Fix position of Bind nodes

The position of a tree should contain the position of all its children,
but that was not the case before this commit for Bind nodes created from
Typed nodes.

Author: smarter

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

@@ -484,7 +484,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
         if (id.name == nme.WILDCARD || id.name == nme.WILDCARD_STAR) ifPat
         else {
           import untpd._
-          typed(Bind(id.name, Typed(Ident(wildName), tree.tpt)).withPos(id.pos), pt)
+          typed(Bind(id.name, Typed(Ident(wildName), tree.tpt)).withPos(tree.pos), pt)
         }
       case _ => ifExpr
     }