fixes #18847 [backport] (#18870)

compiler/parser.nim

@@ -1824,8 +1824,9 @@ proc parseRoutine(p: var Parser, kind: TNodeKind): PNode =
       # => moves comment `foo` to `fn`
       result.comment = body[0].comment
       body[0].comment = ""
-    else:
-      assert false, p.lex.config$body.info # avoids hard to track bugs, fail early.
+    #else:
+    #  assert false, p.lex.config$body.info # avoids hard to track bugs, fail early.
+    # Yeah, that worked so well. There IS a bug in this logic, now what?
 
 proc newCommentStmt(p: var Parser): PNode =
   #| commentStmt = COMMENT

tests/parser/tdoc_comments.nim

@@ -69,3 +69,7 @@ type
 
   MyEnum3* = enum
     value5  ## only document the enum value
+
+# bug #18847
+proc close*() =   ## asdfasdfsdfa
+  discard         ## adsfasdfads