Fix bug in ICD generation

This bug was introduced by merging PR #317. The issue caused the ICD tables for sequences, choices, and similar components to be empty when their child components were primitive types.

BackendAst/DAstACN.fs

@@ -291,7 +291,13 @@ let private createAcnFunction (r: Asn1AcnAst.AstRoot)
     let sInitialExp = ""
     let func, funcDef, auxiliaries, icdResult, ns2  =
             match funcNameAndtasInfo  with
-            | None -> None, None, [], None, ns
+            | None -> 
+                let content, ns1a = funcBody ns errCode [] (NestingScope.init t.acnMaxSizeInBits t.uperMaxSizeInBits []) p
+                let icdResult =
+                    match content with
+                    | None -> None
+                    | Some bodyResult -> bodyResult.icdResult
+                None, None, [], icdResult, ns1a
             | Some funcName ->
                 let precondAnnots = lm.lg.generatePrecond r ACN t codec
                 let postcondAnnots = lm.lg.generatePostcond r ACN funcNameBase p t codec