Merge pull request #5692 from dotty-staging/conserve-more-lists

allanrenucci · web-flow · commit 845fd5921b12 · 2019-01-10T21:12:42.000+01:00
Conserve a more lists to allow a few cpy.Apply to not create a new instance
diff --git a/compiler/src/dotty/tools/dotc/transform/PostTyper.scala b/compiler/src/dotty/tools/dotc/transform/PostTyper.scala
@@ -210,7 +210,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
             if (methType.isErasedMethod)
               tpd.cpy.Apply(tree)(
                 tree.fun,
-                tree.args.map(arg =>
+                tree.args.mapConserve(arg =>
                   if (methType.isImplicitMethod && arg.pos.isSynthetic) ref(defn.Predef_undefined)
                   else dropInlines.transform(arg)))
             else
diff --git a/compiler/src/dotty/tools/dotc/typer/EtaExpansion.scala b/compiler/src/dotty/tools/dotc/typer/EtaExpansion.scala
@@ -85,7 +85,7 @@ abstract class Lifter {
           lifter.liftArg(defs, arg, if (name.firstPart contains '$') EmptyTermName else name)
         }
       case _ =>
-        args.map(liftArg(defs, _))
+        args.mapConserve(liftArg(defs, _))
     }
 
   /** Lift out function prefix and all arguments from application

Original file line number	Diff line number	Diff line change
`@@ -85,7 +85,7 @@ abstract class Lifter {`
`85`	`85`	`lifter.liftArg(defs, arg, if (name.firstPart contains '$') EmptyTermName else name)`
`86`	`86`	`}`
`87`	`87`	`case _ =>`
`88`		`- args.map(liftArg(defs, _))`
	`88`	`+ args.mapConserve(liftArg(defs, _))`
`89`	`89`	`}`
`90`	`90`
`91`	`91`	`/** Lift out function prefix and all arguments from application`