TailRec: Avoid harmless capture of Context

The captured context was passed implicitly to dd.rhs, atGroupEnd is
always run with the same runId as the captured context so this should be okay,
but it's better to avoid using two contexts in the same expression anyway.

Author: smarter

compiler/src/dotty/tools/dotc/transform/TailRec.scala

@@ -119,7 +119,7 @@ class TailRec extends MiniPhaseTransform with DenotTransformer with FullParamete
             // now this speculatively transforms tree and throws away result in many cases
             val rhsSemiTransformed = {
               val transformer = new TailRecElimination(origMeth, dd.tparams, owner, thisTpe, mandatory, label, abstractOverClass = defIsTopLevel)
-              val rhs = atGroupEnd(transformer.transform(dd.rhs)(_))
+              val rhs = atGroupEnd(implicit ctx => transformer.transform(dd.rhs))
               rewrote = transformer.rewrote
               rhs
             }