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kotlinlang

:wave: Hi team! I want to use the `kotlin("compiler-embeddable")` version `1.8.2x` to access `FIR` elements in a Java app and get a `bad class file` error during compilation.
I can use classes like `FirPrimaryConstructor` on version `1.8.0`, an error occurs starting on version `1.8.2x`.
I created a simple project that reproduces the error <https://github.com/traceyyoshima/kotlin-example|here>.

Any helps is greatly appreciated, thanks in advance!

Error:
```/Users/yoshi/Desktop/kotlin-example/src/main/java/org/example/Main.java:3: error: cannot access FirPrimaryConstructor
import org.jetbrains.kotlin.fir.declarations.impl.FirPrimaryConstructor;
                                                 ^
  bad class file: /Users/yoshi/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-compiler-embeddable/1.8.22/e2cf111da088dc807a74157741b4cd4b664edfb7/kotlin-compiler-embeddable-1.8.22.jar(/org/jetbrains/kotlin/fir/declarations/impl/FirPrimaryConstructor.class)
    undeclared type variable: T
    Please remove or make sure it appears in the correct subdirectory of the classpath.```

Could you please report an issue about it?
This problem looks very weird

As a workaround you can just write everything in Kotlin
```fun test(obj: Any?) {
    if (obj is FirPrimaryConstructor) {
        println("hello")
    }
}```
I checked, it works just fine

Yes, it’s a strange error, I created an issue here: <https://youtrack.jetbrains.com/issue/KT-59616/Java-compilation-error-Bad-class-file-while-using-FIR-tree-in-Java>

Ya, I’d expect many failures on the backend if it didn’t work in Kotlin. I appreciate the option, I’ll check in with the team, thanks again!

<@UKPEELJCW>, do you know how complex the issue is, have an estimate on prioritization, and/or how long it will be until a fix is available?

Unfortunately I don't
cc <@U0ANUS2BA> just in case

Thanks for bringing this up, I’ve answered in the issue.

<@UKPEELJCW> FYI any introduction/usages of `@JvmInline` classes will make it difficult to use compiler internals from Java, even when bugs like KT-52706 are fixed. I believe we are OK with this, so it’s just something to remember.