Clean up printing

We don't really need printing facilities for erased function types, since they are
already done for refined types.

Author: natsukagami

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -128,9 +128,8 @@ class PlainPrinter(_ctx: Context) extends Printer {
   /** Pretty-print comma-separated type arguments for a constructor to be inserted among parentheses or brackets
     * (hence with `GlobalPrec` precedence).
     */
-  protected def argsText(args: List[Type], _erased: List[Boolean] = List()): Text =
-    val erased = _erased.padTo(args.length, false)
-    atPrec(GlobalPrec) { Text(args.zip(erased).map((arg, erased) => argText(arg, erased)), ", ") }
+  protected def argsText(args: List[Type]): Text =
+    atPrec(GlobalPrec) { Text(args.map(argText(_)), ", ") }
 
   /** The longest sequence of refinement types, starting at given type
    *  and following parents.

compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -147,17 +147,17 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     def toTextTuple(args: List[Type]): Text =
       "(" ~ argsText(args) ~ ")"
 
-    def toTextFunction(args: List[Type], isGiven: Boolean, isErased: List[Boolean], isPure: Boolean): Text =
+    def toTextFunction(args: List[Type], isGiven: Boolean, isPure: Boolean): Text =
       changePrec(GlobalPrec) {
         val argStr: Text =
           if args.length == 2
              && !defn.isTupleNType(args.head)
              && !isGiven
           then
-            atPrec(InfixPrec) { argText(args.head, isErased.headOption.getOrElse(false)) }
+            atPrec(InfixPrec) { argText(args.head) }
           else
             "("
-            ~ argsText(args.init, isErased)
+            ~ argsText(args.init)
             ~ ")"
         argStr ~ " " ~ arrow(isGiven, isPure) ~ " " ~ argText(args.last, false)
       }
@@ -223,7 +223,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
             if tycon.isRepeatedParam then toTextLocal(args.head) ~ "*"
             else if tp.isConvertibleParam then "into " ~ toText(args.head)
             else if defn.isFunctionSymbol(tsym) then
-              toTextFunction(args, tsym.name.isContextFunction, List(tsym.name.isErasedFunction) /* TODO @natsukagami fix this */,
+              toTextFunction(args, tsym.name.isContextFunction,
                 isPure = Feature.pureFunsEnabled && !tsym.name.isImpureFunction)
             else if isInfixType(tp) then
               val l :: r :: Nil = args: @unchecked