Metals diagnostics only providing syntax errors, no compile errors

[simonmclean-ovo]

On an M1 Macbook Pro. Here's the setup I've done so far:

1. brew install coursier/formulas/coursier && cs setup
2. I then installed JVM 17 with cs java --jvm 17 --version and cs java --jvm 17 --setup
3. Opened a Scala 2.13.8 project in vscode, and installed the Metals extension

Problem: I can compile the code with sbt compile just fine. If I introduce a compile error (like delete a random import or a function param), then sbt compile will output the expected errors. However Metals will not detect the compile errors, and will only detect syntax errors.

Here's the output of Doctor

Build server currently being used is Bloop v1.5.3.

Metals Java: 17.0.4 from Eclipse Adoptium located at /Users/simon.mclean/Library/Caches/Coursier/arc/https/github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.4%252B8/OpenJDK17U-jdk_x64_mac_hotspot_17.0.4_8.tar.gz/jdk-17.0.4+8/Contents/Home

Metals Server version: 0.11.8

[table redacted]

Compilation status:

✅ - code is compiling
❌ - code isn't compiling, open problems tab to see detailed compilation errors
Diagnostics:

✅ - diagnostics correctly being reported by the build server
⚠️ - only syntactic errors being reported
Interactive features (completions, hover):

✅ - supported Scala version
Semanticdb features (references, renames, go to implementation):

✅ - build tool automatically creating needed semanticdb files
Debugging (run/test, breakpoints, evaluation):

✅ - users can run or test their code with debugging capabilities
❌ - the tool does not support debugging in this target
Java Support:

✅ - working non-interactive features (references, rename etc.)

If I open vscode's "PROBLEMS" tab, I can see this:

value ofInstant is not a member of object java.time.LocalDate (bloop)

ofInstant definitely is a member of LocalDate in Java 17, but it isn't in much older versions. So my suspicion is that somehow bloop is not using the same Java version which my JAVA_HOME variable is pointing to. But my understanding is the Metals is supposed to forward the JAVA_HOME value it's using to Bloop. What's more I've checked $HOME/.bloop/.bloop.json, and it seems correct, so I've no idea how this is happening...

[tanishiking]

@simonmclean-ovo Thank you for reporting.
Seems like you already checked, but

• Does HOME/.bloop/bloop.json's jqvaHome field point to Java17?
• Did you restart bloop after updating the global bloop file?

If both true, I also have no idea what's going on...

---

However Metals will not detect the compile errors, and will only detect syntax errors.

Is this another issue than the Java17 stuff? LocalDate error seems not a syntax error, it's a semantic error.

[simonmclean-ovo]

@tanishiking

Did you restart bloop after updating the global bloop file

Not explicitly. I just assumed that if it's no sbt session running, that bloop wouldn't be running either. Is this not the case?

LocalDate error seems not a syntax error, it's a semantic error

True, but it does seem to be preventing Metals from reporting any other other semantic errors

[tgodzik]

Bloop is running underneath to provide compilation. It should actually say which version it is using in the logs, something along the lines of:

2022.08.15 18:15:26 INFO  Bloop uses /usr/lib/jvm/openjdk17 defined at /home/tgodzik/.bloop/bloop.json
2022.08.15 18:15:26 INFO  Bloop currently uses settings: -Xmx3G

do you see it?

[tanishiking]

I just assumed that if it's no sbt session running, that bloop wouldn't be running either. Is this not the case?

Not really. Metals use bloop under the hood to compile the project and emit diagnoses.
So, as long as Metals running, bloop is there. What happens if you restart bloop? by Metals: restart build server.

it does seem to be preventing Metals from reporting any other other semantic errors

Hmm, what else errors should be there?

[simonmclean-ovo]

This seems to be fixed now. I just restarted my machine lol. I think it probably was bloop using the outdated jvmHome value, as you suggested @tanishiking 🤦

[tgodzik]

Next time you should be able to run the Restart build server command which should pick up the new java home. We also show a notification, but that's sometimes easy to miss.