Make hasSimpleKind follow aliases

Author: odersky

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

@@ -211,7 +211,10 @@ class TypeApplications(val self: Type) extends AnyVal {
 
   /** Is self type of kind "*"? */
   def hasSimpleKind(implicit ctx: Context): Boolean =
-    typeParams.isEmpty && !self.hasAnyKind
+    typeParams.isEmpty && !self.hasAnyKind || {
+      val alias = self.dealias
+      (alias ne self) && alias.hasSimpleKind
+    }
 
   /** If self type is higher-kinded, its result type, otherwise NoType.
    *  Note: The hkResult of an any-kinded type is again AnyKind.

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

@@ -799,7 +799,7 @@ trait Checking {
 
   /** Check that `tpt` does not define a higher-kinded type */
   def checkSimpleKinded(tpt: Tree)(implicit ctx: Context): Tree =
-    if (!tpt.tpe.dealias.hasSimpleKind && !ctx.compilationUnit.isJava) {
+    if (!tpt.tpe.hasSimpleKind && !ctx.compilationUnit.isJava) {
         // be more lenient with missing type params in Java,
         // needed to make pos/java-interop/t1196 work.
       errorTree(tpt, MissingTypeParameterFor(tpt.tpe))