[backport] SI-6613 fixed in GenBCode

It was fixed in GenASM in 44807a7.

Author: lrytz

src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala

@@ -329,7 +329,8 @@ abstract class BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
       // If the `sym` is a java module class, we use the java class instead. This ensures that we
       // register the class (instead of the module class) in innerClassBufferASM.
       // The two symbols have the same name, so the resulting internalName is the same.
-      val classSym = if (sym.isJavaDefined && sym.isModuleClass) sym.linkedClassOfClass else sym
+      // Phase travel (exitingPickler) required for SI-6613 - linkedCoC is only reliable in early phases (nesting)
+      val classSym = if (sym.isJavaDefined && sym.isModuleClass) exitingPickler(sym.linkedClassOfClass) else sym
       getClassBTypeAndRegisterInnerClass(classSym).internalName
     }