Make msg in testScala2Mode by-name.

odersky · odersky · commit f992c14ce87e · 2016-12-19T17:01:58.000+01:00
Avoids potentially expensive string assembly operations.
diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -546,7 +546,7 @@ trait TypeOps { this: Context => // TODO: Make standalone object.
   def dynamicsEnabled =
     featureEnabled(defn.LanguageModuleClass, nme.dynamics)
 
-  def testScala2Mode(msg: String, pos: Position) = {
+  def testScala2Mode(msg: => String, pos: Position) = {
     if (scala2Mode) migrationWarning(msg, pos)
     scala2Mode
   }

Original file line number	Diff line number	Diff line change
`@@ -546,7 +546,7 @@ trait TypeOps { this: Context => // TODO: Make standalone object.`
`546`	`546`	`def dynamicsEnabled =`
`547`	`547`	`featureEnabled(defn.LanguageModuleClass, nme.dynamics)`
`548`	`548`
`549`		`- def testScala2Mode(msg: String, pos: Position) = {`
	`549`	`+ def testScala2Mode(msg: => String, pos: Position) = {`
`550`	`550`	`if (scala2Mode) migrationWarning(msg, pos)`
`551`	`551`	`scala2Mode`
`552`	`552`	`}`