diff --git a/examples/sha256/table16/compression/compression_util.rs b/examples/sha256/table16/compression/compression_util.rs
index 52288bb3..9b86d862 100644
--- a/examples/sha256/table16/compression/compression_util.rs
+++ b/examples/sha256/table16/compression/compression_util.rs
@@ -783,7 +783,7 @@ impl CompressionConfig {
                 || {
                     h_prime_carry
                         .map(|value| pallas::Base::from_u64(value as u64))
-                        .ok_or(Error::SynthesisError)
+                        .ok_or(Error::Synthesis)
                 },
             )?;
 
@@ -834,7 +834,7 @@ impl CompressionConfig {
             || {
                 e_new_carry
                     .map(pallas::Base::from_u64)
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
@@ -892,7 +892,7 @@ impl CompressionConfig {
             || {
                 a_new_carry
                     .map(pallas::Base::from_u64)
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
diff --git a/examples/sha256/table16/compression/subregion_digest.rs b/examples/sha256/table16/compression/subregion_digest.rs
index 5aa866da..201fca20 100644
--- a/examples/sha256/table16/compression/subregion_digest.rs
+++ b/examples/sha256/table16/compression/subregion_digest.rs
@@ -42,7 +42,7 @@ impl CompressionConfig {
             abcd_row,
             || {
                 a.map(|a| pallas::Base::from_u64(a as u64))
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
@@ -64,7 +64,7 @@ impl CompressionConfig {
             efgh_row,
             || {
                 e.map(|e| pallas::Base::from_u64(e as u64))
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
@@ -103,7 +103,7 @@ impl CompressionConfig {
             row,
             || {
                 val.map(|val| pallas::Base::from_u64(val as u64))
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
diff --git a/examples/sha256/table16/message_schedule/subregion2.rs b/examples/sha256/table16/message_schedule/subregion2.rs
index 34716569..b5240baf 100644
--- a/examples/sha256/table16/message_schedule/subregion2.rs
+++ b/examples/sha256/table16/message_schedule/subregion2.rs
@@ -253,7 +253,7 @@ impl MessageScheduleConfig {
                 get_word_row(new_word_idx - 16) + 1,
                 || {
                     word.map(|word| pallas::Base::from_u64(word as u64))
-                        .ok_or(Error::SynthesisError)
+                        .ok_or(Error::Synthesis)
                 },
             )?;
             region.assign_advice(
@@ -263,7 +263,7 @@ impl MessageScheduleConfig {
                 || {
                     carry
                         .map(|carry| pallas::Base::from_u64(carry as u64))
-                        .ok_or(Error::SynthesisError)
+                        .ok_or(Error::Synthesis)
                 },
             )?;
             let (word, halves) = self.assign_word_and_halves(region, word, new_word_idx)?;
diff --git a/examples/sha256/table16/message_schedule/subregion3.rs b/examples/sha256/table16/message_schedule/subregion3.rs
index 7183858b..30f8382d 100644
--- a/examples/sha256/table16/message_schedule/subregion3.rs
+++ b/examples/sha256/table16/message_schedule/subregion3.rs
@@ -169,7 +169,7 @@ impl MessageScheduleConfig {
                 get_word_row(new_word_idx - 16) + 1,
                 || {
                     word.map(|word| pallas::Base::from_u64(word as u64))
-                        .ok_or(Error::SynthesisError)
+                        .ok_or(Error::Synthesis)
                 },
             )?;
             region.assign_advice(
@@ -179,7 +179,7 @@ impl MessageScheduleConfig {
                 || {
                     carry
                         .map(|carry| pallas::Base::from_u64(carry as u64))
-                        .ok_or(Error::SynthesisError)
+                        .ok_or(Error::Synthesis)
                 },
             )?;
             let (word, halves) = self.assign_word_and_halves(region, word, new_word_idx)?;
diff --git a/examples/sha256/table16/spread_table.rs b/examples/sha256/table16/spread_table.rs
index 93263271..fd239932 100644
--- a/examples/sha256/table16/spread_table.rs
+++ b/examples/sha256/table16/spread_table.rs
@@ -90,7 +90,7 @@ impl<const DENSE: usize, const SPREAD: usize> SpreadVar<DENSE, SPREAD> {
             row,
             || {
                 tag.map(|tag| pallas::Base::from_u64(tag as u64))
-                    .ok_or(Error::SynthesisError)
+                    .ok_or(Error::Synthesis)
             },
         )?;
 
@@ -229,23 +229,20 @@ impl<F: FieldExt> SpreadTableChip<F> {
                         index,
                         || {
                             row = rows.next();
-                            row.map(|(tag, _, _)| tag).ok_or(Error::SynthesisError)
+                            row.map(|(tag, _, _)| tag).ok_or(Error::Synthesis)
                         },
                     )?;
                     table.assign_cell(
                         || "dense",
                         config.table.dense,
                         index,
-                        || row.map(|(_, dense, _)| dense).ok_or(Error::SynthesisError),
+                        || row.map(|(_, dense, _)| dense).ok_or(Error::Synthesis),
                     )?;
                     table.assign_cell(
                         || "spread",
                         config.table.spread,
                         index,
-                        || {
-                            row.map(|(_, _, spread)| spread)
-                                .ok_or(Error::SynthesisError)
-                        },
+                        || row.map(|(_, _, spread)| spread).ok_or(Error::Synthesis),
                     )?;
                 }
 
@@ -336,7 +333,7 @@ mod tests {
                     || "spread_test",
                     |mut gate| {
                         let mut row = 0;
-                        let mut add_row = |tag, dense, spread| {
+                        let mut add_row = |tag, dense, spread| -> Result<(), Error> {
                             gate.assign_advice(|| "tag", config.input.tag, row, || Ok(tag))?;
                             gate.assign_advice(|| "dense", config.input.dense, row, || Ok(dense))?;
                             gate.assign_advice(