Eliminate Binds without symbol in indexParams

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -432,15 +432,10 @@ class TreePickler(pickler: TastyPickler) {
           bindings.foreach(preRegister)
           withLength { pickleTree(call); pickleTree(expansion); bindings.foreach(pickleTree) }
         case Bind(name, body) =>
-          val sym = tree.symbol
-          // If name is a type wildcard, symbol was removed by Typer#indexPattern.
-          // Use the type(-bounds) of the body instead as type of the Bind
-          if (sym.exists) registerDef(sym) else assert(name == tpnme.WILDCARD)
+          registerDef(tree.symbol)
           writeByte(BIND)
           withLength {
-            pickleName(name)
-            pickleType(if (sym.exists) sym.info else body.tpe)
-            pickleTree(body)
+            pickleName(name); pickleType(tree.symbol.info); pickleTree(body)
           }
         case Alternative(alts) =>
           writeByte(ALTERNATIVE)

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -1026,9 +1026,7 @@ class TreeUnpickler(reader: TastyReader,
               val sym = symAtAddr.getOrElse(start, forkAt(start).createSymbol())
               readName()
               readType()
-              val body = readTerm()
-              if (sym.name == tpnme.WILDCARD) untpd.Bind(sym.name, body).withType(body.tpe)
-              else Bind(sym, body)
+              Bind(sym, readTerm())
             case ALTERNATIVE =>
               Alternative(until(end)(readTerm()))
             case UNAPPLY =>

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

@@ -1010,10 +1010,17 @@ class Typer extends Namer
       override def transform(trt: Tree)(implicit ctx: Context) =
         super.transform(trt.withType(elimWildcardSym(trt.tpe))) match {
           case b: Bind =>
-            if (ctx.scope.lookup(b.name) == NoSymbol) ctx.enter(b.symbol)
-            else ctx.error(new DuplicateBind(b, tree), b.pos)
-            b.symbol.info = elimWildcardSym(b.symbol.info)
-            b
+            val sym = b.symbol
+            if (sym.exists) {
+              if (ctx.scope.lookup(b.name) == NoSymbol) ctx.enter(sym)
+              else ctx.error(new DuplicateBind(b, tree), b.pos)
+              sym.info = elimWildcardSym(sym.info)
+              b
+            }
+            else {
+              assert(b.name == tpnme.WILDCARD)
+              b.body
+            }
           case t => t
         }
     }