Add debug output

Author: odersky

community-build/test/scala/dotty/communitybuild/CommunityBuildTest.scala

@@ -311,11 +311,13 @@ class CommunityBuildTest {
           |""".stripMargin)
     }
   }
-
+/*
   @Test def intent = projects.intent.run()
   @Test def algebra = projects.algebra.run()
+*/
   @Test def scalacheck = projects.scalacheck.run()
   @Test def scalatest = projects.scalatest.run()
+/*
   @Test def scalatestplusScalacheck = projects.scalatestplusScalacheck.run()
   @Test def scalaXml = projects.scalaXml.run()
   @Test def scopt = projects.scopt.run()
@@ -334,7 +336,7 @@ class CommunityBuildTest {
   @Test def shapeless = projects.shapeless.run()
   @Test def xmlInterpolator = projects.xmlInterpolator.run()
   @Test def semanticdb = projects.semanticdb.run()
-  @Test def effpi = projects.effpi.run()
+  @Test def effpi = projects.effpi.run()*/
 }
 
 class TestCategory

compiler/src/dotty/tools/dotc/typer/Inferencing.scala

@@ -100,7 +100,11 @@ object Inferencing {
 
     private var toMaximize: Boolean = false
 
-    def apply(x: Boolean, tp: Type): Boolean = tp.dealias match {
+    private var rootType: Type = null
+
+    def apply(x: Boolean, tp: Type): Boolean =
+      if rootType == null then rootType = tp
+      tp.dealias match {
       case _: WildcardType | _: ProtoType =>
         false
       case tvar: TypeVar if !tvar.isInstantiated =>
@@ -112,9 +116,13 @@ object Inferencing {
             !force.allowBottom &&
             defn.isBottomType(ctx.typeComparer.approximation(tvar.origin, fromBelow = true))
           def preferMin = (force.minimizeAll || variance >= 0) && !avoidBottom
+          def oldPreferMin = force.minimizeAll || variance >= 0 && !avoidBottom
           if (direction != 0) instantiate(tvar, direction < 0)
           else if (preferMin) instantiate(tvar, fromBelow = true)
-          else toMaximize = true
+          else
+            if oldPreferMin then
+              println(i"DIFFERENCE: maximizing $tvar with bounds ${ctx.typeComparer.bounds(tvar.origin)} in $rootType")
+            toMaximize = true
           foldOver(x, tvar)
         }
       case tp =>