fix: make curcuit code less panicy

Author: vmx

storage-proofs/src/circuit/create_label.rs

@@ -44,8 +44,8 @@ where
     let fr = if alloc_bits[0].get_value().is_some() {
         let be_bits = alloc_bits
             .iter()
-            .map(|v| v.get_value().unwrap())
-            .collect::<Vec<bool>>();
+            .map(|v| v.get_value().ok_or(SynthesisError::AssignmentMissing))
+            .collect::<Result<Vec<bool>, SynthesisError>>()?;
 
         let le_bits = be_bits
             .chunks(8)

storage-proofs/src/circuit/variables.rs

@@ -1,5 +1,7 @@
 use std::fmt;
 
+use anyhow::Result;
+
 use bellperson::gadgets::num::AllocatedNum;
 use bellperson::{ConstraintSystem, SynthesisError};
 use paired::Engine;
@@ -39,8 +41,8 @@ impl<E: Engine> Root<E> {
         }
     }
 
-    pub fn var<CS: ConstraintSystem<E>>(cs: CS, fr: E::Fr) -> Self {
-        Root::Var(AllocatedNum::alloc(cs, || Ok(fr)).unwrap())
+    pub fn var<CS: ConstraintSystem<E>>(cs: CS, fr: E::Fr) -> Result<Self> {
+        Ok(Root::Var(AllocatedNum::alloc(cs, || Ok(fr))?))
     }
 
     pub fn is_some(&self) -> bool {