diff --git a/lib/src/sparql/plan.rs b/lib/src/sparql/plan.rs
index 94f25393..c3340dcb 100644
--- a/lib/src/sparql/plan.rs
+++ b/lib/src/sparql/plan.rs
@@ -4,7 +4,7 @@ use crate::sparql::error::EvaluationError;
 use crate::sparql::model::Variable;
 use crate::store::numeric_encoder::{
     EncodedQuad, EncodedTerm, Encoder, MemoryStrStore, StrContainer, StrHash, StrLookup,
-    ENCODED_DEFAULT_GRAPH,
+    WithStoreError, ENCODED_DEFAULT_GRAPH,
 };
 use crate::store::ReadableEncodedStore;
 use std::cell::{RefCell, RefMut};
@@ -630,9 +630,10 @@ fn map_io_err<'a, T>(
     iter.map(|e| e.map_err(|e| e.into().into()))
 }
 
+impl<S: ReadableEncodedStore> WithStoreError for DatasetView<S> {
+    type Error = S::Error;
+}
 impl<S: ReadableEncodedStore> StrLookup for DatasetView<S> {
-    type Error = <S as StrLookup>::Error;
-
     fn get_str(&self, id: StrHash) -> Result<Option<String>, Self::Error> {
         if let Some(value) = self.extra.borrow().get_str(id).unwrap_infallible() {
             Ok(Some(value))
@@ -647,9 +648,11 @@ struct DatasetViewStrContainer<'a, S: ReadableEncodedStore> {
     extra: RefMut<'a, MemoryStrStore>,
 }
 
-impl<'a, S: ReadableEncodedStore> StrContainer for DatasetViewStrContainer<'a, S> {
-    type Error = <S as StrLookup>::Error;
+impl<'a, S: ReadableEncodedStore> WithStoreError for DatasetViewStrContainer<'a, S> {
+    type Error = S::Error;
+}
 
+impl<'a, S: ReadableEncodedStore> StrContainer for DatasetViewStrContainer<'a, S> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Self::Error> {
         if self.store.get_str(key)?.is_none() {
             self.extra.insert_str(key, value).unwrap();
diff --git a/lib/src/store/memory.rs b/lib/src/store/memory.rs
index 65931a3a..ca35e02d 100644
--- a/lib/src/store/memory.rs
+++ b/lib/src/store/memory.rs
@@ -76,10 +76,10 @@ impl Default for MemoryStore {
 impl MemoryStore {
     /// Constructs a new `MemoryStore`
     pub fn new() -> Self {
-        let mut new = Self {
+        let new = Self {
             indexes: Arc::new(RwLock::default()),
         };
-        new.set_first_strings().unwrap_infallible();
+        (&new).set_first_strings().unwrap_infallible();
         new
     }
 
@@ -687,51 +687,28 @@ impl MemoryStore {
     }
 }
 
-impl StrLookup for MemoryStore {
+impl WithStoreError for MemoryStore {
     type Error = Infallible;
-
-    fn get_str(&self, id: StrHash) -> Result<Option<String>, Infallible> {
-        //TODO: avoid copy by adding a lifetime limit to get_str
-        self.indexes().get_str(id)
-    }
 }
 
-impl StrLookup for MemoryStoreIndexes {
+impl<'a> WithStoreError for &'a MemoryStore {
     type Error = Infallible;
+}
 
+impl StrLookup for MemoryStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>, Infallible> {
         //TODO: avoid copy by adding a lifetime limit to get_str
-        Ok(self.id2str.get(&id).cloned())
-    }
-}
-
-impl StrContainer for MemoryStore {
-    type Error = Infallible;
-
-    fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
-        self.indexes_mut().insert_str(key, value)
+        self.indexes().get_str(id)
     }
 }
 
 impl<'a> StrContainer for &'a MemoryStore {
-    type Error = Infallible;
-
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
         self.indexes_mut().insert_str(key, value)
     }
 }
 
-impl StrContainer for MemoryStoreIndexes {
-    type Error = Infallible;
-
-    fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
-        self.id2str.entry(key).or_insert_with(|| value.to_owned());
-        Ok(())
-    }
-}
-
 impl<'a> ReadableEncodedStore for MemoryStore {
-    type Error = Infallible;
     type QuadsIter = EncodedQuadsIter;
 
     fn encoded_quads_for_pattern(
@@ -749,9 +726,7 @@ impl<'a> ReadableEncodedStore for MemoryStore {
     }
 }
 
-impl WritableEncodedStore for MemoryStore {
-    type Error = Infallible;
-
+impl<'a> WritableEncodedStore for &'a MemoryStore {
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         self.indexes_mut().insert_encoded(quad)
     }
@@ -761,21 +736,25 @@ impl WritableEncodedStore for MemoryStore {
     }
 }
 
-impl<'a> WritableEncodedStore for &'a MemoryStore {
+impl WithStoreError for MemoryStoreIndexes {
     type Error = Infallible;
+}
 
-    fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
-        self.indexes_mut().insert_encoded(quad)
+impl StrLookup for MemoryStoreIndexes {
+    fn get_str(&self, id: StrHash) -> Result<Option<String>, Infallible> {
+        //TODO: avoid copy by adding a lifetime limit to get_str
+        Ok(self.id2str.get(&id).cloned())
     }
+}
 
-    fn remove_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
-        self.indexes_mut().remove_encoded(quad)
+impl StrContainer for MemoryStoreIndexes {
+    fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
+        self.id2str.entry(key).or_insert_with(|| value.to_owned());
+        Ok(())
     }
 }
 
 impl WritableEncodedStore for MemoryStoreIndexes {
-    type Error = Infallible;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         insert_into_quad_map(
             &mut self.gosp,
@@ -1057,9 +1036,11 @@ impl<'a> MemoryTransaction<'a> {
     }
 }
 
-impl StrContainer for MemoryTransaction<'_> {
+impl WithStoreError for MemoryTransaction<'_> {
     type Error = Infallible;
+}
 
+impl StrContainer for MemoryTransaction<'_> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
         self.strings.push((key, value.to_owned()));
         Ok(())
@@ -1067,8 +1048,6 @@ impl StrContainer for MemoryTransaction<'_> {
 }
 
 impl WritableEncodedStore for MemoryTransaction<'_> {
-    type Error = Infallible;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         self.ops.push(TransactionOp::Insert(*quad));
         Ok(())
diff --git a/lib/src/store/mod.rs b/lib/src/store/mod.rs
index 4c0e507f..f287c347 100644
--- a/lib/src/store/mod.rs
+++ b/lib/src/store/mod.rs
@@ -34,9 +34,7 @@ use std::io::{BufRead, Write};
 use std::iter::Iterator;
 
 pub(crate) trait ReadableEncodedStore: StrLookup {
-    type Error: From<<Self as StrLookup>::Error> + Error + Into<io::Error> + 'static;
-    type QuadsIter: Iterator<Item = Result<EncodedQuad, <Self as ReadableEncodedStore>::Error>>
-        + 'static;
+    type QuadsIter: Iterator<Item = Result<EncodedQuad, Self::Error>> + 'static;
 
     fn encoded_quads_for_pattern(
         &self,
@@ -48,17 +46,9 @@ pub(crate) trait ReadableEncodedStore: StrLookup {
 }
 
 pub(crate) trait WritableEncodedStore: StrContainer {
-    type Error: From<<Self as StrContainer>::Error> + Error + Into<io::Error>;
+    fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Self::Error>;
 
-    fn insert_encoded(
-        &mut self,
-        quad: &EncodedQuad,
-    ) -> Result<(), <Self as WritableEncodedStore>::Error>;
-
-    fn remove_encoded(
-        &mut self,
-        quad: &EncodedQuad,
-    ) -> Result<(), <Self as WritableEncodedStore>::Error>;
+    fn remove_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Self::Error>;
 }
 
 fn load_graph<S: WritableEncodedStore>(
diff --git a/lib/src/store/numeric_encoder.rs b/lib/src/store/numeric_encoder.rs
index d07002c3..58cbcda5 100644
--- a/lib/src/store/numeric_encoder.rs
+++ b/lib/src/store/numeric_encoder.rs
@@ -853,15 +853,15 @@ pub fn write_term(sink: &mut Vec<u8>, term: EncodedTerm) {
     }
 }
 
-pub(crate) trait StrLookup {
-    type Error: Error + Into<io::Error>;
+pub(crate) trait WithStoreError {
+    type Error: Error + Into<io::Error> + 'static;
+}
 
+pub(crate) trait StrLookup: WithStoreError {
     fn get_str(&self, id: StrHash) -> Result<Option<String>, Self::Error>;
 }
 
-pub(crate) trait StrContainer {
-    type Error: Error + Into<io::Error>;
-
+pub(crate) trait StrContainer: WithStoreError {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Self::Error>;
 
     /// Should be called when the bytes store is created
@@ -901,9 +901,11 @@ impl Default for MemoryStrStore {
     }
 }
 
-impl StrLookup for MemoryStrStore {
+impl WithStoreError for MemoryStrStore {
     type Error = Infallible;
+}
 
+impl StrLookup for MemoryStrStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>, Infallible> {
         //TODO: avoid copy by adding a lifetime limit to get_str
         Ok(self.id2str.get(&id).cloned())
@@ -911,17 +913,13 @@ impl StrLookup for MemoryStrStore {
 }
 
 impl StrContainer for MemoryStrStore {
-    type Error = Infallible;
-
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
         self.id2str.entry(key).or_insert_with(|| value.to_owned());
         Ok(())
     }
 }
 
-pub(crate) trait Encoder {
-    type Error: Error + Into<io::Error>;
-
+pub(crate) trait Encoder: WithStoreError {
     fn encode_named_node(&mut self, named_node: &NamedNode) -> Result<EncodedTerm, Self::Error> {
         self.encode_rio_named_node(named_node.into())
     }
@@ -1051,8 +1049,6 @@ pub(crate) trait Encoder {
 }
 
 impl<S: StrContainer> Encoder for S {
-    type Error = S::Error;
-
     fn encode_rio_named_node(
         &mut self,
         named_node: rio::NamedNode<'_>,
diff --git a/lib/src/store/rocksdb.rs b/lib/src/store/rocksdb.rs
index ff40591a..6d698a15 100644
--- a/lib/src/store/rocksdb.rs
+++ b/lib/src/store/rocksdb.rs
@@ -467,9 +467,11 @@ impl fmt::Display for RocksDbStore {
     }
 }
 
-impl StrLookup for RocksDbStore {
+impl WithStoreError for RocksDbStore {
     type Error = io::Error;
+}
 
+impl StrLookup for RocksDbStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>, io::Error> {
         self.db
             .get_cf(self.id2str_cf(), &id.to_be_bytes())
@@ -481,7 +483,6 @@ impl StrLookup for RocksDbStore {
 }
 
 impl ReadableEncodedStore for RocksDbStore {
-    type Error = io::Error;
     type QuadsIter = DecodingIndexIterator;
 
     fn encoded_quads_for_pattern(
@@ -622,9 +623,11 @@ struct BatchWriter<'a> {
     buffer: Vec<u8>,
 }
 
-impl StrContainer for BatchWriter<'_> {
+impl WithStoreError for BatchWriter<'_> {
     type Error = Infallible;
+}
 
+impl StrContainer for BatchWriter<'_> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
         self.batch
             .put_cf(self.store.id2str_cf(), &key.to_be_bytes(), value);
@@ -633,8 +636,6 @@ impl StrContainer for BatchWriter<'_> {
 }
 
 impl WritableEncodedStore for BatchWriter<'_> {
-    type Error = Infallible;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         write_spog_quad(&mut self.buffer, quad);
         self.batch.put_cf(self.store.spog_cf(), &self.buffer, &[]);
@@ -702,17 +703,17 @@ struct AutoBatchWriter<'a> {
     inner: BatchWriter<'a>,
 }
 
-impl StrContainer for AutoBatchWriter<'_> {
+impl WithStoreError for AutoBatchWriter<'_> {
     type Error = io::Error;
+}
 
+impl StrContainer for AutoBatchWriter<'_> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), io::Error> {
         Ok(self.inner.insert_str(key, value)?)
     }
 }
 
 impl WritableEncodedStore for AutoBatchWriter<'_> {
-    type Error = io::Error;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), io::Error> {
         self.inner.insert_encoded(quad)?;
         self.apply_if_big()
diff --git a/lib/src/store/sled.rs b/lib/src/store/sled.rs
index e7a3647e..f1e50f1f 100644
--- a/lib/src/store/sled.rs
+++ b/lib/src/store/sled.rs
@@ -385,9 +385,11 @@ impl fmt::Display for SledStore {
     }
 }
 
-impl StrLookup for SledStore {
+impl WithStoreError for SledStore {
     type Error = io::Error;
+}
 
+impl StrLookup for SledStore {
     fn get_str(&self, id: StrHash) -> Result<Option<String>, io::Error> {
         self.id2str
             .get(id.to_be_bytes())?
@@ -398,7 +400,6 @@ impl StrLookup for SledStore {
 }
 
 impl ReadableEncodedStore for SledStore {
-    type Error = io::Error;
     type QuadsIter = DecodingQuadIterator;
 
     fn encoded_quads_for_pattern(
@@ -483,9 +484,11 @@ impl<'a> DirectWriter<'a> {
     }
 }
 
-impl<'a> StrContainer for DirectWriter<'a> {
+impl WithStoreError for DirectWriter<'_> {
     type Error = io::Error;
+}
 
+impl<'a> StrContainer for DirectWriter<'a> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), io::Error> {
         self.store
             .id2str
@@ -495,8 +498,6 @@ impl<'a> StrContainer for DirectWriter<'a> {
 }
 
 impl<'a> WritableEncodedStore for DirectWriter<'a> {
-    type Error = io::Error;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), io::Error> {
         write_spog_quad(&mut self.buffer, quad);
         self.store.quads.insert(self.buffer.as_slice(), &[])?;
@@ -580,9 +581,11 @@ impl<'a> BatchWriter<'a> {
     }
 }
 
-impl<'a> StrContainer for BatchWriter<'a> {
+impl WithStoreError for BatchWriter<'_> {
     type Error = Infallible;
+}
 
+impl<'a> StrContainer for BatchWriter<'a> {
     fn insert_str(&mut self, key: StrHash, value: &str) -> Result<(), Infallible> {
         self.id2str.insert(key.to_be_bytes().as_ref(), value);
         Ok(())
@@ -590,8 +593,6 @@ impl<'a> StrContainer for BatchWriter<'a> {
 }
 
 impl<'a> WritableEncodedStore for BatchWriter<'a> {
-    type Error = Infallible;
-
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         write_spog_quad(&mut self.buffer, quad);
         self.quads.insert(self.buffer.as_slice(), &[]);