Optimization: Specialize tpes

odersky · odersky · commit 9d436eafe96e · 2019-01-19T09:15:36.000+01:00
diff --git a/compiler/src/dotty/tools/dotc/ast/tpd.scala b/compiler/src/dotty/tools/dotc/ast/tpd.scala
@@ -978,7 +978,10 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   }
 
   implicit class ListOfTreeDecorator(val xs: List[tpd.Tree]) extends AnyVal {
-    def tpes: List[Type] = xs map (_.tpe)
+    def tpes: List[Type] = xs match {
+      case x :: xs1 => x.tpe :: xs1.tpes
+      case nil => Nil
+    }
   }
 
   /** A trait for loaders that compute trees. Currently implemented just by DottyUnpickler. */

Original file line number	Diff line number	Diff line change
`@@ -978,7 +978,10 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {`
`978`	`978`	`}`
`979`	`979`
`980`	`980`	`implicit class ListOfTreeDecorator(val xs: List[tpd.Tree]) extends AnyVal {`
`981`		`- def tpes: List[Type] = xs map (_.tpe)`
	`981`	`+ def tpes: List[Type] = xs match {`
	`982`	`+ case x :: xs1 => x.tpe :: xs1.tpes`
	`983`	`+ case nil => Nil`
	`984`	`+ }`
`982`	`985`	`}`
`983`	`986`
`984`	`987`	`/** A trait for loaders that compute trees. Currently implemented just by DottyUnpickler. */`