Address next round of comments

Author: odersky

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

@@ -622,7 +622,7 @@ object Denotations {
               tp1.derivedLambdaType(
                 mergeParamNames(tp1, tp2),
                 tp1.paramInfos.zipWithConserve(tp2.paramInfos) { (p1, p2) =>
-                  infoMeet(p1,  p2.subst(tp2, tp1), sym1, sym2, safeIntersection).bounds
+                  infoMeet(p1, p2.subst(tp2, tp1), sym1, sym2, safeIntersection).bounds
                 },
                 infoMeet(tp1.resultType, tp2.resultType.subst(tp2, tp1), sym1, sym2, safeIntersection))
             case _ =>
@@ -674,7 +674,7 @@ object Denotations {
             tp1.derivedLambdaType(
               mergeParamNames(tp1, tp2),
               tp1.paramInfos.zipWithConserve(tp2.paramInfos) { (p1, p2) =>
-                (p1 | p2.subst(tp2, tp1)).bounds
+                infoJoin(p1, p2.subst(tp2, tp1), sym1, sym2).bounds
               },
               infoJoin(tp1.resultType, tp2.resultType.subst(tp2, tp1), sym1, sym2))
           case _ =>

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

@@ -1648,7 +1648,7 @@ class TypeComparer(initctx: Context) extends ConstraintHandling {
             tp1.derivedRefinedType(tp1.parent & tp2.parent, tp1.refinedName, jointInfo)
           }
           catch {
-            case ex: MergeError => tp1.parent & tp2.parent
+            case ex: MergeError => NoType
           }
         case _ =>
           NoType