Add assert that refine infos are legal wrt refined names

Author: odersky

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

@@ -2066,6 +2066,9 @@ object Types {
    */
   abstract case class RefinedType(parent: Type, refinedName: Name, refinedInfo: Type) extends RefinedOrRecType {
 
+    if (refinedName.isTermName) assert(refinedInfo.isInstanceOf[TermType])
+    else assert(refinedInfo.isInstanceOf[TypeType])
+
     override def underlying(implicit ctx: Context) = parent
 
     private def badInst =

tests/run/i2037.check

@@ -0,0 +1 @@
+malformed type

tests/run/i2037.scala

@@ -0,0 +1,26 @@
+import dotty.tools.dotc._
+import core._
+import Types._
+import Contexts._
+import Symbols._
+import Decorators._
+
+object Test {
+  def f(implicit ctx: Context) = {
+    val badType =
+      RefinedType(
+        ctx.requiredClassRef("scala.collection.AbstractIterator"),
+        "GroupedIterator".toTypeName,
+        TypeRef(ctx.requiredClassRef("scala.collection.AbstractIterator"), "GroupedIterator".toTypeName))
+    badType.member("GroupedIterator".toTypeName)
+   // badType.member("T".toTypeName)
+  }
+  def main(args: Array[String]): Unit = {
+    implicit val ctx = (new ContextBase).initialCtx
+    ctx.base.initialize()
+    try f
+    catch {
+      case ex: AssertionError => println("malformed type")
+    }
+  }
+}