Merge pull request scala#3491 from retronym/backport/7902

[backport] SI-7902 Fix spurious kind error due to an unitialized symbol

Author: gkossakowski

src/reflect/scala/reflect/internal/Kinds.scala

@@ -184,6 +184,7 @@ trait Kinds {
           )
         }
         else {
+          hkarg.initialize // SI-7902 otherwise hkarg.typeParams yields List(NoSymbol)!
           debuglog("checkKindBoundsHK recursing to compare params of "+ hkparam +" with "+ hkarg)
           kindErrors ++= checkKindBoundsHK(
             hkarg.typeParams,
@@ -229,4 +230,4 @@ trait Kinds {
       }
     }
   }
-}
+}

test/files/pos/t7902.scala

@@ -0,0 +1,17 @@
+import scala.language.higherKinds
+
+object Bug {
+  class Tag[W[M1[X1]]]
+
+  def ofType[W[M2[X2]]]: Tag[W] = ???
+  type InSeq  [M3[X3]] = Some[M3[Any]]
+
+  // fail
+  val x = ofType[InSeq]
+
+  // okay
+  val y: Any = ofType[InSeq]
+  object T {
+    val z = ofType[InSeq]
+  }
+}