Remove dotty.runtime.LegacyApp

scala.App has been working well enough for a long time now.

Author: smarter

compiler/src/dotty/tools/dotc/sbt/ExtractAPI.scala

@@ -237,8 +237,6 @@ private class ExtractAPICollector(implicit val ctx: Context) extends ThunkHolder
     api.ClassLikeDef.of(name, acc, modifiers, anns, tparams, defType)
   }
 
-  private[this] val LegacyAppClass = ctx.requiredClass("dotty.runtime.LegacyApp")
-
   def apiClassStructure(csym: ClassSymbol): api.Structure = {
     val cinfo = csym.classInfo
 
@@ -274,9 +272,7 @@ private class ExtractAPICollector(implicit val ctx: Context) extends ThunkHolder
     // TODO: We shouldn't have to compute inherited members. Instead, `Structure`
     // should have a lazy `parentStructures` field.
     val inherited = cinfo.baseClasses
-      // We cannot filter out `LegacyApp` because it contains the main method,
-      // see the comment about main class discovery in `computeType`.
-      .filter(bc => !bc.is(Scala2x) || bc.eq(LegacyAppClass))
+      .filter(bc => !bc.is(Scala2x))
       .flatMap(_.classInfo.decls.filter(s => !(s.is(Private) || declSet.contains(s))))
     // Inherited members need to be computed lazily because a class might contain
     // itself as an inherited member, like in `class A { class B extends A }`,

library/src/dotty/runtime/LegacyApp.scala

@@ -1,3 +1,3 @@
-object B extends dotty.runtime.LegacyApp {
+object B extends App {
    println(A.`=`)
 }

sbt-dotty/sbt-test/source-dependencies/backtick-quoted-names/B.scala

@@ -1,3 +1,3 @@
-object E extends dotty.runtime.LegacyApp {
+object E extends App {
 	assert(D.x == "3")
 }

sbt-dotty/sbt-test/source-dependencies/less-inter-inv/E.scala

@@ -1,3 +1,3 @@
-object C extends dotty.runtime.LegacyApp {
+object C extends App {
   println(new B().foo(null))
 }

sbt-dotty/sbt-test/source-dependencies/value-class/changes/C0.scala

@@ -1,3 +1,3 @@
-object C extends dotty.runtime.LegacyApp {
+object C extends App {
   println(new B().bar.x)
 }

sbt-dotty/sbt-test/source-dependencies/value-class/changes/C1.scala

@@ -1,3 +1,3 @@
-object C extends dotty.runtime.LegacyApp {
+object C extends App {
   println(new B().bar("")("").x)
 }

sbt-dotty/sbt-test/source-dependencies/value-class/changes/C2.scala

@@ -1,7 +1,7 @@
 
 import scala.language.{ higherKinds, existentials }
 
-object Test extends dotty.runtime.LegacyApp {
+object Test extends App {
   def get[T](x: T) = { println("get: "+ x); x }
 
   // TESTS

tests/disabled/existential/run/names-defaults.scala

@@ -1,4 +1,4 @@
-object Test extends dotty.runtime.LegacyApp {
+object Test extends App {
   println(classOf[java.util.ArrayList[_]])
   println(classOf[java.util.ArrayList[T] forSome { type T }])
 }

tests/disabled/existential/run/t0412.scala

@@ -9,7 +9,7 @@ class RichStr extends Sequ[Char] {
   def toArray: Array[Char] = Array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9')
 }
 
-object Test extends dotty.runtime.LegacyApp {
+object Test extends App {
   val x: RichStr = new RichStr
 
   println((x: Sequ[Char]).toArray.deep) // calling through the bridge misses unboxing