The undoLog is being cleared before a typer run...

The undoLog is being cleared before a typer run, but not afterward. This
meant a huge amount of unnecessary garbage persisted beyond typer. Now,
more clearing. Review by moors.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala b/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala
index c0b4ab5ca5..56f1fd4c53 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala
@@ -76,10 +76,17 @@ trait Analyzer extends AnyRef
     def newPhase(_prev: Phase): StdPhase = new StdPhase(_prev) {
       override def keepsTypeParams = false
       resetTyper()
+      // the log accumulates entries over time, even though it should not (Adriaan, Martin said so).
+      // Lacking a better fix, we clear it here (before the phase is created, meaning for each
+      // compiler run). This is good enough for the resident compiler, which was the most affected.
+      undoLog.clear()
       override def run {
         val start = startTimer(typerNanos)
         global.echoPhaseSummary(this)
         currentRun.units foreach applyPhase
+        undoLog.clear()
+        // need to clear it after as well or 10K+ accumulated entries are
+        // uncollectable the rest of the way.
         stopTimer(typerNanos, start)
       }
       def apply(unit: CompilationUnit) {