Move findMember count tracking from TypeComparer to Context

Typecomparer is not a good place because it gets re-generated for new context,
which causes the counts to be reset.

Author: odersky

src/dotty/tools/dotc/core/Contexts.scala

@@ -165,6 +165,14 @@ object Contexts {
       _typeComparer
     }
 
+    /** Number of findMember calls on stack */
+    private[core] var findMemberCount: Int = 0
+
+    /** List of names which have a findMemberCall on stack,
+     *  after Config.LogPendingFindMemberThreshold is reached.
+     */
+    private[core] var pendingMemberSearches: List[Name] = Nil
+
     /** The new implicit references that are introduced by this scope */
     private var implicitsCache: ContextualImplicits = null
     def implicits: ContextualImplicits = {

src/dotty/tools/dotc/core/TypeComparer.scala

@@ -25,9 +25,6 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling wi
   private var pendingSubTypes: mutable.Set[(Type, Type)] = null
   private var recCount = 0
 
-  private[core] var findMemberCount = 0
-  private[core] var pendingMemberSearches: List[Name] = Nil
-
   private var needsGc = false
 
   /** Is a subtype check in progress? In that case we may not

src/dotty/tools/dotc/core/Types.scala

@@ -455,7 +455,7 @@ object Types {
           val jointInfo =
             if (rinfo.isAlias) rinfo
             else if (pdenot.info.isAlias) pdenot.info
-            else if (ctx.typeComparer.pendingMemberSearches.contains(name)) safeAnd(pdenot.info, rinfo)
+            else if (ctx.pendingMemberSearches.contains(name)) safeAnd(pdenot.info, rinfo)
             else pdenot.info & rinfo
           pdenot.asSingleDenotation.derivedSingleDenotation(pdenot.symbol, jointInfo)
         } else
@@ -493,12 +493,12 @@ object Types {
         case _ => tp1 & tp2
       }
 
-      val cmp = ctx.typeComparer
-      val recCount = cmp.findMemberCount
-      cmp.findMemberCount = recCount + 1
-      if (recCount >= Config.LogPendingFindMemberThreshold) {
-        cmp.pendingMemberSearches = name :: cmp.pendingMemberSearches
+      { val recCount = ctx.findMemberCount + 1
+        ctx.findMemberCount = recCount
+        if (recCount >= Config.LogPendingFindMemberThreshold)
+          ctx.pendingMemberSearches = name :: ctx.pendingMemberSearches
       }
+
       try go(this)
       catch {
         case ex: MergeError =>
@@ -508,9 +508,10 @@ object Types {
           throw ex // DEBUG
       }
       finally {
-        cmp.findMemberCount = recCount - 1
+        val recCount = ctx.findMemberCount
         if (recCount >= Config.LogPendingFindMemberThreshold)
-          cmp.pendingMemberSearches = cmp.pendingMemberSearches.tail
+          ctx.pendingMemberSearches = ctx.pendingMemberSearches.tail
+        ctx.findMemberCount = recCount - 1
       }
     }