fix

Author: sai-deng

circuit/src/builder/circuit_builder.rs

@@ -117,11 +117,13 @@ where
     }
 
     /// Allocates a witness hint (uninitialized witness slot set during non-primitive execution).
+    #[must_use]
     pub fn alloc_witness_hint(&mut self, label: &'static str) -> ExprId {
         self.expr_builder.add_witness_hint(label)
     }
 
     /// Allocates multiple witness hints.
+    #[must_use]
     pub fn alloc_witness_hints(&mut self, count: usize, label: &'static str) -> Vec<ExprId> {
         self.expr_builder.add_witness_hints(count, label)
     }
@@ -245,9 +247,6 @@ where
     }
 
     /// Pushes a non-primitive op. Returns op id.
-    // TODO: The lowerer needs to map the hinted `ExprId`s to `WitnessId`s, hence
-    // the provided `witness_exprs` must contain the generated outputs.
-    // Would maybe need to change that.
     #[allow(unused_variables)]
     pub(crate) fn push_non_primitive_op(
         &mut self,

circuit/src/builder/compiler/expression_lowerer.rs

@@ -270,9 +270,6 @@ where
                     // The output of Div is the b_widx.
                     expr_to_widx.insert(expr_id, b_widx);
                 }
-                Expr::NonPrimitiveOp { .. } => {
-                    // Skip non-primitive operations
-                }
             }
         }
 

circuit/src/builder/expression_builder.rs

@@ -101,6 +101,7 @@ where
     /// Adds a witness hint to the graph.
     /// It will allocate a `WitnessId` during lowering, with no primitive op.
     #[allow(unused_variables)]
+    #[must_use]
     pub fn add_witness_hint(&mut self, label: &'static str) -> ExprId {
         let expr_id = self.graph.add_expr(Expr::Witness);
 
@@ -117,6 +118,7 @@ where
     }
 
     /// Adds multiple witness hints.
+    #[must_use]
     pub fn add_witness_hints(&mut self, count: usize, label: &'static str) -> Vec<ExprId> {
         (0..count).map(|_| self.add_witness_hint(label)).collect()
     }

circuit/src/expr.rs

@@ -1,6 +1,5 @@
 use alloc::vec::Vec;
 
-use crate::NonPrimitiveOpType;
 use crate::types::ExprId;
 
 /// Expression DAG for field operations
@@ -21,13 +20,6 @@ pub enum Expr<F> {
     Mul { lhs: ExprId, rhs: ExprId },
     /// Division of two expressions
     Div { lhs: ExprId, rhs: ExprId },
-
-    /// Non-primitive operation
-    NonPrimitiveOp {
-        inputs: Vec<ExprId>,
-        outputs: Vec<ExprId>,
-        op: NonPrimitiveOpType,
-    },
 }
 
 /// Graph for storing expression DAG nodes

circuit/src/tables/runner.rs

@@ -1,3 +1,4 @@
+use alloc::string::ToString;
 use alloc::vec::Vec;
 use alloc::{format, vec};
 
@@ -87,25 +88,24 @@ impl<F: CircuitField> CircuitRunner<F> {
                     return Err(CircuitError::IncorrectNonPrimitiveOpPrivateData {
                         op: op_ty.clone(),
                         operation_index: op_id,
-                        expected: format!("no private data"),
-                        got: format!("{private_data:?}"),
+                        expected: "no private data".to_string(),
+                        got: alloc::format!("{private_data:?}"),
                     });
                 }
             }
         }
 
         // Disallow double-setting private data
-        if self.non_primitive_op_private_data[op_id.0 as usize].is_some() {
-            if let Op::NonPrimitiveOpWithExecutor { executor, .. } =
+        if self.non_primitive_op_private_data[op_id.0 as usize].is_some()
+            && let Op::NonPrimitiveOpWithExecutor { executor, .. } =
                 &self.circuit.non_primitive_ops[op_id.0 as usize]
-            {
-                return Err(CircuitError::IncorrectNonPrimitiveOpPrivateData {
-                    op: executor.op_type().clone(),
-                    operation_index: op_id,
-                    expected: format!("private data not previously set"),
-                    got: format!("already set"),
-                });
-            }
+        {
+            return Err(CircuitError::IncorrectNonPrimitiveOpPrivateData {
+                op: executor.op_type().clone(),
+                operation_index: op_id,
+                expected: "private data not previously set".to_string(),
+                got: "already set".to_string(),
+            });
         }
 
         // Store private data for this operation