 RC2?

[snjeza]

We can use https://download.eclipse.org/eclipse/updates/4.20-I-builds/I20210603-0040/

[rgrunber]

Yup, and we'll likely be able to adopt the final release final release of 2021-06 (4.20) next Wednesday : https://wiki.eclipse.org/Category:SimRel-2021-06 . We can at least use the I-build to verify.