2 files changed, 11 insertions, 5 deletions
diff --git a/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala b/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
index 42df53fed..3aa20f15b 100644
--- a/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
+++ b/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
@@ -79,12 +79,12 @@ trait ConstraintHandling {
       if (Config.failOnInstantiationToNothing) assert(false, msg)
       else ctx.log(msg)
     }
-    constr.println(i"adding $description")
+    constr.println(i"adding $description in ${ctx.typerState.hashesStr}")
     val lower = constraint.lower(param)
     val res =
       addOneBound(param, bound, isUpper = true) &&
       lower.forall(addOneBound(_, bound, isUpper = true))
-    constr.println(i"added $description = $res")
+    constr.println(i"added $description = $res in ${ctx.typerState.hashesStr}")
     res
   }
 
@@ -95,7 +95,7 @@ trait ConstraintHandling {
     val res =
       addOneBound(param, bound, isUpper = false) &&
       upper.forall(addOneBound(_, bound, isUpper = false))
-    constr.println(i"added $description = $res")
+    constr.println(i"added $description = $res in ${ctx.typerState.hashesStr}")
     res
   }
 
@@ -108,12 +108,12 @@ trait ConstraintHandling {
         val up2 = p2 :: constraint.exclusiveUpper(p2, p1)
         val lo1 = constraint.nonParamBounds(p1).lo
         val hi2 = constraint.nonParamBounds(p2).hi
-        constr.println(i"adding $description down1 = $down1, up2 = $up2")
+        constr.println(i"adding $description down1 = $down1, up2 = $up2 ${ctx.typerState.hashesStr}")
         constraint = constraint.addLess(p1, p2)
         down1.forall(addOneBound(_, hi2, isUpper = true)) &&
         up2.forall(addOneBound(_, lo1, isUpper = false))
       }
-    constr.println(i"added $description = $res")
+    constr.println(i"added $description = $res ${ctx.typerState.hashesStr}")
     res
   }
 
diff --git a/compiler/src/dotty/tools/dotc/core/TyperState.scala b/compiler/src/dotty/tools/dotc/core/TyperState.scala
index 5c476c1cb..206438d86 100644
--- a/compiler/src/dotty/tools/dotc/core/TyperState.scala
+++ b/compiler/src/dotty/tools/dotc/core/TyperState.scala
@@ -79,6 +79,9 @@ class TyperState(r: Reporter) extends DotClass with Showable {
   def tryWithFallback[T](op: => T)(fallback: => T)(implicit ctx: Context): T = unsupported("tryWithFallBack")
 
   override def toText(printer: Printer): Text = "ImmutableTyperState"
+
+  /** A string showing the hashes of all nested mutable typerstates */
+  def hashesStr: String = ""
 }
 
 class MutableTyperState(previous: TyperState, r: Reporter, override val isCommittable: Boolean)
@@ -207,4 +210,7 @@ extends TyperState(r) {
   }
 
   override def toText(printer: Printer): Text = constraint.toText(printer)
+
+  override def hashesStr: String = hashCode.toString + " -> " + previous.hashesStr
+
 }