diff --git a/build.sbt b/build.sbt
index d2a84b2d5..1bfde5b9a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -185,6 +185,8 @@ lazy val sbtRoot: Project = (project in file("."))
     collectionProj,
     coreMacrosProj,
     utilLogging,
+    utilControl,
+    completeProj,
   )
   .settings(
     minimalSettings,
diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala b/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
index 41f0b9014..265f76d72 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/LineReader.scala
@@ -238,17 +238,9 @@ abstract class JLine extends LineReader {
 
 @deprecated("Use LineReader apis", "1.4.0")
 private[sbt] object JLine {
-  @deprecated("For binary compatibility only", "1.4.0")
-  protected[this] val originalIn = new FileInputStream(FileDescriptor.in)
-
   @deprecated("Handled by Terminal.fixTerminalProperty", "1.4.0")
   private[sbt] def fixTerminalProperty(): Unit = ()
 
-  @deprecated("For binary compatibility only", "1.4.0")
-  private[sbt] def makeInputStream(injectThreadSleep: Boolean): InputStream =
-    if (injectThreadSleep) new InputStreamWrapper(originalIn, 2.milliseconds)
-    else originalIn
-
   // When calling this, ensure that enableEcho has been or will be called.
   // TerminalFactory.get will initialize the terminal to disable echo.
   @deprecated("Don't use jline.Terminal directly", "1.4.0")
@@ -258,11 +250,11 @@ private[sbt] object JLine {
    * For accessing the JLine Terminal object. This ensures synchronized access as well as
    * re-enabling echo after getting the Terminal.
    */
-  @deprecated(
-    "Don't use jline.Terminal directly. Use Terminal.get.withCanonicalIn instead.",
-    "1.4.0"
-  )
-  def usingTerminal[T](f: jline.Terminal => T): T = f(Terminal.get.toJLine)
+  // @deprecated(
+  //   "Don't use jline.Terminal directly. Use Terminal.get.withCanonicalIn instead.",
+  //   "1.4.0"
+  // )
+  // def usingTerminal[T](f: jline.Terminal => T): T = f(Terminal.get.toJLine)
 
   @deprecated("unused", "1.4.0")
   def createReader(): ConsoleReader = createReader(None, Terminal.wrappedSystemIn)
@@ -298,31 +290,6 @@ private[sbt] object JLine {
   val HandleCONT = LineReader.HandleCONT
 }
 
-@deprecated("For binary compatibility only", "1.4.0")
-private[sbt] class InputStreamWrapper(is: InputStream, val poll: Duration)
-    extends FilterInputStream(is) {
-  @tailrec final override def read(): Int =
-    if (is.available() != 0) is.read()
-    else {
-      Thread.sleep(poll.toMillis)
-      read()
-    }
-
-  @tailrec final override def read(b: Array[Byte]): Int =
-    if (is.available() != 0) is.read(b)
-    else {
-      Thread.sleep(poll.toMillis)
-      read(b)
-    }
-
-  @tailrec final override def read(b: Array[Byte], off: Int, len: Int): Int =
-    if (is.available() != 0) is.read(b, off, len)
-    else {
-      Thread.sleep(poll.toMillis)
-      read(b, off, len)
-    }
-}
-
 final class FullReader(
     historyPath: Option[File],
     complete: Parser[_],
diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Completions.scala b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Completions.scala
index 1297784de..b0f999f1d 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Completions.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Completions.scala
@@ -158,14 +158,4 @@ object Completion {
   def tokenDisplay(append: String, display: String): Completion = new Token(display, append)
 
   def suggestion(value: String): Completion = new Suggestion(value)
-
-  @deprecated("No longer used. for binary compatibility", "1.1.0")
-  private[complete] def displayOnly(value: => String): Completion = new DisplayOnly(value)
-
-  @deprecated("No longer used. for binary compatibility", "1.1.0")
-  private[complete] def token(prepend: => String, append: => String): Completion =
-    new Token(prepend + append, append)
-
-  @deprecated("No longer used. for binary compatibility", "1.1.0")
-  private[complete] def suggestion(value: => String): Completion = new Suggestion(value)
 }
diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
index 6b56ec4a5..9d6639134 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parser.scala
@@ -270,16 +270,18 @@ object Parser extends ParserMain {
     }
 
   def choiceParser[A, B](a: Parser[A], b: Parser[B]): Parser[Either[A, B]] =
-    if (a.valid)
-      if (b.valid) new HetParser(a, b) else a.map(left.fn)
-    else
-      b.map(right.fn)
+    if a.valid then
+      if b.valid then new HetParser(a, b)
+      else a.map(left[A])
+    else b.map(right[B])
 
   def opt[T](a: Parser[T]): Parser[Option[T]] =
-    if (a.valid) new Optional(a) else success(None)
+    if a.valid then new Optional(a)
+    else success(None)
 
   def onFailure[T](delegate: Parser[T], msg: String): Parser[T] =
-    if (delegate.valid) new OnFailure(delegate, msg) else failure(msg)
+    if delegate.valid then new OnFailure(delegate, msg)
+    else failure(msg)
 
   def trapAndFail[T](delegate: Parser[T]): Parser[T] =
     delegate.ifValid(new TrapAndFail(delegate))
@@ -437,8 +439,9 @@ trait ParserMain {
   /** Presents a single Char `ch` as a Parser that only parses that exact character. */
   implicit def literal(ch: Char): Parser[Char] = new ValidParser[Char] {
     def result = None
-    def resultEmpty = mkFailure("Expected '" + ch + "'")
-    def derive(c: Char) = if (c == ch) success(ch) else new Invalid(resultEmpty)
+    private[this] lazy val fail = mkFailure("Expected '" + ch + "'")
+    def resultEmpty = fail
+    def derive(c: Char) = if (c == ch) success(ch) else new Invalid(fail)
     def completions(level: Int) = Completions.single(Completion.suggestion(ch.toString))
     override def toString = "'" + ch + "'"
   }
@@ -640,7 +643,7 @@ trait ParserMain {
 
   def seq0[T](p: Seq[Parser[T]], errors: => Seq[String]): Parser[Seq[T]] = {
     val (newErrors, valid) = separate(p) {
-      case Invalid(f) => Left(f.errors _): Either[() => Seq[String], Parser[T]]
+      case Invalid(f) => Left(() => f.errors): Either[() => Seq[String], Parser[T]]
       case ok         => Right(ok): Either[() => Seq[String], Parser[T]]
     }
     def combinedErrors = errors ++ newErrors.flatMap(_())
@@ -944,11 +947,12 @@ private final class StringLiteral(str: String, start: Int) extends ValidParser[S
   assert(0 <= start && start < str.length)
 
   def failMsg = "Expected '" + str + "'"
+  private[this] lazy val fail = mkFailure(failMsg)
   def resultEmpty = mkFailure(failMsg)
   def result = None
 
   def derive(c: Char) =
-    if (str.charAt(start) == c) stringLiteral(str, start + 1) else new Invalid(resultEmpty)
+    if (str.charAt(start) == c) stringLiteral(str, start + 1) else new Invalid(fail)
 
   def completions(level: Int) = Completions.single(Completion.suggestion(str.substring(start)))
   override def toString = "\"" + str + "\""
@@ -956,16 +960,17 @@ private final class StringLiteral(str: String, start: Int) extends ValidParser[S
 
 private final class CharacterClass(f: Char => Boolean, label: String) extends ValidParser[Char] {
   def result = None
-  def resultEmpty = mkFailure("Expected " + label)
-  def derive(c: Char) = if (f(c)) success(c) else Invalid(resultEmpty)
+  private[this] def fail: Failure = mkFailure("Expected " + label)
+  def resultEmpty = fail
+  def derive(c: Char) = if (f(c)) success(c) else Invalid(fail)
   def completions(level: Int) = Completions.empty
   override def toString = "class(" + label + ")"
 }
 
-private final class Optional[T](delegate: Parser[T]) extends ValidParser[Option[T]] {
-  def result = delegate.result map some.fn
+private final class Optional[A](delegate: Parser[A]) extends ValidParser[Option[A]] {
+  def result = delegate.result.map(some[A])
   def resultEmpty = Value(None)
-  def derive(c: Char) = (delegate derive c).map(some.fn)
+  def derive(c: Char) = (delegate derive c).map(some[A])
   def completions(level: Int) = Completion.empty +: delegate.completions(level)
   override def toString = delegate.toString + "?"
 }
diff --git a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parsers.scala b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parsers.scala
index f73122c01..3c4e81fee 100644
--- a/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parsers.scala
+++ b/internal/util-complete/src/main/scala/sbt/internal/util/complete/Parsers.scala
@@ -125,7 +125,8 @@ trait Parsers {
   def isOpType(cat: Int) = cat match {
     case MATH_SYMBOL | OTHER_SYMBOL | DASH_PUNCTUATION | OTHER_PUNCTUATION | MODIFIER_SYMBOL |
         CURRENCY_SYMBOL =>
-      true; case _ => false
+      true
+    case _ => false
   }
 
   /** Returns true if `c` is a dash `-`, a letter, digit, or an underscore `_`. */
@@ -182,18 +183,14 @@ trait Parsers {
   /** Matches any character except a double quote or whitespace. */
   lazy val NotDQuoteSpaceClass =
     charClass(
-      { c: Char =>
-        (c != DQuoteChar) && !c.isWhitespace
-      },
+      (c: Char) => { (c != DQuoteChar) && !c.isWhitespace },
       "non-double-quote-space character"
     )
 
   /** Matches any character except a double quote or backslash. */
   lazy val NotDQuoteBackslashClass =
     charClass(
-      { c: Char =>
-        (c != DQuoteChar) && (c != BackslashChar)
-      },
+      (c: Char) => { (c != DQuoteChar) && (c != BackslashChar) },
       "non-double-quote-backslash character"
     )
 
diff --git a/internal/util-complete/src/test/scala/ParserTest.scala b/internal/util-complete/src/test/scala/ParserTest.scala
index 4694f974a..15843b5c7 100644
--- a/internal/util-complete/src/test/scala/ParserTest.scala
+++ b/internal/util-complete/src/test/scala/ParserTest.scala
@@ -8,6 +8,8 @@
 package sbt.internal.util
 package complete
 
+import scala.collection.StringOps
+
 object JLineTest {
   import DefaultParsers._
 
@@ -153,12 +155,12 @@ object ParserExample {
     val an = repeat(a, min = n, max = n)
     val ann = aqn ~ an
 
-    def r = apply(ann)("a" * (n * 2)).resultEmpty
+    def r = apply(ann)(new StringOps("a") * (n * 2)).resultEmpty
     println(r.isValid)
   }
   def run2(n: Int): Unit = {
     val ab = "ab".?.*
-    val r = apply(ab)("a" * n).resultEmpty
+    val r = apply(ab)(new StringOps("a") * n).resultEmpty
     println(r)
   }
 }
diff --git a/util-collection/src/main/scala/sbt/internal/util/TypeFunctions.scala b/util-collection/src/main/scala/sbt/internal/util/TypeFunctions.scala
index a205d2baa..8a0663e6d 100644
--- a/util-collection/src/main/scala/sbt/internal/util/TypeFunctions.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/TypeFunctions.scala
@@ -17,15 +17,21 @@ trait TypeFunctions:
   sealed trait ConstK[A] { type l[L[x]] = A }
   sealed trait Compose[A[_], B[_]] { type Apply[T] = A[B[T]] }
   sealed trait ∙[A[_], B[_]] { type l[T] = A[B[T]] }
+
+   */
   private type AnyLeft[T] = Left[T, Nothing]
   private type AnyRight[T] = Right[Nothing, T]
+  final val left: [A] => A => Left[A, Nothing] = [A] => (a: A) => Left(a)
+
+  final val right: [A] => A => Right[Nothing, A] = [A] => (a: A) => Right(a)
+
+  final val some: [A] => A => Some[A] = [A] => (a: A) => Some(a)
+  // Id ~> Left[*, Nothing] =
+  // λ[Id ~> AnyLeft](Left(_)).setToString("TypeFunctions.left")
+  // final val right: Id ~> Right[Nothing, *] =
+  //   λ[Id ~> AnyRight](Right(_)).setToString("TypeFunctions.right")
+  // final val some: Id ~> Some[*] = λ[Id ~> Some](Some(_)).setToString("TypeFunctions.some")
 
-  final val left: Id ~> Left[*, Nothing] =
-    λ[Id ~> AnyLeft](Left(_)).setToString("TypeFunctions.left")
-  final val right: Id ~> Right[Nothing, *] =
-    λ[Id ~> AnyRight](Right(_)).setToString("TypeFunctions.right")
-  final val some: Id ~> Some[*] = λ[Id ~> Some](Some(_)).setToString("TypeFunctions.some")
-   */
   final def idFun[A]: A => A = ((a: A) => a) // .setToString("TypeFunctions.id")
   final def const[A, B](b: B): A => B = ((_: A) => b) // .setToString(s"TypeFunctions.const($b)")
 /*