Flipped varargs eta-expansion behavior.

(T*)U now eta-expands to Seq[T] => U, not T* => U. There is a transition
command line switch to get the old behavior for any who may have relied
upon it:

  -Yeta-expand-keeps-star

Closes SI-4176, no review.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 604379d33f..e166b42436 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -300,6 +300,12 @@ class Global(var currentSettings: Settings, var reporter: Reporter) extends Symb
     def lubDebug      = (sys.props contains "scalac.debug.lub")
   }
 
+  // The current division between scala.reflect.* and scala.tools.nsc.* is pretty
+  // clunky.  It is often difficult to have a setting influence something without having
+  // to create it on that side.  For this one my strategy is a constant def at the file
+  // where I need it, and then an override in Global with the setting.
+  override protected val etaExpandKeepsStar = settings.etaExpandKeepsStar.value
+
   // True if -Xscript has been set, indicating a script run.
   def isScriptRun = opt.script.isDefined