Implemented clippy improvements

lib/codegen/src/regalloc/coalescing.rs

@@ -1012,7 +1012,7 @@ impl VirtualCopies {
     /// Returns `None` if none of the currently active parameters are defined at `ebb`. Otherwise
     /// returns `(set_id, argnum)` for an active parameter defined at `ebb`.
     fn lookup(&self, ebb: Ebb) -> Option<(u8, usize)> {
-        self.filter.get(&ebb).map(|t| *t)
+        self.filter.get(&ebb).cloned()
     }
 
     /// Get an iterator of dom-forest nodes corresponding to the current filter.

lib/codegen/src/regalloc/pressure.rs

@@ -204,16 +204,16 @@ impl Pressure {
     ///
     /// This does not check if there are enough registers available.
     pub fn take(&mut self, rc: RegClass) {
-        self.toprc
-            .get_mut(rc.toprc as usize)
-            .map(|t| t.base_count += 1);
+        if let Some(t) = self.toprc.get_mut(rc.toprc as usize) {
+            t.base_count += 1;
+        }
     }
 
     /// Free a register in `rc`.
     pub fn free(&mut self, rc: RegClass) {
-        self.toprc
-            .get_mut(rc.toprc as usize)
-            .map(|t| t.base_count -= 1);
+        if let Some(t) = self.toprc.get_mut(rc.toprc as usize) {
+            t.base_count -= 1;
+        }
     }
 
     /// Reset all counts to 0, both base and transient.
@@ -230,9 +230,10 @@ impl Pressure {
     pub fn take_transient(&mut self, rc: RegClass) -> Result<(), RegClassMask> {
         let mask = self.check_avail(rc);
         if mask == 0 {
-            self.toprc
-                .get_mut(rc.toprc as usize)
-                .map(|t| t.transient_count += 1);
+            if let Some(t) = self.toprc.get_mut(rc.toprc as usize) {
+                t.transient_count += 1;
+            }
+
             Ok(())
         } else {
             Err(mask)