Fix up DEFAULTPARAM semantics.

I foolishly believed the deprecation message on "hasDefaultFlag"
which suggested I use "hasDefault" instead. After lots of head
scratching, I hardened the semantics so it's like this:

  - A method parameter with a default value is PARAM | DEFAULTPARAM
  - A default getter for such a parameter is METHOD | DEFAULTPARAM
  - And "hasDefault" is has(DEFAULTPARAM) && has(PARAM | METHOD)

Why all the bonus logic, why not just hasFlag(DEFAULTPARAM)? For
some reason we have a handful of overloaded flags spanning uses
which someone apparently thinks can never intersect but I have
not been so lucky overall. So since DEFAULTPARAM is overloaded with
TRAIT, unless we think it's fine that default getters and method
parameters with defaults will pose as traits all the time, there
has to be an anchor bit alongside it.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 61759a9f00..0ac81af56f 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -127,14 +127,14 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
       // those with the DEFAULTPARAM flag, and infer the methods. Looking for the methods
       // directly requires inspecting the parameter list of every one. That modification
       // shaved 95% off the time spent in this method.
-      val defaultGetters     = defaultClass.info.findMembers(0L, DEFAULTPARAM)
+      val defaultGetters     = defaultClass.info.findMembers(excludedFlags = PARAM, requiredFlags = DEFAULTPARAM)
       val defaultMethodNames = defaultGetters map (sym => nme.defaultGetterToMethod(sym.name))
 
       defaultMethodNames.toList.distinct foreach { name =>
-        val methods      = clazz.info.findMember(name, 0L, METHOD, stableOnly = false).alternatives
+        val methods      = clazz.info.findMember(name, 0L, requiredFlags = METHOD, stableOnly = false).alternatives
         def hasDefaultParam(tpe: Type): Boolean = tpe match {
           case MethodType(params, restpe) => (params exists (_.hasDefault)) || hasDefaultParam(restpe)
-          case _ => false
+          case _                          => false
         }
         val haveDefaults = methods filter (sym => hasDefaultParam(sym.info) && !nme.isProtectedAccessorName(sym.name))