Reduce flag fiddling

There isn't much point to the late* flags in a world where
we're mutating flags left and right in tree and info transformers...

So, lets get rid of the indirection until we can include flags
in a symbol's type history, like we do for its info.

This retires lateDEFERRED (redundant with SYNTHESIZE_IMPL_IN_SUBCLASS).
Since it's introduced so late, it makes little sense to have these
synthetic members go back to DEFERRED. Instead, just set DEFERRED directly.

Also remove unused late* and not* flags.
notPRIVATE subsumes lateFINAL for effective finality (scala/scala-dev#126)

1 files changed, 8 insertions, 16 deletions

diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala
index e438856160..487aadf5e5 100644
--- a/src/reflect/scala/reflect/internal/Symbols.scala
+++ b/src/reflect/scala/reflect/internal/Symbols.scala
@@ -746,10 +746,10 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     final def hasGetter = isTerm && nme.isLocalName(name)
 
     /**
-     * Nested modules which have no static owner when ModuleDefs are eliminated (refchecks) are
-     * given the lateMETHOD flag, which makes them appear as methods after refchecks.
+     * Nested modules with a non-static owner receive the METHOD flag during UnCurry's info transform.
+     * (They are replaced by a ClassDef and DefDef for the module accessor during the fields phase.)
      *
-     * Note: the lateMETHOD flag is added lazily in the info transformer of the RefChecks phase.
+     * Note: the METHOD flag is added lazily in the info transformer of the UnCurry phase.
      * This means that forcing the `sym.info` may change the value of `sym.isMethod`. Forcing the
      * info is in the responsibility of the caller. Doing it eagerly here was tried (0ccdb151f) but
      * has proven to lead to bugs (SI-8907).
@@ -985,10 +985,7 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     final def isEffectivelyFinal: Boolean = (
          (this hasFlag FINAL | PACKAGE)
       || isModuleOrModuleClass && (isTopLevel || !settings.overrideObjects)
-      || isTerm && (
-             isPrivate
-          || isLocalToBlock
-         )
+      || isTerm && (isPrivate || isLocalToBlock || (hasAllFlags(notPRIVATE | METHOD) && !hasFlag(DEFERRED)))
       || isClass && originalOwner.isTerm && children.isEmpty // we track known subclasses of term-owned classes, use that infer finality
     )
     /** Is this symbol effectively final or a concrete term member of sealed class whose children do not override it */
@@ -2450,14 +2447,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
      */
     final def makeNotPrivate(base: Symbol) {
       if (this.isPrivate) {
-        setFlag(notPRIVATE)
-        // Marking these methods final causes problems for proxies which use subclassing. If people
-        // write their code with no usage of final, we probably shouldn't introduce it ourselves
-        // unless we know it is safe. ... Unfortunately if they aren't marked final the inliner
-        // thinks it can't inline them. So once again marking lateFINAL, and in genjvm we no longer
-        // generate ACC_FINAL on "final" methods which are actually lateFINAL.
-        if (isMethod && !isDeferred)
-          setFlag(lateFINAL)
+        setFlag(notPRIVATE) // this makes it effectively final (isEffectivelyFinal)
+        // don't set FINAL -- methods not marked final by user should not end up final in bytecode
+        // inliner will know it's effectively final (notPRIVATE non-deferred method)
         if (!isStaticModule && !isClassConstructor) {
           expandName(base)
           if (isModule) moduleClass.makeNotPrivate(base)
@@ -2886,7 +2878,7 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
 
     override def owner = {
       if (Statistics.hotEnabled) Statistics.incCounter(ownerCount)
-      // a module symbol may have the lateMETHOD flag after refchecks, see isModuleNotMethod
+      // a non-static module symbol gets the METHOD flag in uncurry's info transform -- see isModuleNotMethod
       if (!isMethod && needsFlatClasses) rawowner.owner
       else rawowner
     }