diff --git a/src/dotty/tools/dotc/core/TypeErasure.scala b/src/dotty/tools/dotc/core/TypeErasure.scala
index 92e32d4b1c12..01c47d1357c2 100644
--- a/src/dotty/tools/dotc/core/TypeErasure.scala
+++ b/src/dotty/tools/dotc/core/TypeErasure.scala
@@ -308,12 +308,8 @@ class TypeErasure(isJava: Boolean, semiEraseVCs: Boolean, isConstructor: Boolean
       val parent = tp.parent
       if (parent isRef defn.ArrayClass) eraseArray(tp)
       else this(parent)
-    case tp: TermRef =>
+    case _: TermRef | _: ThisType =>
       this(tp.widen)
-    case tp: ThisType =>
-      def thisTypeErasure(tpToErase: Type) =
-        erasureFn(isJava, semiEraseVCs = false, isConstructor, wildcardOK)(tpToErase)
-      thisTypeErasure(tp.cls.typeRef)
     case SuperType(thistpe, supertpe) =>
       SuperType(this(thistpe), this(supertpe))
     case ExprType(rt) =>
diff --git a/src/dotty/tools/dotc/transform/Erasure.scala b/src/dotty/tools/dotc/transform/Erasure.scala
index 962297517fad..5b6420aa224d 100644
--- a/src/dotty/tools/dotc/transform/Erasure.scala
+++ b/src/dotty/tools/dotc/transform/Erasure.scala
@@ -271,6 +271,7 @@ object Erasure extends TypeTestsCasts{
     def erasedType(tree: untpd.Tree, semiEraseVCs: Boolean = true)(implicit ctx: Context): Type =
       tree.typeOpt match {
         case tp: TermRef if tree.isTerm => erasedRef(tp)
+        case tp: ThisType => tp
         case tp => erasure(tp, semiEraseVCs)
       }
 
diff --git a/tests/pending/run/unittest_collection.check b/tests/pending/run/unittest_collection.check
deleted file mode 100644
index df1629dd7eb1..000000000000
--- a/tests/pending/run/unittest_collection.check
+++ /dev/null
@@ -1 +0,0 @@
-warning: there was one deprecation warning; re-run with -deprecation for details
diff --git a/tests/pending/run/unittest_collection.scala b/tests/run/unittest_collection.scala
similarity index 86%
rename from tests/pending/run/unittest_collection.scala
rename to tests/run/unittest_collection.scala
index d10845475b74..5db9b56d2bdc 100644
--- a/tests/pending/run/unittest_collection.scala
+++ b/tests/run/unittest_collection.scala
@@ -4,11 +4,11 @@ object Test {
 
   def main(args: Array[String]): Unit = {
     test(collection.mutable.ArrayBuffer[String]())
-    test(collection.mutable.ListBuffer[String]())
-    class BBuf(z:ListBuffer[String]) extends BufferProxy[String] {
-      def self = z
-    }
-    test(new BBuf(collection.mutable.ListBuffer[String]()))
+//    test(collection.mutable.ListBuffer[String]())
+//    class BBuf(z:ListBuffer[String]) extends BufferProxy[String] {
+//      def self = z
+//    }
+//    test(new BBuf(collection.mutable.ListBuffer[String]()))
   }
 
   def test(x: Buffer[String]): Unit = {