diff --git a/compiler/src/dotty/tools/dotc/core/TypeApplications.scala b/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
index 30bd3c168269..fdc37000735f 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeApplications.scala
@@ -14,16 +14,10 @@ import StdNames.nme
 import Flags.{Module, Provisional}
 import dotty.tools.dotc.config.Config
 
-object TypeApplications {
+object TypeApplications:
 
   type TypeParamInfo = ParamInfo.Of[TypeName]
 
-  /** Assert type is not a TypeBounds instance and return it unchanged */
-  def noBounds(tp: Type): Type = tp match {
-    case tp: TypeBounds => throw new AssertionError("no TypeBounds allowed")
-    case _ => tp
-  }
-
   /** Extractor for
    *
    *    [X1: B1, ..., Xn: Bn] -> C[X1, ..., Xn]
@@ -154,13 +148,13 @@ object TypeApplications {
         mapOver(t)
     }
   }
-}
-
-import TypeApplications.*
 
-/** A decorator that provides methods for modeling type application */
-class TypeApplications(val self: Type) extends AnyVal {
+/** Extensions that model type application.
+ */
+class TypeApplications:
+  import TypeApplications.*
 
+  extension (self: Type) { // braces to avoid indenting existing code
   /** The type parameters of this type are:
    *  For a ClassInfo type, the type parameters of its class.
    *  For a typeref referring to a class, the type parameters of the class.
@@ -562,7 +556,7 @@ class TypeApplications(val self: Type) extends AnyVal {
     case _ => self.dropDependentRefinement.dealias.argInfos
 
   /** Argument types where existential types in arguments are disallowed */
-  def argTypes(using Context): List[Type] = argInfos mapConserve noBounds
+  def argTypes(using Context): List[Type] = argInfos.mapConserve(_.noBounds)
 
   /** Argument types where existential types in arguments are approximated by their lower bound */
   def argTypesLo(using Context): List[Type] = argInfos.mapConserve(_.loBound)
@@ -596,4 +590,9 @@ class TypeApplications(val self: Type) extends AnyVal {
       .orElse(self.baseType(defn.ArrayClass))
       .argInfos.headOption.getOrElse(NoType)
   }
-}
+
+  /** Assert type is not a TypeBounds instance and return it unchanged */
+  def noBounds: self.type =
+    assert(!self.isInstanceOf[TypeBounds], "no TypeBounds allowed")
+    self
+  }
diff --git a/compiler/src/dotty/tools/dotc/core/TypeUtils.scala b/compiler/src/dotty/tools/dotc/core/TypeUtils.scala
index 594249065d98..cb4beee434c5 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeUtils.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeUtils.scala
@@ -11,7 +11,7 @@ import Names.Name
 import StdNames.nme
 import config.Feature
 
-class TypeUtils:
+class TypeUtils extends TypeApplications:
   /** A decorator that provides methods on types
    *  that are needed in the transformer pipeline.
    */
diff --git a/compiler/src/dotty/tools/dotc/core/Types.scala b/compiler/src/dotty/tools/dotc/core/Types.scala
index 6bf19c5a27a1..ad3c0b7fbf3c 100644
--- a/compiler/src/dotty/tools/dotc/core/Types.scala
+++ b/compiler/src/dotty/tools/dotc/core/Types.scala
@@ -2169,8 +2169,7 @@ object Types extends TypeUtils {
     /** Is the `hash` of this type the same for all possible sequences of enclosing binders? */
     def hashIsStable: Boolean = true
   }
-
-  // end Type
+  end Type
 
 // ----- Type categories ----------------------------------------------
 
@@ -7302,8 +7301,6 @@ object Types extends TypeUtils {
 
   // ----- Helpers and Decorator implicits --------------------------------------
 
-  implicit def decorateTypeApplications(tpe: Type): TypeApplications = new TypeApplications(tpe)
-
   extension (tps1: List[Type]) {
     @tailrec def hashIsStable: Boolean =
       tps1.isEmpty || tps1.head.hashIsStable && tps1.tail.hashIsStable
diff --git a/compiler/src/dotty/tools/dotc/transform/MixinOps.scala b/compiler/src/dotty/tools/dotc/transform/MixinOps.scala
index 3a3fa65ff64b..d0725f05ca95 100644
--- a/compiler/src/dotty/tools/dotc/transform/MixinOps.scala
+++ b/compiler/src/dotty/tools/dotc/transform/MixinOps.scala
@@ -4,6 +4,7 @@ package transform
 import core.*
 import Symbols.*, Types.*, Contexts.*, DenotTransformers.*, Flags.*
 import NameKinds.*
+import TypeApplications.*
 import util.Spans.*
 
 import StdNames.*, NameOps.*
diff --git a/compiler/src/dotty/tools/dotc/transform/localopt/StringInterpolatorOpt.scala b/compiler/src/dotty/tools/dotc/transform/localopt/StringInterpolatorOpt.scala
index db3a0c6c71f2..0e02ddc57266 100644
--- a/compiler/src/dotty/tools/dotc/transform/localopt/StringInterpolatorOpt.scala
+++ b/compiler/src/dotty/tools/dotc/transform/localopt/StringInterpolatorOpt.scala
@@ -12,6 +12,7 @@ import dotty.tools.dotc.core.Symbols.*
 import dotty.tools.dotc.core.Types.*
 import dotty.tools.dotc.printing.Formatting.*
 import dotty.tools.dotc.reporting.BadFormatInterpolation
+import dotty.tools.dotc.core.TypeApplications.*
 import dotty.tools.dotc.transform.MegaPhase.MiniPhase
 import dotty.tools.dotc.typer.ConstFold
 
diff --git a/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala b/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
index 3a7f7704edff..f8dc48f28c3a 100644
--- a/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
+++ b/compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala
@@ -1911,9 +1911,9 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
           dotc.core.Symbols.defn.isTupleNType(self)
         def select(sym: Symbol): TypeRepr = self.select(sym)
         def appliedTo(targ: TypeRepr): TypeRepr =
-          dotc.core.Types.decorateTypeApplications(self).appliedTo(targ)
+          Types.appliedTo(self)(targ)
         def appliedTo(targs: List[TypeRepr]): TypeRepr =
-          dotc.core.Types.decorateTypeApplications(self).appliedTo(targs)
+          Types.appliedTo(self)(targs)
         def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr =
           self.subst(from, to)