Replace topoSortDistinctsBy with topoSortDistinctsWith

Author: gzm0

compiler/src/main/scala/org/scalajs/nscplugin/GenJSExports.scala

@@ -525,8 +525,22 @@ trait GenJSExports[G <: Global with Singleton] extends SubComponent {
         } else {
           // Sort them so that, e.g., isInstanceOf[String]
           // comes before isInstanceOf[Object]
-          val sortedAltsByTypeTest = topoSortDistinctsBy(
-              altsByTypeTest)(_._1)(RTTypeTest.Ordering)
+          val sortedAltsByTypeTest = topoSortDistinctsWith(altsByTypeTest) { (lhs, rhs) =>
+            (lhs._1, rhs._1) match {
+              // NoTypeTest is always last
+              case (_, NoTypeTest) => true
+              case (NoTypeTest, _) => false
+
+              case (PrimitiveTypeTest(_, rank1), PrimitiveTypeTest(_, rank2)) =>
+                rank1 <= rank2
+
+              case (InstanceOfTypeTest(t1), InstanceOfTypeTest(t2)) =>
+                t1 <:< t2
+
+              case (_: PrimitiveTypeTest, _: InstanceOfTypeTest) => true
+              case (_: InstanceOfTypeTest, _: PrimitiveTypeTest) => false
+            }
+          }
 
           val defaultCase = genThrowTypeError()
 
@@ -946,47 +960,16 @@ trait GenJSExports[G <: Global with Singleton] extends SubComponent {
 
   private case object NoTypeTest extends RTTypeTest
 
-  private object RTTypeTest {
-    implicit object Ordering extends PartialOrdering[RTTypeTest] {
-      override def tryCompare(lhs: RTTypeTest, rhs: RTTypeTest): Option[Int] = {
-        if (lteq(lhs, rhs)) if (lteq(rhs, lhs)) Some(0) else Some(-1)
-        else                if (lteq(rhs, lhs)) Some(1) else None
-      }
-
-      override def lteq(lhs: RTTypeTest, rhs: RTTypeTest): Boolean = {
-        (lhs, rhs) match {
-          // NoTypeTest is always last
-          case (_, NoTypeTest) => true
-          case (NoTypeTest, _) => false
-
-          case (PrimitiveTypeTest(_, rank1), PrimitiveTypeTest(_, rank2)) =>
-            rank1 <= rank2
-
-          case (InstanceOfTypeTest(t1), InstanceOfTypeTest(t2)) =>
-            t1 <:< t2
-
-          case (_: PrimitiveTypeTest, _: InstanceOfTypeTest) => true
-          case (_: InstanceOfTypeTest, _: PrimitiveTypeTest) => false
-        }
-      }
-
-      override def equiv(lhs: RTTypeTest, rhs: RTTypeTest): Boolean = {
-        lhs == rhs
-      }
-    }
-  }
-
   // Very simple O(n²) topological sort for elements assumed to be distinct
-  private def topoSortDistinctsBy[A <: AnyRef, B](coll: List[A])(f: A => B)(
-      implicit ord: PartialOrdering[B]): List[A] = {
-
+  private def topoSortDistinctsWith[A <: AnyRef](coll: List[A])(
+      lteq: (A, A) => Boolean): List[A] = {
     @scala.annotation.tailrec
     def loop(coll: List[A], acc: List[A]): List[A] = {
       if (coll.isEmpty) acc
       else if (coll.tail.isEmpty) coll.head :: acc
       else {
         val (lhs, rhs) = coll.span(x => !coll.forall(
-            y => (x eq y) || !ord.lteq(f(x), f(y))))
+            y => (x eq y) || !lteq(x, y)))
         assert(!rhs.isEmpty, s"cycle while ordering $coll")
         loop(lhs ::: rhs.tail, rhs.head :: acc)
       }