Handle pure argumens while reordering

Author: nicolasstucki

compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -624,7 +624,13 @@ trait Applications extends Compatibility { self: Typer with Dynamic =>
               prefixShift = 1
             }
             for (l <- liftable) {
-              if (!args.contains(l)) {
+              val pure = l match {
+                case NamedArg(_, arg) => isPureExpr(arg)
+                case arg => isPureExpr(arg)
+              }
+
+              if (pure) { }
+              else if (!args.contains(l)) {
                 indices += prefixShift + nextDefaultParamIndex
                 nextDefaultParamIndex += 1
               }

tests/run/i2916.check

@@ -28,6 +28,11 @@
 2
 5
 
+1
+4
+2
+5
+
 0
 1
 3

tests/run/i2916.scala

@@ -13,6 +13,9 @@ object Test {
     foo(p(1), x3 = p(3), x4 = p(4), x2 = p(2)) // 1 3 4 2 5
     println()
 
+    foo(p(1), x3 = 3, x4 = p(4), x2 = p(2)) // 1 4 2 5
+    println()
+
     def test = { println(0); Test }
     test.foo(p(1), x3 = p(3), x4 = p(4), x2 = p(2)) // 0 1 3 4 2 5
     println()