From 70b3b90d686f3444e6b16cbf9deedc8aed0c62e8 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Fri, 17 Mar 2017 13:30:19 +0100
Subject: Rename PolyParam --> TypeParamRef

---
 compiler/src/dotty/tools/dotc/config/Config.scala  |  2 +-
 compiler/src/dotty/tools/dotc/core/Constants.scala |  2 +-
 .../src/dotty/tools/dotc/core/Constraint.scala     | 42 +++++-----
 .../dotty/tools/dotc/core/ConstraintHandling.scala | 36 ++++----
 .../src/dotty/tools/dotc/core/Definitions.scala    |  6 +-
 compiler/src/dotty/tools/dotc/core/Mode.scala      |  2 +-
 .../dotty/tools/dotc/core/OrderingConstraint.scala | 98 +++++++++++-----------
 .../dotty/tools/dotc/core/TypeApplications.scala   |  8 +-
 .../src/dotty/tools/dotc/core/TypeComparer.scala   | 32 +++----
 .../src/dotty/tools/dotc/core/TypeErasure.scala    |  6 +-
 compiler/src/dotty/tools/dotc/core/TypeOps.scala   |  2 +-
 .../src/dotty/tools/dotc/core/TyperState.scala     |  2 +-
 compiler/src/dotty/tools/dotc/core/Types.scala     | 33 +++-----
 .../dotty/tools/dotc/core/tasty/TreePickler.scala  |  2 +-
 .../tools/dotc/core/tasty/TreeUnpickler.scala      |  2 +-
 .../src/dotty/tools/dotc/printing/Formatting.scala | 10 +--
 .../dotty/tools/dotc/printing/PlainPrinter.scala   | 10 +--
 .../dotty/tools/dotc/printing/RefinedPrinter.scala |  2 +-
 .../dotty/tools/dotc/sbt/ExtractDependencies.scala |  2 +-
 .../dotc/transform/FullParameterization.scala      |  2 +-
 .../dotty/tools/dotc/transform/TreeChecker.scala   |  2 +-
 .../src/dotty/tools/dotc/typer/Applications.scala  |  2 +-
 .../dotty/tools/dotc/typer/ErrorReporting.scala    |  4 +-
 .../src/dotty/tools/dotc/typer/Inferencing.scala   |  2 +-
 compiler/src/dotty/tools/dotc/typer/Inliner.scala  |  2 +-
 .../src/dotty/tools/dotc/typer/ProtoTypes.scala    | 20 ++---
 .../src/dotty/tools/dotc/typer/TypeAssigner.scala  |  4 +-
 compiler/src/dotty/tools/dotc/typer/Typer.scala    |  2 +-
 28 files changed, 166 insertions(+), 173 deletions(-)

(limited to 'compiler/src/dotty/tools')

diff --git a/compiler/src/dotty/tools/dotc/config/Config.scala b/compiler/src/dotty/tools/dotc/config/Config.scala
index 903efd794..46b1896f1 100644
--- a/compiler/src/dotty/tools/dotc/config/Config.scala
+++ b/compiler/src/dotty/tools/dotc/config/Config.scala
@@ -40,7 +40,7 @@ object Config {
    *  accesses javac's settings.)
    *
    *  It is recommended to turn this option on only when chasing down
-   *  a PolyParam instantiation error. See comment in Types.TypeVar.instantiate.
+   *  a TypeParamRef instantiation error. See comment in Types.TypeVar.instantiate.
    */
   final val debugCheckConstraintsClosed = false
 
diff --git a/compiler/src/dotty/tools/dotc/core/Constants.scala b/compiler/src/dotty/tools/dotc/core/Constants.scala
index e8b27c0ba..ed388b7ec 100644
--- a/compiler/src/dotty/tools/dotc/core/Constants.scala
+++ b/compiler/src/dotty/tools/dotc/core/Constants.scala
@@ -169,7 +169,7 @@ object Constants {
     def convertTo(pt: Type)(implicit ctx: Context): Constant = {
       def classBound(pt: Type): Type = pt.dealias.stripTypeVar match {
         case tref: TypeRef if !tref.symbol.isClass => classBound(tref.info.bounds.lo)
-        case param: PolyParam =>
+        case param: TypeParamRef =>
           ctx.typerState.constraint.entry(param) match {
             case TypeBounds(lo, hi) =>
               if (hi.classSymbol.isPrimitiveValueClass) hi //constrain further with high bound
diff --git a/compiler/src/dotty/tools/dotc/core/Constraint.scala b/compiler/src/dotty/tools/dotc/core/Constraint.scala
index 50136a26c..fe14aa53c 100644
--- a/compiler/src/dotty/tools/dotc/core/Constraint.scala
+++ b/compiler/src/dotty/tools/dotc/core/Constraint.scala
@@ -14,9 +14,9 @@ import config.Printers.constr
  *  over values of the following types:
  *
  *   - PolyType    A constraint constrains the type parameters of a set of PolyTypes
- *   - PolyParam   The parameters of the constrained polytypes
+ *   - TypeParamRef   The parameters of the constrained polytypes
  *   - TypeVar     Every constrained parameter might be associated with a TypeVar
- *                 that has the PolyParam as origin.
+ *                 that has the TypeParamRef as origin.
  */
 abstract class Constraint extends Showable {
 
@@ -26,7 +26,7 @@ abstract class Constraint extends Showable {
   def contains(pt: PolyType): Boolean
 
   /** Does the constraint's domain contain the type parameter `param`? */
-  def contains(param: PolyParam): Boolean
+  def contains(param: TypeParamRef): Boolean
 
   /** Does this constraint contain the type variable `tvar` and is it uninstantiated? */
   def contains(tvar: TypeVar): Boolean
@@ -34,43 +34,43 @@ abstract class Constraint extends Showable {
   /** The constraint entry for given type parameter `param`, or NoType if `param` is not part of
    *  the constraint domain. Note: Low level, implementation dependent.
    */
-  def entry(param: PolyParam): Type
+  def entry(param: TypeParamRef): Type
 
   /** The type variable corresponding to parameter `param`, or
    *  NoType, if `param` is not in constrained or is not paired with a type variable.
    */
-  def typeVarOfParam(param: PolyParam): Type
+  def typeVarOfParam(param: TypeParamRef): Type
 
   /** Is it known that `param1 <:< param2`? */
-  def isLess(param1: PolyParam, param2: PolyParam): Boolean
+  def isLess(param1: TypeParamRef, param2: TypeParamRef): Boolean
 
   /** The parameters that are known to be smaller wrt <: than `param` */
-  def lower(param: PolyParam): List[PolyParam]
+  def lower(param: TypeParamRef): List[TypeParamRef]
 
   /** The parameters that are known to be greater wrt <: than `param` */
-  def upper(param: PolyParam): List[PolyParam]
+  def upper(param: TypeParamRef): List[TypeParamRef]
 
   /** lower(param) \ lower(butNot) */
-  def exclusiveLower(param: PolyParam, butNot: PolyParam): List[PolyParam]
+  def exclusiveLower(param: TypeParamRef, butNot: TypeParamRef): List[TypeParamRef]
 
   /** upper(param) \ upper(butNot) */
-  def exclusiveUpper(param: PolyParam, butNot: PolyParam): List[PolyParam]
+  def exclusiveUpper(param: TypeParamRef, butNot: TypeParamRef): List[TypeParamRef]
 
   /** The constraint bounds for given type parameter `param`.
    *  Poly params that are known to be smaller or greater than `param`
    *  are not contained in the return bounds.
    *  @pre `param` is not part of the constraint domain.
    */
-  def nonParamBounds(param: PolyParam): TypeBounds
+  def nonParamBounds(param: TypeParamRef): TypeBounds
 
   /** The lower bound of `param` including all known-to-be-smaller parameters */
-  def fullLowerBound(param: PolyParam)(implicit ctx: Context): Type
+  def fullLowerBound(param: TypeParamRef)(implicit ctx: Context): Type
 
   /** The upper bound of `param` including all known-to-be-greater parameters */
-  def fullUpperBound(param: PolyParam)(implicit ctx: Context): Type
+  def fullUpperBound(param: TypeParamRef)(implicit ctx: Context): Type
 
   /** The bounds of `param` including all known-to-be-smaller and -greater parameters */
-  def fullBounds(param: PolyParam)(implicit ctx: Context): TypeBounds
+  def fullBounds(param: TypeParamRef)(implicit ctx: Context): TypeBounds
 
   /** A new constraint which is derived from this constraint by adding
    *  entries for all type parameters of `poly`.
@@ -90,18 +90,18 @@ abstract class Constraint extends Showable {
    *
    * @pre  `this contains param`.
    */
-  def updateEntry(param: PolyParam, tp: Type)(implicit ctx: Context): This
+  def updateEntry(param: TypeParamRef, tp: Type)(implicit ctx: Context): This
 
   /** A constraint that includes the relationship `p1 <: p2`.
    *  `<:` relationships between parameters ("edges") are propagated, but
    *  non-parameter bounds are left alone.
    */
-  def addLess(p1: PolyParam, p2: PolyParam)(implicit ctx: Context): This
+  def addLess(p1: TypeParamRef, p2: TypeParamRef)(implicit ctx: Context): This
 
   /** A constraint resulting from adding p2 = p1 to this constraint, and at the same
    *  time transferring all bounds of p2 to p1
    */
-  def unify(p1: PolyParam, p2: PolyParam)(implicit ctx: Context): This
+  def unify(p1: TypeParamRef, p2: TypeParamRef)(implicit ctx: Context): This
 
   /** A new constraint which is derived from this constraint by removing
    *  the type parameter `param` from the domain and replacing all top-level occurrences
@@ -109,7 +109,7 @@ abstract class Constraint extends Showable {
    *  approximation of it if that is needed to avoid cycles.
    *  Occurrences nested inside a refinement or prefix are not affected.
    */
-  def replace(param: PolyParam, tp: Type)(implicit ctx: Context): This
+  def replace(param: TypeParamRef, tp: Type)(implicit ctx: Context): This
 
   /** Is entry associated with `pt` removable? This is the case if
    *  all type parameters of the entry are associated with type variables
@@ -124,10 +124,10 @@ abstract class Constraint extends Showable {
   def domainPolys: List[PolyType]
 
   /** The polytype parameters constrained by this constraint */
-  def domainParams: List[PolyParam]
+  def domainParams: List[TypeParamRef]
 
   /** Check whether predicate holds for all parameters in constraint */
-  def forallParams(p: PolyParam => Boolean): Boolean
+  def forallParams(p: TypeParamRef => Boolean): Boolean
 
   /** Perform operation `op` on all typevars, or only on uninstantiated
    *  typevars, depending on whether `uninstOnly` is set or not.
@@ -143,6 +143,6 @@ abstract class Constraint extends Showable {
   /** Check that no constrained parameter contains itself as a bound */
   def checkNonCyclic()(implicit ctx: Context): Unit
 
-  /** Check that constraint only refers to PolyParams bound by itself */
+  /** Check that constraint only refers to TypeParamRefs bound by itself */
   def checkClosed()(implicit ctx: Context): Unit
 }
diff --git a/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala b/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
index 34662cbff..ab176b632 100644
--- a/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
+++ b/compiler/src/dotty/tools/dotc/core/ConstraintHandling.scala
@@ -47,7 +47,7 @@ trait ConstraintHandling {
    */
   protected var comparedPolyTypes: Set[PolyType] = Set.empty
 
-  private def addOneBound(param: PolyParam, bound: Type, isUpper: Boolean): Boolean =
+  private def addOneBound(param: TypeParamRef, bound: Type, isUpper: Boolean): Boolean =
     !constraint.contains(param) || {
       def occursIn(bound: Type): Boolean = {
         val b = bound.dealias
@@ -75,7 +75,7 @@ trait ConstraintHandling {
    *  If `isUpper` is true, ensure that `param <: `bound`, otherwise ensure
    *  that `param >: bound`.
    */
-  def narrowedBound(param: PolyParam, bound: Type, isUpper: Boolean)(implicit ctx: Context): TypeBounds = {
+  def narrowedBound(param: TypeParamRef, bound: Type, isUpper: Boolean)(implicit ctx: Context): TypeBounds = {
     val oldBounds @ TypeBounds(lo, hi) = constraint.nonParamBounds(param)
     val saved = homogenizeArgs
     homogenizeArgs = Config.alignArgsInAnd
@@ -85,7 +85,7 @@ trait ConstraintHandling {
     finally homogenizeArgs = saved
   }
 
-  protected def addUpperBound(param: PolyParam, bound: Type): Boolean = {
+  protected def addUpperBound(param: TypeParamRef, bound: Type): Boolean = {
     def description = i"constraint $param <: $bound to\n$constraint"
     if (bound.isRef(defn.NothingClass) && ctx.typerState.isGlobalCommittable) {
       def msg = s"!!! instantiated to Nothing: $param, constraint = ${constraint.show}"
@@ -101,7 +101,7 @@ trait ConstraintHandling {
     res
   }
 
-  protected def addLowerBound(param: PolyParam, bound: Type): Boolean = {
+  protected def addLowerBound(param: TypeParamRef, bound: Type): Boolean = {
     def description = i"constraint $param >: $bound to\n$constraint"
     constr.println(i"adding $description")
     val upper = constraint.upper(param)
@@ -112,7 +112,7 @@ trait ConstraintHandling {
     res
   }
 
-  protected def addLess(p1: PolyParam, p2: PolyParam): Boolean = {
+  protected def addLess(p1: TypeParamRef, p2: TypeParamRef): Boolean = {
     def description = i"ordering $p1 <: $p2 to\n$constraint"
     val res =
       if (constraint.isLess(p2, p1)) unify(p2, p1)
@@ -133,7 +133,7 @@ trait ConstraintHandling {
   /** Make p2 = p1, transfer all bounds of p2 to p1
    *  @pre  less(p1)(p2)
    */
-  private def unify(p1: PolyParam, p2: PolyParam): Boolean = {
+  private def unify(p1: TypeParamRef, p2: TypeParamRef): Boolean = {
     constr.println(s"unifying $p1 $p2")
     assert(constraint.isLess(p1, p2))
     val down = constraint.exclusiveLower(p2, p1)
@@ -191,7 +191,7 @@ trait ConstraintHandling {
    *  @return the instantiating type
    *  @pre `param` is in the constraint's domain.
    */
-  final def approximation(param: PolyParam, fromBelow: Boolean): Type = {
+  final def approximation(param: TypeParamRef, fromBelow: Boolean): Type = {
     val avoidParam = new TypeMap {
       override def stopAtStatic = true
       def apply(tp: Type) = mapOver {
@@ -235,7 +235,7 @@ trait ConstraintHandling {
    *  a lower bound instantiation can be a singleton type only if the upper bound
    *  is also a singleton type.
    */
-  def instanceType(param: PolyParam, fromBelow: Boolean): Type = {
+  def instanceType(param: TypeParamRef, fromBelow: Boolean): Type = {
     def upperBound = constraint.fullUpperBound(param)
     def isSingleton(tp: Type): Boolean = tp match {
       case tp: SingletonType => true
@@ -301,7 +301,7 @@ trait ConstraintHandling {
     }
 
   /** The current bounds of type parameter `param` */
-  final def bounds(param: PolyParam): TypeBounds = {
+  final def bounds(param: TypeParamRef): TypeBounds = {
     val e = constraint.entry(param)
     if (e.exists) e.bounds else param.binder.paramInfos(param.paramNum)
   }
@@ -315,7 +315,7 @@ trait ConstraintHandling {
       checkPropagated(i"initialized $pt") {
         constraint = constraint.add(pt, tvars)
         pt.paramNames.indices.forall { i =>
-          val param = PolyParam(pt, i)
+          val param = TypeParamRef(pt, i)
           val bounds = constraint.nonParamBounds(param)
           val lower = constraint.lower(param)
           val upper = constraint.upper(param)
@@ -328,7 +328,7 @@ trait ConstraintHandling {
     }
 
   /** Can `param` be constrained with new bounds? */
-  final def canConstrain(param: PolyParam): Boolean =
+  final def canConstrain(param: TypeParamRef): Boolean =
     !frozenConstraint && (constraint contains param)
 
   /** Add constraint `param <: bound` if `fromBelow` is false, `param >: bound` otherwise.
@@ -338,7 +338,7 @@ trait ConstraintHandling {
    *  not be AndTypes and lower bounds may not be OrTypes. This is assured by the
    *  way isSubType is organized.
    */
-  protected def addConstraint(param: PolyParam, bound: Type, fromBelow: Boolean): Boolean = {
+  protected def addConstraint(param: TypeParamRef, bound: Type, fromBelow: Boolean): Boolean = {
     def description = i"constr $param ${if (fromBelow) ">:" else "<:"} $bound:\n$constraint"
     //checkPropagated(s"adding $description")(true) // DEBUG in case following fails
     checkPropagated(s"added $description") {
@@ -360,7 +360,7 @@ trait ConstraintHandling {
         if (comparedPolyTypes.nonEmpty) {
           val approx = new ApproximatingTypeMap {
             def apply(t: Type): Type = t match {
-              case t @ PolyParam(pt: PolyType, n) if comparedPolyTypes contains pt =>
+              case t @ TypeParamRef(pt: PolyType, n) if comparedPolyTypes contains pt =>
                 val effectiveVariance = if (fromBelow) -variance else variance
                 val bounds = pt.paramInfos(n)
                 if (effectiveVariance > 0) bounds.lo
@@ -374,7 +374,7 @@ trait ConstraintHandling {
         }
         else tp
 
-      def addParamBound(bound: PolyParam) =
+      def addParamBound(bound: TypeParamRef) =
         if (fromBelow) addLess(bound, param) else addLess(param, bound)
 
       /** Drop all constrained parameters that occur at the toplevel in `bound` and
@@ -419,7 +419,7 @@ trait ConstraintHandling {
           else NoType
         case bound: TypeVar if constraint contains bound.origin =>
           prune(bound.underlying)
-        case bound: PolyParam =>
+        case bound: TypeParamRef =>
           constraint.entry(bound) match {
             case NoType => pruneLambdaParams(bound)
             case _: TypeBounds =>
@@ -434,7 +434,7 @@ trait ConstraintHandling {
       }
 
       try bound match {
-        case bound: PolyParam if constraint contains bound =>
+        case bound: TypeParamRef if constraint contains bound =>
           addParamBound(bound)
         case _ =>
           val pbound = prune(bound)
@@ -446,7 +446,7 @@ trait ConstraintHandling {
   }
 
   /** Instantiate `param` to `tp` if the constraint stays satisfiable */
-  protected def tryInstantiate(param: PolyParam, tp: Type): Boolean = {
+  protected def tryInstantiate(param: TypeParamRef, tp: Type): Boolean = {
     val saved = constraint
     constraint =
       if (addConstraint(param, tp, fromBelow = true) &&
@@ -461,7 +461,7 @@ trait ConstraintHandling {
       val saved = frozenConstraint
       frozenConstraint = true
       for (p <- constraint.domainParams) {
-        def check(cond: => Boolean, q: PolyParam, ordering: String, explanation: String): Unit =
+        def check(cond: => Boolean, q: TypeParamRef, ordering: String, explanation: String): Unit =
           assert(cond, i"propagation failure for $p $ordering $q: $explanation\n$msg")
         for (u <- constraint.upper(p))
           check(bounds(p).hi <:< bounds(u).hi, u, "<:", "upper bound not propagated")
diff --git a/compiler/src/dotty/tools/dotc/core/Definitions.scala b/compiler/src/dotty/tools/dotc/core/Definitions.scala
index 0c1d6521d..9360cabb1 100644
--- a/compiler/src/dotty/tools/dotc/core/Definitions.scala
+++ b/compiler/src/dotty/tools/dotc/core/Definitions.scala
@@ -242,7 +242,7 @@ class Definitions {
     lazy val Any_##       = enterMethod(AnyClass, nme.HASHHASH, ExprType(IntType), Final)
     lazy val Any_getClass = enterMethod(AnyClass, nme.getClass_, MethodType(Nil, ClassClass.typeRef.appliedTo(TypeBounds.empty)), Final)
     lazy val Any_isInstanceOf = enterT1ParameterlessMethod(AnyClass, nme.isInstanceOf_, _ => BooleanType, Final)
-    lazy val Any_asInstanceOf = enterT1ParameterlessMethod(AnyClass, nme.asInstanceOf_, PolyParam(_, 0), Final)
+    lazy val Any_asInstanceOf = enterT1ParameterlessMethod(AnyClass, nme.asInstanceOf_, TypeParamRef(_, 0), Final)
 
     def AnyMethods = List(Any_==, Any_!=, Any_equals, Any_hashCode,
       Any_toString, Any_##, Any_getClass, Any_isInstanceOf, Any_asInstanceOf)
@@ -268,7 +268,7 @@ class Definitions {
     lazy val Object_eq = enterMethod(ObjectClass, nme.eq, methOfAnyRef(BooleanType), Final)
     lazy val Object_ne = enterMethod(ObjectClass, nme.ne, methOfAnyRef(BooleanType), Final)
     lazy val Object_synchronized = enterPolyMethod(ObjectClass, nme.synchronized_, 1,
-        pt => MethodType(List(PolyParam(pt, 0)), PolyParam(pt, 0)), Final)
+        pt => MethodType(List(TypeParamRef(pt, 0)), TypeParamRef(pt, 0)), Final)
     lazy val Object_clone = enterMethod(ObjectClass, nme.clone_, MethodType(Nil, ObjectType), Protected)
     lazy val Object_finalize = enterMethod(ObjectClass, nme.finalize_, MethodType(Nil, UnitType), Protected)
     lazy val Object_notify = enterMethod(ObjectClass, nme.notify_, MethodType(Nil, UnitType))
@@ -283,7 +283,7 @@ class Definitions {
   /** Dummy method needed by elimByName */
   lazy val dummyApply = enterPolyMethod(
       OpsPackageClass, nme.dummyApply, 1,
-      pt => MethodType(List(FunctionOf(Nil, PolyParam(pt, 0))), PolyParam(pt, 0)))
+      pt => MethodType(List(FunctionOf(Nil, TypeParamRef(pt, 0))), TypeParamRef(pt, 0)))
 
   /** Method representing a throw */
   lazy val throwMethod = enterMethod(OpsPackageClass, nme.THROWkw,
diff --git a/compiler/src/dotty/tools/dotc/core/Mode.scala b/compiler/src/dotty/tools/dotc/core/Mode.scala
index 406a84af6..c835f677e 100644
--- a/compiler/src/dotty/tools/dotc/core/Mode.scala
+++ b/compiler/src/dotty/tools/dotc/core/Mode.scala
@@ -34,7 +34,7 @@ object Mode {
    *  context with typerstate and constraint. This is typically done when we
    *  cache the eligibility of implicits. Caching needs to be done across different constraints.
    *  Therefore, if TypevarsMissContext is set, subtyping becomes looser, and assumes
-   *  that PolyParams can be sub- and supertypes of anything. See TypeComparer.
+   *  that TypeParamRefs can be sub- and supertypes of anything. See TypeComparer.
    */
   val TypevarsMissContext = newMode(4, "TypevarsMissContext")
   val CheckCyclic = newMode(5, "CheckCyclic")
diff --git a/compiler/src/dotty/tools/dotc/core/OrderingConstraint.scala b/compiler/src/dotty/tools/dotc/core/OrderingConstraint.scala
index 3387f20e3..dbb952369 100644
--- a/compiler/src/dotty/tools/dotc/core/OrderingConstraint.scala
+++ b/compiler/src/dotty/tools/dotc/core/OrderingConstraint.scala
@@ -20,7 +20,7 @@ object OrderingConstraint {
   type ParamBounds = ArrayValuedMap[Type]
 
   /** The type of `OrderingConstraint#lowerMap`, `OrderingConstraint#upperMap` */
-  type ParamOrdering = ArrayValuedMap[List[PolyParam]]
+  type ParamOrdering = ArrayValuedMap[List[TypeParamRef]]
 
   /** A new constraint with given maps */
   private def newConstraint(boundsMap: ParamBounds, lowerMap: ParamOrdering, upperMap: ParamOrdering)(implicit ctx: Context) : OrderingConstraint = {
@@ -68,7 +68,7 @@ object OrderingConstraint {
     }
 
     def update(prev: OrderingConstraint, current: OrderingConstraint,
-        param: PolyParam, entry: T)(implicit ctx: Context): OrderingConstraint =
+        param: TypeParamRef, entry: T)(implicit ctx: Context): OrderingConstraint =
       update(prev, current, param.binder, param.paramNum, entry)
 
     def map(prev: OrderingConstraint, current: OrderingConstraint,
@@ -76,7 +76,7 @@ object OrderingConstraint {
      update(prev, current, poly, idx, f(apply(current, poly, idx)))
 
     def map(prev: OrderingConstraint, current: OrderingConstraint,
-        param: PolyParam, f: T => T)(implicit ctx: Context): OrderingConstraint =
+        param: TypeParamRef, f: T => T)(implicit ctx: Context): OrderingConstraint =
       map(prev, current, param.binder, param.paramNum, f)
   }
 
@@ -88,18 +88,18 @@ object OrderingConstraint {
     def initial = NoType
   }
 
-  val lowerLens = new ConstraintLens[List[PolyParam]] {
-    def entries(c: OrderingConstraint, poly: PolyType): Array[List[PolyParam]] =
+  val lowerLens = new ConstraintLens[List[TypeParamRef]] {
+    def entries(c: OrderingConstraint, poly: PolyType): Array[List[TypeParamRef]] =
       c.lowerMap(poly)
-    def updateEntries(c: OrderingConstraint, poly: PolyType, entries: Array[List[PolyParam]])(implicit ctx: Context): OrderingConstraint =
+    def updateEntries(c: OrderingConstraint, poly: PolyType, entries: Array[List[TypeParamRef]])(implicit ctx: Context): OrderingConstraint =
       newConstraint(c.boundsMap, c.lowerMap.updated(poly, entries), c.upperMap)
     def initial = Nil
   }
 
-  val upperLens = new ConstraintLens[List[PolyParam]] {
-    def entries(c: OrderingConstraint, poly: PolyType): Array[List[PolyParam]] =
+  val upperLens = new ConstraintLens[List[TypeParamRef]] {
+    def entries(c: OrderingConstraint, poly: PolyType): Array[List[TypeParamRef]] =
       c.upperMap(poly)
-    def updateEntries(c: OrderingConstraint, poly: PolyType, entries: Array[List[PolyParam]])(implicit ctx: Context): OrderingConstraint =
+    def updateEntries(c: OrderingConstraint, poly: PolyType, entries: Array[List[TypeParamRef]])(implicit ctx: Context): OrderingConstraint =
       newConstraint(c.boundsMap, c.lowerMap, c.upperMap.updated(poly, entries))
     def initial = Nil
   }
@@ -141,7 +141,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
     entries(paramCount(entries) + n)
 
   /** The `boundsMap` entry corresponding to `param` */
-  def entry(param: PolyParam): Type = {
+  def entry(param: TypeParamRef): Type = {
     val entries = boundsMap(param.binder)
     if (entries == null) NoType
     else entries(param.paramNum)
@@ -151,7 +151,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
 
   def contains(pt: PolyType): Boolean = boundsMap(pt) != null
 
-  def contains(param: PolyParam): Boolean = {
+  def contains(param: TypeParamRef): Boolean = {
     val entries = boundsMap(param.binder)
     entries != null && isBounds(entries(param.paramNum))
   }
@@ -167,43 +167,43 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
 
 // ---------- Dependency handling ----------------------------------------------
 
-  def lower(param: PolyParam): List[PolyParam] = lowerLens(this, param.binder, param.paramNum)
-  def upper(param: PolyParam): List[PolyParam] = upperLens(this, param.binder, param.paramNum)
+  def lower(param: TypeParamRef): List[TypeParamRef] = lowerLens(this, param.binder, param.paramNum)
+  def upper(param: TypeParamRef): List[TypeParamRef] = upperLens(this, param.binder, param.paramNum)
 
-  def minLower(param: PolyParam): List[PolyParam] = {
+  def minLower(param: TypeParamRef): List[TypeParamRef] = {
     val all = lower(param)
     all.filterNot(p => all.exists(isLess(p, _)))
   }
 
-  def minUpper(param: PolyParam): List[PolyParam] = {
+  def minUpper(param: TypeParamRef): List[TypeParamRef] = {
     val all = upper(param)
     all.filterNot(p => all.exists(isLess(_, p)))
   }
 
-  def exclusiveLower(param: PolyParam, butNot: PolyParam): List[PolyParam] =
+  def exclusiveLower(param: TypeParamRef, butNot: TypeParamRef): List[TypeParamRef] =
     lower(param).filterNot(isLess(_, butNot))
 
-  def exclusiveUpper(param: PolyParam, butNot: PolyParam): List[PolyParam] =
+  def exclusiveUpper(param: TypeParamRef, butNot: TypeParamRef): List[TypeParamRef] =
     upper(param).filterNot(isLess(butNot, _))
 
-// ---------- Info related to PolyParams -------------------------------------------
+// ---------- Info related to TypeParamRefs -------------------------------------------
 
-  def isLess(param1: PolyParam, param2: PolyParam): Boolean =
+  def isLess(param1: TypeParamRef, param2: TypeParamRef): Boolean =
     upper(param1).contains(param2)
 
-  def nonParamBounds(param: PolyParam): TypeBounds =
+  def nonParamBounds(param: TypeParamRef): TypeBounds =
     entry(param).asInstanceOf[TypeBounds]
 
-  def fullLowerBound(param: PolyParam)(implicit ctx: Context): Type =
+  def fullLowerBound(param: TypeParamRef)(implicit ctx: Context): Type =
     (nonParamBounds(param).lo /: minLower(param))(_ | _)
 
-  def fullUpperBound(param: PolyParam)(implicit ctx: Context): Type =
+  def fullUpperBound(param: TypeParamRef)(implicit ctx: Context): Type =
     (nonParamBounds(param).hi /: minUpper(param))(_ & _)
 
-  def fullBounds(param: PolyParam)(implicit ctx: Context): TypeBounds =
+  def fullBounds(param: TypeParamRef)(implicit ctx: Context): TypeBounds =
     nonParamBounds(param).derivedTypeBounds(fullLowerBound(param), fullUpperBound(param))
 
-  def typeVarOfParam(param: PolyParam): Type = {
+  def typeVarOfParam(param: TypeParamRef): Type = {
     val entries = boundsMap(param.binder)
     if (entries == null) NoType
     else {
@@ -219,8 +219,8 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
    *    Q <: tp  implies  Q <: P      and isUpper = true, or
    *    tp <: Q  implies  P <: Q      and isUpper = false
    */
-  def dependentParams(tp: Type, isUpper: Boolean): List[PolyParam] = tp match {
-    case param: PolyParam if contains(param) =>
+  def dependentParams(tp: Type, isUpper: Boolean): List[TypeParamRef] = tp match {
+    case param: TypeParamRef if contains(param) =>
       param :: (if (isUpper) upper(param) else lower(param))
     case tp: AndOrType =>
       val ps1 = dependentParams(tp.tp1, isUpper)
@@ -255,9 +255,9 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
    *
    *  @param isUpper   If true, `bound` is an upper bound, else a lower bound.
    */
-  private def stripParams(tp: Type, paramBuf: mutable.ListBuffer[PolyParam],
+  private def stripParams(tp: Type, paramBuf: mutable.ListBuffer[TypeParamRef],
       isUpper: Boolean)(implicit ctx: Context): Type = tp match {
-    case param: PolyParam if contains(param) =>
+    case param: TypeParamRef if contains(param) =>
       if (!paramBuf.contains(param)) paramBuf += param
       NoType
     case tp: AndOrType if isUpper == tp.isAnd =>
@@ -275,7 +275,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
    *  A top or bottom type if type consists only of dependent parameters.
    *  @param isUpper   If true, `bound` is an upper bound, else a lower bound.
    */
-  private def normalizedType(tp: Type, paramBuf: mutable.ListBuffer[PolyParam],
+  private def normalizedType(tp: Type, paramBuf: mutable.ListBuffer[TypeParamRef],
       isUpper: Boolean)(implicit ctx: Context): Type =
     stripParams(tp, paramBuf, isUpper)
       .orElse(if (isUpper) defn.AnyType else defn.NothingType)
@@ -295,10 +295,10 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
    */
   private def init(poly: PolyType)(implicit ctx: Context): This = {
     var current = this
-    val loBuf, hiBuf = new mutable.ListBuffer[PolyParam]
+    val loBuf, hiBuf = new mutable.ListBuffer[TypeParamRef]
     var i = 0
     while (i < poly.paramNames.length) {
-      val param = PolyParam(poly, i)
+      val param = TypeParamRef(poly, i)
       val bounds = nonParamBounds(param)
       val lo = normalizedType(bounds.lo, loBuf, isUpper = false)
       val hi = normalizedType(bounds.hi, hiBuf, isUpper = true)
@@ -318,7 +318,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
   /** Add the fact `param1 <: param2` to the constraint `current` and propagate
    *  `<:<` relationships between parameters ("edges") but not bounds.
    */
-  private def order(current: This, param1: PolyParam, param2: PolyParam)(implicit ctx: Context): This =
+  private def order(current: This, param1: TypeParamRef, param2: TypeParamRef)(implicit ctx: Context): This =
     if (param1 == param2 || current.isLess(param1, param2)) this
     else {
       assert(contains(param1))
@@ -330,10 +330,10 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
       current2
     }
 
-  def addLess(param1: PolyParam, param2: PolyParam)(implicit ctx: Context): This =
+  def addLess(param1: TypeParamRef, param2: TypeParamRef)(implicit ctx: Context): This =
     order(this, param1, param2)
 
-  def updateEntry(current: This, param: PolyParam, tp: Type)(implicit ctx: Context): This = {
+  def updateEntry(current: This, param: TypeParamRef, tp: Type)(implicit ctx: Context): This = {
     var current1 = boundsLens.update(this, current, param, tp)
     tp match {
       case TypeBounds(lo, hi) =>
@@ -346,10 +346,10 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
     current1
   }
 
-  def updateEntry(param: PolyParam, tp: Type)(implicit ctx: Context): This =
+  def updateEntry(param: TypeParamRef, tp: Type)(implicit ctx: Context): This =
     updateEntry(this, param, tp)
 
-  def unify(p1: PolyParam, p2: PolyParam)(implicit ctx: Context): This = {
+  def unify(p1: TypeParamRef, p2: TypeParamRef)(implicit ctx: Context): This = {
     val p1Bounds = (nonParamBounds(p1) & nonParamBounds(p2)).substParam(p2, p1)
     updateEntry(p1, p1Bounds).replace(p2, p1)
   }
@@ -381,7 +381,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
    *  would not find out where we need to approximate. Occurrences of parameters
    *  that are not top-level are not affected.
    */
-  def replace(param: PolyParam, tp: Type)(implicit ctx: Context): OrderingConstraint = {
+  def replace(param: TypeParamRef, tp: Type)(implicit ctx: Context): OrderingConstraint = {
     val replacement = tp.dealias.stripTypeVar
     if (param == replacement) this
     else {
@@ -389,7 +389,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
       val poly = param.binder
       val idx = param.paramNum
 
-      def removeParam(ps: List[PolyParam]) =
+      def removeParam(ps: List[TypeParamRef]) =
         ps.filterNot(p => p.binder.eq(poly) && p.paramNum == idx)
 
       def replaceParam(tp: Type, atPoly: PolyType, atIdx: Int): Type = tp match {
@@ -404,7 +404,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
           }
 
           def normalize(tp: Type, isUpper: Boolean): Type = tp match {
-            case p: PolyParam if p.binder == atPoly && p.paramNum == atIdx =>
+            case p: TypeParamRef if p.binder == atPoly && p.paramNum == atIdx =>
               if (isUpper) defn.AnyType else defn.NothingType
             case tp: AndOrType if isUpper == tp.isAnd => recombine(tp, normalize, isUpper)
             case _ => tp
@@ -434,7 +434,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
 
   def remove(pt: PolyType)(implicit ctx: Context): This = {
     def removeFromOrdering(po: ParamOrdering) = {
-      def removeFromBoundss(key: PolyType, bndss: Array[List[PolyParam]]): Array[List[PolyParam]] = {
+      def removeFromBoundss(key: PolyType, bndss: Array[List[TypeParamRef]]): Array[List[TypeParamRef]] = {
         val bndss1 = bndss.map(_.filterConserve(_.binder ne pt))
         if (bndss.corresponds(bndss1)(_ eq _)) bndss else bndss1
       }
@@ -458,17 +458,17 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
 
   def domainPolys: List[PolyType] = boundsMap.keys
 
-  def domainParams: List[PolyParam] =
+  def domainParams: List[TypeParamRef] =
     for {
       (poly, entries) <- boundsMap.toList
       n <- 0 until paramCount(entries)
       if entries(n).exists
-    } yield PolyParam(poly, n)
+    } yield TypeParamRef(poly, n)
 
-  def forallParams(p: PolyParam => Boolean): Boolean = {
+  def forallParams(p: TypeParamRef => Boolean): Boolean = {
     boundsMap.foreachBinding { (poly, entries) =>
       for (i <- 0 until paramCount(entries))
-        if (isBounds(entries(i)) && !p(PolyParam(poly, i))) return false
+        if (isBounds(entries(i)) && !p(TypeParamRef(poly, i))) return false
     }
     true
   }
@@ -503,7 +503,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
       merged
     }
 
-    def mergeParams(ps1: List[PolyParam], ps2: List[PolyParam]) =
+    def mergeParams(ps1: List[TypeParamRef], ps2: List[TypeParamRef]) =
       (ps1 /: ps2)((ps1, p2) => if (ps1.contains(p2)) ps1 else p2 :: ps1)
 
     def mergeEntries(e1: Type, e2: Type): Type = e1 match {
@@ -532,13 +532,13 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
   }
 
   override def checkClosed()(implicit ctx: Context): Unit = {
-    def isFreePolyParam(tp: Type) = tp match {
-      case PolyParam(binder: PolyType, _) => !contains(binder)
+    def isFreeTypeParamRef(tp: Type) = tp match {
+      case TypeParamRef(binder: PolyType, _) => !contains(binder)
       case _ => false
     }
     def checkClosedType(tp: Type, where: String) =
       if (tp != null)
-        assert(!tp.existsPart(isFreePolyParam), i"unclosed constraint: $this refers to $tp in $where")
+        assert(!tp.existsPart(isFreeTypeParamRef), i"unclosed constraint: $this refers to $tp in $where")
     boundsMap.foreachBinding((_, tps) => tps.foreach(checkClosedType(_, "bounds")))
     lowerMap.foreachBinding((_, paramss) => paramss.foreach(_.foreach(checkClosedType(_, "lower"))))
     upperMap.foreachBinding((_, paramss) => paramss.foreach(_.foreach(checkClosedType(_, "upper"))))
@@ -567,7 +567,7 @@ class OrderingConstraint(private val boundsMap: ParamBounds,
   def checkNonCyclic()(implicit ctx: Context): Unit =
     domainParams.foreach(checkNonCyclic)
 
-  private def checkNonCyclic(param: PolyParam)(implicit ctx: Context): Unit =
+  private def checkNonCyclic(param: TypeParamRef)(implicit ctx: Context): Unit =
     assert(!isLess(param, param), i"cyclic constraint involving $param in $this")
 
 // ---------- toText -----------------------------------------------------
diff --git a/compiler/src/dotty/tools/dotc/core/TypeApplications.scala b/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
index 931f0dc74..77767a38c 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
@@ -163,15 +163,15 @@ object TypeApplications {
   class Reducer(tycon: PolyType, args: List[Type])(implicit ctx: Context) extends TypeMap {
     private var available = (0 until args.length).toSet
     var allReplaced = true
-    def hasWildcardArg(p: PolyParam) =
+    def hasWildcardArg(p: TypeParamRef) =
       p.binder == tycon && args(p.paramNum).isInstanceOf[TypeBounds]
-    def canReduceWildcard(p: PolyParam) =
+    def canReduceWildcard(p: TypeParamRef) =
       !ctx.mode.is(Mode.AllowLambdaWildcardApply) || available.contains(p.paramNum)
     def apply(t: Type) = t match {
-      case t @ TypeAlias(p: PolyParam) if hasWildcardArg(p) && canReduceWildcard(p) =>
+      case t @ TypeAlias(p: TypeParamRef) if hasWildcardArg(p) && canReduceWildcard(p) =>
         available -= p.paramNum
         args(p.paramNum)
-      case p: PolyParam if p.binder == tycon =>
+      case p: TypeParamRef if p.binder == tycon =>
         args(p.paramNum) match {
           case TypeBounds(lo, hi) =>
             if (ctx.mode.is(Mode.AllowLambdaWildcardApply)) { allReplaced = false; p }
diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
index 9f4db5edd..a4ea1d28f 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -280,7 +280,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
         case _ =>
       }
       thirdTry(tp1, tp2)
-    case tp1: PolyParam =>
+    case tp1: TypeParamRef =>
       def flagNothingBound = {
         if (!frozenConstraint && tp2.isRef(defn.NothingClass) && state.isGlobalCommittable) {
           def msg = s"!!! instantiated to Nothing: $tp1, constraint = ${constraint.show}"
@@ -289,13 +289,13 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
         }
         true
       }
-      def comparePolyParam =
+      def compareTypeParamRef =
         ctx.mode.is(Mode.TypevarsMissContext) ||
         isSubTypeWhenFrozen(bounds(tp1).hi, tp2) || {
           if (canConstrain(tp1)) addConstraint(tp1, tp2, fromBelow = false) && flagNothingBound
           else thirdTry(tp1, tp2)
         }
-      comparePolyParam
+      compareTypeParamRef
     case tp1: ThisType =>
       val cls1 = tp1.cls
       tp2 match {
@@ -373,8 +373,8 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
   private def thirdTry(tp1: Type, tp2: Type): Boolean = tp2 match {
     case tp2: NamedType =>
       thirdTryNamed(tp1, tp2)
-    case tp2: PolyParam =>
-      def comparePolyParam =
+    case tp2: TypeParamRef =>
+      def compareTypeParamRef =
         (ctx.mode is Mode.TypevarsMissContext) || {
         val alwaysTrue =
           // The following condition is carefully formulated to catch all cases
@@ -391,7 +391,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
           else fourthTry(tp1, tp2)
         }
       }
-      comparePolyParam
+      compareTypeParamRef
     case tp2: RefinedType =>
       def compareRefinedSlow: Boolean = {
         val name2 = tp2.refinedName
@@ -618,7 +618,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
     def isMatchingApply(tp1: Type): Boolean = tp1 match {
       case HKApply(tycon1, args1) =>
         tycon1.dealias match {
-          case tycon1: PolyParam =>
+          case tycon1: TypeParamRef =>
             (tycon1 == tycon2 ||
              canConstrain(tycon1) && tryInstantiate(tycon1, tycon2)) &&
             isSubArgs(args1, args2, tparams)
@@ -646,7 +646,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
      *  and the resulting type application is a supertype of `tp1`,
      *  or fallback to fourthTry.
      */
-    def canInstantiate(tycon2: PolyParam): Boolean = {
+    def canInstantiate(tycon2: TypeParamRef): Boolean = {
 
       /** Let
        *
@@ -672,7 +672,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
               tycon1b = PolyType(tparams1.map(_.paramName))(
                 tl => tparams1.map(tparam => tl.lifted(tparams, tparam.paramInfo).bounds),
                 tl => tycon1a.appliedTo(args1.take(lengthDiff) ++
-                        tparams1.indices.toList.map(PolyParam(tl, _))))
+                        tparams1.indices.toList.map(TypeParamRef(tl, _))))
             (ctx.mode.is(Mode.TypevarsMissContext) ||
               tryInstantiate(tycon2, tycon1b.ensureHK)) &&
               isSubType(tp1, tycon1b.appliedTo(args2))
@@ -725,7 +725,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
         fallback(tycon2bounds.lo)
 
     tycon2 match {
-      case param2: PolyParam =>
+      case param2: TypeParamRef =>
         isMatchingApply(tp1) || {
           if (canConstrain(param2)) canInstantiate(param2)
           else compareLower(bounds(param2), tyconIsTypeRef = false)
@@ -746,7 +746,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
    */
   def compareHkApply1(tp1: HKApply, tycon1: Type, args1: List[Type], tp2: Type): Boolean =
     tycon1 match {
-      case param1: PolyParam =>
+      case param1: TypeParamRef =>
         def canInstantiate = tp2 match {
           case AppliedType(tycon2, args2) =>
             tryInstantiate(param1, tycon2.ensureHK) && isSubArgs(args1, args2, tycon2.typeParams)
@@ -806,7 +806,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
     def fix(tp: Type): Type = tp.stripTypeVar match {
       case tp: RecType => fix(tp.parent).substRecThis(tp, anchor)
       case tp @ RefinedType(parent, rname, rinfo) => tp.derivedRefinedType(fix(parent), rname, rinfo)
-      case tp: PolyParam => fixOrElse(bounds(tp).hi, tp)
+      case tp: TypeParamRef => fixOrElse(bounds(tp).hi, tp)
       case tp: TypeProxy => fixOrElse(tp.underlying, tp)
       case tp: AndOrType => tp.derivedAndOrType(fix(tp.tp1), fix(tp.tp2))
       case tp => tp
@@ -967,7 +967,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
 
   /** Defer constraining type variables when compared against prototypes */
   def isMatchedByProto(proto: ProtoType, tp: Type) = tp.stripTypeVar match {
-    case tp: PolyParam if constraint contains tp => true
+    case tp: TypeParamRef if constraint contains tp => true
     case _ => proto.isMatchedBy(tp)
   }
 
@@ -978,7 +978,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
    *  type variable with (the corresponding type in) `tp2` instead.
    */
   private def isCappable(tp: Type): Boolean = tp match {
-    case tp: PolyParam => constraint contains tp
+    case tp: TypeParamRef => constraint contains tp
     case tp: TypeProxy => isCappable(tp.underlying)
     case tp: AndOrType => isCappable(tp.tp1) || isCappable(tp.tp2)
     case _ => false
@@ -1424,7 +1424,7 @@ class TypeComparer(initctx: Context) extends DotClass with ConstraintHandling {
   def showGoal(tp1: Type, tp2: Type)(implicit ctx: Context) = {
     println(ex"assertion failure for $tp1 <:< $tp2, frozen = $frozenConstraint")
     def explainPoly(tp: Type) = tp match {
-      case tp: PolyParam => ctx.echo(s"polyparam ${tp.show} found in ${tp.binder.show}")
+      case tp: TypeParamRef => ctx.echo(s"TypeParamRef ${tp.show} found in ${tp.binder.show}")
       case tp: TypeRef if tp.symbol.exists => ctx.echo(s"typeref ${tp.show} found in ${tp.symbol.owner.show}")
       case tp: TypeVar => ctx.echo(s"typevar ${tp.show}, origin = ${tp.origin}")
       case _ => ctx.echo(s"${tp.show} is a ${tp.getClass}")
@@ -1503,7 +1503,7 @@ class ExplainingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
       super.glb(tp1, tp2)
     }
 
-  override def addConstraint(param: PolyParam, bound: Type, fromBelow: Boolean): Boolean =
+  override def addConstraint(param: TypeParamRef, bound: Type, fromBelow: Boolean): Boolean =
     traceIndented(i"add constraint $param ${if (fromBelow) ">:" else "<:"} $bound $frozenConstraint, constraint = ${ctx.typerState.constraint}") {
       super.addConstraint(param, bound, fromBelow)
     }
diff --git a/compiler/src/dotty/tools/dotc/core/TypeErasure.scala b/compiler/src/dotty/tools/dotc/core/TypeErasure.scala
index b716318c1..07d613c57 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeErasure.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeErasure.scala
@@ -28,7 +28,7 @@ import scala.annotation.tailrec
  *  WildcardType
  *  ErrorType
  *
- *  only for isInstanceOf, asInstanceOf: PolyType, PolyParam, TypeBounds
+ *  only for isInstanceOf, asInstanceOf: PolyType, TypeParamRef, TypeBounds
  *
  */
 object TypeErasure {
@@ -204,7 +204,7 @@ object TypeErasure {
       !tp.symbol.isClass &&
       !tp.derivesFrom(defn.ObjectClass) &&
       !tp.symbol.is(JavaDefined)
-    case tp: PolyParam =>
+    case tp: TypeParamRef =>
       !tp.derivesFrom(defn.ObjectClass) &&
       !tp.binder.resultType.isInstanceOf[JavaMethodType]
     case tp: TypeAlias => isUnboundedGeneric(tp.alias)
@@ -304,7 +304,7 @@ object TypeErasure {
         case _: ClassInfo => true
         case _ => false
       }
-    case tp: PolyParam => false
+    case tp: TypeParamRef => false
     case tp: TypeProxy => hasStableErasure(tp.superType)
     case tp: AndOrType => hasStableErasure(tp.tp1) && hasStableErasure(tp.tp2)
     case _ => false
diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
index 3d2906320..9593bfe93 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeOps.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -157,7 +157,7 @@ trait TypeOps { this: Context => // TODO: Make standalone object.
           tp2
         case tp1 => tp1
       }
-    case tp: PolyParam =>
+    case tp: TypeParamRef =>
       typerState.constraint.typeVarOfParam(tp) orElse tp
     case  _: ThisType | _: BoundType | NoPrefix =>
       tp
diff --git a/compiler/src/dotty/tools/dotc/core/TyperState.scala b/compiler/src/dotty/tools/dotc/core/TyperState.scala
index 206438d86..08bef86b7 100644
--- a/compiler/src/dotty/tools/dotc/core/TyperState.scala
+++ b/compiler/src/dotty/tools/dotc/core/TyperState.scala
@@ -42,7 +42,7 @@ class TyperState(r: Reporter) extends DotClass with Showable {
    */
   def instType(tvar: TypeVar)(implicit ctx: Context): Type = constraint.entry(tvar.origin) match {
     case _: TypeBounds => NoType
-    case tp: PolyParam =>
+    case tp: TypeParamRef =>
       var tvar1 = constraint.typeVarOfParam(tp)
       if (tvar1.exists) tvar1 else tp
     case tp => tp
diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 5629668c1..59c84910b 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -57,7 +57,7 @@ object Types {
    *        |              |                +--- TermParamRef
    *        |              |                +----RecThis
    *        |              |                +--- SkolemType
-   *        |              +- PolyParam
+   *        |              +- TypeParamRef
    *        |              +- RefinedOrRecType -+-- RefinedType
    *        |              |                   -+-- RecType
    *        |              +- HKApply
@@ -446,7 +446,7 @@ object Types {
             if mt.paramInfos.isEmpty && (tp.symbol is Stable) => mt.resultType
             case tp1 => tp1
           })
-        case tp: PolyParam =>
+        case tp: TypeParamRef =>
           goParam(tp)
         case tp: RecType =>
           goRec(tp)
@@ -563,7 +563,7 @@ object Types {
           // loadClassWithPrivateInnerAndSubSelf in ShowClassTests
           go(tp.cls.typeRef) orElse d
       }
-      def goParam(tp: PolyParam) = {
+      def goParam(tp: TypeParamRef) = {
         val next = tp.underlying
         ctx.typerState.constraint.entry(tp) match {
           case bounds: TypeBounds if bounds ne next =>
@@ -1180,8 +1180,8 @@ object Types {
     final def substDealias(from: List[Symbol], to: List[Type])(implicit ctx: Context): Type =
       ctx.substDealias(this, from, to, null)
 
-    /** Substitute all types of the form `PolyParam(from, N)` by
-     *  `PolyParam(to, N)`.
+    /** Substitute all types of the form `TypeParamRef(from, N)` by
+     *  `TypeParamRef(to, N)`.
      */
     final def subst(from: BindingType, to: BindingType)(implicit ctx: Context): Type =
       ctx.subst(this, from, to, null)
@@ -2673,7 +2673,7 @@ object Types {
 
     def isDependent(implicit ctx: Context) = true
     def isParamDependent(implicit ctx: Context) = true
-    def newParamRef(n: Int) = PolyParam(this, n)
+    def newParamRef(n: Int) = TypeParamRef(this, n)
 
     /** Instantiate parameter bounds by substituting parameters with given arguments */
     final def instantiateBounds(argTypes: List[Type])(implicit ctx: Context): List[Type] =
@@ -2709,7 +2709,7 @@ object Types {
       case that: PolyType =>
         val shift = new TypeMap {
           def apply(t: Type) = t match {
-            case PolyParam(`that`, n) => PolyParam(that, n + paramNames.length)
+            case TypeParamRef(`that`, n) => TypeParamRef(that, n + paramNames.length)
             case t => mapOver(t)
           }
         }
@@ -2742,11 +2742,6 @@ object Types {
     override def computeHash = doHash(paramNames, resType, paramInfos)
   }
 
-  object PolyParam {
-    def apply(pt: PolyType, n: Int) = new TypeParamRef(pt, n)
-    def unapply(poly: PolyParam) = Some(poly.binder, poly.paramNum)
-  }
-
   object PolyType {
     def apply(paramNames: List[TypeName])(
         paramInfosExp: PolyType => List[TypeBounds],
@@ -2772,8 +2767,8 @@ object Types {
     def paramInfoAsSeenFrom(pre: Type)(implicit ctx: Context): Type = paramInfo
     def paramInfoOrCompleter(implicit ctx: Context): Type = paramInfo
     def paramVariance(implicit ctx: Context): Int = tl.paramNames(n).variance
-    def toArg: Type = PolyParam(tl, n)
-    def paramRef(implicit ctx: Context): Type = PolyParam(tl, n)
+    def toArg: Type = TypeParamRef(tl, n)
+    def paramRef(implicit ctx: Context): Type = TypeParamRef(tl, n)
   }
 
   /** A higher kinded type application `C[T_1, ..., T_n]` */
@@ -2826,7 +2821,7 @@ object Types {
     protected def checkInst(implicit ctx: Context): this.type = {
       def check(tycon: Type): Unit = tycon.stripTypeVar match {
         case tycon: TypeRef if !tycon.symbol.isClass =>
-        case _: PolyParam | _: ErrorType | _: WildcardType =>
+        case _: TypeParamRef | _: ErrorType | _: WildcardType =>
         case _: PolyType =>
           assert(args.exists(_.isInstanceOf[TypeBounds]), s"unreduced type apply: $this")
         case tycon: AnnotatedType =>
@@ -2846,7 +2841,7 @@ object Types {
       unique(new CachedHKApply(tycon, args)).checkInst
   }
 
-  // ----- Bound types: MethodParam, PolyParam --------------------------
+  // ----- Bound types: MethodParam, TypeParamRef --------------------------
 
   abstract class BoundType extends CachedProxyType with ValueType {
     type BT <: Type
@@ -2907,8 +2902,6 @@ object Types {
     }
   }
 
-  type PolyParam = TypeParamRef
-
   /** a self-reference to an enclosing recursive type. */
   case class RecThis(binder: RecType) extends BoundType with SingletonType {
     type BT = RecType
@@ -2977,7 +2970,7 @@ object Types {
    *  `owningTree` and `owner` are used to determine whether a type-variable can be instantiated
    *  at some given point. See `Inferencing#interpolateUndetVars`.
    */
-  final class TypeVar(val origin: PolyParam, creatorState: TyperState, val bindingTree: untpd.Tree, val owner: Symbol) extends CachedProxyType with ValueType {
+  final class TypeVar(val origin: TypeParamRef, creatorState: TyperState, val bindingTree: untpd.Tree, val owner: Symbol) extends CachedProxyType with ValueType {
 
     /** The permanent instance type of the variable, or NoType is none is given yet */
     private[core] var inst: Type = NoType
@@ -3854,7 +3847,7 @@ object Types {
             apply(x, tp.underlying)
           case tp: TermParamRef =>
             apply(x, tp.underlying)
-          case tp: PolyParam =>
+          case tp: TypeParamRef =>
             apply(x, tp.underlying)
           case _ =>
             foldOver(x, tp)
diff --git a/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala b/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
index a9cd9be1d..0b361f1f4 100644
--- a/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
+++ b/compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala
@@ -259,7 +259,7 @@ class TreePickler(pickler: TastyPickler) {
     case tpe: MethodType if richTypes =>
       writeByte(METHODtype)
       pickleMethodic(tpe.resultType, tpe.paramNames, tpe.paramInfos)
-    case tpe: PolyParam =>
+    case tpe: TypeParamRef =>
       if (!pickleParamType(tpe))
       // TODO figure out why this case arises in e.g. pickling AbstractFileReader.
         ctx.typerState.constraint.entry(tpe) match {
diff --git a/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala b/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
index 067fd6076..c4ff3898c 100644
--- a/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
+++ b/compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
@@ -283,7 +283,7 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table, posUnpickle
               result
             case PARAMtype =>
               readTypeRef() match {
-                case binder: PolyType => PolyParam(binder, readNat())
+                case binder: PolyType => TypeParamRef(binder, readNat())
                 case binder: MethodType => binder.newParamRef(readNat())
               }
             case CLASSconst =>
diff --git a/compiler/src/dotty/tools/dotc/printing/Formatting.scala b/compiler/src/dotty/tools/dotc/printing/Formatting.scala
index 760b22689..e8fa45403 100644
--- a/compiler/src/dotty/tools/dotc/printing/Formatting.scala
+++ b/compiler/src/dotty/tools/dotc/printing/Formatting.scala
@@ -107,7 +107,7 @@ object Formatting {
     else nonSensicalStartTag + str + nonSensicalEndTag
   }
 
-  private type Recorded = AnyRef /*Symbol | PolyParam*/
+  private type Recorded = AnyRef /*Symbol | TypeParamRef*/
 
   private class Seen extends mutable.HashMap[String, List[Recorded]] {
 
@@ -135,8 +135,8 @@ object Formatting {
       if ((sym is ModuleClass) && sym.sourceModule.exists) simpleNameString(sym.sourceModule)
       else seen.record(super.simpleNameString(sym), sym)
 
-    override def polyParamNameString(param: PolyParam): String =
-      seen.record(super.polyParamNameString(param), param)
+    override def TypeParamRefNameString(param: TypeParamRef): String =
+      seen.record(super.TypeParamRefNameString(param), param)
   }
 
   /** Create explanation for single `Recorded` type or symbol */
@@ -161,7 +161,7 @@ object Formatting {
     }
 
     entry match {
-      case param: PolyParam =>
+      case param: TypeParamRef =>
         s"is a type variable${addendum("constraint", ctx.typeComparer.bounds(param))}"
       case sym: Symbol =>
         s"is a ${ctx.printer.kindString(sym)}${sym.showExtendedLocation}${addendum("bounds", sym.info)}"
@@ -175,7 +175,7 @@ object Formatting {
     */
   private def explanations(seen: Seen)(implicit ctx: Context): String = {
     def needsExplanation(entry: Recorded) = entry match {
-      case param: PolyParam => ctx.typerState.constraint.contains(param)
+      case param: TypeParamRef => ctx.typerState.constraint.contains(param)
       case _ => false
     }
 
diff --git a/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala b/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
index a4f9921db..94621056f 100644
--- a/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
+++ b/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
@@ -182,8 +182,8 @@ class PlainPrinter(_ctx: Context) extends Printer {
           "]" ~ (" => " provided !tp.resultType.isInstanceOf[MethodType]) ~
           toTextGlobal(tp.resultType)
         }
-      case tp: PolyParam =>
-        polyParamNameString(tp) ~ lambdaHash(tp.binder)
+      case tp: TypeParamRef =>
+        TypeParamRefNameString(tp) ~ lambdaHash(tp.binder)
       case AnnotatedType(tpe, annot) =>
         toTextLocal(tpe) ~ " " ~ toText(annot)
       case HKApply(tycon, args) =>
@@ -206,10 +206,10 @@ class PlainPrinter(_ctx: Context) extends Printer {
     }
   }.close
 
-  protected def polyParamNameString(name: TypeName): String = name.toString
+  protected def TypeParamRefNameString(name: TypeName): String = name.toString
 
-  protected def polyParamNameString(param: PolyParam): String =
-    polyParamNameString(param.binder.paramNames(param.paramNum))
+  protected def TypeParamRefNameString(param: TypeParamRef): String =
+    TypeParamRefNameString(param.binder.paramNames(param.paramNum))
 
   /** The name of the symbol without a unique id. Under refined printing,
    *  the decoded original name.
diff --git a/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala b/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
index 8a33472b8..488e66d8d 100644
--- a/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
+++ b/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
@@ -604,7 +604,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
   def optText[T >: Untyped](tree: List[Tree[T]])(encl: Text => Text): Text =
     if (tree.exists(!_.isEmpty)) encl(blockText(tree)) else ""
 
-  override protected def polyParamNameString(name: TypeName): String =
+  override protected def TypeParamRefNameString(name: TypeName): String =
     name.unexpandedName.toString
 
   override protected def treatAsTypeParam(sym: Symbol): Boolean = sym is TypeParam
diff --git a/compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala b/compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala
index d608dc7c4..28ce9aa5a 100644
--- a/compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala
+++ b/compiler/src/dotty/tools/dotc/sbt/ExtractDependencies.scala
@@ -258,7 +258,7 @@ private class ExtractDependenciesCollector(implicit val ctx: Context) extends tp
           traverse(tp.underlying)
         case tp: TermParamRef =>
           traverse(tp.underlying)
-        case tp: PolyParam =>
+        case tp: TypeParamRef =>
           traverse(tp.underlying)
         case _ =>
           traverseChildren(tp)
diff --git a/compiler/src/dotty/tools/dotc/transform/FullParameterization.scala b/compiler/src/dotty/tools/dotc/transform/FullParameterization.scala
index dd318861a..0b9ec9085 100644
--- a/compiler/src/dotty/tools/dotc/transform/FullParameterization.scala
+++ b/compiler/src/dotty/tools/dotc/transform/FullParameterization.scala
@@ -113,7 +113,7 @@ trait FullParameterization {
     /** Replace class type parameters by the added type parameters of the polytype `pt` */
     def mapClassParams(tp: Type, pt: PolyType): Type = {
       val classParamsRange = (mtparamCount until mtparamCount + ctparams.length).toList
-      tp.substDealias(ctparams, classParamsRange map (PolyParam(pt, _)))
+      tp.substDealias(ctparams, classParamsRange map (TypeParamRef(pt, _)))
     }
 
     /** The bounds for the added type parameters of the polytype `pt` */
diff --git a/compiler/src/dotty/tools/dotc/transform/TreeChecker.scala b/compiler/src/dotty/tools/dotc/transform/TreeChecker.scala
index dd4d95257..dde037938 100644
--- a/compiler/src/dotty/tools/dotc/transform/TreeChecker.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TreeChecker.scala
@@ -287,7 +287,7 @@ class TreeChecker extends Phase with SymTransformer {
       res
     }
 
-    /** Check that PolyParams and MethodParams refer to an enclosing type */
+    /** Check that TypeParamRefs and MethodParams refer to an enclosing type */
     def checkNoOrphans(tp: Type)(implicit ctx: Context) = new TypeMap() {
       val definedBinders = mutable.Set[Type]()
       def apply(tp: Type): Type = {
diff --git a/compiler/src/dotty/tools/dotc/typer/Applications.scala b/compiler/src/dotty/tools/dotc/typer/Applications.scala
index d1a73fd65..ceaf3471a 100644
--- a/compiler/src/dotty/tools/dotc/typer/Applications.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Applications.scala
@@ -195,7 +195,7 @@ trait Applications extends Compatibility { self: Typer with Dynamic =>
     }
 
     /** The function's type after widening and instantiating polytypes
-     *  with polyparams in constraint set
+     *  with TypeParamRefs in constraint set
      */
     val methType = funType.widen match {
       case funType: MethodType => funType
diff --git a/compiler/src/dotty/tools/dotc/typer/ErrorReporting.scala b/compiler/src/dotty/tools/dotc/typer/ErrorReporting.scala
index ff998e233..5f9eae3da 100644
--- a/compiler/src/dotty/tools/dotc/typer/ErrorReporting.scala
+++ b/compiler/src/dotty/tools/dotc/typer/ErrorReporting.scala
@@ -121,12 +121,12 @@ object ErrorReporting {
     }
 
     def typeMismatchMsg(found: Type, expected: Type, postScript: String = "") = {
-      // replace constrained polyparams and their typevars by their bounds where possible
+      // replace constrained TypeParamRefs and their typevars by their bounds where possible
       object reported extends TypeMap {
         def setVariance(v: Int) = variance = v
         val constraint = ctx.typerState.constraint
         def apply(tp: Type): Type = tp match {
-          case tp: PolyParam =>
+          case tp: TypeParamRef =>
             constraint.entry(tp) match {
               case bounds: TypeBounds =>
                 if (variance < 0) apply(constraint.fullUpperBound(tp))
diff --git a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
index 20efd4083..18a1982e1 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inferencing.scala
@@ -176,7 +176,7 @@ object Inferencing {
    *           -1 (minimize) if constraint is uniformly from below,
    *            0 if unconstrained, or constraint is from below and above.
    */
-  private def instDirection(param: PolyParam)(implicit ctx: Context): Int = {
+  private def instDirection(param: TypeParamRef)(implicit ctx: Context): Int = {
     val constrained = ctx.typerState.constraint.fullBounds(param)
     val original = param.binder.paramInfos(param.paramNum)
     val cmp = ctx.typeComparer
diff --git a/compiler/src/dotty/tools/dotc/typer/Inliner.scala b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
index 8520dcdfc..cf3076fce 100644
--- a/compiler/src/dotty/tools/dotc/typer/Inliner.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Inliner.scala
@@ -358,7 +358,7 @@ class Inliner(call: tpd.Tree, rhs: tpd.Tree)(implicit ctx: Context) {
    *  2.  If given type refers to a parameter, make `paramProxy` refer to the entry stored
    *      in `paramNames` under the parameter's name. This roundabout way to bind parameter
    *      references to proxies is done because  we not known a priori what the parameter
-   *      references of a method are (we only know the method's type, but that contains PolyParams
+   *      references of a method are (we only know the method's type, but that contains TypeParamRefs
    *      and MethodParams, not TypeRefs or TermRefs.
    */
   private def registerType(tpe: Type): Unit = tpe match {
diff --git a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
index 89e4f93e2..2dccbbcc1 100644
--- a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
+++ b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
@@ -192,7 +192,7 @@ object ProtoTypes {
 
     /** Forget the types of any arguments that have been typed producing a constraint in a
      *  typer state that is not yet committed into the one of the current context `ctx`.
-     *  This is necessary to avoid "orphan" PolyParams that are referred to from
+     *  This is necessary to avoid "orphan" TypeParamRefs that are referred to from
      *  type variables in the typed arguments, but that are not registered in the
      *  current constraint. A test case is pos/t1756.scala.
      *  @return True if all arguments have types (in particular, no types were forgotten).
@@ -385,7 +385,7 @@ object ProtoTypes {
       for (n <- (0 until pt.paramNames.length).toList)
       yield {
         val tt = new TypeTree().withPos(owningTree.pos)
-        tt.withType(new TypeVar(PolyParam(pt, n), state, tt, ctx.owner))
+        tt.withType(new TypeVar(TypeParamRef(pt, n), state, tt, ctx.owner))
       }
 
     val added =
@@ -399,22 +399,22 @@ object ProtoTypes {
   /**  Same as `constrained(pt, EmptyTree)`, but returns just the created polytype */
   def constrained(pt: PolyType)(implicit ctx: Context): PolyType = constrained(pt, EmptyTree)._1
 
-  /** Create a new polyparam that represents a dependent method parameter singleton */
-  def newDepPolyParam(tp: Type)(implicit ctx: Context): PolyParam = {
+  /** Create a new TypeParamRef that represents a dependent method parameter singleton */
+  def newDepTypeParamRef(tp: Type)(implicit ctx: Context): TypeParamRef = {
     val poly = PolyType(ctx.freshName(nme.DEP_PARAM_PREFIX).toTypeName :: Nil)(
         pt => TypeBounds.upper(AndType(tp, defn.SingletonType)) :: Nil,
         pt => defn.AnyType)
     ctx.typeComparer.addToConstraint(poly, Nil)
-    PolyParam(poly, 0)
+    TypeParamRef(poly, 0)
   }
 
   /** The result type of `mt`, where all references to parameters of `mt` are
-   *  replaced by either wildcards (if typevarsMissContext) or polyparams.
+   *  replaced by either wildcards (if typevarsMissContext) or TypeParamRefs.
    */
   def resultTypeApprox(mt: MethodType)(implicit ctx: Context): Type =
     if (mt.isDependent) {
       def replacement(tp: Type) =
-        if (ctx.mode.is(Mode.TypevarsMissContext)) WildcardType else newDepPolyParam(tp)
+        if (ctx.mode.is(Mode.TypevarsMissContext)) WildcardType else newDepTypeParamRef(tp)
       mt.resultType.substParams(mt, mt.paramInfos.map(replacement))
     }
     else mt.resultType
@@ -458,7 +458,7 @@ object ProtoTypes {
   /** Approximate occurrences of parameter types and uninstantiated typevars
    *  by wildcard types.
    */
-  final def wildApprox(tp: Type, theMap: WildApproxMap, seen: Set[PolyParam])(implicit ctx: Context): Type = tp match {
+  final def wildApprox(tp: Type, theMap: WildApproxMap, seen: Set[TypeParamRef])(implicit ctx: Context): Type = tp match {
     case tp: NamedType => // default case, inlined for speed
       if (tp.symbol.isStatic) tp
       else tp.derivedSelect(wildApprox(tp.prefix, theMap, seen))
@@ -469,7 +469,7 @@ object ProtoTypes {
           wildApprox(tp.refinedInfo, theMap, seen))
     case tp: TypeAlias => // default case, inlined for speed
       tp.derivedTypeAlias(wildApprox(tp.alias, theMap, seen))
-    case tp @ PolyParam(poly, pnum) =>
+    case tp @ TypeParamRef(poly, pnum) =>
       def wildApproxBounds(bounds: TypeBounds) =
         if (bounds.lo.isInstanceOf[NamedType] && bounds.hi.isInstanceOf[NamedType])
           WildcardType(wildApprox(bounds, theMap, seen).bounds)
@@ -532,7 +532,7 @@ object ProtoTypes {
 
   @sharable object AssignProto extends UncachedGroundType with MatchAlways
 
-  private[ProtoTypes] class WildApproxMap(val seen: Set[PolyParam])(implicit ctx: Context) extends TypeMap {
+  private[ProtoTypes] class WildApproxMap(val seen: Set[TypeParamRef])(implicit ctx: Context) extends TypeMap {
     def apply(tp: Type) = wildApprox(tp, this, seen)
   }
 
diff --git a/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala b/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
index 717429848..ed71f2239 100644
--- a/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
+++ b/compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
@@ -348,7 +348,7 @@ trait TypeAssigner {
             val newIndex = gapBuf.length
             gapBuf += idx
             // Re-index unassigned type arguments that remain after transformation
-            PolyParam(pt, newIndex)
+            TypeParamRef(pt, newIndex)
           }
 
           // Type parameters after naming assignment, conserving paramNames order
@@ -358,7 +358,7 @@ trait TypeAssigner {
 
           val transform = new TypeMap {
             def apply(t: Type) = t match {
-              case PolyParam(`pt`, idx) => normArgs(idx)
+              case TypeParamRef(`pt`, idx) => normArgs(idx)
               case _ => mapOver(t)
             }
           }
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 5e845a807..145410f65 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -1871,7 +1871,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
         case TypeBounds(lo, hi)
         if (lo eq hi) || (hi <:< lo)(ctx.fresh.setExploreTyperState) =>
           inst(lo)
-        case tp: PolyParam =>
+        case tp: TypeParamRef =>
           constraint.typeVarOfParam(tp).orElse(tp)
         case _ => tp
       }
-- 
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