Restore the docstring during the .async. transform (#10404) [backport]

Fixes #9816

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/pure/asyncmacro.nim b/lib/pure/asyncmacro.nim
index b18d20d55..f1e0aa568 100644
--- a/lib/pure/asyncmacro.nim
+++ b/lib/pure/asyncmacro.nim
@@ -245,6 +245,12 @@ proc asyncSingleProc(prc: NimNode): NimNode {.compileTime.} =
 
   var outerProcBody = newNimNode(nnkStmtList, prc.body)
 
+  # Extract the documentation comment from the original procedure declaration.
+  # Note that we're not removing it from the body in order not to make this
+  # transformation even more complex.
+  if prc.body.len > 1 and prc.body[0].kind == nnkCommentStmt:
+    outerProcBody.add(prc.body[0])
+
   # -> var retFuture = newFuture[T]()
   var retFutureSym = genSym(nskVar, "retFuture")
   var subRetType =