Remove FunctionRefinementOf

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1193,23 +1193,12 @@ class Definitions {
   }
 
   object DependentFunctionRefinementOf {
-    /** Matches a refined function type and extracts the function type and apply info.
+    /** Matches a refined `FunctionN[...]` or `ContextFunctionN[...]` type and extracts the function type and apply info.
      *
      *  Pattern: `$ft { def apply: $mt }`
      */
     def unapply(ft: Type)(using Context): Option[(Type, MethodType)] = ft.dealias match
-      case FunctionRefinementOf(parent, mt: MethodType) if !parent.derivesFrom(PolyFunctionClass) =>
-        Some((parent, mt))
-      case _ => None
-  }
-
-  object FunctionRefinementOf {
-    /** Matches a refined function type or PolyFunction and extracts the function type and apply info.
-     *
-     *  Pattern: `$ft { def apply: $mt }`
-     */
-    def unapply(ft: Type)(using Context): Option[(Type, MethodType)] = ft.dealias match
-      case RefinedType(parent, nme.apply, mt: MethodType) if isFunctionType(parent) =>
+      case RefinedType(parent, nme.apply, mt: MethodType) if isFunctionNType(parent) =>
         Some((parent, mt))
       case _ => None
   }

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -1321,7 +1321,10 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
       case tp: TypeParamRef =>
         decomposeProtoFunction(ctx.typerState.constraint.entry(tp).bounds.hi, defaultArity, pos)
       case _ => pt1.findFunctionType match {
-        case ft @ defn.FunctionRefinementOf(_, mt @ MethodTpe(_, formals, restpe)) =>
+        case ft @ defn.PolyFunctionOf(mt @ MethodTpe(_, formals, restpe)) =>
+          if formals.length != defaultArity then fallbackProto
+          else (formals, untpd.InLambdaTypeTree(isResult = true, (_, syms) => restpe.substParams(mt, syms.map(_.termRef))))
+        case ft @ defn.DependentFunctionRefinementOf(_, mt @ MethodTpe(_, formals, restpe)) =>
           if formals.length != defaultArity then fallbackProto
           else (formals, untpd.InLambdaTypeTree(isResult = true, (_, syms) => restpe.substParams(mt, syms.map(_.termRef))))
         case ft @ defn.FunctionNOf(_, _, _) =>