Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514

Remove useless borrows and derefs

They are nothing more than noise.
<sub>These are not all of them, but my clippy started crashing (stack overflow), so rip :(</sub>

compiler/rustc_span/src/analyze_source_file.rs

@@ -247,7 +247,7 @@ fn analyze_source_file_generic(
             // The slow path:
             // This is either ASCII control character "DEL" or the beginning of
             // a multibyte char. Just decode to `char`.
-            let c = (&src[i..]).chars().next().unwrap();
+            let c = src[i..].chars().next().unwrap();
             char_len = c.len_utf8();
 
             let pos = BytePos::from_usize(i) + output_offset;

compiler/rustc_span/src/caching_source_map_view.rs

@@ -165,7 +165,7 @@ impl<'sm> CachingSourceMapView<'sm> {
             Some(new_file_and_idx)
         } else {
             let file = &self.line_cache[oldest].file;
-            if !file_contains(&file, span_data.hi) {
+            if !file_contains(file, span_data.hi) {
                 return None;
             }
 

compiler/rustc_span/src/hygiene.rs

@@ -381,7 +381,7 @@ impl HygieneData {
     }
 
     pub fn with<T, F: FnOnce(&mut HygieneData) -> T>(f: F) -> T {
-        with_session_globals(|session_globals| f(&mut *session_globals.hygiene_data.borrow_mut()))
+        with_session_globals(|session_globals| f(&mut session_globals.hygiene_data.borrow_mut()))
     }
 
     #[inline]

compiler/rustc_span/src/lib.rs

@@ -238,7 +238,7 @@ impl RealFileName {
     pub fn remapped_path_if_available(&self) -> &Path {
         match self {
             RealFileName::LocalPath(p)
-            | RealFileName::Remapped { local_path: _, virtual_name: p } => &p,
+            | RealFileName::Remapped { local_path: _, virtual_name: p } => p,
         }
     }
 

compiler/rustc_span/src/span_encoding.rs

@@ -166,5 +166,5 @@ impl SpanInterner {
 // If an interner exists, return it. Otherwise, prepare a fresh one.
 #[inline]
 fn with_span_interner<T, F: FnOnce(&mut SpanInterner) -> T>(f: F) -> T {
-    crate::with_session_globals(|session_globals| f(&mut *session_globals.span_interner.lock()))
+    crate::with_session_globals(|session_globals| f(&mut session_globals.span_interner.lock()))
 }

compiler/rustc_span/src/symbol.rs

@@ -1877,7 +1877,7 @@ impl<S: Encoder> Encodable<S> for Symbol {
 impl<D: Decoder> Decodable<D> for Symbol {
     #[inline]
     default fn decode(d: &mut D) -> Symbol {
-        Symbol::intern(&d.read_str())
+        Symbol::intern(d.read_str())
     }
 }