Don't crash GenBCode for value classes with a self declaration

If a value class has a self declaration

  class V(x: Long) extends AnyVal { self => /* ... */ }

`vClassSymbol.typeOfThis.typeSymbol` is `class Long` in the backend.

The InlineInfo for traits contains a field for the self type of the
trait. This is required for re-writing calls to final trait methods
to the static implementation method: the self type appears in the
impl method signature.

By mistake, the backend was recording the self type of all classes,
not only of traits. In the case of a value class with a self
declaration, this broke the assumption that the self type is always
a class type (not a primitive type).

The simple fix: only record the self type for traits.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
index 162da4236a..eadc404bee 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
@@ -329,10 +329,12 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
    * Build the [[InlineInfo]] for a class symbol.
    */
   def buildInlineInfoFromClassSymbol(classSym: Symbol, classSymToInternalName: Symbol => InternalName, methodSymToDescriptor: Symbol => String): InlineInfo = {
-    val selfType = {
+    val traitSelfType = if (classSym.isTrait && !classSym.isImplClass) {
       // The mixin phase uses typeOfThis for the self parameter in implementation class methods.
       val selfSym = classSym.typeOfThis.typeSymbol
       if (selfSym != classSym) Some(classSymToInternalName(selfSym)) else None
+    } else {
+      None
     }
 
     val isEffectivelyFinal = classSym.isEffectivelyFinal
@@ -394,6 +396,6 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
         }
     }).toMap
 
-    InlineInfo(selfType, isEffectivelyFinal, methodInlineInfos, warning)
+    InlineInfo(traitSelfType, isEffectivelyFinal, methodInlineInfos, warning)
   }
 }