Also desugar with-do (#691)

effekt/shared/src/main/scala/effekt/RecursiveDescent.scala

@@ -221,6 +221,8 @@ class RecursiveDescent(positions: Positions, tokens: Seq[Token], source: Source)
      case Var(id) =>
        val tgt = IdTarget(id)
        Return(Call(tgt, Nil, Nil, (BlockLiteral(Nil, vparams, bparams, body)) :: Nil))
+     case Do(effect, id, targs, vargs, bargs) =>
+      Return(Do(effect, id, targs, vargs, bargs :+ BlockLiteral(Nil, vparams, bparams, body)))
      case term =>
        Return(Call(ExprTarget(term), Nil, Nil, (BlockLiteral(Nil, vparams, bparams, body)) :: Nil))
   }

examples/pos/issue684.check

@@ -0,0 +1,3 @@
+before
+hi
+after

examples/pos/issue684.effekt

@@ -0,0 +1,12 @@
+effect wrap() { program: () => Unit }: Unit
+
+def main() = try {
+  with do wrap();
+  println("hi")
+} with wrap {
+  resume { {p} =>
+    println("before")
+    p()
+    println("after")
+  }
+}