Yield in try

lib/system/embedded.nim

@@ -41,3 +41,6 @@ proc reraiseException() {.compilerRtl.} =
 proc writeStackTrace() = discard
 
 proc setControlCHook(hook: proc () {.noconv.}) = discard
+
+proc closureIterSetupExc(e: ref Exception) {.compilerproc, inline.} =
+  sysFatal(ReraiseError, "exception handling is not available")

lib/system/excpt.nim

@@ -131,6 +131,10 @@ proc popCurrentExceptionEx(id: uint) {.compilerRtl.} =
       quitOrDebug()
     prev.up = cur.up
 
+proc closureIterSetupExc(e: ref Exception) {.compilerproc, inline.} =
+  if not e.isNil:
+    currException = e
+
 # some platforms have native support for stack traces:
 const
   nativeStackTraceSupported* = (defined(macosx) or defined(linux)) and