Making namedPartsWith more robust.

When called from implicitScope, we formed an AndType with a WildcardType. No problem, except that this broke the AndType assertion. The assertion is not needed for this sepcial case.

2 files changed, 7 insertions, 3 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index a3639cbde..8fe813e4d 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -1385,7 +1385,6 @@ object Types {
   }
 
   abstract case class AndType(tp1: Type, tp2: Type) extends CachedGroundType with AndOrType {
-    assert(tp1.isInstanceOf[ValueType] && tp2.isInstanceOf[ValueType], s"$tp1 & $tp2")
 
     def derivedAndType(tp1: Type, tp2: Type)(implicit ctx: Context) =
       if ((tp1 eq this.tp1) && (tp2 eq this.tp2)) this
@@ -1397,8 +1396,13 @@ object Types {
   final class CachedAndType(tp1: Type, tp2: Type) extends AndType(tp1, tp2)
 
   object AndType {
-    def apply(tp1: Type, tp2: Type)(implicit ctx: Context) =
+    def apply(tp1: Type, tp2: Type)(implicit ctx: Context) = {
+      assert(tp1.isInstanceOf[ValueType] && tp2.isInstanceOf[ValueType], s"$tp1 & $tp2")
+      unchecked(tp1, tp2)
+    }
+    def unchecked(tp1: Type, tp2: Type)(implicit ctx: Context) = {
       unique(new CachedAndType(tp1, tp2))
+    }
   }
 
   abstract case class OrType(tp1: Type, tp2: Type) extends CachedGroundType with AndOrType {
diff --git a/src/dotty/tools/dotc/typer/Inferencing.scala b/src/dotty/tools/dotc/typer/Inferencing.scala
index 76e701fee..b85b7b6ca 100644
--- a/src/dotty/tools/dotc/typer/Inferencing.scala
+++ b/src/dotty/tools/dotc/typer/Inferencing.scala
@@ -140,7 +140,7 @@ object Inferencing {
       ctx.typer.isApplicable(tp, argType :: Nil, resultType)
     }
     override def namedPartsWith(p: NamedType => Boolean)(implicit ctx: Context): collection.Set[NamedType] =
-      AndType(argType, resultType).namedPartsWith(p) // this is more efficient than oring two namedParts sets
+      AndType.unchecked(argType, resultType).namedPartsWith(p) // this is more efficient than oring two namedParts sets
     override def computeHash = doHash(argType, resultType)
   }