Add comment

nicolasstucki · web-flow · commit 1745af1ca0fc · 2018-11-02T08:28:29.000+01:00
diff --git a/compiler/src/dotty/tools/dotc/typer/Applications.scala b/compiler/src/dotty/tools/dotc/typer/Applications.scala
@@ -61,6 +61,8 @@ object Applications {
   def productSelectorTypes(tp: Type, errorPos: Position = NoPosition)(implicit ctx: Context): List[Type] = {
     def tupleSelectors(n: Int, tp: Type): List[Type] = {
       val sel = extractorMemberType(tp, nme.selectorName(n), errorPos)
+      // extractorMemberType will return NoType if this is the tail of tuple with an unknown tail 
+      // such as `Int *: T` where `T <: Tuple`.
       if (sel.exists) sel :: tupleSelectors(n + 1, tp) else Nil
     }
     def genTupleSelectors(n: Int, tp: Type): List[Type] = tp match {

Original file line number	Diff line number	Diff line change
`@@ -61,6 +61,8 @@ object Applications {`
`61`	`61`	`def productSelectorTypes(tp: Type, errorPos: Position = NoPosition)(implicit ctx: Context): List[Type] = {`
`62`	`62`	`def tupleSelectors(n: Int, tp: Type): List[Type] = {`
`63`	`63`	`val sel = extractorMemberType(tp, nme.selectorName(n), errorPos)`
	`64`	`+ // extractorMemberType will return NoType if this is the tail of tuple with an unknown tail`
	`65`	+ // such as `Int *: T` where `T <: Tuple`.
`64`	`66`	`if (sel.exists) sel :: tupleSelectors(n + 1, tp) else Nil`
`65`	`67`	`}`
`66`	`68`	`def genTupleSelectors(n: Int, tp: Type): List[Type] = tp match {`