diff --git a/libafl_qemu/src/asan.rs b/libafl_qemu/src/asan.rs
index 5eb9cf24bd..0de137cd5b 100644
--- a/libafl_qemu/src/asan.rs
+++ b/libafl_qemu/src/asan.rs
@@ -99,7 +99,7 @@ extern "C" {
 static mut ASAN_INITED: bool = false;
 
 pub fn init_with_asan(args: &mut Vec<String>, env: &mut [(String, String)]) -> i32 {
-    assert!(args.len() > 0);
+    assert!(!args.is_empty());
     let current = env::current_exe().unwrap();
     let asan_lib = fs::canonicalize(&current)
         .unwrap()
@@ -117,7 +117,7 @@ pub fn init_with_asan(args: &mut Vec<String>, env: &mut [(String, String)]) -> i
     for (k, v) in env.iter_mut() {
         if k == "QEMU_SET_ENV" {
             let mut new_v = vec![];
-            for e in v.split(",") {
+            for e in v.split(',') {
                 if e.starts_with("LD_PRELOAD=") {
                     added = true;
                     new_v.push(add_asan(e));
@@ -129,11 +129,9 @@ pub fn init_with_asan(args: &mut Vec<String>, env: &mut [(String, String)]) -> i
         }
     }
     for i in 0..args.len() {
-        if args[i] == "-E" && i + 1 < args.len() {
-            if args[i + 1].starts_with("LD_PRELOAD=") {
-                added = true;
-                args[i + 1] = add_asan(&args[i + 1])
-            }
+        if args[i] == "-E" && i + 1 < args.len() && args[i + 1].starts_with("LD_PRELOAD=") {
+            added = true;
+            args[i + 1] = add_asan(&args[i + 1]);
         }
     }
 
@@ -158,7 +156,7 @@ pub struct QemuAsanHelper {
 impl QemuAsanHelper {
     #[must_use]
     pub fn new() -> Self {
-        assert!(unsafe { ASAN_INITED == true }, "The ASan runtime is not initialized, use init_with_asan(...) instead of just init(...)");
+        assert!(unsafe { ASAN_INITED }, "The ASan runtime is not initialized, use init_with_asan(...) instead of just init(...)");
         Self {
             enabled: true,
             filter: QemuInstrumentationFilter::None,
@@ -216,6 +214,7 @@ impl QemuAsanHelper {
     }
 
     #[allow(clippy::unused_self)]
+    #[must_use]
     pub fn is_poisoned(&self, addr: u64, size: usize) -> bool {
         unsafe { asan_giovese_loadN(emu::g2h(addr), size) != 0 }
     }
@@ -454,6 +453,7 @@ pub fn trace_write_n_asan<I, QT, S>(
     h.read_n(addr, size);
 }
 
+#[allow(clippy::too_many_arguments)]
 pub fn qasan_fake_syscall<I, QT, S>(
     helpers: &mut QT,
     _state: &mut S,
diff --git a/libafl_qemu/src/cmplog.rs b/libafl_qemu/src/cmplog.rs
index db7cbf08ab..47ba7f3613 100644
--- a/libafl_qemu/src/cmplog.rs
+++ b/libafl_qemu/src/cmplog.rs
@@ -1,9 +1,9 @@
+use hashbrown::{hash_map::Entry, HashMap};
 use libafl::{executors::ExitKind, inputs::Input, observers::ObserversTuple, state::HasMetadata};
 pub use libafl_targets::{
     cmplog::__libafl_targets_cmplog_instructions, CmpLogObserver, CMPLOG_MAP, CMPLOG_MAP_W,
 };
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 
 use crate::{
     emu,
@@ -101,13 +101,11 @@ where
         .get_mut::<QemuCmpsMapMetadata>()
         .unwrap();
     let id = meta.current_id as usize;
-    if meta.map.contains_key(&pc) {
-        Some(*meta.map.get(&pc).unwrap())
-    } else {
+
+    Some(*meta.map.entry(pc).or_insert_with(|| {
         meta.current_id = ((id + 1) & (CMPLOG_MAP_W - 1)) as u64;
-        meta.map.insert(pc, id as u64);
-        Some(id as u64)
-    }
+        id as u64
+    }))
 }
 
 pub extern "C" fn trace_cmp1_cmplog(id: u64, v0: u8, v1: u8) {
diff --git a/libafl_qemu/src/edges.rs b/libafl_qemu/src/edges.rs
index 484b21732f..b9e9c6aac5 100644
--- a/libafl_qemu/src/edges.rs
+++ b/libafl_qemu/src/edges.rs
@@ -1,7 +1,8 @@
+use hashbrown::{hash_map::Entry, HashMap};
 use libafl::{executors::ExitKind, inputs::Input, observers::ObserversTuple, state::HasMetadata};
 pub use libafl_targets::{EDGES_MAP, EDGES_MAP_SIZE, MAX_EDGES_NUM};
 use serde::{Deserialize, Serialize};
-use std::{cell::UnsafeCell, cmp::max, collections::HashMap};
+use std::{cell::UnsafeCell, cmp::max};
 
 use crate::{
     emu,
@@ -104,21 +105,25 @@ where
         .metadata_mut()
         .get_mut::<QemuEdgesMapMetadata>()
         .unwrap();
-    if meta.map.contains_key(&(src, dest)) {
-        let id = *meta.map.get(&(src, dest)).unwrap();
-        let nxt = (id as usize + 1) & (EDGES_MAP_SIZE - 1);
-        unsafe {
-            MAX_EDGES_NUM = max(MAX_EDGES_NUM, nxt);
+
+    match meta.map.entry((src, dest)) {
+        Entry::Occupied(e) => {
+            let id = *e.get();
+            let nxt = (id as usize + 1) & (EDGES_MAP_SIZE - 1);
+            unsafe {
+                MAX_EDGES_NUM = max(MAX_EDGES_NUM, nxt);
+            }
+            Some(id)
         }
-        Some(id)
-    } else {
-        let id = meta.current_id;
-        meta.map.insert((src, dest), id);
-        meta.current_id = (id + 1) & (EDGES_MAP_SIZE as u64 - 1);
-        unsafe {
-            MAX_EDGES_NUM = meta.current_id as usize;
+        Entry::Vacant(e) => {
+            let id = meta.current_id;
+            e.insert(id);
+            meta.current_id = (id + 1) & (EDGES_MAP_SIZE as u64 - 1);
+            unsafe {
+                MAX_EDGES_NUM = meta.current_id as usize;
+            }
+            Some(id as u64)
         }
-        Some(id as u64)
     }
 }
 
diff --git a/libafl_qemu/src/emu.rs b/libafl_qemu/src/emu.rs
index 6d65e65a4b..bf28803fa0 100644
--- a/libafl_qemu/src/emu.rs
+++ b/libafl_qemu/src/emu.rs
@@ -232,7 +232,7 @@ extern "C" {
 
 #[allow(clippy::must_use_candidate, clippy::similar_names)]
 pub fn init(args: &[String], env: &[(String, String)]) -> i32 {
-    assert!(args.len() > 0);
+    assert!(!args.is_empty());
     let args: Vec<String> = args.iter().map(|x| x.clone() + "\0").collect();
     let argv: Vec<*const u8> = args.iter().map(|x| x.as_bytes().as_ptr()).collect();
     assert!(argv.len() < i32::MAX as usize);