The following piece of code crashes the compiler.

object O {
trait T {
private[this] val c : Int = 0
def f = { x : Int => c }
}
}

With assertion:

error: java.lang.AssertionError: assertion failed
at scala.Predef$.assert(Predef.scala:89)
at scala.tools.nsc.transform.Mixin$MixinTransformer.scala$tools$nsc$transform$Mixin$MixinTransformer$$postTransform(Mixin.scala:1236)
at scala.tools.nsc.transform.Mixin$MixinTransformer$$anonfun$23.apply(Mixin.scala:1262)
at scala.tools.nsc.transform.Mixin$MixinTransformer$$anonfun$23.apply(Mixin.scala:1262)
at scala.tools.nsc.symtab.SymbolTable.atPhase(SymbolTable.scala:95)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1262)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$5.apply(Trees.scala:783)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$5.apply(Trees.scala:781)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:780)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:891)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:889)
at scala.collection.immutable.List.loop$1(List.scala:117)
at scala.collection.immutable.List.mapConserve(List.scala:133)
at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:889)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:797)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer.transformTemplate(Trees.scala:875)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$2.apply(Trees.scala:767)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$2.apply(Trees.scala:766)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:765)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:891)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:889)
at scala.collection.immutable.List.loop$1(List.scala:117)
at scala.collection.immutable.List.mapConserve(List.scala:133)
at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:889)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$1.apply(Trees.scala:761)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$1.apply(Trees.scala:761)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:760)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:892)
at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30)
at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:329)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.collection.Iterator$class.foreach(Iterator.scala:660)
at scala.collection.mutable.ListBuffer$$anon$1.foreach(ListBuffer.scala:316)
at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:297)
at scala.tools.nsc.Global$Run.compileSources(Global.scala:953)
at scala.tools.nsc.Global$Run.compile(Global.scala:1038)
at scala.tools.nsc.Main$.process(Main.scala:106)
at scala.tools.nsc.Main$.main(Main.scala:123)
at scala.tools.nsc.Main.main(Main.scala)

Exception in thread "main" java.lang.AssertionError: assertion failed
at scala.Predef$.assert(Predef.scala:89)
at scala.tools.nsc.transform.Mixin$MixinTransformer.scala$tools$nsc$transform$Mixin$MixinTransformer$$postTransform(Mixin.scala:1236)
at scala.tools.nsc.transform.Mixin$MixinTransformer$$anonfun$23.apply(Mixin.scala:1262)
at scala.tools.nsc.transform.Mixin$MixinTransformer$$anonfun$23.apply(Mixin.scala:1262)
at scala.tools.nsc.symtab.SymbolTable.atPhase(SymbolTable.scala:95)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1262)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$5.apply(Trees.scala:783)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$5.apply(Trees.scala:781)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:780)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:891)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:889)
at scala.collection.immutable.List.loop$1(List.scala:117)
at scala.collection.immutable.List.mapConserve(List.scala:133)
at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:889)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:797)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer.transformTemplate(Trees.scala:875)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$2.apply(Trees.scala:767)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$2.apply(Trees.scala:766)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:765)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:891)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:889)
at scala.collection.immutable.List.loop$1(List.scala:117)
at scala.collection.immutable.List.mapConserve(List.scala:133)
at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:889)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$1.apply(Trees.scala:761)
at scala.tools.nsc.ast.Trees$Transformer$$anonfun$transform$1.apply(Trees.scala:761)
at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:899)
at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:760)
at scala.tools.nsc.transform.Mixin$MixinTransformer.transform(Mixin.scala:1261)
at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:892)
at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30)
at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:329)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:297)
at scala.collection.Iterator$class.foreach(Iterator.scala:660)
at scala.collection.mutable.ListBuffer$$anon$1.foreach(ListBuffer.scala:316)
at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:297)
at scala.tools.nsc.Global$Run.compileSources(Global.scala:953)
at scala.tools.nsc.Global$Run.compile(Global.scala:1038)
at scala.tools.nsc.Main$.process(Main.scala:106)
at scala.tools.nsc.Main$.main(Main.scala:123)
at scala.tools.nsc.Main.main(Main.scala)