Java type inference fails with this program

Environment

Operating System: macOS Sonoma
JDK version: 21
Visual Studio Code version: 1.90.2
Java extension version: 1.31.0

Steps To Reproduce

Create a file Main.java, paste the following content into it and then open it with VS Code and the Java extension:

import java.util.*;
import java.util.stream.Collectors;

public class Main {

    record Foo(String id, List<Bar> bars) {}

    record Bar(String id) {}

    public static void main(String[] args) {
        var barsByFooIdAndBarId = Collections.<Foo>emptyList()
            .stream()
            .collect(
                Collectors.toMap(
                    Foo::id,
                    foo ->
                        Collections.<String, Bar>emptyMap()
                            .entrySet()
                            .stream()
                            .collect(
                                Collectors.toMap(
                                    Map.Entry::getKey,
                                    entry ->
                                        foo
                                            .bars()
                                            .get(0)
                                )
                            )
                )
            );

        Bar bar = barsByFooIdAndBarId
            .computeIfAbsent("fooId", id -> Collections.emptyMap())
            .get("barId");

        System.out.println(bar);
    }
}

Current Result

The program doesn't compile. barsByFooIdAndBarId's type is inferred as Map<String, Map<String, Object>> instead of Map<String, Map<String, Bar>>. As a result, the assignment to Bar bar is invalid because Object is not assignable to Bar. However, if you replace var with Map<String, Map<String, Bar>> directly, then the program will be just fine. You can even run it and it will print null.

I know that this doesn't happen with javac nor IntelliJ because I noticed this at work and my colleagues using IntelliJ don't have the issue and manual compilation with Maven is also fine.

I suspect that the issue comes from the Eclipse Java language server which the Java extension is based on. But I cannot confirm this for now as I'm still trying to build and run the language server locally. And this is harder than I thought.

Expected Result

The program compiles and runs with VS Code and the Java extension. I understand that this may not be easy to solve. I would already appreciate some insights on the issue. If you think that I should open an issue on Eclipse's side, please let me know!

Additional Informations

Last but not least, thank you for your amazing work! 💪 I'm so happy to be able to write Java in VS Code thanks to the extension. I was able to move away from IntelliJ which I genuinely dislike. So thank you so much for the dedication in making this possible! ❤️

redhat-developer / vscode-java