Lambda evaluation - Cannot evaluate because of compilation error(s): Evaluations must contain either an expression or a block of well-formed statements

Environment

Operating System: Win 10
JDK version: openjdk version "11.0.5" 2019-10-15
Java extension version: ?? do you mean "Language Support for Java(TM) by Red Hat"? if so 0.55.1
Java Debugger extension version: 0.24.0
Visual Studio Code Version: 1.41.1 (user setup)
Commit: 26076a4de974ead31f97692a0d32f90d735645c0
Date: 2019-12-18T14:58:56.166Z
Electron: 6.1.5
Chrome: 76.0.3809.146
Node.js: 12.4.0
V8: 7.6.303.31-electron.0
OS: Windows_NT x64 10.0.18363

Steps To Reproduce

Use a Stream.forEach() and try to evaluate something in the debug console

Sample project

java test runner - can't evaluate.log

Current Result

maybe it more has to do w/ lambda's? 🤔

Expected Result

Additional Informations

Also, the debugger variables window is able to see the values:

Michael DePouw (@spottedmahn)

Michael DePouw (@spottedmahn) thanks for reaching out. It looks like a bug to me. Jinbo Wang (@testforstephen) please take a look.

The upstream jdt has the same error on inspecting variable in the lambda expression. Need take a look at the upstream jdt first.

upstream jdt is https://github.com/eclipse/eclipse.jdt.debug? 🤔

Apologies for slightly hijacking this issue, but i have a very similar issue and want to check if it is same/related. When trying to evaluate in generic code, all evaluations fail with "Cannot evaluate because of a compilation error(s): Evaluations must contain either an expression or a block of well-formed statements". This is not a lambda, it's just a plain method of a (generic) type. I tried a trivial example and expressions worked with generics, so does this sound like the same bug ?

Any update on this issue? This is adding a lot of friction for me while debugging.

Ben Jackson (@puremourning)

The upstream has added the support for the lambda support in 2020-03 release, and already integrated to the debugger extension. See the upstream issue https://bugs.eclipse.org/bugs/show_bug.cgi?id=560392

Ben Jackson (@puremourning) Noel Yap (@noel-yap) Could you please open a new bug for your issue? Also please add the code snippet to explain your scenario.

Rome Li (@akaroml)

Rome Li (@akaroml) Jinbo Wang (@testforstephen) - any idea when that eclipse fix will be incorporated with vs code extension / tools? Also, looking at the issue on the eclipse site it appears that working with streams it's still not fixed.

Debugger 0.27.0 just released today, the fix should be already there. Could you try again?

BTW, you also need update Language Support for Java by Red Hat extension to latest version 0.64.1.

Obviously, this problem is still unresolved, sad.

Hi all,

I've the same issue trying to evaluating expression in a Tomcat application. Do you know how to solve it?

Thanks,

Rome Li (@akaroml)

Rome Li (@akaroml) since this is not fixed, please consider reopening.

let's reopen the issue and revisit it.

The evaluation of partial lambda expressions has been supported in the latest version of the debugger, and we will keep investigating the root cause of the unsupported cases.

Supported cases
- Can evaluate lambda variables in non-chain calls.
- Can evaluate local variables in chain calls of standard Java Streams.
Unsupported cases
- Cannot evaluate variables from enclosing methods when using lambda in a chain call.
- Cannot evaluate variables in self-defined chain calls.

Opened issues on the upstream JDT to track the progress.

Bug 578145 - Evaluations are not working on chain calls for lambda variables.
Bug 578147 - Evaluations for lambda variables are not working when using generic type arguments on lambda.

Michael DePouw (@spottedmahn)

Hi all, we have fixed the lambda evaluation bug in the upstream eclipse jdt repository.

Please update Language Support for Java(TM) by Red Hat to latest version 1.5.0, which includes our fix for lambda evaluation.

// fyi: Michael DePouw (@spottedmahn) Noel Yap (@noel-yap) Ryan Posener (@rposener) Ben Jackson (@puremourning) refcell (@refcell) Michael Lill (@michaellilltokiwa) massimeddu-sonic peter rumsey (@prumseycsi) vic (@acodervic) praxem Rana Ahmed (@ahmednrana)

Apparently not a duplicate of my problem reported to #844. Redhat 1.5 does not fix it. Please reopen something, or tell me to open something new.

peter rumsey (@prumseycsi)

peter rumsey (@prumseycsi) The original issue reported at #844 is about the compilation errors for lambda variable evaluation. Have a look at your comment #844 (comment), I don't understand what's your use case, could you pls open a new issue to describe your problem?

Hi, I have a similar problem with internal field initializer.

import java.util.*;
public class RomanToInteger {
    public int romanToInt(String s) {
        var ri = new HashMap<Character,Integer>() {{ 
            put('I', 1);
        }};
        var c = ri.get(s.charAt(0)); // ri returns cannot evaluate
        return 0;
    }
}

Environment
Operating System: Win 11
JDK version: openjdk version "11.0.12" 2021-07-20
Java extension version: Language Support for Java(TM) by Red Hat 0.40.1
Java Debugger extension version: 0.40.1
Visual Studio Code Version: 1.67.1
Commit: da15b6fd3ef856477bf6f4fb29ba1b7af717770d

Martin Kunc (@martinkunc)

Martin Kunc (@martinkunc) Your case is not related with this issue, I created a new one to track your case. #1163

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Lambda evaluation - Cannot evaluate because of compilation error(s): Evaluations must contain either an expression or a block of well-formed statements #754

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Lambda evaluation - Cannot evaluate because of compilation error(s): Evaluations must contain either an expression or a block of well-formed statements #754

Description

Environment

Steps To Reproduce

Current Result

Expected Result

Additional Informations

Activity

spottedmahn commented on Feb 3, 2020

akaroml commented on Feb 7, 2020

testforstephen commented on Feb 10, 2020

spottedmahn commented on Feb 10, 2020

puremourning commented on May 13, 2020

noel-yap commented on Jul 14, 2020

testforstephen commented on Jul 15, 2020

rposener commented on Jul 16, 2020

testforstephen commented on Jul 17, 2020

Faputa commented on Nov 2, 2020

massimeddu-sonic commented on Jan 13, 2021

michaellilltokiwa commented on Nov 12, 2021

testforstephen commented on Nov 15, 2021

testforstephen commented on Dec 14, 2021

testforstephen commented on Jan 11, 2022

testforstephen commented on Apr 15, 2022

prumseycsi commented on Apr 20, 2022

testforstephen commented on Apr 20, 2022

martinkunc commented on May 15, 2022

testforstephen commented on May 16, 2022

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