diff --git a/libafl/src/bolts/serdeany.rs b/libafl/src/bolts/serdeany.rs
index 1d0062b36f..2ed0f77359 100644
--- a/libafl/src/bolts/serdeany.rs
+++ b/libafl/src/bolts/serdeany.rs
@@ -71,7 +71,6 @@ macro_rules! create_serde_registry_for_trait {
         pub mod $mod_name {
 
             use alloc::boxed::Box;
-            use alloc::string::String;
             use core::any::{Any, TypeId};
             use core::fmt;
             use postcard;
@@ -260,7 +259,7 @@ macro_rules! create_serde_registry_for_trait {
 
             impl NamedSerdeAnyMap {
                 #[inline]
-                pub fn get<T>(&self, name: &String) -> Option<&T>
+                pub fn get<T>(&self, name: &str) -> Option<&T>
                 where
                     T: Any,
                 {
@@ -273,11 +272,7 @@ macro_rules! create_serde_registry_for_trait {
                 }
 
                 #[inline]
-                pub fn by_typeid(
-                    &self,
-                    name: &String,
-                    typeid: &TypeId,
-                ) -> Option<&dyn $trait_name> {
+                pub fn by_typeid(&self, name: &str, typeid: &TypeId) -> Option<&dyn $trait_name> {
                     match self.map.get(&unpack_type_id(*typeid)) {
                         None => None,
                         Some(h) => h
@@ -287,7 +282,7 @@ macro_rules! create_serde_registry_for_trait {
                 }
 
                 #[inline]
-                pub fn get_mut<T>(&mut self, name: &String) -> Option<&mut T>
+                pub fn get_mut<T>(&mut self, name: &str) -> Option<&mut T>
                 where
                     T: Any,
                 {
@@ -302,7 +297,7 @@ macro_rules! create_serde_registry_for_trait {
                 #[inline]
                 pub fn by_typeid_mut(
                     &mut self,
-                    name: &String,
+                    name: &str,
                     typeid: &TypeId,
                 ) -> Option<&mut dyn $trait_name> {
                     match self.map.get_mut(&unpack_type_id(*typeid)) {
@@ -423,7 +418,7 @@ macro_rules! create_serde_registry_for_trait {
                 }
 
                 #[inline]
-                pub fn insert(&mut self, val: Box<dyn $trait_name>, name: &String) {
+                pub fn insert(&mut self, val: Box<dyn $trait_name>, name: &str) {
                     let id = unpack_type_id((*val).type_id());
                     if !self.map.contains_key(&id) {
                         self.map.insert(id, HashMap::default());
@@ -448,7 +443,7 @@ macro_rules! create_serde_registry_for_trait {
                 }
 
                 #[inline]
-                pub fn contains<T>(&self, name: &String) -> bool
+                pub fn contains<T>(&self, name: &str) -> bool
                 where
                     T: Any,
                 {
diff --git a/libafl/src/bolts/shmem.rs b/libafl/src/bolts/shmem.rs
index f6edf33ff8..6ddb7cbfed 100644
--- a/libafl/src/bolts/shmem.rs
+++ b/libafl/src/bolts/shmem.rs
@@ -71,7 +71,7 @@ pub trait ShMem: Sized + Debug {
     fn description(&self) -> ShMemDescription {
         ShMemDescription {
             size: self.map().len(),
-            str_bytes: self.shm_slice().clone(),
+            str_bytes: *self.shm_slice(),
         }
     }
 
@@ -103,7 +103,7 @@ pub trait ShMem: Sized + Debug {
 #[cfg(feature = "std")]
 pub mod shmem {
 
-    use core::{mem::size_of, slice};
+    use core::{mem::size_of, ptr, slice};
     use libc::{c_char, c_int, c_long, c_uchar, c_uint, c_ulong, c_ushort, c_void};
     use std::ffi::CStr;
 
@@ -222,7 +222,7 @@ pub mod shmem {
         pub fn from_str(shm_str: &CStr, map_size: usize) -> Result<Self, Error> {
             let mut ret = afl_shmem_unitialized();
             let map = unsafe { afl_shmem_by_str(&mut ret, shm_str, map_size) };
-            if map != 0 as *mut u8 {
+            if !map.is_null() {
                 Ok(ret)
             } else {
                 Err(Error::Unknown(format!(
@@ -235,7 +235,7 @@ pub mod shmem {
         pub fn new(map_size: usize) -> Result<Self, Error> {
             let mut ret = afl_shmem_unitialized();
             let map = unsafe { afl_shmem_init(&mut ret, map_size) };
-            if map != 0 as *mut u8 {
+            if !map.is_null() {
                 Ok(ret)
             } else {
                 Err(Error::Unknown(format!(
@@ -253,24 +253,24 @@ pub mod shmem {
             // Not set or not initialized;
             return;
         }
-        (*shm).shm_str[0 as usize] = '\u{0}' as u8;
-        shmctl((*shm).shm_id, 0 as c_int, 0 as *mut shmid_ds);
-        (*shm).map = 0 as *mut c_uchar;
+        (*shm).shm_str[0 as usize] = 0u8;
+        shmctl((*shm).shm_id, 0 as c_int, ptr::null_mut());
+        (*shm).map = ptr::null_mut();
     }
 
     /// Functions to create Shared memory region, for observation channels and
     /// opening inputs and stuff.
     unsafe fn afl_shmem_init(shm: *mut UnixShMem, map_size: usize) -> *mut c_uchar {
         (*shm).map_size = map_size;
-        (*shm).map = 0 as *mut c_uchar;
+        (*shm).map = ptr::null_mut();
         (*shm).shm_id = shmget(
             0 as c_int,
             map_size as c_ulong,
             0o1000 as c_int | 0o2000 as c_int | 0o600 as c_int,
         );
         if (*shm).shm_id < 0 as c_int {
-            (*shm).shm_str[0] = '\u{0}' as u8;
-            return 0 as *mut c_uchar;
+            (*shm).shm_str[0] = 0u8;
+            return ptr::null_mut();
         }
         snprintf(
             (*shm).shm_str.as_mut_ptr() as *mut c_char,
@@ -280,13 +280,13 @@ pub mod shmem {
         );
         (*shm).shm_str
             [(size_of::<[c_char; 20]>() as c_ulong).wrapping_sub(1 as c_int as c_ulong) as usize] =
-            '\u{0}' as u8;
-        (*shm).map = shmat((*shm).shm_id, 0 as *const c_void, 0 as c_int) as *mut c_uchar;
+            0u8;
+        (*shm).map = shmat((*shm).shm_id, ptr::null(), 0 as c_int) as *mut c_uchar;
         if (*shm).map == -(1 as c_int) as *mut c_void as *mut c_uchar || (*shm).map.is_null() {
-            shmctl((*shm).shm_id, 0 as c_int, 0 as *mut shmid_ds);
+            shmctl((*shm).shm_id, 0 as c_int, ptr::null_mut());
             (*shm).shm_id = -(1 as c_int);
-            (*shm).shm_str[0 as c_int as usize] = '\u{0}' as u8;
-            return 0 as *mut c_uchar;
+            (*shm).shm_str[0 as c_int as usize] = 0u8;
+            return ptr::null_mut();
         }
         return (*shm).map;
     }
@@ -297,10 +297,10 @@ pub mod shmem {
         shm_str: &CStr,
         map_size: usize,
     ) -> *mut c_uchar {
-        if shm.is_null() || shm_str.to_bytes().len() == 0 || map_size == 0 {
-            return 0 as *mut c_uchar;
+        if shm.is_null() || shm_str.to_bytes().is_empty() || map_size == 0 {
+            return ptr::null_mut();
         }
-        (*shm).map = 0 as *mut c_uchar;
+        (*shm).map = ptr::null_mut();
         (*shm).map_size = map_size;
         strncpy(
             (*shm).shm_str.as_mut_ptr() as *mut c_char,
@@ -312,12 +312,12 @@ pub mod shmem {
             .expect(&format!("illegal shm_str {:?}", shm_str))
             .parse::<i32>()
             .unwrap();
-        (*shm).map = shmat((*shm).shm_id, 0 as *const c_void, 0 as c_int) as *mut c_uchar;
+        (*shm).map = shmat((*shm).shm_id, ptr::null(), 0 as c_int) as *mut c_uchar;
         if (*shm).map == -(1 as c_int) as *mut c_void as *mut c_uchar {
-            (*shm).map = 0 as *mut c_uchar;
+            (*shm).map = ptr::null_mut();
             (*shm).map_size = 0;
-            (*shm).shm_str[0] = '\u{0}' as u8;
-            return 0 as *mut c_uchar;
+            (*shm).shm_str[0] = 0u8;
+            return ptr::null_mut();
         }
         return (*shm).map;
     }
diff --git a/libafl/src/bolts/tuples.rs b/libafl/src/bolts/tuples.rs
index 162bea12ce..21d93442c7 100644
--- a/libafl/src/bolts/tuples.rs
+++ b/libafl/src/bolts/tuples.rs
@@ -6,6 +6,9 @@ use core::any::TypeId;
 
 pub trait HasLen {
     fn len(&self) -> usize;
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
 }
 
 impl HasLen for () {
diff --git a/libafl/src/corpus/minimizer.rs b/libafl/src/corpus/minimizer.rs
index 42c37d9d84..a57dc0d4cd 100644
--- a/libafl/src/corpus/minimizer.rs
+++ b/libafl/src/corpus/minimizer.rs
@@ -37,6 +37,12 @@ impl TopRatedsMetadata {
     }
 }
 
+impl Default for TopRatedsMetadata {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 pub trait FavFactor<I>
 where
     I: Input,
diff --git a/libafl/src/corpus/mod.rs b/libafl/src/corpus/mod.rs
index 6b2fc082d5..7e9baa3a53 100644
--- a/libafl/src/corpus/mod.rs
+++ b/libafl/src/corpus/mod.rs
@@ -128,6 +128,7 @@ where
     I: Input,
     R: Rand,
 {
+    /// Create a new RandCorpusScheduler that just schedules randomly.
     pub fn new() -> Self {
         Self {
             phantom: PhantomData,
@@ -135,4 +136,16 @@ where
     }
 }
 
+impl<C, I, R, S> Default for RandCorpusScheduler<C, I, R, S>
+where
+    S: HasCorpus<C, I> + HasRand<R>,
+    C: Corpus<I>,
+    I: Input,
+    R: Rand,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 pub type StdCorpusScheduler<C, I, R, S> = RandCorpusScheduler<C, I, R, S>;
diff --git a/libafl/src/corpus/ondisk.rs b/libafl/src/corpus/ondisk.rs
index f597d45bdd..e0787d6816 100644
--- a/libafl/src/corpus/ondisk.rs
+++ b/libafl/src/corpus/ondisk.rs
@@ -35,18 +35,15 @@ where
     /// Add an entry to the corpus and return its index
     #[inline]
     fn add(&mut self, mut testcase: Testcase<I>) -> Result<usize, Error> {
-        match testcase.filename() {
-            None => {
-                // TODO walk entry metadata to ask for pices of filename (e.g. :havoc in AFL)
-                let filename = self.dir_path.join(format!("id_{}", &self.entries.len()));
-                let filename_str = filename.to_str().expect("Invalid Path");
-                testcase.set_filename(filename_str.into());
-            }
-            _ => {}
-        }
+        if let None = testcase.filename() {
+            // TODO walk entry metadata to ask for pices of filename (e.g. :havoc in AFL)
+            let filename = self.dir_path.join(format!("id_{}", &self.entries.len()));
+            let filename_str = filename.to_str().expect("Invalid Path");
+            testcase.set_filename(filename_str.into());
+        };
         testcase
             .store_input()
-            .expect("Could not save testcase to disk".into());
+            .expect("Could not save testcase to disk");
         self.entries.push(RefCell::new(testcase));
         Ok(self.entries.len() - 1)
     }
diff --git a/libafl/src/corpus/queue.rs b/libafl/src/corpus/queue.rs
index 5257a52d8e..3bd3727ff8 100644
--- a/libafl/src/corpus/queue.rs
+++ b/libafl/src/corpus/queue.rs
@@ -59,6 +59,17 @@ where
     }
 }
 
+impl<C, I, S> Default for QueueCorpusScheduler<C, I, S>
+where
+    S: HasCorpus<C, I>,
+    C: Corpus<I>,
+    I: Input,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 /*
 #[cfg(test)]
 #[cfg(feature = "std")]
diff --git a/libafl/src/corpus/testcase.rs b/libafl/src/corpus/testcase.rs
index 625e005ca2..d84f9835d9 100644
--- a/libafl/src/corpus/testcase.rs
+++ b/libafl/src/corpus/testcase.rs
@@ -181,7 +181,7 @@ where
     #[inline]
     pub fn with_fitness(input: I, fitness: u32) -> Self {
         Testcase {
-            input: Some(input.into()),
+            input: Some(input),
             filename: None,
             fitness: fitness,
             metadata: SerdeAnyMap::new(),
diff --git a/libafl/src/events/llmp.rs b/libafl/src/events/llmp.rs
index 102cab12d9..b47f70cb8b 100644
--- a/libafl/src/events/llmp.rs
+++ b/libafl/src/events/llmp.rs
@@ -167,10 +167,7 @@ where
 
     /// Returns if we are the broker
     pub fn is_broker(&self) -> bool {
-        match self.llmp {
-            llmp::LlmpConnection::IsBroker { broker: _ } => true,
-            _ => false,
-        }
+        matches!(self.llmp, llmp::LlmpConnection::IsBroker { broker: _ })
     }
 
     /// Run forever in the broker
@@ -284,9 +281,9 @@ where
                 // TODO include ExitKind in NewTestcase
                 let fitness = state.is_interesting(&input, &observers, ExitKind::Ok)?;
                 if fitness > 0 {
-                    if !state
+                    if state
                         .add_if_interesting(&input, fitness, scheduler)?
-                        .is_none()
+                        .is_some()
                     {
                         #[cfg(feature = "std")]
                         println!("Added received Testcase");
@@ -312,12 +309,9 @@ where
     /// The llmp client needs to wait until a broker mapped all pages, before shutting down.
     /// Otherwise, the OS may already have removed the shared maps,
     fn await_restart_safe(&mut self) {
-        match &self.llmp {
-            llmp::LlmpConnection::IsClient { client } => {
-                // wait until we can drop the message safely.
-                client.await_save_to_unmap_blocking();
-            }
-            _ => (),
+        if let llmp::LlmpConnection::IsClient { client } = &self.llmp {
+            // wait until we can drop the message safely.
+            client.await_save_to_unmap_blocking();
         }
     }
 
diff --git a/libafl/src/events/simple.rs b/libafl/src/events/simple.rs
index ec91e2c1b1..2420a68eff 100644
--- a/libafl/src/events/simple.rs
+++ b/libafl/src/events/simple.rs
@@ -43,7 +43,7 @@ where
         OT: ObserversTuple,
     {
         let count = self.events.len();
-        while self.events.len() > 0 {
+        while !self.events.is_empty() {
             let event = self.events.pop().unwrap();
             self.handle_in_client(state, event)?;
         }
@@ -118,11 +118,9 @@ where
 
     // Handle arriving events in the client
     fn handle_in_client(&mut self, _state: &mut S, event: Event<I>) -> Result<(), Error> {
-        match event {
-            _ => Err(Error::Unknown(format!(
-                "Received illegal message that message should not have arrived: {:?}.",
-                event
-            ))),
-        }
+        Err(Error::Unknown(format!(
+            "Received illegal message that message should not have arrived: {:?}.",
+            event
+        )))
     }
 }
diff --git a/libafl/src/executors/inprocess.rs b/libafl/src/executors/inprocess.rs
index 5c59f9df29..9cd91a940a 100644
--- a/libafl/src/executors/inprocess.rs
+++ b/libafl/src/executors/inprocess.rs
@@ -77,9 +77,7 @@ where
     {
         #[cfg(unix)]
         #[cfg(feature = "std")]
-        unsafe {
-            reset_oncrash_ptrs();
-        }
+        reset_oncrash_ptrs();
         Ok(())
     }
 
@@ -206,7 +204,7 @@ pub mod unix_signals {
         S: HasObjectives<OFT, I> + HasSolutions<OC, I>,
         I: Input,
     {
-        if CURRENT_INPUT_PTR == ptr::null() {
+        if CURRENT_INPUT_PTR.is_null() {
             #[cfg(target_os = "android")]
             let si_addr = { ((info._pad[0] as usize) | ((info._pad[1] as usize) << 32)) as usize };
             #[cfg(not(target_os = "android"))]
@@ -250,19 +248,19 @@ pub mod unix_signals {
         let obj_fitness = state
             .objectives_mut()
             .is_interesting_all(&input, observers, ExitKind::Crash)
-            .expect("In crash handler objectives failure.".into());
+            .expect("In crash handler objectives failure.");
         if obj_fitness > 0 {
             state
                 .solutions_mut()
                 .add(Testcase::new(input.clone()))
-                .expect("In crash handler solutions failure.".into());
+                .expect("In crash handler solutions failure.");
             mgr.fire(
                 state,
                 Event::Objective {
                     objective_size: state.solutions().count(),
                 },
             )
-            .expect("Could not send crashing input".into());
+            .expect("Could not send crashing input");
         }
 
         mgr.on_restart(state).unwrap();
@@ -305,19 +303,19 @@ pub mod unix_signals {
         let obj_fitness = state
             .objectives_mut()
             .is_interesting_all(&input, observers, ExitKind::Crash)
-            .expect("In timeout handler objectives failure.".into());
+            .expect("In timeout handler objectives failure.");
         if obj_fitness > 0 {
             state
                 .solutions_mut()
                 .add(Testcase::new(input.clone()))
-                .expect("In timeout handler solutions failure.".into());
+                .expect("In timeout handler solutions failure.");
             mgr.fire(
                 state,
                 Event::Objective {
                     objective_size: state.solutions().count(),
                 },
             )
-            .expect("Could not send timeouting input".into());
+            .expect("Could not send timeouting input");
         }
 
         mgr.on_restart(state).unwrap();
@@ -331,6 +329,10 @@ pub mod unix_signals {
         std::process::exit(1);
     }
 
+    /// Sets the oncrash pointers before executing a single testcase
+    /// # Safety
+    /// As long as no signals are called, this is fine.
+    /// Once a signal occurs, the pointer needs to be up to date.
     #[inline]
     pub unsafe fn set_oncrash_ptrs<EM, I, OT, S>(
         state: &mut S,
@@ -344,14 +346,20 @@ pub mod unix_signals {
         OBSERVERS_PTR = observers as *const _ as *const c_void;
     }
 
+    /// Resets the oncrash pointers to null
     #[inline]
-    pub unsafe fn reset_oncrash_ptrs() {
-        CURRENT_INPUT_PTR = ptr::null();
-        STATE_PTR = ptr::null_mut();
-        EVENT_MGR_PTR = ptr::null_mut();
-        OBSERVERS_PTR = ptr::null();
+    pub fn reset_oncrash_ptrs() {
+        unsafe {
+            CURRENT_INPUT_PTR = ptr::null();
+            STATE_PTR = ptr::null_mut();
+            EVENT_MGR_PTR = ptr::null_mut();
+            OBSERVERS_PTR = ptr::null();
+        }
     }
 
+    /// Sets up the crash handler
+    /// # Safety
+    /// Everything using signals is unsafe. Don't do it unless you really need to.
     pub unsafe fn setup_crash_handlers<EM, I, OC, OFT, OT, S>()
     where
         EM: EventManager<I, S>,
diff --git a/libafl/src/executors/mod.rs b/libafl/src/executors/mod.rs
index dfe2740203..82f01de97c 100644
--- a/libafl/src/executors/mod.rs
+++ b/libafl/src/executors/mod.rs
@@ -59,7 +59,7 @@ where
     I: Input + HasTargetBytes,
 {
     fn run_target(&mut self, input: &I) -> Result<ExitKind, Error> {
-        if input.target_bytes().as_slice().len() == 0 {
+        if input.target_bytes().as_slice().is_empty() {
             Err(Error::Empty("Input Empty".into()))
         } else {
             Ok(ExitKind::Ok)
diff --git a/libafl/src/feedbacks/map.rs b/libafl/src/feedbacks/map.rs
index 18daa5cd5a..fa4628a0e7 100644
--- a/libafl/src/feedbacks/map.rs
+++ b/libafl/src/feedbacks/map.rs
@@ -218,19 +218,13 @@ where
     }
 
     fn append_metadata(&mut self, testcase: &mut Testcase<I>) -> Result<(), Error> {
-        match self.indexes.as_mut() {
-            Some(v) => {
-                let meta = MapIndexesMetadata::new(core::mem::take(v));
-                testcase.add_metadata(meta);
-            }
-            None => {}
+        if let Some(v) = self.indexes.as_mut() {
+            let meta = MapIndexesMetadata::new(core::mem::take(v));
+            testcase.add_metadata(meta);
         };
-        match self.novelties.as_mut() {
-            Some(v) => {
-                let meta = MapNoveltiesMetadata::new(core::mem::take(v));
-                testcase.add_metadata(meta);
-            }
-            None => {}
+        if let Some(v) = self.novelties.as_mut() {
+            let meta = MapNoveltiesMetadata::new(core::mem::take(v));
+            testcase.add_metadata(meta);
         };
         Ok(())
     }
diff --git a/libafl/src/feedbacks/mod.rs b/libafl/src/feedbacks/mod.rs
index 76ac3abad5..617dadf1ae 100644
--- a/libafl/src/feedbacks/mod.rs
+++ b/libafl/src/feedbacks/mod.rs
@@ -184,3 +184,9 @@ impl CrashFeedback {
         Self {}
     }
 }
+
+impl Default for CrashFeedback {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/libafl/src/generators/mod.rs b/libafl/src/generators/mod.rs
index 07ab0bd4e6..262381df96 100644
--- a/libafl/src/generators/mod.rs
+++ b/libafl/src/generators/mod.rs
@@ -93,7 +93,7 @@ where
     /// Generates up to DUMMY_BYTES_MAX non-random dummy bytes (0)
     fn generate_dummy(&self) -> BytesInput {
         let size = min(self.max_size, DUMMY_BYTES_MAX);
-        BytesInput::new(vec!['0' as u8; size])
+        BytesInput::new(vec![0u8; size])
     }
 }
 
diff --git a/libafl/src/inputs/mod.rs b/libafl/src/inputs/mod.rs
index 6d00b34c4e..cb409ed408 100644
--- a/libafl/src/inputs/mod.rs
+++ b/libafl/src/inputs/mod.rs
@@ -97,6 +97,10 @@ pub trait HasBytesVec {
 
 /// Has a length field
 pub trait HasLen {
-    /// The lenght
+    /// The length
     fn len(&self) -> usize;
+
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
 }
diff --git a/libafl/src/mutators/mutations.rs b/libafl/src/mutators/mutations.rs
index a4ac24c46d..0c405c8a51 100644
--- a/libafl/src/mutators/mutations.rs
+++ b/libafl/src/mutators/mutations.rs
@@ -41,7 +41,7 @@ where
 /// Mem move in the own vec
 #[inline]
 pub fn buffer_self_copy(data: &mut [u8], from: usize, to: usize, len: usize) {
-    debug_assert!(data.len() > 0);
+    debug_assert!(!data.is_empty());
     debug_assert!(from + len <= data.len());
     debug_assert!(to + len <= data.len());
     if len != 0 && from != to {
@@ -53,8 +53,8 @@ pub fn buffer_self_copy(data: &mut [u8], from: usize, to: usize, len: usize) {
 /// Mem move between vecs
 #[inline]
 pub fn buffer_copy(dst: &mut [u8], src: &[u8], from: usize, to: usize, len: usize) {
-    debug_assert!(dst.len() > 0);
-    debug_assert!(src.len() > 0);
+    debug_assert!(!dst.is_empty());
+    debug_assert!(!src.is_empty());
     debug_assert!(from + len <= src.len());
     debug_assert!(to + len <= dst.len());
     let dst_ptr = dst.as_mut_ptr();
@@ -124,7 +124,7 @@ where
     S: HasRand<R> + HasMaxSize,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let bit = state.rand_mut().below((input.bytes().len() << 3) as u64) as usize;
@@ -142,7 +142,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -160,7 +160,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -179,7 +179,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -198,7 +198,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -216,7 +216,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -234,7 +234,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
@@ -335,7 +335,7 @@ where
     S: HasRand<R>,
     R: Rand,
 {
-    if input.bytes().len() == 0 {
+    if input.bytes().is_empty() {
         Ok(MutationResult::Skipped)
     } else {
         let idx = state.rand_mut().below(input.bytes().len() as u64) as usize;
diff --git a/libafl/src/mutators/token_mutations.rs b/libafl/src/mutators/token_mutations.rs
index 9a43602bfb..27ce1715a7 100644
--- a/libafl/src/mutators/token_mutations.rs
+++ b/libafl/src/mutators/token_mutations.rs
@@ -76,10 +76,10 @@ impl Tokens {
 
             // we are only interested in '"..."', not prefixed 'foo = '
             let start = line.chars().nth(0);
-            if line.len() == 0 || start == Some('#') {
+            if line.is_empty() || start == Some('#') {
                 continue;
             }
-            let pos_quote = match line.find("\"") {
+            let pos_quote = match line.find('\"') {
                 Some(x) => x,
                 _ => return Err(Error::IllegalArgument("Illegal line: ".to_owned() + line)),
             };
@@ -92,7 +92,7 @@ impl Tokens {
                 Some(x) => x,
                 _ => return Err(Error::IllegalArgument("Illegal line: ".to_owned() + line)),
             };
-            if item.len() == 0 {
+            if item.is_empty() {
                 continue;
             }
 
@@ -134,7 +134,7 @@ where
         if meta.is_none() {
             return Ok(MutationResult::Skipped);
         }
-        if meta.unwrap().tokens().len() == 0 {
+        if meta.unwrap().tokens().is_empty() {
             return Ok(MutationResult::Skipped);
         }
         meta.unwrap().tokens().len()
@@ -180,7 +180,7 @@ where
         if meta.is_none() {
             return Ok(MutationResult::Skipped);
         }
-        if meta.unwrap().tokens().len() == 0 {
+        if meta.unwrap().tokens().is_empty() {
             return Ok(MutationResult::Skipped);
         }
         meta.unwrap().tokens().len()
diff --git a/libafl/src/observers/map.rs b/libafl/src/observers/map.rs
index a63155c030..8c6fa0ef00 100644
--- a/libafl/src/observers/map.rs
+++ b/libafl/src/observers/map.rs
@@ -118,7 +118,7 @@ where
 {
     /// Creates a new MapObserver
     pub fn new(name: &'static str, map: &'static mut [T]) -> Self {
-        let initial = if map.len() > 0 { map[0] } else { T::default() };
+        let initial = if map.is_empty() { T::default() } else { map[0] };
         Self {
             map: ArrayMut::Cptr((map.as_mut_ptr(), map.len())),
             name: name.to_string(),
@@ -128,13 +128,15 @@ where
 
     /// Creates a new MapObserver from a raw pointer
     pub fn new_from_ptr(name: &'static str, map_ptr: *mut T, len: usize) -> Self {
-        unsafe {
-            let initial = if len > 0 { *map_ptr } else { T::default() };
-            StdMapObserver {
-                map: ArrayMut::Cptr((map_ptr, len)),
-                name: name.to_string(),
-                initial,
-            }
+        let initial = if len > 0 {
+            unsafe { *map_ptr }
+        } else {
+            T::default()
+        };
+        StdMapObserver {
+            map: ArrayMut::Cptr((map_ptr, len)),
+            name: name.to_string(),
+            initial,
         }
     }
 }
@@ -229,14 +231,16 @@ where
         max_len: usize,
         size_ptr: *const usize,
     ) -> Self {
-        unsafe {
-            let initial = if max_len > 0 { *map_ptr } else { T::default() };
-            VariableMapObserver {
-                map: ArrayMut::Cptr((map_ptr, max_len)),
-                size: Cptr::Cptr(size_ptr),
-                name: name.into(),
-                initial,
-            }
+        let initial = if max_len > 0 {
+            unsafe { *map_ptr }
+        } else {
+            T::default()
+        };
+        VariableMapObserver {
+            map: ArrayMut::Cptr((map_ptr, max_len)),
+            size: Cptr::Cptr(size_ptr),
+            name: name.into(),
+            initial,
         }
     }
 }
diff --git a/libafl/src/state/mod.rs b/libafl/src/state/mod.rs
index ef6a467eae..ae771d703d 100644
--- a/libafl/src/state/mod.rs
+++ b/libafl/src/state/mod.rs
@@ -515,9 +515,9 @@ where
             self.solutions_mut().add(Testcase::new(input.clone()))?;
         }
 
-        if !self
+        if self
             .add_if_interesting(&input, fitness, scheduler)?
-            .is_none()
+            .is_some()
         {
             let observers_buf = manager.serialize_observers(observers)?;
             manager.fire(
@@ -564,7 +564,7 @@ where
             let path = entry.path();
             let attributes = fs::metadata(&path);
 
-            if !attributes.is_ok() {
+            if attributes.is_err() {
                 continue;
             }