refactor(dfir_lang): remove stratum from chain, chain_first_n

PR: #2967

Author: MingweiSamuel

dfir_lang/src/graph/ops/chain.rs

@@ -1,7 +1,5 @@
-use crate::graph::PortIndexValue;
-
 use super::{
-    DelayType, OperatorCategory, OperatorConstraints, RANGE_0, RANGE_1
+    OperatorCategory, OperatorConstraints, RANGE_0, RANGE_1
 };
 
 /// > 2 input streams of the same type, 1 output stream of the same type
@@ -32,11 +30,6 @@ pub const CHAIN: OperatorConstraints = OperatorConstraints {
     flo_type: None,
     ports_inn: None,
     ports_out: None,
-    input_delaytype_fn: |idx| match idx {
-        PortIndexValue::Int(idx) if idx.value == 0 => {
-            Some(DelayType::Stratum)
-        }
-        _else => None,
-    },
+    input_delaytype_fn: |_| None,
     write_fn: super::union::UNION.write_fn,
 };

dfir_lang/src/graph/ops/chain_first_n.rs

@@ -1,11 +1,10 @@
 use quote::quote_spanned;
 
 use crate::graph::{
-    PortIndexValue,
     ops::{OperatorWriteOutput, WriteContextArgs},
 };
 
-use super::{DelayType, OperatorCategory, OperatorConstraints, RANGE_0, RANGE_1};
+use super::{OperatorCategory, OperatorConstraints, RANGE_0, RANGE_1};
 
 /// > 2 input streams of the same type, 1 output stream of the same type
 ///
@@ -36,13 +35,7 @@ pub const CHAIN_FIRST_N: OperatorConstraints = OperatorConstraints {
     flo_type: None,
     ports_inn: None,
     ports_out: None,
-    input_delaytype_fn: |idx| match idx {
-        PortIndexValue::Int(idx) if idx.value == 0 => {
-            // will no longer be needed once subgraphs are always DAGs (only run once per tick)
-            Some(DelayType::Stratum)
-        }
-        _else => None,
-    },
+    input_delaytype_fn: |_| None,
     write_fn: |wc @ &WriteContextArgs {
                    root,
                    op_span,