Merge pull request #3078 from allanrenucci/0.3.x

allanrenucci · web-flow · commit 2118a0c376ee · 2017-09-06T13:26:08.000+02:00
Backport #3076
diff --git a/compiler/src/dotty/tools/dotc/core/Decorators.scala b/compiler/src/dotty/tools/dotc/core/Decorators.scala
@@ -112,9 +112,12 @@ object Decorators {
         else x1 :: xs1
       }
 
-    def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs match {
-      case Nil => z
-      case x :: xs1 => op(x, xs1.foldRightBN(z)(op))
+    def foldRightBN[U](z: => U)(op: (T, => U) => U): U = {
+      @tailrec def foldLeftBN(xs: List[T], acc: => U): U = xs match {
+        case x :: xs1 => foldLeftBN(xs1, op(x, acc))
+        case Nil => acc
+      }
+      foldLeftBN(xs.reverse, z)
     }
 
     final def hasSameLengthAs[U](ys: List[U]): Boolean = {

Original file line number	Diff line number	Diff line change
`@@ -112,9 +112,12 @@ object Decorators {`
`112`	`112`	`else x1 :: xs1`
`113`	`113`	`}`
`114`	`114`
`115`		`- def foldRightBN[U](z: => U)(op: (T, => U) => U): U = xs match {`
`116`		`- case Nil => z`
`117`		`- case x :: xs1 => op(x, xs1.foldRightBN(z)(op))`
	`115`	`+ def foldRightBN[U](z: => U)(op: (T, => U) => U): U = {`
	`116`	`+ @tailrec def foldLeftBN(xs: List[T], acc: => U): U = xs match {`
	`117`	`+ case x :: xs1 => foldLeftBN(xs1, op(x, acc))`
	`118`	`+ case Nil => acc`
	`119`	`+ }`
	`120`	`+ foldLeftBN(xs.reverse, z)`
`118`	`121`	`}`
`119`	`122`
`120`	`123`	`final def hasSameLengthAs[U](ys: List[U]): Boolean = {`