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

gkossakowski · gkossakowski · commit b66a39653b9b · 2014-02-09T18:00:20.000+01:00
[backport] SI-7902 Fix spurious kind error due to an unitialized symbol
diff --git a/src/reflect/scala/reflect/internal/Kinds.scala b/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 {
       }
     }
   }
-}
+}
diff --git a/test/files/pos/t7902.scala b/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]
+  }
+}

Original file line number	Diff line number	Diff line change
`@@ -184,6 +184,7 @@ trait Kinds {`
`184`	`184`	`)`
`185`	`185`	`}`
`186`	`186`	`else {`
	`187`	`+ hkarg.initialize // SI-7902 otherwise hkarg.typeParams yields List(NoSymbol)!`
`187`	`188`	`debuglog("checkKindBoundsHK recursing to compare params of "+ hkparam +" with "+ hkarg)`
`188`	`189`	`kindErrors ++= checkKindBoundsHK(`
`189`	`190`	`hkarg.typeParams,`
`@@ -229,4 +230,4 @@ trait Kinds {`
`229`	`230`	`}`
`230`	`231`	`}`
`231`	`232`	`}`
`232`		`-}`
	`233`	`+}`