Refine dependency tracking for bounds in replace

Author: odersky

compiler/src/dotty/tools/dotc/core/OrderingConstraint.scala

@@ -11,6 +11,7 @@ import config.Config
 import config.Printers.constr
 import reflect.ClassTag
 import Constraint.ReverseDeps
+import Substituters.SubstParamMap
 import annotation.tailrec
 import annotation.internal.sharable
 import cc.{CapturingType, derivedCapturingType}
@@ -411,7 +412,6 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
     tvars.copyToArray(entries1, nparams)
     newConstraint(boundsMap = this.boundsMap.updated(poly, entries1))
       .init(poly)
-      .adjustDeps(poly, entries1, add = true)
   }
 
   /** Split dependent parameters off the bounds for parameters in `poly`.
@@ -433,7 +433,8 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
         todos.dropInPlace(1)
       i += 1
     }
-    current.checkWellFormed()
+    current.adjustDeps(poly, current.boundsMap(poly).nn, add = true)
+      .checkWellFormed()
   }
 
 // ---------- Updates ------------------------------------------------------------
@@ -609,11 +610,10 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
         current = lowerLens.map(this, current, hi, removeParam)
 
       current.foreachParam { (p, i) =>
-        current = boundsLens.map(this, current, p, i,
-          entry =>
-            val newEntry = replaceParam(entry, p, i)
-            adjustDeps(newEntry, entry, p.paramRefs(i))
-            newEntry)
+        val other = p.paramRefs(i)
+        val oldEntry = current.entry(other)
+        val newEntry = current.ensureNonCyclic(other, oldEntry.substParam(param, replacement))
+        current = updateEntryNoOrdering(current, other, newEntry, oldEntry)
       }
       current.dropDeps(param)
       current.checkWellFormed()

compiler/src/dotty/tools/dotc/core/Substituters.scala

@@ -193,7 +193,7 @@ object Substituters:
     def apply(tp: Type): Type = substRecThis(tp, from, to, this)(using mapCtx)
   }
 
-  final class SubstParamMap(from: ParamRef, to: Type)(using Context) extends DeepTypeMap, IdempotentCaptRefMap {
+  class SubstParamMap(from: ParamRef, to: Type)(using Context) extends DeepTypeMap, IdempotentCaptRefMap {
     def apply(tp: Type): Type = substParam(tp, from, to, this)(using mapCtx)
   }