Fix clippy errors

Add clippy job

Add clippy job to CI

.github/workflows/rust.yml

@@ -66,6 +66,24 @@ jobs:
         with:
           command: clippy
 
+  clippy:
+    name: Run Clippy
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+          components: clippy
+      - name: Cache dependencies
+        uses: Swatinem/rust-cache@v2.0.0
+      - name: Run cargo clippy
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+
   fmt:
     name: Run Rustfmt
     runs-on: ubuntu-20.04

milli/src/search/criteria/mod.rs

@@ -432,18 +432,10 @@ pub fn resolve_phrase(ctx: &dyn Context, phrase: &[Option<String>]) -> Result<Ro
         // Get all the documents with the matching distance for each word pairs.
         let mut bitmaps = Vec::with_capacity(winsize.pow(2));
         for (offset, s1) in win.iter().enumerate().filter_map(|(index, word)| {
-            if let Some(word) = word {
+            word.as_ref().map(|word| (index, word))
-                Some((index, word))
-            } else {
-                None
-            }
         }) {
             for (dist, s2) in win.iter().skip(offset + 1).enumerate().filter_map(|(index, word)| {
-                if let Some(word) = word {
+                word.as_ref().map(|word| (index, word))
-                    Some((index, word))
-                } else {
-                    None
-                }
             }) {
                 if dist == 0 {
                     match ctx.word_pair_proximity_docids(s1, s2, 1)? {

milli/src/search/criteria/proximity.rs

@@ -488,7 +488,7 @@ fn resolve_plane_sweep_candidates(
                     }
                     // make a consecutive plane-sweep on the subgroup of words.
                     let mut subgroup = Vec::with_capacity(words.len());
-                    for word in words.into_iter().map(|w| w.as_deref().unwrap()) {
+                    for word in words.iter().map(|w| w.as_deref().unwrap()) {
                         match words_positions.get(word) {
                             Some(positions) => {
                                 subgroup.push(positions.iter().map(|p| (p, 0, p)).collect())

milli/src/search/query_tree.rs

@@ -591,7 +591,7 @@ fn create_matching_words(
                     (0..words.len()).into_iter().map(|i| id + i as PrimitiveWordId).collect();
                 let words = words
                     .into_iter()
-                    .filter_map(|w| w)
+                    .flatten()
                     .map(|w| MatchingWord::new(w, 0, false))
                     .collect();
                 matching_words.push((words, ids));

milli/src/update/index_documents/extract/extract_docid_word_positions.rs

@@ -80,7 +80,7 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
                                 .map_err(|_| SerializationError::InvalidNumberSerialization)?;
                             let position = absolute_from_relative_position(field_id, position);
                             docid_word_positions_sorter
-                                .insert(&key_buffer, &position.to_ne_bytes())?;
+                                .insert(&key_buffer, position.to_ne_bytes())?;
                         }
                     }
                 }

milli/src/update/index_documents/extract/extract_facet_string_docids.rs

@@ -43,7 +43,7 @@ pub fn extract_facet_string_docids<R: io::Read + io::Seek>(
         let key_bytes = FacetGroupKeyCodec::<StrRefCodec>::bytes_encode(&key).unwrap();
 
         // document id is encoded in native-endian because of the CBO roaring bitmap codec
-        facet_string_docids_sorter.insert(&key_bytes, &document_id.to_ne_bytes())?;
+        facet_string_docids_sorter.insert(&key_bytes, document_id.to_ne_bytes())?;
     }
 
     sorter_into_reader(facet_string_docids_sorter, indexer)

milli/src/update/index_documents/extract/extract_word_pair_proximity_docids.rs

@@ -145,7 +145,7 @@ fn document_word_positions_into_sorter(
         key_buffer.push(0);
         key_buffer.extend_from_slice(w2.as_bytes());
 
-        word_pair_proximity_docids_sorter.insert(&key_buffer, &document_id.to_ne_bytes())?;
+        word_pair_proximity_docids_sorter.insert(&key_buffer, document_id.to_ne_bytes())?;
     }
 
     Ok(())

milli/src/update/index_documents/extract/extract_word_position_docids.rs

@@ -41,7 +41,7 @@ pub fn extract_word_position_docids<R: io::Read + io::Seek>(
             key_buffer.extend_from_slice(word_bytes);
             key_buffer.extend_from_slice(&position.to_be_bytes());
 
-            word_position_docids_sorter.insert(&key_buffer, &document_id.to_ne_bytes())?;
+            word_position_docids_sorter.insert(&key_buffer,document_id.to_ne_bytes())?;
         }
     }
 

milli/src/update/index_documents/transform.rs

@@ -248,7 +248,7 @@ impl<'a, 'i> Transform<'a, 'i> {
                     skip_insertion = true;
                 } else {
                     // we associate the base document with the new key, everything will get merged later.
-                    self.original_sorter.insert(&docid.to_be_bytes(), base_obkv)?;
+                    self.original_sorter.insert(docid.to_be_bytes(), base_obkv)?;
                     match self.flatten_from_fields_ids_map(KvReader::new(base_obkv))? {
                         Some(buffer) => {
                             self.flattened_sorter.insert(docid.to_be_bytes(), &buffer)?
@@ -261,7 +261,7 @@ impl<'a, 'i> Transform<'a, 'i> {
             if !skip_insertion {
                 self.new_documents_ids.insert(docid);
                 // We use the extracted/generated user id as the key for this document.
-                self.original_sorter.insert(&docid.to_be_bytes(), obkv_buffer.clone())?;
+                self.original_sorter.insert(docid.to_be_bytes(), obkv_buffer.clone())?;
 
                 match self.flatten_from_fields_ids_map(KvReader::new(&obkv_buffer))? {
                     Some(buffer) => self.flattened_sorter.insert(docid.to_be_bytes(), &buffer)?,