Merge pull request #9620 from dotty-staging/cache-definitions

Avoid recomputations of definitions

Author: odersky

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -487,10 +487,10 @@ class Definitions {
     @tu lazy val Predef_identity : Symbol = ScalaPredefModule.requiredMethod(nme.identity)
     @tu lazy val Predef_undefined: Symbol = ScalaPredefModule.requiredMethod(nme.???)
 
-  def SubTypeClass(using Context): ClassSymbol = requiredClass("scala.<:<")
+  @tu lazy val SubTypeClass: ClassSymbol = requiredClass("scala.<:<")
   @tu lazy val SubType_refl: Symbol = SubTypeClass.companionModule.requiredMethod(nme.refl)
 
-  def DummyImplicitClass(using Context): ClassSymbol = requiredClass("scala.DummyImplicit")
+  @tu lazy val DummyImplicitClass: ClassSymbol = requiredClass("scala.DummyImplicit")
 
   @tu lazy val ScalaRuntimeModule: Symbol = requiredModule("scala.runtime.ScalaRunTime")
     def runtimeMethodRef(name: PreName): TermRef = ScalaRuntimeModule.requiredMethodRef(name)
@@ -528,8 +528,11 @@ class Definitions {
     methodNames.map(getWrapVarargsArrayModule.requiredMethod(_))
   })
 
-  @tu lazy val ListModule: Symbol = requiredModule("scala.collection.immutable.List")
-  @tu lazy val NilModule: Symbol = requiredModule("scala.collection.immutable.Nil")
+  @tu lazy val ListClass: Symbol       = requiredClass("scala.collection.immutable.List")
+  @tu lazy val ListModule: Symbol      = requiredModule("scala.collection.immutable.List")
+  @tu lazy val NilModule: Symbol       = requiredModule("scala.collection.immutable.Nil")
+  @tu lazy val ConsClass: Symbol       = requiredClass("scala.collection.immutable.::")
+  @tu lazy val SeqFactoryClass: Symbol = requiredClass("scala.collection.SeqFactory")
 
   @tu lazy val SingletonClass: ClassSymbol =
     // needed as a synthetic class because Scala 2.x refers to it in classfiles

compiler/src/dotty/tools/dotc/core/Denotations.scala

@@ -1267,6 +1267,7 @@ object Denotations {
     recur(path)
   }
 
+
   /** If we are looking for a non-existing term name in a package,
     *  assume it is a package for which we do not have a directory and
     *  enter it.

compiler/src/dotty/tools/dotc/transform/patmat/Space.scala

@@ -317,10 +317,10 @@ class SpaceEngine(using Context) extends SpaceLogic {
   import tpd._
   import SpaceEngine._
 
-  private val scalaSeqFactoryClass = requiredClass("scala.collection.SeqFactory")
-  private val scalaListType        = requiredClassRef("scala.collection.immutable.List")
-  private val scalaNilType         = requiredModuleRef("scala.collection.immutable.Nil")
-  private val scalaConsType        = requiredClassRef("scala.collection.immutable.::")
+  private val scalaSeqFactoryClass = defn.SeqFactoryClass
+  private val scalaListType        = defn.ListClass.typeRef
+  private val scalaNilType         = defn.NilModule.termRef
+  private val scalaConsType        = defn.ConsClass.typeRef
 
   private val constantNullType     = ConstantType(Constant(null))
   private val constantNullSpace    = Typ(constantNullType)