OutOfMemoryError: Metaspace when compiling multiple functions with Viper verification enabled

[pawinkler]

Description
When running ./gradlew compileKotlin multiple times with the Gradle daemon enabled (the default), the compiler eventually crashes with:

e: java.lang.OutOfMemoryError: Metaspace                                                                                                                                                                 
    at scala.collection.immutable.List$.<clinit>(List.scala:682)                                                                                                                                         
    ...
    at org.jetbrains.kotlin.formver.viper.Verifier.<init>(Verifier.kt:27)
    at org.jetbrains.kotlin.formver.plugin.compiler.ViperPoweredDeclarationChecker.check(ViperPoweredDeclarationChecker.kt:82)

Suspected Root Cause

ViperPoweredDeclarationChecker.check() is called once per function declaration. On line 82, it constructs a new Verifier instance for every function: val verifier = Verifier()

Each Verifier construction initializes a Config with seqOf(...), which triggers loading of Scala's collections library (List$, Seq$, etc.) into JVM Metaspace. Because the Gradle daemon is a long-lived process, these class definitions accumulate across builds until Metaspace is exhausted.

Steps to Reproduce

1. Enable conversionTargetsSelection("all_targets") in the Gradle plugin config
2. Have a project with several Kotlin functions to verify
3. Run ./gradlew compileKotlin --rerun-tasks three or more times in succession

Expected Behavior

Metaspace usage should remain stable across repeated compilations.

Workaround

Add to gradle.properties:
kotlin.daemon.jvm.options=-XX:MaxMetaspaceSize=512m

This delays the OOM but does not fix the underlying issue.

[jesyspa]

I'm a bit confused, why does loading Scala's collections library cause an issue? How is it different from any other build?