diff --git a/internal/util-collection/src/main/scala/sbt/Dag.scala b/internal/util-collection/src/main/scala/sbt/Dag.scala
index 118cd0dff..3eb3d8ccb 100644
--- a/internal/util-collection/src/main/scala/sbt/Dag.scala
+++ b/internal/util-collection/src/main/scala/sbt/Dag.scala
@@ -26,6 +26,7 @@ object Dag {
           discovered(node) = true;
           try { visitAll(dependencies(node)); } catch { case c: Cyclic => throw node :: c }
           finished += node
+          ()
         } else if (!finished(node))
           throw new Cyclic(node)
       }
diff --git a/internal/util-collection/src/main/scala/sbt/IDSet.scala b/internal/util-collection/src/main/scala/sbt/IDSet.scala
index 4f5245a26..7c21c48a7 100644
--- a/internal/util-collection/src/main/scala/sbt/IDSet.scala
+++ b/internal/util-collection/src/main/scala/sbt/IDSet.scala
@@ -33,7 +33,7 @@ object IDSet {
     def apply(t: T) = contains(t)
     def contains(t: T) = backing.containsKey(t)
     def foreach(f: T => Unit) = all foreach f
-    def +=(t: T) = backing.put(t, Dummy)
+    def +=(t: T) = { backing.put(t, Dummy); () }
     def ++=(t: Iterable[T]) = t foreach +=
     def -=(t: T) = if (backing.remove(t) eq null) false else true
     def all = collection.JavaConversions.collectionAsScalaIterable(backing.keySet)
diff --git a/internal/util-collection/src/main/scala/sbt/INode.scala b/internal/util-collection/src/main/scala/sbt/INode.scala
index ce39fadad..e55ee9683 100644
--- a/internal/util-collection/src/main/scala/sbt/INode.scala
+++ b/internal/util-collection/src/main/scala/sbt/INode.scala
@@ -79,7 +79,7 @@ abstract class EvaluateSettings[Scope] {
       workComplete()
     }
 
-  private[this] def startWork(): Unit = running.incrementAndGet()
+  private[this] def startWork(): Unit = { running.incrementAndGet(); () }
   private[this] def workComplete(): Unit =
     if (running.decrementAndGet() == 0)
       complete.put(None)
@@ -154,6 +154,7 @@ abstract class EvaluateSettings[Scope] {
         case Evaluated => submitCallComplete(by, value)
         case _         => calledBy += by
       }
+      ()
     }
     protected def dependsOn: Seq[INode[_]]
     protected def evaluate0(): Unit
diff --git a/internal/util-collection/src/main/scala/sbt/PMap.scala b/internal/util-collection/src/main/scala/sbt/PMap.scala
index cf0454fd9..979e776fa 100644
--- a/internal/util-collection/src/main/scala/sbt/PMap.scala
+++ b/internal/util-collection/src/main/scala/sbt/PMap.scala
@@ -15,7 +15,7 @@ trait RMap[K[_], V[_]] {
   def values: Iterable[V[_]]
   def isEmpty: Boolean
 
-  final case class TPair[T](key: K[T], value: V[T])
+  sealed case class TPair[T](key: K[T], value: V[T])
 }
 
 trait IMap[K[_], V[_]] extends (K ~> V) with RMap[K, V] {
diff --git a/internal/util-collection/src/main/scala/sbt/Settings.scala b/internal/util-collection/src/main/scala/sbt/Settings.scala
index eb4227d09..018d5dfc0 100644
--- a/internal/util-collection/src/main/scala/sbt/Settings.scala
+++ b/internal/util-collection/src/main/scala/sbt/Settings.scala
@@ -19,7 +19,7 @@ sealed trait Settings[Scope] {
 private final class Settings0[Scope](val data: Map[Scope, AttributeMap], val delegates: Scope => Seq[Scope]) extends Settings[Scope] {
   def scopes: Set[Scope] = data.keySet
   def keys(scope: Scope) = data(scope).keys.toSet
-  def allKeys[T](f: (Scope, AttributeKey[_]) => T): Seq[T] = data.flatMap { case (scope, map) => map.keys.map(k => f(scope, k)) } toSeq
+  def allKeys[T](f: (Scope, AttributeKey[_]) => T): Seq[T] = data.flatMap { case (scope, map) => map.keys.map(k => f(scope, k)) }.toSeq
 
   def get[T](scope: Scope, key: AttributeKey[T]): Option[T] =
     delegates(scope).toStream.flatMap(sc => getDirect(sc, key)).headOption
@@ -42,7 +42,7 @@ trait Init[Scope] {
   /** The Show instance used when a detailed String needs to be generated.  It is typically used when no context is available.*/
   def showFullKey: Show[ScopedKey[_]]
 
-  final case class ScopedKey[T](scope: Scope, key: AttributeKey[T]) extends KeyedInitialize[T] {
+  sealed case class ScopedKey[T](scope: Scope, key: AttributeKey[T]) extends KeyedInitialize[T] {
     def scopedKey = this
   }
 
@@ -154,9 +154,9 @@ trait Init[Scope] {
   def compile(sMap: ScopedMap): CompiledMap =
     sMap.toTypedSeq.map {
       case sMap.TPair(k, ss) =>
-        val deps = ss flatMap { _.dependencies } toSet;
+        val deps = ss.flatMap(_.dependencies).toSet
         (k, new Compiled(k, deps, ss))
-    } toMap;
+    }.toMap
 
   def grouped(init: Seq[Setting[_]]): ScopedMap =
     ((IMap.empty: ScopedMap) /: init)((m, s) => add(m, s))
@@ -445,7 +445,7 @@ trait Init[Scope] {
       def join: Initialize[Seq[T]] = uniform(s)(idFun)
     }
     def join[T](inits: Seq[Initialize[T]]): Initialize[Seq[T]] = uniform(inits)(idFun)
-    def joinAny[M[_]](inits: Seq[Initialize[M[T]] forSome { type T }]): Initialize[Seq[M[_]]] =
+    def joinAny[M[_], T](inits: Seq[Initialize[M[T]]]): Initialize[Seq[M[_]]] =
       join(inits.asInstanceOf[Seq[Initialize[M[Any]]]]).asInstanceOf[Initialize[Seq[M[T] forSome { type T }]]]
   }
   object SettingsDefinition {
diff --git a/internal/util-collection/src/main/scala/sbt/Signal.scala b/internal/util-collection/src/main/scala/sbt/Signal.scala
index e8c9e7e6c..5aa5fc86e 100644
--- a/internal/util-collection/src/main/scala/sbt/Signal.scala
+++ b/internal/util-collection/src/main/scala/sbt/Signal.scala
@@ -37,6 +37,7 @@ object Signals {
       object unregisterNewHandler extends Registration {
         override def remove(): Unit = {
           Signal.handle(intSignal, oldHandler)
+          ()
         }
       }
       unregisterNewHandler
@@ -80,6 +81,6 @@ private final class Signals0 {
 
       try Right(action())
       catch { case e: LinkageError => Left(e) }
-      finally Signal.handle(intSignal, oldHandler)
+      finally { Signal.handle(intSignal, oldHandler); () }
     }
-}
\ No newline at end of file
+}
diff --git a/internal/util-complete/src/main/scala/sbt/LineReader.scala b/internal/util-complete/src/main/scala/sbt/LineReader.scala
index b85190f92..41679ab6e 100644
--- a/internal/util-complete/src/main/scala/sbt/LineReader.scala
+++ b/internal/util-complete/src/main/scala/sbt/LineReader.scala
@@ -65,7 +65,7 @@ private object JLine {
 
   // translate explicit class names to type in order to support
   //  older Scala, since it shaded classes but not the system property
-  private[sbt] def fixTerminalProperty() {
+  private[sbt] def fixTerminalProperty(): Unit = {
     val newValue = System.getProperty(TerminalProperty) match {
       case "jline.UnixTerminal" => "unix"
       case null if System.getProperty("sbt.cygwin") != null => "unix"
@@ -75,6 +75,7 @@ private object JLine {
       case x => x
     }
     if (newValue != null) System.setProperty(TerminalProperty, newValue)
+    ()
   }
 
   // When calling this, ensure that enableEcho has been or will be called.
diff --git a/internal/util-complete/src/main/scala/sbt/complete/History.scala b/internal/util-complete/src/main/scala/sbt/complete/History.scala
index 26d0a27c6..614244b9e 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/History.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/History.scala
@@ -13,7 +13,7 @@ final class History private (val lines: IndexedSeq[String], val path: Option[Fil
   def all: Seq[String] = lines
   def size = lines.length
   def !! : Option[String] = !-(1)
-  def apply(i: Int): Option[String] = if (0 <= i && i < size) Some(lines(i)) else { sys.error("Invalid history index: " + i); None }
+  def apply(i: Int): Option[String] = if (0 <= i && i < size) Some(lines(i)) else { sys.error("Invalid history index: " + i) }
   def !(i: Int): Option[String] = apply(i)
 
   def !(s: String): Option[String] =
@@ -26,14 +26,13 @@ final class History private (val lines: IndexedSeq[String], val path: Option[Fil
   def !?(s: String): Option[String] = nonEmpty(s) { reversed.drop(1).find(_.contains(s)) }
 
   private def nonEmpty[T](s: String)(act: => Option[T]): Option[T] =
-    if (s.isEmpty) {
+    if (s.isEmpty)
       sys.error("No action specified to history command")
-      None
-    } else
+    else
       act
 
   def list(historySize: Int, show: Int): Seq[String] =
-    lines.toList.drop((lines.size - historySize) max 0).zipWithIndex.map { case (line, number) => "   " + number + "  " + line }.takeRight(show max 1)
+    lines.toList.drop(scala.math.max(0, lines.size - historySize)).zipWithIndex.map { case (line, number) => "   " + number + "  " + line }.takeRight(show max 1)
 }
 
 object History {
@@ -42,4 +41,4 @@ object History {
   def number(s: String): Option[Int] =
     try { Some(s.toInt) }
     catch { case e: NumberFormatException => None }
-}
\ No newline at end of file
+}
diff --git a/internal/util-complete/src/main/scala/sbt/complete/HistoryCommands.scala b/internal/util-complete/src/main/scala/sbt/complete/HistoryCommands.scala
index ff58fe9d2..b66d3272e 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/HistoryCommands.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/HistoryCommands.scala
@@ -45,7 +45,7 @@ object HistoryCommands {
 
   val MaxLines = 500
   lazy val num = token(NatBasic, "<integer>")
-  lazy val last = Last ^^^ { execute(_ !!) }
+  lazy val last = Last ^^^ { execute(_.!!) }
   lazy val list = ListCommands ~> (num ?? Int.MaxValue) map { show =>
     (h: History) => { printHistory(h, MaxLines, show); Some(Nil) }
   }
diff --git a/internal/util-complete/src/main/scala/sbt/complete/JLineCompletion.scala b/internal/util-complete/src/main/scala/sbt/complete/JLineCompletion.scala
index fed89541f..2445fd111 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/JLineCompletion.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/JLineCompletion.scala
@@ -149,7 +149,7 @@ object JLineCompletion {
   def commonPrefix(s: Seq[String]): String = if (s.isEmpty) "" else s reduceLeft commonPrefix
   def commonPrefix(a: String, b: String): String =
     {
-      val len = a.length min b.length
+      val len = scala.math.min(a.length, b.length)
       @tailrec def loop(i: Int): Int = if (i >= len) len else if (a(i) != b(i)) i else loop(i + 1)
       a.substring(0, loop(0))
     }
diff --git a/internal/util-complete/src/main/scala/sbt/complete/Parser.scala b/internal/util-complete/src/main/scala/sbt/complete/Parser.scala
index 892119f6c..7ae7ea0fd 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/Parser.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/Parser.scala
@@ -300,9 +300,9 @@ trait ParserMain {
     def !!!(msg: String): Parser[A] = onFailure(a, msg)
     def failOnException: Parser[A] = trapAndFail(a)
 
-    def unary_- = not(a)
+    def unary_- = not(a, "Unexpected: " + a)
     def &(o: Parser[_]) = and(a, o)
-    def -(o: Parser[_]) = sub(a, o)
+    def -(o: Parser[_]) = and(a, not(o, "Unexpected: " + o))
     def examples(s: String*): Parser[A] = examples(s.toSet)
     def examples(s: Set[String], check: Boolean = false): Parser[A] = examples(new FixedSetExamples(s), s.size, check)
     def examples(s: ExampleSource, maxNumberOfExamples: Int, removeInvalidExamples: Boolean): Parser[A] = Parser.examples(a, s, maxNumberOfExamples, removeInvalidExamples)
@@ -366,7 +366,7 @@ trait ParserMain {
     def result = None
     def resultEmpty = mkFailure("Expected '" + ch + "'")
     def derive(c: Char) = if (c == ch) success(ch) else new Invalid(resultEmpty)
-    def completions(level: Int) = Completions.single(Completion.suggestStrict(ch.toString))
+    def completions(level: Int) = Completions.single(Completion.suggestion(ch.toString))
     override def toString = "'" + ch + "'"
   }
   /** Presents a literal String `s` as a Parser that only parses that exact text and provides it as the result.*/
@@ -812,7 +812,7 @@ private final class Repeat[T](partial: Option[Parser[T]], repeated: Parser[T], m
       case None => repeatDerive(c, accumulatedReverse)
     }
 
-  def repeatDerive(c: Char, accRev: List[T]): Parser[Seq[T]] = repeat(Some(repeated derive c), repeated, (min - 1) max 0, max.decrement, accRev)
+  def repeatDerive(c: Char, accRev: List[T]): Parser[Seq[T]] = repeat(Some(repeated derive c), repeated, scala.math.max(0, min - 1), max.decrement, accRev)
 
   def completions(level: Int) =
     {
diff --git a/internal/util-complete/src/main/scala/sbt/complete/Parsers.scala b/internal/util-complete/src/main/scala/sbt/complete/Parsers.scala
index 3183929e8..af5849870 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/Parsers.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/Parsers.scala
@@ -11,7 +11,7 @@ import java.lang.Character.{ getType, MATH_SYMBOL, OTHER_SYMBOL, DASH_PUNCTUATIO
 /** Provides standard implementations of commonly useful [[Parser]]s. */
 trait Parsers {
   /** Matches the end of input, providing no useful result on success. */
-  lazy val EOF = not(any)
+  lazy val EOF = not(any, "Expected EOF")
 
   /** Parses any single character and provides that character as the result. */
   lazy val any: Parser[Char] = charClass(_ => true, "any character")
@@ -265,4 +265,4 @@ object DefaultParsers extends Parsers with ParserMain {
 
   /** Returns `true` if `s` parses successfully according to [[ID]].*/
   def validID(s: String): Boolean = matches(ID, s)
-}
\ No newline at end of file
+}
diff --git a/internal/util-complete/src/main/scala/sbt/complete/ProcessError.scala b/internal/util-complete/src/main/scala/sbt/complete/ProcessError.scala
index 7e6c9794e..d85e523c9 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/ProcessError.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/ProcessError.scala
@@ -25,5 +25,5 @@ object ProcessError {
           s.substring(i + 1)
       loop(s.length - 1)
     }
-  def pointerSpace(s: String, i: Int): String = (s take i) map { case '\t' => '\t'; case _ => ' ' } mkString;
-}
\ No newline at end of file
+  def pointerSpace(s: String, i: Int): String = (s take i) map { case '\t' => '\t'; case _ => ' ' } mkString ""
+}
diff --git a/internal/util-complete/src/main/scala/sbt/complete/TokenCompletions.scala b/internal/util-complete/src/main/scala/sbt/complete/TokenCompletions.scala
index 96e70d2f1..1285507cc 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/TokenCompletions.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/TokenCompletions.scala
@@ -1,6 +1,6 @@
 package sbt.complete
 
-import Completion.{ displayStrict, token => ctoken, tokenDisplay }
+import Completion.{ token => ctoken, tokenDisplay }
 
 sealed trait TokenCompletions {
   def hideWhen(f: Int => Boolean): TokenCompletions
@@ -24,7 +24,7 @@ object TokenCompletions {
   val default: TokenCompletions = mapDelegateCompletions((seen, level, c) => ctoken(seen, c.append))
 
   def displayOnly(msg: String): TokenCompletions = new Fixed {
-    def completions(seen: String, level: Int) = Completions.single(displayStrict(msg))
+    def completions(seen: String, level: Int) = Completions.single(Completion.displayOnly(msg))
   }
   def overrideDisplay(msg: String): TokenCompletions = mapDelegateCompletions((seen, level, c) => tokenDisplay(display = msg, append = c.append))
 
@@ -34,4 +34,4 @@ object TokenCompletions {
   def mapDelegateCompletions(f: (String, Int, Completion) => Completion): TokenCompletions = new Delegating {
     def completions(seen: String, level: Int, delegate: Completions) = Completions(delegate.get.map(c => f(seen, level, c)))
   }
-}
\ No newline at end of file
+}
diff --git a/internal/util-complete/src/main/scala/sbt/complete/UpperBound.scala b/internal/util-complete/src/main/scala/sbt/complete/UpperBound.scala
index 66a32e1a2..2d954d4c5 100644
--- a/internal/util-complete/src/main/scala/sbt/complete/UpperBound.scala
+++ b/internal/util-complete/src/main/scala/sbt/complete/UpperBound.scala
@@ -38,10 +38,10 @@ final case class Finite(value: Int) extends UpperBound {
   def >=(min: Int) = value >= min
   def isOne = value == 1
   def isZero = value == 0
-  def decrement = Finite((value - 1) max 0)
+  def decrement = Finite(scala.math.max(0, value - 1))
   def isInfinite = false
   override def toString = value.toString
 }
 object UpperBound {
   implicit def intToFinite(i: Int): Finite = Finite(i)
-}
\ No newline at end of file
+}
diff --git a/internal/util-complete/src/test/scala/ParserTest.scala b/internal/util-complete/src/test/scala/ParserTest.scala
index f02431e53..c70c6207b 100644
--- a/internal/util-complete/src/test/scala/ParserTest.scala
+++ b/internal/util-complete/src/test/scala/ParserTest.scala
@@ -109,13 +109,13 @@ object ParserTest extends Properties("Completing Parser") {
   property("repeatDep accepts two tokens") = matches(repeat, colors.toSeq.take(2).mkString(" "))
 }
 object ParserExample {
-  val ws = charClass(_.isWhitespace)+
-  val notws = charClass(!_.isWhitespace)+
+  val ws = charClass(_.isWhitespace).+
+  val notws = charClass(!_.isWhitespace).+
 
   val name = token("test")
-  val options = (ws ~> token("quick" | "failed" | "new"))*
+  val options = (ws ~> token("quick" | "failed" | "new")).*
   val exampleSet = Set("am", "is", "are", "was", "were")
-  val include = (ws ~> token(examples(notws.string, new FixedSetExamples(exampleSet), exampleSet.size, false)))*
+  val include = (ws ~> token(examples(notws.string, new FixedSetExamples(exampleSet), exampleSet.size, false))).*
 
   val t = name ~ options ~ include
 
diff --git a/internal/util-logic/src/test/scala/sbt/logic/Test.scala b/internal/util-logic/src/test/scala/sbt/logic/Test.scala
index da1f0b706..f9957414b 100644
--- a/internal/util-logic/src/test/scala/sbt/logic/Test.scala
+++ b/internal/util-logic/src/test/scala/sbt/logic/Test.scala
@@ -26,7 +26,10 @@ object LogicTest extends Properties("Logic") {
     case Left(err) => false
     case Right(res) =>
       val actual = res.provenSet
-      (actual == expected) || sys.error(s"Expected to prove $expected, but actually proved $actual")
+      if (actual != expected)
+        sys.error(s"Expected to prove $expected, but actually proved $actual")
+      else
+        true
   }
 }