Drop blocks with empty statements from inlined expansions

Author: odersky

compiler/src/dotty/tools/dotc/typer/Inliner.scala

@@ -602,7 +602,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
               newOwners = ctx.owner :: Nil,
               substFrom = ddef.vparamss.head.map(_.symbol),
               substTo = argSyms)
-            Block(bindingsBuf.toList, expander.transform(ddef.rhs))
+            seq(bindingsBuf.toList, expander.transform(ddef.rhs))
           case _ => tree
         }
       case _ => tree
@@ -885,6 +885,8 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
         case t: Apply =>
           val t1 = super.transform(t)
           if (t1 `eq` t) t else reducer.betaReduce(t1)
+        case Block(Nil, expr) =>
+          super.transform(expr)
         case _ =>
           super.transform(t)
       }

compiler/src/dotty/tools/dotc/util/Set.scala

@@ -1,7 +1,3 @@
-/* NSC -- new Scala compiler
- * Copyright 2005-2012 LAMP/EPFL
- * @author  Martin Odersky
- */
 package dotty.tools.dotc.util
 
 /** A common class for lightweight sets.