Mitigate #2924

nicolasstucki · web-flow · commit 00cf7f609c3c · 2017-09-05T17:39:30.000+02:00
diff --git a/compiler/src/dotty/tools/dotc/core/Decorators.scala b/compiler/src/dotty/tools/dotc/core/Decorators.scala
@@ -112,9 +112,11 @@ object Decorators {
         else x1 :: xs1
       }
 
-    def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs match {
+    def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs.reverse.foldLeftBN(z)(op)
+
+    @tailrec final def foldLeftBN[U](z: => U)(op: (T, => U) => U): U = xs match {
       case Nil => z
-      case x :: xs1 => op(x, xs1.foldRightBN(z)(op))
+      case x :: xs1 => xs1.foldLeftBN(op(x, z))(op)
     }
 
     final def hasSameLengthAs[U](ys: List[U]): Boolean = {

Original file line number	Diff line number	Diff line change
`@@ -112,9 +112,11 @@ object Decorators {`
`112`	`112`	`else x1 :: xs1`
`113`	`113`	`}`
`114`	`114`
`115`		`- def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs match {`
	`115`	`+ def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs.reverse.foldLeftBN(z)(op)`
	`116`	`+`
	`117`	`+ @tailrec final def foldLeftBN[U](z: => U)(op: (T, => U) => U): U = xs match {`
`116`	`118`	`case Nil => z`
`117`		`- case x :: xs1 => op(x, xs1.foldRightBN(z)(op))`
	`119`	`+ case x :: xs1 => xs1.foldLeftBN(op(x, z))(op)`
`118`	`120`	`}`
`119`	`121`
`120`	`122`	`final def hasSameLengthAs[U](ys: List[U]): Boolean = {`