From c1cc6703cd08ee159ddfebf1212a4597b9ac6f85 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Tue, 16 Jan 2024 14:43:10 +0100
Subject: [PATCH 1/2] Derive some more debugs.

---
 executor/src/constant_evaluator/mod.rs | 2 +-
 executor/src/witgen/query_processor.rs | 2 +-
 pil_analyzer/src/condenser.rs          | 2 +-
 pil_analyzer/src/evaluator.rs          | 9 +++++----
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/executor/src/constant_evaluator/mod.rs b/executor/src/constant_evaluator/mod.rs
index cf86fded05..091d71edd2 100644
--- a/executor/src/constant_evaluator/mod.rs
+++ b/executor/src/constant_evaluator/mod.rs
@@ -129,7 +129,7 @@ impl<'a, T: FieldElement> SymbolLookup<'a, T, FixedColumnRef<'a>> for Symbols<'a
     }
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 pub struct FixedColumnRef<'a> {
     pub name: &'a str,
 }
diff --git a/executor/src/witgen/query_processor.rs b/executor/src/witgen/query_processor.rs
index c4bfa2aa28..e7e4861d2b 100644
--- a/executor/src/witgen/query_processor.rs
+++ b/executor/src/witgen/query_processor.rs
@@ -143,7 +143,7 @@ impl<'a, T: FieldElement> SymbolLookup<'a, T, Reference<'a>> for Symbols<'a, T>
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 struct Reference<'a> {
     name: &'a str,
     poly_id: PolyID,
diff --git a/pil_analyzer/src/condenser.rs b/pil_analyzer/src/condenser.rs
index 0cd8c8edeb..19e3d4c56c 100644
--- a/pil_analyzer/src/condenser.rs
+++ b/pil_analyzer/src/condenser.rs
@@ -355,7 +355,7 @@ impl<'a, T: FieldElement> SymbolLookup<'a, T, Condensate<T>> for &'a Condenser<T
     }
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 enum Condensate<T> {
     Expression(AlgebraicExpression<T>),
     Identity(AlgebraicExpression<T>, AlgebraicExpression<T>),
diff --git a/pil_analyzer/src/evaluator.rs b/pil_analyzer/src/evaluator.rs
index fd39642f52..ff9331848b 100644
--- a/pil_analyzer/src/evaluator.rs
+++ b/pil_analyzer/src/evaluator.rs
@@ -1,3 +1,4 @@
+use std::fmt;
 use std::{collections::HashMap, fmt::Display, rc::Rc};
 
 use ast::{
@@ -76,7 +77,7 @@ pub enum EvalError {
     DataNotAvailable,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 pub enum Value<'a, T, C> {
     Number(T),
     String(String),
@@ -103,7 +104,7 @@ impl<'a, T: FieldElement, C: Custom> Value<'a, T, C> {
     }
 }
 
-pub trait Custom: Display + Clone + PartialEq {}
+pub trait Custom: Display + fmt::Debug + Clone + PartialEq {}
 
 impl<'a, T: Display, C: Custom> Display for Value<'a, T, C> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -118,7 +119,7 @@ impl<'a, T: Display, C: Custom> Display for Value<'a, T, C> {
     }
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 pub enum NoCustom {}
 
 impl Custom for NoCustom {}
@@ -129,7 +130,7 @@ impl Display for NoCustom {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Closure<'a, T, C> {
     pub lambda: &'a LambdaExpression<T, Reference>,
     pub environment: Vec<Rc<Value<'a, T, C>>>,

From 91ccb0bfd875e1e3fcd81c395378aa9f8b350995 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Tue, 16 Jan 2024 14:51:05 +0100
Subject: [PATCH 2/2] Some more explanation.

---
 executor/src/witgen/query_processor.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/executor/src/witgen/query_processor.rs b/executor/src/witgen/query_processor.rs
index e7e4861d2b..9400021686 100644
--- a/executor/src/witgen/query_processor.rs
+++ b/executor/src/witgen/query_processor.rs
@@ -51,7 +51,10 @@ impl<'a, 'b, T: FieldElement, QueryCallback: super::QueryCallback<T>>
                         Ok(EvalValue::incomplete(IncompleteCause::DataNotYetAvailable))
                     }
                     // All other errors are non-recoverable
-                    e => Err(super::EvalError::ProverQueryError(format!("{e:?}"))),
+                    e => Err(super::EvalError::ProverQueryError(format!(
+                        "Error occurred when evaluating prover query {query} on {}:\n{e:?}",
+                        rows.current_row_index
+                    ))),
                 };
             }
         };