Add span when translating with to an and type

Author: tgodzik

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1549,7 +1549,7 @@ object Parsers {
         else
           if sourceVersion.isAtLeast(`3.1`) then
             deprecationWarning(DeprecatedWithOperator(), withOffset)
-          makeAndType(t, withType())
+          atSpan(in.lastOffset, withOffset) { makeAndType(t, withType()) }
       else t
 
     /** AnnotType ::= SimpleType {Annotation}

tests/neg-scalajs/js-native-members.scala

@@ -93,3 +93,8 @@ object A5 {
     var apply: Int = js.native // ok
   }
 }
+
+  @js.native
+  trait A6 extends js.Object {
+    def assign[T, U](target: T, source: U): T with U = js.native
+  }