Make milli use edition 2021 (#4770)

* Make milli use edition 2021

* Add lifetime annotations to milli.

* Run cargo fmt

milli/src/documents/enriched.rs

@@ -95,7 +95,7 @@ impl<R: io::Read + io::Seek> EnrichedDocumentsBatchCursor<R> {
     /// `next_document` advance the document reader until all the documents have been read.
     pub fn next_enriched_document(
         &mut self,
-    ) -> Result<Option<EnrichedDocument>, DocumentsBatchCursorError> {
+    ) -> Result<Option<EnrichedDocument<'_>>, DocumentsBatchCursorError> {
         let document = self.documents.next_document()?;
         let document_id = match self.external_ids.move_on_next()? {
             Some((_, bytes)) => serde_json::from_slice(bytes).map(Some)?,

milli/src/documents/mod.rs

@@ -27,7 +27,7 @@ use crate::{FieldId, Object, Result};
 const DOCUMENTS_BATCH_INDEX_KEY: [u8; 8] = u64::MAX.to_be_bytes();
 
 /// Helper function to convert an obkv reader into a JSON object.
-pub fn obkv_to_object(obkv: &KvReader<FieldId>, index: &DocumentsBatchIndex) -> Result<Object> {
+pub fn obkv_to_object(obkv: &KvReader<'_, FieldId>, index: &DocumentsBatchIndex) -> Result<Object> {
     obkv.iter()
         .map(|(field_id, value)| {
             let field_name = index
@@ -64,7 +64,7 @@ impl DocumentsBatchIndex {
         self.0.len()
     }
 
-    pub fn iter(&self) -> bimap::hash::Iter<FieldId, String> {
+    pub fn iter(&self) -> bimap::hash::Iter<'_, FieldId, String> {
         self.0.iter()
     }
 
@@ -76,7 +76,7 @@ impl DocumentsBatchIndex {
         self.0.get_by_right(name).cloned()
     }
 
-    pub fn recreate_json(&self, document: &obkv::KvReaderU16) -> Result<Object> {
+    pub fn recreate_json(&self, document: &obkv::KvReaderU16<'_>) -> Result<Object> {
         let mut map = Object::new();
 
         for (k, v) in document.iter() {

milli/src/documents/primary_key.rs

@@ -52,7 +52,7 @@ impl<'a> PrimaryKey<'a> {
 
     pub fn document_id(
         &self,
-        document: &obkv::KvReader<FieldId>,
+        document: &obkv::KvReader<'_, FieldId>,
         fields: &impl FieldIdMapper,
     ) -> Result<StdResult<String, DocumentIdExtractionError>> {
         match self {

milli/src/documents/reader.rs

@@ -76,7 +76,7 @@ impl<R: io::Read + io::Seek> DocumentsBatchCursor<R> {
     /// `next_document` advance the document reader until all the documents have been read.
     pub fn next_document(
         &mut self,
-    ) -> Result<Option<KvReader<FieldId>>, DocumentsBatchCursorError> {
+    ) -> Result<Option<KvReader<'_, FieldId>>, DocumentsBatchCursorError> {
         match self.cursor.move_on_next()? {
             Some((key, value)) if key != DOCUMENTS_BATCH_INDEX_KEY => {
                 Ok(Some(KvReader::new(value)))
@@ -108,7 +108,7 @@ impl From<serde_json::Error> for DocumentsBatchCursorError {
 impl error::Error for DocumentsBatchCursorError {}
 
 impl fmt::Display for DocumentsBatchCursorError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             DocumentsBatchCursorError::Grenad(e) => e.fmt(f),
             DocumentsBatchCursorError::SerdeJson(e) => e.fmt(f),

milli/src/documents/serde_impl.rs

@@ -56,7 +56,7 @@ impl<'a, 'de, W: Write> Visitor<'de> for &mut DocumentVisitor<'a, W> {
         Ok(Ok(()))
     }
 
-    fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "a documents, or a sequence of documents.")
     }
 }