Cannot evaluate because of compilation error(s). Occurs within watch expressions.

[mpette200]

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While debugging, watches display "Cannot evaluate because of compilation error(s): ......". This is annoying, and actually the same issue seems to prevent conditional breakpoints from working. This seems to occur whenever an inner class is present within the method.

Environment

• Operating System: Microsoft Windows [Version 10.0.19042.1348]
• JDK version: jdk-11.0.12
• Visual Studio Code version: 1.62.3 (user setup)
• Java extension version: Java(TM) by Red Hat v1.1.0
• Java Debugger extension version: v0.37.0

Steps To Reproduce

1. Create the slightly modified "Hello World" by copy / pasting the code below.
2. Add a breakpoint then debug.
3. Set a watch expression for msg.length()

import java.util.List;
import java.util.ArrayList;

public class Hello {
    public static void main(String[] args) {
        
        class Position {
            int x;
            int y;
        }
        
        String msg = "Hello World";
        List<Position> x = new ArrayList<>();
        System.out.println(msg + x);
    }

}

Current Result

Expected Result

msg.length() should evaluate to a number.

Additional Informations

If I move the "class Position {}" so that it is no longer an inner class then the debugger seems to work correctly.

[testforstephen]

Thanks for the information. I can reproduce it, it's a bug.

[testforstephen]

Opened an issue at the upstream JDT. https://bugs.eclipse.org/bugs/show_bug.cgi?id=578148

[jasondamour]

RIP