1 files changed, 15 insertions, 9 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
index 4285858bf8..328ec8a033 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
@@ -6,7 +6,6 @@
 package scala.tools.nsc.backend.jvm
 
 import scala.tools.nsc.Global
-import PartialFunction._
 
 /**
  * This trait contains code shared between GenBCode and GenASM that depends on types defined in
@@ -19,7 +18,7 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
   val ExcludedForwarderFlags = {
     import scala.tools.nsc.symtab.Flags._
     // Should include DEFERRED but this breaks findMember.
-    ( SPECIALIZED | LIFTED | PROTECTED | STATIC | EXPANDEDNAME | BridgeAndPrivateFlags | MACRO )
+    SPECIALIZED | LIFTED | PROTECTED | STATIC | EXPANDEDNAME | BridgeAndPrivateFlags | MACRO
   }
 
   /**
@@ -30,10 +29,10 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
    */
   def isAnonymousOrLocalClass(classSym: Symbol): Boolean = {
     assert(classSym.isClass, s"not a class: $classSym")
-    val res = (classSym.isAnonymousClass || !classSym.originalOwner.isClass)
-    // lambda classes are always top-level classes.
-    if (res) assert(!classSym.isDelambdafyFunction)
-    res
+    // Here used to be an `assert(!classSym.isDelambdafyFunction)`: delambdafy lambda classes are
+    // always top-level. However, SI-8900 shows an example where the weak name-based implementation
+    // of isDelambdafyFunction failed (for a function declared in a package named "lambda").
+    classSym.isAnonymousClass || !classSym.originalOwner.isClass
   }
 
   /**
@@ -147,9 +146,16 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
       annot.args.isEmpty
   }
 
-  def isRuntimeVisible(annot: AnnotationInfo): Boolean =
-    annot.atp.typeSymbol.getAnnotation(AnnotationRetentionAttr)
-      .exists(_.assocs.contains((nme.value -> LiteralAnnotArg(Constant(AnnotationRetentionPolicyRuntimeValue)))))
+  def isRuntimeVisible(annot: AnnotationInfo): Boolean = {
+    annot.atp.typeSymbol.getAnnotation(AnnotationRetentionAttr) match {
+      case Some(retentionAnnot) =>
+        retentionAnnot.assocs.contains(nme.value -> LiteralAnnotArg(Constant(AnnotationRetentionPolicyRuntimeValue)))
+      case _ =>
+        // SI-8926: if the annotation class symbol doesn't have a @RetentionPolicy annotation, the
+        // annotation is emitted with visibility `RUNTIME`
+        true
+    }
+  }
 
   private def retentionPolicyOf(annot: AnnotationInfo): Symbol =
     annot.atp.typeSymbol.getAnnotation(AnnotationRetentionAttr).map(_.assocs).map(assoc =>