diff --git a/compiler/src/dotty/tools/dotc/reporting/trace.scala b/compiler/src/dotty/tools/dotc/reporting/trace.scala
index 9036ba1c1dc7..8e111950bacc 100644
--- a/compiler/src/dotty/tools/dotc/reporting/trace.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/trace.scala
@@ -33,7 +33,7 @@ trait TraceSyntax:
       apply(question, if cond then Printers.default else Printers.noPrinter, show)(op)
     else op
 
-  inline def apply[T](inline question: String, inline printer: Printers.Printer, inline showOp: Any => String)(inline op: T)(using Context): T =
+  inline def apply[T, U >: T](inline question: String, inline printer: Printers.Printer, inline showOp: U => String)(inline op: T)(using Context): T =
     inline if isEnabled then
       doTrace[T](question, printer, showOp)(op)
     else op
@@ -60,7 +60,7 @@ trait TraceSyntax:
 
   private def doTrace[T](question: => String,
                          printer: Printers.Printer = Printers.default,
-                         showOp: Any => String = alwaysToString)
+                         showOp: T => String = alwaysToString)
                         (op: => T)(using Context): T =
     if ctx.mode.is(Mode.Printing) || !isForced && (printer eq Printers.noPrinter) then op
     else
@@ -68,7 +68,7 @@ trait TraceSyntax:
       // may cause some extra logging output.
       val q = question
       val leading = s"==> $q?"
-      val trailing = (res: Any) => s"<== $q = ${showOp(res)}"
+      val trailing = (res: T) => s"<== $q = ${showOp(res)}"
       var finalized = false
       var logctx = ctx
       while logctx.reporter.isInstanceOf[StoreReporter] do logctx = logctx.outer
diff --git a/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala b/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
index 1aa9656a2084..acf5f99aa925 100644
--- a/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
+++ b/compiler/src/dotty/tools/dotc/transform/init/Semantic.scala
@@ -321,7 +321,7 @@ class Semantic {
     def widenArgs: List[Value] = values.map(_.widenArg).toList
 
   extension (value: Value)
-    def select(field: Symbol, source: Tree, needResolve: Boolean = true): Contextual[Result] = log("select " + field.show, printer, res => res.asInstanceOf[Result].show) {
+    def select(field: Symbol, source: Tree, needResolve: Boolean = true): Contextual[Result] = log("select " + field.show, printer, (_: Result).show) {
       if promoted.isCurrentObjectPromoted then Result(Hot, Nil)
       else value match {
         case Hot  =>
@@ -371,7 +371,7 @@ class Semantic {
       }
     }
 
-    def call(meth: Symbol, args: List[ArgInfo], superType: Type, source: Tree, needResolve: Boolean = true): Contextual[Result] = log("call " + meth.show + ", args = " + args, printer, res => res.asInstanceOf[Result].show) {
+    def call(meth: Symbol, args: List[ArgInfo], superType: Type, source: Tree, needResolve: Boolean = true): Contextual[Result] = log("call " + meth.show + ", args = " + args, printer, (_: Result).show) {
       def checkArgs = args.flatMap(_.promote)
 
       // fast track if the current object is already initialized
@@ -445,7 +445,7 @@ class Semantic {
     }
 
     /** Handle a new expression `new p.C` where `p` is abstracted by `value` */
-    def instantiate(klass: ClassSymbol, ctor: Symbol, args: List[ArgInfo], source: Tree): Contextual[Result] = log("instantiating " + klass.show + ", value = " + value + ", args = " + args, printer, res => res.asInstanceOf[Result].show) {
+    def instantiate(klass: ClassSymbol, ctor: Symbol, args: List[ArgInfo], source: Tree): Contextual[Result] = log("instantiating " + klass.show + ", value = " + value + ", args = " + args, printer, (_: Result).show) {
       val trace1 = trace.add(source)
       if promoted.isCurrentObjectPromoted then Result(Hot, Nil)
       else value match {
@@ -702,7 +702,7 @@ class Semantic {
    *
    *  This method only handles cache logic and delegates the work to `cases`.
    */
-  def eval(expr: Tree, thisV: Addr, klass: ClassSymbol, cacheResult: Boolean = false): Contextual[Result] = log("evaluating " + expr.show + ", this = " + thisV.show, printer, res => res.asInstanceOf[Result].show) {
+  def eval(expr: Tree, thisV: Addr, klass: ClassSymbol, cacheResult: Boolean = false): Contextual[Result] = log("evaluating " + expr.show + ", this = " + thisV.show, printer, (_: Result).show) {
     val innerMap = cache.getOrElseUpdate(thisV, new EqHashMap[Tree, Value])
     if (innerMap.contains(expr)) Result(innerMap(expr), Errors.empty)
     else {
@@ -911,7 +911,7 @@ class Semantic {
     }
 
   /** Handle semantics of leaf nodes */
-  def cases(tp: Type, thisV: Addr, klass: ClassSymbol, source: Tree): Contextual[Result] = log("evaluating " + tp.show, printer, res => res.asInstanceOf[Result].show) {
+  def cases(tp: Type, thisV: Addr, klass: ClassSymbol, source: Tree): Contextual[Result] = log("evaluating " + tp.show, printer, (_: Result).show) {
     tp match {
       case _: ConstantType =>
         Result(Hot, Errors.empty)
@@ -941,7 +941,7 @@ class Semantic {
   }
 
   /** Resolve C.this that appear in `klass` */
-  def resolveThis(target: ClassSymbol, thisV: Value, klass: ClassSymbol, source: Tree): Contextual[Value] = log("resolving " + target.show + ", this = " + thisV.show + " in " + klass.show, printer, res => res.asInstanceOf[Value].show) {
+  def resolveThis(target: ClassSymbol, thisV: Value, klass: ClassSymbol, source: Tree): Contextual[Value] = log("resolving " + target.show + ", this = " + thisV.show + " in " + klass.show, printer, (_: Value).show) {
     if target == klass then thisV
     else if target.is(Flags.Package) then Hot
     else
@@ -969,7 +969,7 @@ class Semantic {
    *
    *  See `tpd.outerSelect` and `ElimOuterSelect`.
    */
-  def resolveOuterSelect(target: ClassSymbol, thisV: Value, hops: Int, source: Tree): Contextual[Value] = log("resolving outer " + target.show + ", this = " + thisV.show + ", hops = " + hops, printer, res => res.asInstanceOf[Value].show) {
+  def resolveOuterSelect(target: ClassSymbol, thisV: Value, hops: Int, source: Tree): Contextual[Value] = log("resolving outer " + target.show + ", this = " + thisV.show + ", hops = " + hops, printer, (_: Value).show) {
     // Is `target` reachable from `cls` with the given `hops`?
     def reachable(cls: ClassSymbol, hops: Int): Boolean =
       if hops == 0 then cls == target
@@ -1011,7 +1011,7 @@ class Semantic {
       else cases(tref.prefix, thisV, klass, source)
 
   /** Initialize part of an abstract object in `klass` of the inheritance chain */
-  def init(tpl: Template, thisV: Addr, klass: ClassSymbol): Contextual[Result] = log("init " + klass.show, printer, res => res.asInstanceOf[Result].show) {
+  def init(tpl: Template, thisV: Addr, klass: ClassSymbol): Contextual[Result] = log("init " + klass.show, printer, (_: Result).show) {
     val errorBuffer = new mutable.ArrayBuffer[Error]
 
     val paramsMap = tpl.constr.termParamss.flatten.map { vdef =>
diff --git a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
index 42fa39749f9d..9c95aa76d356 100644
--- a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
+++ b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
@@ -114,7 +114,7 @@ trait SpaceLogic {
   def show(sp: Space): String
 
   /** Simplify space such that a space equal to `Empty` becomes `Empty` */
-  def simplify(space: Space)(using Context): Space = trace(s"simplify ${show(space)} --> ", debug, x => show(x.asInstanceOf[Space]))(space match {
+  def simplify(space: Space)(using Context): Space = trace(s"simplify ${show(space)} --> ", debug, show)(space match {
     case Prod(tp, fun, spaces) =>
       val sps = spaces.map(simplify(_))
       if (sps.contains(Empty)) Empty
@@ -194,7 +194,7 @@ trait SpaceLogic {
   }
 
   /** Intersection of two spaces  */
-  def intersect(a: Space, b: Space)(using Context): Space = trace(s"${show(a)} & ${show(b)}", debug, x => show(x.asInstanceOf[Space])) {
+  def intersect(a: Space, b: Space)(using Context): Space = trace(s"${show(a)} & ${show(b)}", debug, show) {
     def tryDecompose1(tp: Type) = intersect(Or(decompose(tp)), b)
     def tryDecompose2(tp: Type) = intersect(a, Or(decompose(tp)))
 
@@ -226,7 +226,7 @@ trait SpaceLogic {
   }
 
   /** The space of a not covered by b */
-  def minus(a: Space, b: Space)(using Context): Space = trace(s"${show(a)} - ${show(b)}", debug, x => show(x.asInstanceOf[Space])) {
+  def minus(a: Space, b: Space)(using Context): Space = trace(s"${show(a)} - ${show(b)}", debug, show) {
     def tryDecompose1(tp: Type) = minus(Or(decompose(tp)), b)
     def tryDecompose2(tp: Type) = minus(a, Or(decompose(tp)))