diff --git a/lib/codegen/src/postopt.rs b/lib/codegen/src/postopt.rs
index 517621bef5..29ef49f758 100644
--- a/lib/codegen/src/postopt.rs
+++ b/lib/codegen/src/postopt.rs
@@ -218,7 +218,7 @@ fn optimize_complex_addresses(pos: &mut EncCursor, inst: Inst, isa: &TargetIsa)
     if let ValueDef::Result(result_inst, _) = pos.func.dfg.value_def(info.arg) {
         match pos.func.dfg[result_inst] {
             InstructionData::Binary { opcode, args } if opcode == Opcode::Iadd => {
-                info.add_args = Some(args.clone());
+                info.add_args = Some(args);
             }
             _ => return,
         }
diff --git a/lib/codegen/src/print_errors.rs b/lib/codegen/src/print_errors.rs
index 068997e5c4..3cf6af6daa 100644
--- a/lib/codegen/src/print_errors.rs
+++ b/lib/codegen/src/print_errors.rs
@@ -61,7 +61,7 @@ fn pretty_function_error(
                 )
             }
         }
-        _ => write!(w, "{}", "\n"),
+        _ => writeln!(w),
     }
 }
 
diff --git a/lib/codegen/src/regalloc/coalescing.rs b/lib/codegen/src/regalloc/coalescing.rs
index 0f00730fb8..687cb84c71 100644
--- a/lib/codegen/src/regalloc/coalescing.rs
+++ b/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.
diff --git a/lib/codegen/src/regalloc/pressure.rs b/lib/codegen/src/regalloc/pressure.rs
index 65651987a7..ef8ec425aa 100644
--- a/lib/codegen/src/regalloc/pressure.rs
+++ b/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)
diff --git a/lib/faerie/src/backend.rs b/lib/faerie/src/backend.rs
index 3b18c21d0e..a2ce1e2b4b 100644
--- a/lib/faerie/src/backend.rs
+++ b/lib/faerie/src/backend.rs
@@ -157,7 +157,7 @@ impl Backend for FaerieBackend {
                 artifact: &mut self.artifact,
                 name,
                 namespace,
-                libcall_names: &self.libcall_names,
+                libcall_names: &*self.libcall_names,
             };
 
             if let Some(ref mut trap_manifest) = self.trap_manifest {
@@ -347,7 +347,7 @@ struct FaerieRelocSink<'a> {
     artifact: &'a mut faerie::Artifact,
     name: &'a str,
     namespace: &'a ModuleNamespace<'a, FaerieBackend>,
-    libcall_names: &'a Box<Fn(ir::LibCall) -> String>,
+    libcall_names: &'a Fn(ir::LibCall) -> String,
 }
 
 impl<'a> RelocSink for FaerieRelocSink<'a> {