Erasure phase PoC

Still missing: bridge method generation, signatures.

Other changes

 - Turned around Checking and NoChecking. Checking is the default, NoChecking
   disables it.

 - Refactored Typer#typed to expose typedNamed, so that it can be overridden in
   erasure.

 - Made logging more forgiving wrt off-buy-one phase errors.

Conflicts:
	src/dotty/tools/dotc/typer/Typer.scala

1 files changed, 9 insertions, 1 deletions

diff --git a/src/dotty/tools/dotc/reporting/Reporter.scala b/src/dotty/tools/dotc/reporting/Reporter.scala
index e2b320588..933262861 100644
--- a/src/dotty/tools/dotc/reporting/Reporter.scala
+++ b/src/dotty/tools/dotc/reporting/Reporter.scala
@@ -106,8 +106,16 @@ trait Reporting { this: Context =>
   def incompleteInputError(msg: String, pos: SourcePosition = NoSourcePosition)(implicit ctx: Context): Unit =
     reporter.incomplete(Diagnostic(msg, pos, ERROR))(ctx)
 
+  /** Log msg if current phase or its precedessor is mentioned in
+   *  settings.log.
+   *  The reason we also pick the predecessor is that during the
+   *  tree transform of phase X, we often are already in phase X+1.
+   *  It's convenient to have logging work independently of whether
+   *  we have advanced the phase or not.
+   */
   def log(msg: => String): Unit =
-    if (this.settings.log.value.containsPhase(phase))
+    if (this.settings.log.value.containsPhase(phase) ||
+        this.settings.log.value.containsPhase(phase.prev))
       echo(s"[log ${ctx.phasesStack.reverse.mkString(" -> ")}] $msg")
 
   def debuglog(msg: => String): Unit =