Avoid some argument reorderings

Avoid reordering arguments if all explicitly given arguments are pure.
In that case they can be freely interspersed with default getters.

Author: odersky

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

@@ -750,13 +750,23 @@ trait Applications extends Compatibility {
     }
     private def sameSeq[T <: Trees.Tree[?]](xs: List[T], ys: List[T]): Boolean = firstDiff(xs, ys) < 0
 
+    /** An argument is safe if it is a pure expression or a default getter call
+     *  If all arguments are safe, no reordering is necessary
+     */
+    def isSafeArg(arg: Tree) =
+      isPureExpr(arg)
+      || arg.isInstanceOf[RefTree | Apply | TypeApply] && arg.symbol.name.is(DefaultGetterName)
+
     val result:   Tree = {
       var typedArgs = typedArgBuf.toList
       def app0 = cpy.Apply(app)(normalizedFun, typedArgs) // needs to be a `def` because typedArgs can change later
       val app1 =
         if (!success) app0.withType(UnspecifiedErrorType)
         else {
-          if !sameSeq(args, orderedArgs) && !isJavaAnnotConstr(methRef.symbol) then
+          if !sameSeq(args, orderedArgs)
+             && !isJavaAnnotConstr(methRef.symbol)
+             && !typedArgs.forall(isSafeArg)
+          then
             // need to lift arguments to maintain evaluation order in the
             // presence of argument reorderings.