Improves slightly code style

lib/src/model/literal.rs

@@ -72,10 +72,10 @@ impl Literal {
 
     /// The literal [lexical form](https://www.w3.org/TR/rdf11-concepts/#dfn-lexical-form)
     pub fn value(&self) -> &str {
-        match self.0 {
-            LiteralContent::String(ref value)
-            | LiteralContent::LanguageTaggedString { ref value, .. }
-            | LiteralContent::TypedLiteral { ref value, .. } => value,
+        match &self.0 {
+            LiteralContent::String(value)
+            | LiteralContent::LanguageTaggedString { value, .. }
+            | LiteralContent::TypedLiteral { value, .. } => value,
         }
     }
 
@@ -83,9 +83,9 @@ impl Literal {
     ///
     /// Language tags are defined by the [BCP47](https://tools.ietf.org/html/bcp47).
     /// They are normalized to lowercase by this implementation.
-    pub fn language(&self) -> Option<&String> {
-        match self.0 {
-            LiteralContent::LanguageTaggedString { ref language, .. } => Some(language),
+    pub fn language(&self) -> Option<&str> {
+        match &self.0 {
+            LiteralContent::LanguageTaggedString { language, .. } => Some(language),
             _ => None,
         }
     }
@@ -95,10 +95,10 @@ impl Literal {
     /// The datatype of [language-tagged string](https://www.w3.org/TR/rdf11-concepts/#dfn-language-tagged-string) is always [rdf:langString](http://www.w3.org/1999/02/22-rdf-syntax-ns#langString).
     /// The datatype of [simple literals](https://www.w3.org/TR/rdf11-concepts/#dfn-simple-literal) is [xsd:string](http://www.w3.org/2001/XMLSchema#string).
     pub fn datatype(&self) -> &NamedNode {
-        match self.0 {
+        match &self.0 {
             LiteralContent::String(_) => &xsd::STRING,
             LiteralContent::LanguageTaggedString { .. } => &rdf::LANG_STRING,
-            LiteralContent::TypedLiteral { ref datatype, .. } => datatype,
+            LiteralContent::TypedLiteral { datatype, .. } => datatype,
         }
     }
 

lib/src/repository.rs

@@ -113,6 +113,7 @@ pub trait RepositoryConnection: Clone {
     /// assert_eq!(vec![quad], results?);
     /// # Result::Ok(())
     /// ```
+    #[allow(clippy::option_option)]
     fn quads_for_pattern<'a>(
         &'a self,
         subject: Option<&NamedOrBlankNode>,

lib/src/sparql/eval.rs

@@ -2503,6 +2503,7 @@ impl Accumulator for AvgAccumulator {
     }
 }
 
+#[allow(clippy::option_option)]
 struct MinAccumulator<'a, S: StoreConnection + 'a> {
     eval: &'a SimpleEvaluator<S>,
     min: Option<Option<EncodedTerm>>,
@@ -2530,6 +2531,7 @@ impl<'a, S: StoreConnection + 'a> Accumulator for MinAccumulator<'a, S> {
     }
 }
 
+#[allow(clippy::option_option)]
 struct MaxAccumulator<'a, S: StoreConnection + 'a> {
     eval: &'a SimpleEvaluator<S>,
     max: Option<Option<EncodedTerm>>,
@@ -2574,6 +2576,7 @@ impl Accumulator for SampleAccumulator {
     }
 }
 
+#[allow(clippy::option_option)]
 struct GroupConcatAccumulator<'a, S: StoreConnection + 'a> {
     eval: &'a SimpleEvaluator<S>,
     concat: Option<String>,

lib/src/sparql/mod.rs

@@ -63,9 +63,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
         let dataset = DatasetView::new(connection, options.default_graph_as_union);
         Ok(Self(match read_sparql_query(query, options.base_iri)? {
             QueryVariants::Select {
-                algebra,
-                dataset: _,
-                base_iri,
+                algebra, base_iri, ..
             } => {
                 let (plan, variables) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Select {
@@ -75,9 +73,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                 }
             }
             QueryVariants::Ask {
-                algebra,
-                dataset: _,
-                base_iri,
+                algebra, base_iri, ..
             } => {
                 let (plan, _) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Ask {
@@ -88,8 +84,8 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
             QueryVariants::Construct {
                 construct,
                 algebra,
-                dataset: _,
                 base_iri,
+                ..
             } => {
                 let (plan, variables) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Construct {
@@ -103,9 +99,7 @@ impl<'a, S: StoreConnection + 'a> SimplePreparedQuery<S> {
                 }
             }
             QueryVariants::Describe {
-                algebra,
-                dataset: _,
-                base_iri,
+                algebra, base_iri, ..
             } => {
                 let (plan, _) = PlanBuilder::build(dataset.encoder(), &algebra)?;
                 SimplePreparedQueryAction::Describe {

lib/src/sparql/xml_results.rs

@@ -78,7 +78,7 @@ pub fn write_xml_results<W: Write>(results: QueryResult<'_>, sink: W) -> Result<
                             Term::Literal(literal) => {
                                 let mut literal_tag = BytesStart::borrowed_name(b"literal");
                                 if let Some(language) = literal.language() {
-                                    literal_tag.push_attribute(("xml:lang", language.as_str()));
+                                    literal_tag.push_attribute(("xml:lang", language));
                                 } else if !literal.is_plain() {
                                     literal_tag
                                         .push_attribute(("datatype", literal.datatype().as_str()));

lib/src/store/memory.rs

@@ -7,7 +7,7 @@ use std::iter::{empty, once};
 use std::sync::{PoisonError, RwLock, RwLockReadGuard, RwLockWriteGuard};
 
 /// Memory based implementation of the `Repository` trait.
-/// They are cheap to build using the `MemoryRepository::default()` method.
+/// It is cheap to build using the `MemoryRepository::default()` method.
 ///
 /// Usage example:
 /// ```

lib/src/store/rocksdb.rs

@@ -11,7 +11,7 @@ use std::str;
 
 /// `Repository` implementation based on the [RocksDB](https://rocksdb.org/) key-value store
 ///
-/// To use it, the `"rocksdb"` feature need to be activated.
+/// To use it, the `"rocksdb"` feature needs to be activated.
 ///
 /// Usage example:
 /// ```