Fields phase expands lazy vals like modules

They remain ValDefs until then.

- remove lazy accessor logic
  now that we have a single ValDef for lazy vals,
  with the underlying machinery being hidden until the fields phase
  leave a `@deprecated def lazyAccessor` for scala-refactoring

- don't skolemize in purely synthetic getters,
  but *do* skolemize in lazy accessor during typers

  Lazy accessors have arbitrary user code, so have to skolemize.
  We exempt the purely synthetic accessors (`isSyntheticAccessor`)
  for strict vals, and lazy accessors emitted by the fields phase
  to avoid spurious type mismatches due to issues with existentials
  (That bug is tracked as https://github.com/scala/scala-dev/issues/165)

  When we're past typer, lazy accessors are synthetic,
  but before they are user-defined to make this hack less hacky,
  we could rework our flag usage to allow for
  requiring both the ACCESSOR and the SYNTHETIC bits
  to identify synthetic accessors and trigger the exemption.

  see also https://github.com/scala/scala-dev/issues/165

  ok 7 - pos/existentials-harmful.scala
  ok 8 - pos/t2435.scala
  ok 9 - pos/existentials.scala

  previous attempt: skolemize type of val inside the private[this] val

  because its type is only observed from inside the
  accessor methods (inside the method scope its existentials are skolemized)

- bean accessors have regular method types, not nullary method types

- must re-infer type for param accessor
  some weirdness with scoping of param accessor vals and defs?

- tailcalls detect lazy vals, which are defdefs after fields

- can inline constant lazy val from trait

- don't mix in fields etc for an overridden lazy val

- need try-lift in lazy vals: the assign is not seen in uncurry
  because fields does the transform (see run/t2333.scala)

- ensure field members end up final in bytecode

- implicit class companion method: annot filter in completer

- update check: previous error message was tangled up with unrelated
  field definitions (`var s` and `val s_scope`),
  now it behaves consistently whether those are val/vars or defs

- analyzer plugin check update seems benign, but no way to know...

- error message gen: there is no underlying symbol for a deferred var
  look for missing getter/setter instead

- avoid retypechecking valdefs while duplicating for specialize
  see pos/spec-private

- Scaladoc uniformly looks to field/accessor symbol

- test updates to innerClassAttribute by Lukas

1 files changed, 15 insertions, 20 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 8449260fe6..8034d056d7 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -450,9 +450,9 @@ abstract class RefChecks extends Transform {
           } else if (other.isStable && !member.isStable) { // (1.4)
             overrideError("needs to be a stable, immutable value")
           } else if (member.isValue && member.isLazy &&
-                     other.isValue && !other.isSourceMethod && !other.isDeferred && !other.isLazy) {
+                     other.isValue && other.hasFlag(STABLE) && !(other.isDeferred || other.isLazy)) {
             overrideError("cannot override a concrete non-lazy value")
-          } else if (other.isValue && other.isLazy && !other.isSourceMethod && !other.isDeferred && // !(other.hasFlag(MODULE) && other.hasFlag(PACKAGE | JAVA)) && other.hasFlag(LAZY)  && (!other.isMethod || other.hasFlag(STABLE)) && !other.hasFlag(DEFERRED)
+          } else if (other.isValue && other.isLazy &&
                      member.isValue && !member.isLazy) {
             overrideError("must be declared lazy to override a concrete lazy value")
           } else if (other.isDeferred && member.isTermMacro && member.extendedOverriddenSymbols.forall(_.isDeferred)) { // (1.9)
@@ -609,7 +609,7 @@ abstract class RefChecks extends Transform {
           val (missing, rest) = memberList partition (m => m.isDeferred && !ignoreDeferred(m))
           // Group missing members by the name of the underlying symbol,
           // to consolidate getters and setters.
-          val grouped = missing groupBy (sym => analyzer.underlyingSymbol(sym).name)
+          val grouped = missing groupBy (_.name.getterName)
           val missingMethods = grouped.toList flatMap {
             case (name, syms) =>
               if (syms exists (_.isSetter)) syms filterNot (_.isGetter)
@@ -651,15 +651,16 @@ abstract class RefChecks extends Transform {
 
             // Give a specific error message for abstract vars based on why it fails:
             // It could be unimplemented, have only one accessor, or be uninitialized.
-            if (underlying.isVariable) {
-              val isMultiple = grouped.getOrElse(underlying.name, Nil).size > 1
+            val groupedAccessors = grouped.getOrElse(member.name.getterName, Nil)
+            val isMultiple = groupedAccessors.size > 1
 
+            if (groupedAccessors.exists(_.isSetter) || (member.isGetter && !isMultiple && member.setterIn(member.owner).exists)) {
               // If both getter and setter are missing, squelch the setter error.
               if (member.isSetter && isMultiple) ()
               else undefined(
                 if (member.isSetter) "\n(Note that an abstract var requires a setter in addition to the getter)"
                 else if (member.isGetter && !isMultiple) "\n(Note that an abstract var requires a getter in addition to the setter)"
-                else analyzer.abstractVarMessage(member)
+                else "\n(Note that variables need to be initialized to be defined)"
               )
             }
             else if (underlying.isMethod) {
@@ -919,17 +920,11 @@ abstract class RefChecks extends Transform {
       var index = -1
       for (stat <- stats) {
         index = index + 1
-        def enterSym(sym: Symbol) = if (sym.isLocalToBlock) {
-          currentLevel.scope.enter(sym)
-          symIndex(sym) = index
-        }
 
         stat match {
-          case DefDef(_, _, _, _, _, _) if stat.symbol.isLazy                 =>
-            enterSym(stat.symbol)
-          case ClassDef(_, _, _, _) | DefDef(_, _, _, _, _, _) | ModuleDef(_, _, _) | ValDef(_, _, _, _) =>
-            //assert(stat.symbol != NoSymbol, stat);//debug
-            enterSym(stat.symbol.lazyAccessorOrSelf)
+          case _ : MemberDef if stat.symbol.isLocalToBlock =>
+            currentLevel.scope.enter(stat.symbol)
+            symIndex(stat.symbol) = index
           case _ =>
         }
       }
@@ -1180,10 +1175,10 @@ abstract class RefChecks extends Transform {
         val tree1 = transform(tree) // important to do before forward reference check
         if (tree1.symbol.isLazy) tree1 :: Nil
         else {
-          val lazySym = tree.symbol.lazyAccessorOrSelf
-          if (lazySym.isLocalToBlock && index <= currentLevel.maxindex) {
+          val sym = tree.symbol
+          if (sym.isLocalToBlock && index <= currentLevel.maxindex) {
             debuglog("refsym = " + currentLevel.refsym)
-            reporter.error(currentLevel.refpos, "forward reference extends over definition of " + lazySym)
+            reporter.error(currentLevel.refpos, "forward reference extends over definition of " + sym)
           }
           tree1 :: Nil
         }
@@ -1451,9 +1446,9 @@ abstract class RefChecks extends Transform {
             )
       }
 
-      sym.isSourceMethod &&
+      sym.name == nme.apply &&
+        !(sym hasFlag STABLE) && // ???
         sym.isCase &&
-        sym.name == nme.apply &&
         isClassTypeAccessible(tree) &&
         !tree.tpe.finalResultType.typeSymbol.primaryConstructor.isLessAccessibleThan(tree.symbol)
     }