Avoiding to record constraints of the form P <:< P.

This will become redundant once poly params and typevars are identified.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index 305261213..d07bdc6fc 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -1972,6 +1972,7 @@ object Types {
 
     /** Instantiate variable with given type */
     def instantiateWith(tp: Type)(implicit ctx: Context): Type = {
+      assert(tp ne this)
       println(s"instantiating ${this.show} with ${tp.show}") // !!!DEBUG
       assert(ctx.typerState.undetVars contains this)
       ctx.typerState.undetVars -= this
@@ -2004,7 +2005,7 @@ object Types {
     }
 
     /** If the variable is instantiated, its instance, otherwise its origin */
-    override def stripTypeVar(implicit ctx: Context) = {
+    override def stripTypeVar(implicit ctx: Context) = { // todo: what about multiple instantiations?
       val inst = instanceOpt
       if (inst.exists) inst else origin
     }