diff --git a/fuzzers/libfuzzer_libpng/src/mod.rs b/fuzzers/libfuzzer_libpng/src/mod.rs
index 50a02df796..66097da495 100644
--- a/fuzzers/libfuzzer_libpng/src/mod.rs
+++ b/fuzzers/libfuzzer_libpng/src/mod.rs
@@ -5,10 +5,11 @@ use std::{env, path::PathBuf};
 
 use libafl::{
     bolts::{shmem::UnixShMem, tuples::tuple_list},
-    corpus::{Corpus, InMemoryCorpus, OnDiskCorpus},
+    corpus::{Corpus, InMemoryCorpus, OnDiskCorpus, RandCorpusScheduler},
     events::setup_restarting_mgr,
     executors::{inprocess::InProcessExecutor, Executor, ExitKind},
     feedbacks::{CrashFeedback, MaxMapFeedback},
+    fuzzer::{Fuzzer, StdFuzzer},
     inputs::Input,
     mutators::scheduled::HavocBytesMutator,
     mutators::token_mutations::TokensMetadata,
@@ -17,7 +18,7 @@ use libafl::{
     state::{HasCorpus, HasMetadata, State},
     stats::SimpleStats,
     utils::{current_nanos, StdRand},
-    Error, Fuzzer, StdFuzzer,
+    Error,
 };
 
 /// The name of the coverage map observer, to find it again in the observer list
@@ -69,13 +70,12 @@ pub fn main() {
 
 /// The actual fuzzer
 fn fuzz(corpus_dirs: Vec<PathBuf>, objective_dir: PathBuf, broker_port: u16) -> Result<(), Error> {
-    let mut rand = StdRand::new(current_nanos());
     // 'While the stats are state, they are usually used in the broker - which is likely never restarted
     let stats = SimpleStats::new(|s| println!("{}", s));
 
     // The restarting state will spawn the same process again as child, then restarted it each time it crashes.
     let (state, mut restarting_mgr) =
-        setup_restarting_mgr::<_, _, _, _, _, _, UnixShMem, _>(stats, broker_port)
+        setup_restarting_mgr::<_, _, UnixShMem, _>(stats, broker_port)
             .expect("Failed to setup the restarter".into());
 
     // Create an observation channel using the coverage map
@@ -86,6 +86,7 @@ fn fuzz(corpus_dirs: Vec<PathBuf>, objective_dir: PathBuf, broker_port: u16) ->
 
     // If not restarting, create a State from scratch
     let mut state = state.unwrap_or(State::new(
+        StdRand::new(current_nanos()),
         InMemoryCorpus::new(),
         tuple_list!(MaxMapFeedback::new_with_observer(
             &NAME_COV_MAP,
@@ -111,7 +112,7 @@ fn fuzz(corpus_dirs: Vec<PathBuf>, objective_dir: PathBuf, broker_port: u16) ->
     // Setup a basic mutator with a mutational stage
     let mutator = HavocBytesMutator::default();
     let stage = StdMutationalStage::new(mutator);
-    let mut fuzzer = StdFuzzer::new(tuple_list!(stage));
+    let fuzzer = StdFuzzer::new(RandCorpusScheduler::new(), tuple_list!(stage));
 
     // Create the executor
     let mut executor = InProcessExecutor::new(
@@ -141,5 +142,7 @@ fn fuzz(corpus_dirs: Vec<PathBuf>, objective_dir: PathBuf, broker_port: u16) ->
         println!("We imported {} inputs from disk.", state.corpus().count());
     }
 
-    fuzzer.fuzz_loop(&mut rand, &mut executor, &mut state, &mut restarting_mgr)
+    fuzzer.fuzz_loop(&mut state, &mut executor, &mut restarting_mgr)?;
+
+    Ok(())
 }
diff --git a/libafl/src/corpus/inmemory.rs b/libafl/src/corpus/inmemory.rs
index 22a28ff67a..72ede51924 100644
--- a/libafl/src/corpus/inmemory.rs
+++ b/libafl/src/corpus/inmemory.rs
@@ -72,3 +72,15 @@ where
         &mut self.current
     }
 }
+
+impl<I> InMemoryCorpus<I>
+where
+    I: Input,
+{
+    pub fn new() -> Self {
+        Self {
+            entries: vec![],
+            current: None,
+        }
+    }
+}
diff --git a/libafl/src/corpus/mod.rs b/libafl/src/corpus/mod.rs
index 6ed7f18bb1..cd194bcfdb 100644
--- a/libafl/src/corpus/mod.rs
+++ b/libafl/src/corpus/mod.rs
@@ -6,6 +6,11 @@ pub use testcase::Testcase;
 pub mod inmemory;
 pub use inmemory::InMemoryCorpus;
 
+#[cfg(feature = "std")]
+pub mod ondisk;
+#[cfg(feature = "std")]
+pub use ondisk::OnDiskCorpus;
+
 pub mod queue;
 pub use queue::QueueCorpusScheduler;
 
@@ -110,4 +115,18 @@ where
     }
 }
 
+impl<C, I, R, S> RandCorpusScheduler<C, I, R, S>
+where
+    S: HasCorpus<C, I> + HasRand<R>,
+    C: Corpus<I>,
+    I: Input,
+    R: Rand,
+{
+    pub fn new() -> Self {
+        Self {
+            phantom: PhantomData,
+        }
+    }
+}
+
 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 00dd84e852..d4d8706f92 100644
--- a/libafl/src/corpus/ondisk.rs
+++ b/libafl/src/corpus/ondisk.rs
@@ -1,104 +1,104 @@
 //! The ondisk corpus stores unused testcases to disk.
 
 use alloc::vec::Vec;
-use core::{cell::RefCell, marker::PhantomData};
+use core::cell::RefCell;
 use serde::{Deserialize, Serialize};
 
 #[cfg(feature = "std")]
 use std::path::PathBuf;
 
-use crate::{
-    corpus::Corpus, corpus::HasTestcaseVec, corpus::Testcase, inputs::Input, utils::Rand, Error,
-};
+use crate::{corpus::Corpus, corpus::Testcase, inputs::Input, Error};
 
 /// A corpus able to store testcases to disk, and load them from disk, when they are being used.
 #[cfg(feature = "std")]
-#[derive(Serialize, Deserialize, Clone, Debug)]
+#[derive(Default, Serialize, Deserialize, Clone, Debug)]
 #[serde(bound = "I: serde::de::DeserializeOwned")]
-pub struct OnDiskCorpus<I, R>
+pub struct OnDiskCorpus<I>
 where
     I: Input,
-    R: Rand,
 {
     entries: Vec<RefCell<Testcase<I>>>,
+    current: Option<usize>,
     dir_path: PathBuf,
-    pos: usize,
-    phantom: PhantomData<R>,
 }
 
-#[cfg(feature = "std")]
-impl<I, R> HasTestcaseVec<I> for OnDiskCorpus<I, R>
+impl<I> Corpus<I> for OnDiskCorpus<I>
 where
     I: Input,
-    R: Rand,
 {
+    /// Returns the number of elements
     #[inline]
-    fn entries(&self) -> &[RefCell<Testcase<I>>] {
-        &self.entries
+    fn count(&self) -> usize {
+        self.entries.len()
     }
-    #[inline]
-    fn entries_mut(&mut self) -> &mut Vec<RefCell<Testcase<I>>> {
-        &mut self.entries
-    }
-}
 
-#[cfg(feature = "std")]
-impl<I, R> Corpus<I, R> for OnDiskCorpus<I, R>
-where
-    I: Input,
-    R: Rand,
-{
-    /// Add an entry and save it to disk
-    fn add(&mut self, mut entry: Testcase<I>) -> usize {
-        match entry.filename() {
+    /// 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 metadatas 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");
-                entry.set_filename(filename_str.into());
+                testcase.set_filename(filename_str.into());
             }
             _ => {}
         }
-        entry
+        testcase
             .store_input()
             .expect("Could not save testcase to disk".into());
-        self.entries.push(RefCell::new(entry));
-        self.entries.len() - 1
+        self.entries.push(RefCell::new(testcase));
+        Ok(self.entries.len() - 1)
     }
 
+    /// Replaces the testcase at the given idx
     #[inline]
-    fn current_testcase(&self) -> (&RefCell<Testcase<I>>, usize) {
-        (self.get(self.pos), self.pos)
+    fn replace(&mut self, idx: usize, testcase: Testcase<I>) -> Result<(), Error> {
+        if idx >= self.entries.len() {
+            return Err(Error::KeyNotFound(format!("Index {} out of bounds", idx)));
+        }
+        self.entries[idx] = RefCell::new(testcase);
+        Ok(())
     }
 
-    /// Gets the next entry
+    /// Removes an entry from the corpus, returning it if it was present.
     #[inline]
-    fn next(&mut self, rand: &mut R) -> Result<(&RefCell<Testcase<I>>, usize), Error> {
-        if self.count() == 0 {
-            Err(Error::Empty("No entries in corpus".to_owned()))
+    fn remove(&mut self, idx: usize) -> Result<Option<Testcase<I>>, Error> {
+        if idx >= self.entries.len() {
+            Ok(None)
         } else {
-            let len = { self.entries().len() };
-            let id = rand.below(len as u64) as usize;
-            self.pos = id;
-            Ok((self.get(id), id))
+            Ok(Some(self.entries.remove(idx).into_inner()))
         }
     }
 
-    // TODO save and remove files, cache, etc..., ATM use just InMemoryCorpus
+    /// Get by id
+    #[inline]
+    fn get(&self, idx: usize) -> Result<&RefCell<Testcase<I>>, Error> {
+        Ok(&self.entries[idx])
+    }
+
+    /// Current testcase scheduled
+    #[inline]
+    fn current(&self) -> &Option<usize> {
+        &self.current
+    }
+
+    /// Current testcase scheduled (mut)
+    #[inline]
+    fn current_mut(&mut self) -> &mut Option<usize> {
+        &mut self.current
+    }
 }
 
-#[cfg(feature = "std")]
-impl<I, R> OnDiskCorpus<I, R>
+impl<I> OnDiskCorpus<I>
 where
     I: Input,
-    R: Rand,
 {
     pub fn new(dir_path: PathBuf) -> Self {
         Self {
-            dir_path: dir_path,
             entries: vec![],
-            pos: 0,
-            phantom: PhantomData,
+            current: None,
+            dir_path: dir_path,
         }
     }
 }
diff --git a/libafl/src/corpus/queue.rs b/libafl/src/corpus/queue.rs
index 12fa682e14..2d7abdf3b2 100644
--- a/libafl/src/corpus/queue.rs
+++ b/libafl/src/corpus/queue.rs
@@ -46,6 +46,19 @@ where
     }
 }
 
+impl<C, I, S> QueueCorpusScheduler<C, I, S>
+where
+    S: HasCorpus<C, I>,
+    C: Corpus<I>,
+    I: Input,
+{
+    pub fn new() -> Self {
+        Self {
+            phantom: PhantomData,
+        }
+    }
+}
+
 /*
 #[cfg(test)]
 #[cfg(feature = "std")]
diff --git a/libafl/src/executors/inprocess.rs b/libafl/src/executors/inprocess.rs
index 65222ab004..feb4bc5a37 100644
--- a/libafl/src/executors/inprocess.rs
+++ b/libafl/src/executors/inprocess.rs
@@ -15,7 +15,6 @@ use crate::{
     inputs::{HasTargetBytes, Input},
     observers::ObserversTuple,
     state::{HasObjectives, HasSolutions},
-    utils::Rand,
     Error,
 };
 
@@ -124,7 +123,7 @@ where
     /// * `name` - the name of this executor (to address it along the way)
     /// * `harness_fn` - the harness, executiong the function
     /// * `observers` - the observers observing the target during execution
-    pub fn new<EM, OC, OFT, R, S>(
+    pub fn new<EM, OC, OFT, S>(
         name: &'static str,
         harness_fn: HarnessFunction<Self>,
         observers: OT,
@@ -136,12 +135,11 @@ where
         OC: Corpus<I>,
         OFT: FeedbacksTuple<I>,
         S: HasObjectives<OFT, I> + HasSolutions<OC, I>,
-        R: Rand,
     {
         #[cfg(feature = "std")]
         #[cfg(unix)]
         unsafe {
-            setup_crash_handlers::<EM, I, OC, OFT, OT, R, S>();
+            setup_crash_handlers::<EM, I, OC, OFT, OT, S>();
         }
 
         Self {
@@ -179,7 +177,6 @@ pub mod unix_signals {
         inputs::Input,
         observers::ObserversTuple,
         state::{HasObjectives, HasSolutions},
-        utils::Rand,
     };
     /// Let's get 8 mb for now.
     const SIGNAL_STACK_SIZE: usize = 2 << 22;
@@ -195,18 +192,14 @@ pub mod unix_signals {
     /// This is needed for certain non-rust side effects, as well as unix signal handling.
     static mut CURRENT_INPUT_PTR: *const c_void = ptr::null();
 
-    unsafe fn inmem_handle_crash<EM, I, OC, OFT, OT, R, S>(
-        _sig: c_int,
-        info: siginfo_t,
-        _void: c_void,
-    ) where
+    unsafe fn inmem_handle_crash<EM, I, OC, OFT, OT, S>(_sig: c_int, info: siginfo_t, _void: c_void)
+    where
         EM: EventManager<I, S>,
         OT: ObserversTuple,
         OC: Corpus<I>,
         OFT: FeedbacksTuple<I>,
         S: HasObjectives<OFT, I> + HasSolutions<OC, I>,
         I: Input,
-        R: Rand,
     {
         if CURRENT_INPUT_PTR == ptr::null() {
             println!(
@@ -271,7 +264,7 @@ pub mod unix_signals {
         std::process::exit(1);
     }
 
-    unsafe fn inmem_handle_timeout<EM, I, OC, OFT, OT, R, S>(
+    unsafe fn inmem_handle_timeout<EM, I, OC, OFT, OT, S>(
         _sig: c_int,
         _info: siginfo_t,
         _void: c_void,
@@ -282,7 +275,6 @@ pub mod unix_signals {
         OFT: FeedbacksTuple<I>,
         S: HasObjectives<OFT, I> + HasSolutions<OC, I>,
         I: Input,
-        R: Rand,
     {
         dbg!("TIMEOUT/SIGUSR2 received");
         if CURRENT_INPUT_PTR.is_null() {
@@ -350,7 +342,7 @@ pub mod unix_signals {
         OBSERVERS_PTR = ptr::null();
     }
 
-    pub unsafe fn setup_crash_handlers<EM, I, OC, OFT, OT, R, S>()
+    pub unsafe fn setup_crash_handlers<EM, I, OC, OFT, OT, S>()
     where
         EM: EventManager<I, S>,
         OT: ObserversTuple,
@@ -358,7 +350,6 @@ pub mod unix_signals {
         OFT: FeedbacksTuple<I>,
         S: HasObjectives<OFT, I> + HasSolutions<OC, I>,
         I: Input,
-        R: Rand,
     {
         // First, set up our own stack to be used during segfault handling. (and specify `SA_ONSTACK` in `sigaction`)
         if SIGNAL_STACK_PTR.is_null() {
@@ -375,7 +366,7 @@ pub mod unix_signals {
         let mut sa: sigaction = mem::zeroed();
         libc::sigemptyset(&mut sa.sa_mask as *mut libc::sigset_t);
         sa.sa_flags = SA_NODEFER | SA_SIGINFO | SA_ONSTACK;
-        sa.sa_sigaction = inmem_handle_crash::<EM, I, OC, OFT, OT, R, S> as usize;
+        sa.sa_sigaction = inmem_handle_crash::<EM, I, OC, OFT, OT, S> as usize;
         for (sig, msg) in &[
             (SIGSEGV, "segfault"),
             (SIGBUS, "sigbus"),
@@ -389,7 +380,7 @@ pub mod unix_signals {
             }
         }
 
-        sa.sa_sigaction = inmem_handle_timeout::<EM, I, OC, OFT, OT, R, S> as usize;
+        sa.sa_sigaction = inmem_handle_timeout::<EM, I, OC, OFT, OT, S> as usize;
         if sigaction(SIGUSR2, &mut sa as *mut sigaction, ptr::null_mut()) < 0 {
             panic!("Could not set up sigusr2 handler for timeouts");
         }
diff --git a/libafl/src/fuzzer.rs b/libafl/src/fuzzer.rs
index 37c986a26c..da4b20e3f3 100644
--- a/libafl/src/fuzzer.rs
+++ b/libafl/src/fuzzer.rs
@@ -12,9 +12,12 @@ use crate::{
 use core::marker::PhantomData;
 
 /// Holds a set of stages
-pub trait HasStages<ST, E, EM, S>: Sized
+pub trait HasStages<ST, E, EM, I, S>
 where
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
+    E: Executor<I>,
+    EM: EventManager<I, S>,
+    I: Input,
 {
     fn stages(&self) -> &ST;
 
@@ -44,7 +47,9 @@ pub trait Fuzzer<E, EM, S> {
 pub struct StdFuzzer<CS, ST, E, EM, I, OT, S>
 where
     CS: CorpusScheduler<I, S>,
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
+    E: Executor<I>,
+    EM: EventManager<I, S>,
     I: Input,
 {
     scheduler: CS,
@@ -52,10 +57,12 @@ where
     phantom: PhantomData<(E, EM, I, OT, S)>,
 }
 
-impl<CS, ST, E, EM, I, OT, S> HasStages<ST, E, EM, S> for StdFuzzer<CS, ST, E, EM, I, OT, S>
+impl<CS, ST, E, EM, I, OT, S> HasStages<ST, E, EM, I, S> for StdFuzzer<CS, ST, E, EM, I, OT, S>
 where
     CS: CorpusScheduler<I, S>,
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
+    E: Executor<I>,
+    EM: EventManager<I, S>,
     I: Input,
 {
     fn stages(&self) -> &ST {
@@ -70,7 +77,9 @@ where
 impl<CS, ST, E, EM, I, OT, S> HasCorpusScheduler<CS, I, S> for StdFuzzer<CS, ST, E, EM, I, OT, S>
 where
     CS: CorpusScheduler<I, S>,
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
+    E: Executor<I>,
+    EM: EventManager<I, S>,
     I: Input,
 {
     fn scheduler(&self) -> &CS {
@@ -86,7 +95,7 @@ impl<CS, ST, E, EM, I, OT, S> Fuzzer<E, EM, S> for StdFuzzer<CS, ST, E, EM, I, O
 where
     CS: CorpusScheduler<I, S>,
     S: HasExecutions,
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
     EM: EventManager<I, S>,
     E: Executor<I> + HasObservers<OT>,
     OT: ObserversTuple,
@@ -95,8 +104,7 @@ where
     fn fuzz_one(&self, state: &mut S, executor: &mut E, manager: &mut EM) -> Result<usize, Error> {
         let idx = self.scheduler().next(state)?;
 
-        self.stages()
-            .perform_all(self, state, executor, manager, idx)?;
+        self.stages().perform_all(state, executor, manager, idx)?;
 
         manager.process(state, executor)?;
         Ok(idx)
@@ -125,7 +133,9 @@ where
 impl<CS, ST, E, EM, I, OT, S> StdFuzzer<CS, ST, E, EM, I, OT, S>
 where
     CS: CorpusScheduler<I, S>,
-    ST: StagesTuple<E, EM, Self, S>,
+    ST: StagesTuple<E, EM, I, S>,
+    E: Executor<I>,
+    EM: EventManager<I, S>,
     I: Input,
 {
     pub fn new(scheduler: CS, stages: ST) -> Self {
diff --git a/libafl/src/mutators/mod.rs b/libafl/src/mutators/mod.rs
index 73c5203663..2337152477 100644
--- a/libafl/src/mutators/mod.rs
+++ b/libafl/src/mutators/mod.rs
@@ -14,18 +14,16 @@ use crate::{inputs::Input, Error};
 
 /// A mutator takes input, and mutates it.
 /// Simple as that.
-pub trait Mutator<F, I, S>
+pub trait Mutator<I, S>
 where
     I: Input,
 {
     /// Mutate a given input
-    fn mutate(&self, fuzzer: &F, state: &mut S, input: &mut I, stage_idx: i32)
-        -> Result<(), Error>;
+    fn mutate(&self, state: &mut S, input: &mut I, stage_idx: i32) -> Result<(), Error>;
 
     /// Post-process given the outcome of the execution
     fn post_exec(
         &self,
-        _fuzzer: &F,
         _state: &mut S,
         _is_interesting: u32,
         _stage_idx: i32,
diff --git a/libafl/src/mutators/mutations.rs b/libafl/src/mutators/mutations.rs
index 730efad2a1..4b394e65a6 100644
--- a/libafl/src/mutators/mutations.rs
+++ b/libafl/src/mutators/mutations.rs
@@ -27,20 +27,20 @@ pub enum MutationResult {
 
 // TODO maybe the mutator arg is not needed
 /// The generic function type that identifies mutations
-pub type MutationFunction<F, I, M, S> = fn(&M, &F, &mut S, &mut I) -> Result<MutationResult, Error>;
+pub type MutationFunction<I, M, S> = fn(&M, &mut S, &mut I) -> Result<MutationResult, Error>;
 
-pub trait ComposedByMutations<F, I, S>
+pub trait ComposedByMutations<I, S>
 where
     I: Input,
 {
     /// Get a mutation by index
-    fn mutation_by_idx(&self, index: usize) -> MutationFunction<F, I, Self, S>;
+    fn mutation_by_idx(&self, index: usize) -> MutationFunction<I, Self, S>;
 
     /// Get the number of mutations
     fn mutations_count(&self) -> usize;
 
     /// Add a mutation
-    fn add_mutation(&mut self, mutation: MutationFunction<F, I, Self, S>);
+    fn add_mutation(&mut self, mutation: MutationFunction<I, Self, S>);
 }
 
 /// Mem move in the own vec
@@ -123,9 +123,9 @@ const INTERESTING_32: [i32; 27] = [
 ];
 
 /// Bitflip mutation for inputs with a bytes vector
-pub fn mutation_bitflip<F, I, M, R, S>(
+pub fn mutation_bitflip<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -146,9 +146,9 @@ where
     }
 }
 
-pub fn mutation_byteflip<F, I, M, R, S>(
+pub fn mutation_byteflip<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -169,9 +169,9 @@ where
     }
 }
 
-pub fn mutation_byteinc<F, I, M, R, S>(
+pub fn mutation_byteinc<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -193,9 +193,9 @@ where
     }
 }
 
-pub fn mutation_bytedec<F, I, M, R, S>(
+pub fn mutation_bytedec<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -217,9 +217,9 @@ where
     }
 }
 
-pub fn mutation_byteneg<F, I, M, R, S>(
+pub fn mutation_byteneg<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -240,9 +240,9 @@ where
     }
 }
 
-pub fn mutation_byterand<F, I, M, R, S>(
+pub fn mutation_byterand<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -263,9 +263,9 @@ where
     }
 }
 
-pub fn mutation_byteadd<F, I, M, R, S>(
+pub fn mutation_byteadd<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -291,9 +291,9 @@ where
     }
 }
 
-pub fn mutation_wordadd<F, I, M, R, S>(
+pub fn mutation_wordadd<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -321,9 +321,9 @@ where
     }
 }
 
-pub fn mutation_dwordadd<F, I, M, R, S>(
+pub fn mutation_dwordadd<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -351,9 +351,9 @@ where
     }
 }
 
-pub fn mutation_qwordadd<F, I, M, R, S>(
+pub fn mutation_qwordadd<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -381,9 +381,9 @@ where
     }
 }
 
-pub fn mutation_byteinteresting<F, I, M, R, S>(
+pub fn mutation_byteinteresting<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -405,9 +405,9 @@ where
     }
 }
 
-pub fn mutation_wordinteresting<F, I, M, R, S>(
+pub fn mutation_wordinteresting<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -435,9 +435,9 @@ where
     }
 }
 
-pub fn mutation_dwordinteresting<F, I, M, R, S>(
+pub fn mutation_dwordinteresting<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -465,9 +465,9 @@ where
     }
 }
 
-pub fn mutation_bytesdelete<F, I, M, R, S>(
+pub fn mutation_bytesdelete<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -488,9 +488,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesexpand<F, I, M, R, S>(
+pub fn mutation_bytesexpand<I, M, R, S>(
     mutator: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -518,9 +518,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesinsert<F, I, M, R, S>(
+pub fn mutation_bytesinsert<I, M, R, S>(
     mutator: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -551,9 +551,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesrandinsert<F, I, M, R, S>(
+pub fn mutation_bytesrandinsert<I, M, R, S>(
     mutator: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -584,9 +584,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesset<F, I, M, R, S>(
+pub fn mutation_bytesset<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -609,9 +609,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesrandset<F, I, M, R, S>(
+pub fn mutation_bytesrandset<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -634,9 +634,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytescopy<F, I, M, R, S>(
+pub fn mutation_bytescopy<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -659,9 +659,9 @@ where
     Ok(MutationResult::Mutated)
 }
 
-pub fn mutation_bytesswap<F, I, M, R, S>(
+pub fn mutation_bytesswap<I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -687,9 +687,9 @@ where
 }
 
 /// Crossover insert mutation
-pub fn mutation_crossover_insert<C, F, I, M, R, S>(
+pub fn mutation_crossover_insert<C, I, M, R, S>(
     mutator: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -745,9 +745,9 @@ where
 }
 
 /// Crossover replace mutation
-pub fn mutation_crossover_replace<C, F, I, M, R, S>(
+pub fn mutation_crossover_replace<C, I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -808,9 +808,9 @@ fn locate_diffs(this: &[u8], other: &[u8]) -> (i64, i64) {
 }
 
 /// Splicing mutation from AFL
-pub fn mutation_splice<C, F, I, M, R, S>(
+pub fn mutation_splice<C, I, M, R, S>(
     _: &M,
-    _: &F,
+
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
diff --git a/libafl/src/mutators/scheduled.rs b/libafl/src/mutators/scheduled.rs
index 2a3feeb1f7..7192eedfb8 100644
--- a/libafl/src/mutators/scheduled.rs
+++ b/libafl/src/mutators/scheduled.rs
@@ -15,7 +15,7 @@ use crate::{
 pub use crate::mutators::mutations::*;
 pub use crate::mutators::token_mutations::*;
 
-pub trait ScheduledMutator<F, I, S>: Mutator<F, I, S> + ComposedByMutations<F, I, S>
+pub trait ScheduledMutator<I, S>: Mutator<I, S> + ComposedByMutations<I, S>
 where
     I: Input,
 {
@@ -27,34 +27,28 @@ where
 
     /// New default implementation for mutate
     /// Implementations must forward mutate() to this method
-    fn scheduled_mutate(
-        &self,
-        fuzzer: &F,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<(), Error> {
+    fn scheduled_mutate(&self, state: &mut S, input: &mut I, _stage_idx: i32) -> Result<(), Error> {
         let num = self.iterations(state, input);
         for _ in 0..num {
             let idx = self.schedule(self.mutations_count(), state, input);
-            self.mutation_by_idx(idx)(self, fuzzer, state, input)?;
+            self.mutation_by_idx(idx)(self, state, input)?;
         }
         Ok(())
     }
 }
 
-pub struct StdScheduledMutator<F, I, R, S>
+pub struct StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
     R: Rand,
 {
-    mutations: Vec<MutationFunction<F, I, Self, S>>,
+    mutations: Vec<MutationFunction<I, Self, S>>,
     max_size: usize,
     phantom: PhantomData<R>,
 }
 
-impl<F, I, R, S> Debug for StdScheduledMutator<F, I, R, S>
+impl<I, R, S> Debug for StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
@@ -71,31 +65,25 @@ where
     }
 }
 
-impl<F, I, R, S> Mutator<F, I, S> for StdScheduledMutator<F, I, R, S>
+impl<I, R, S> Mutator<I, S> for StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
     R: Rand,
 {
-    fn mutate(
-        &self,
-        fuzzer: &F,
-        state: &mut S,
-        input: &mut I,
-        _stage_idx: i32,
-    ) -> Result<(), Error> {
-        self.scheduled_mutate(fuzzer, state, input, _stage_idx)
+    fn mutate(&self, state: &mut S, input: &mut I, _stage_idx: i32) -> Result<(), Error> {
+        self.scheduled_mutate(state, input, _stage_idx)
     }
 }
 
-impl<F, I, R, S> ComposedByMutations<F, I, S> for StdScheduledMutator<F, I, R, S>
+impl<I, R, S> ComposedByMutations<I, S> for StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
     R: Rand,
 {
     #[inline]
-    fn mutation_by_idx(&self, index: usize) -> MutationFunction<F, I, Self, S> {
+    fn mutation_by_idx(&self, index: usize) -> MutationFunction<I, Self, S> {
         self.mutations[index]
     }
 
@@ -105,12 +93,12 @@ where
     }
 
     #[inline]
-    fn add_mutation(&mut self, mutation: MutationFunction<F, I, Self, S>) {
+    fn add_mutation(&mut self, mutation: MutationFunction<I, Self, S>) {
         self.mutations.push(mutation)
     }
 }
 
-impl<F, I, R, S> ScheduledMutator<F, I, S> for StdScheduledMutator<F, I, R, S>
+impl<I, R, S> ScheduledMutator<I, S> for StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
@@ -128,7 +116,7 @@ where
     }
 }
 
-impl<F, I, R, S> HasMaxSize for StdScheduledMutator<F, I, R, S>
+impl<I, R, S> HasMaxSize for StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
@@ -145,7 +133,7 @@ where
     }
 }
 
-impl<F, I, R, S> StdScheduledMutator<F, I, R, S>
+impl<I, R, S> StdScheduledMutator<I, R, S>
 where
     I: Input,
     S: HasRand<R>,
@@ -161,7 +149,7 @@ where
     }
 
     /// Create a new StdScheduledMutator instance specifying mutations
-    pub fn with_mutations(mutations: Vec<MutationFunction<F, I, Self, S>>) -> Self {
+    pub fn with_mutations(mutations: Vec<MutationFunction<I, Self, S>>) -> Self {
         StdScheduledMutator {
             mutations: mutations,
             max_size: DEFAULT_MAX_SIZE,
@@ -172,35 +160,29 @@ where
 
 /// Schedule some selected byte level mutations given a ScheduledMutator type
 #[derive(Clone, Debug)]
-pub struct HavocBytesMutator<C, F, I, R, S, SM>
+pub struct HavocBytesMutator<C, I, R, S, SM>
 where
-    SM: ScheduledMutator<F, I, S> + HasMaxSize,
+    SM: ScheduledMutator<I, S> + HasMaxSize,
     I: Input + HasBytesVec,
     S: HasRand<R> + HasCorpus<C, I> + HasMetadata,
     C: Corpus<I>,
     R: Rand,
 {
     scheduled: SM,
-    phantom: PhantomData<(C, F, I, R, S)>,
+    phantom: PhantomData<(C, I, R, S)>,
 }
 
-impl<C, F, I, R, S, SM> Mutator<F, I, S> for HavocBytesMutator<C, F, I, R, S, SM>
+impl<C, I, R, S, SM> Mutator<I, S> for HavocBytesMutator<C, I, R, S, SM>
 where
-    SM: ScheduledMutator<F, I, S> + HasMaxSize,
+    SM: ScheduledMutator<I, S> + HasMaxSize,
     I: Input + HasBytesVec,
     S: HasRand<R> + HasCorpus<C, I> + HasMetadata,
     C: Corpus<I>,
     R: Rand,
 {
     /// Mutate bytes
-    fn mutate(
-        &self,
-        fuzzer: &F,
-        state: &mut S,
-        input: &mut I,
-        stage_idx: i32,
-    ) -> Result<(), Error> {
-        self.scheduled.mutate(fuzzer, state, input, stage_idx)?;
+    fn mutate(&self, state: &mut S, input: &mut I, stage_idx: i32) -> Result<(), Error> {
+        self.scheduled.mutate(state, input, stage_idx)?;
         /*let num = self.scheduled.iterations(state, input);
         for _ in 0..num {
             let idx = self.scheduled.schedule(14, state, input);
@@ -226,9 +208,9 @@ where
     }
 }
 
-impl<C, F, I, R, S, SM> HasMaxSize for HavocBytesMutator<C, F, I, R, S, SM>
+impl<C, I, R, S, SM> HasMaxSize for HavocBytesMutator<C, I, R, S, SM>
 where
-    SM: ScheduledMutator<F, I, S> + HasMaxSize,
+    SM: ScheduledMutator<I, S> + HasMaxSize,
     I: Input + HasBytesVec,
     S: HasRand<R> + HasCorpus<C, I> + HasMetadata,
     C: Corpus<I>,
@@ -245,9 +227,9 @@ where
     }
 }
 
-impl<C, F, I, R, S, SM> HavocBytesMutator<C, F, I, R, S, SM>
+impl<C, I, R, S, SM> HavocBytesMutator<C, I, R, S, SM>
 where
-    SM: ScheduledMutator<F, I, S> + HasMaxSize,
+    SM: ScheduledMutator<I, S> + HasMaxSize,
     I: Input + HasBytesVec,
     S: HasRand<R> + HasCorpus<C, I> + HasMetadata,
     C: Corpus<I>,
@@ -264,7 +246,7 @@ where
     }
 }
 
-impl<C, F, I, R, S> Default for HavocBytesMutator<C, F, I, R, S, StdScheduledMutator<F, I, R, S>>
+impl<C, I, R, S> Default for HavocBytesMutator<C, I, R, S, StdScheduledMutator<I, R, S>>
 where
     I: Input + HasBytesVec,
     S: HasRand<R> + HasCorpus<C, I> + HasMetadata,
@@ -273,7 +255,7 @@ where
 {
     /// Create a new HavocBytesMutator instance wrapping StdScheduledMutator
     fn default() -> Self {
-        let mut scheduled = StdScheduledMutator::<F, I, R, S>::new();
+        let mut scheduled = StdScheduledMutator::<I, R, S>::new();
         scheduled.add_mutation(mutation_bitflip);
         scheduled.add_mutation(mutation_byteflip);
         scheduled.add_mutation(mutation_byteinc);
diff --git a/libafl/src/mutators/token_mutations.rs b/libafl/src/mutators/token_mutations.rs
index 252b17fcfb..f0d6ff352a 100644
--- a/libafl/src/mutators/token_mutations.rs
+++ b/libafl/src/mutators/token_mutations.rs
@@ -30,9 +30,8 @@ impl TokensMetadata {
 }
 
 /// Insert a dictionary token
-pub fn mutation_tokeninsert<F, I, M, R, S>(
+pub fn mutation_tokeninsert<I, M, R, S>(
     mutator: &M,
-    _: &F,
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
@@ -77,9 +76,8 @@ where
 }
 
 /// Overwrite with a dictionary token
-pub fn mutation_tokenreplace<F, I, M, R, S>(
+pub fn mutation_tokenreplace<I, M, R, S>(
     _: &M,
-    _: &F,
     state: &mut S,
     input: &mut I,
 ) -> Result<MutationResult, Error>
diff --git a/libafl/src/stages/mod.rs b/libafl/src/stages/mod.rs
index 01e729ac0f..abb2aadce4 100644
--- a/libafl/src/stages/mod.rs
+++ b/libafl/src/stages/mod.rs
@@ -1,15 +1,21 @@
 pub mod mutational;
 pub use mutational::StdMutationalStage;
 
-use crate::{bolts::tuples::TupleList, Error};
+use crate::{
+    bolts::tuples::TupleList, events::EventManager, executors::Executor, inputs::Input, Error,
+};
 
 /// A stage is one step in the fuzzing process.
 /// Multiple stages will be scheduled one by one for each input.
-pub trait Stage<E, EM, F, S> {
+pub trait Stage<E, EM, I, S>
+where
+    EM: EventManager<I, S>,
+    E: Executor<I>,
+    I: Input,
+{
     /// Run the stage
     fn perform(
         &self,
-        fuzzer: &F,
         state: &mut S,
         executor: &mut E,
         manager: &mut EM,
@@ -17,10 +23,14 @@ pub trait Stage<E, EM, F, S> {
     ) -> Result<(), Error>;
 }
 
-pub trait StagesTuple<E, EM, F, S> {
+pub trait StagesTuple<E, EM, I, S>
+where
+    EM: EventManager<I, S>,
+    E: Executor<I>,
+    I: Input,
+{
     fn perform_all(
         &self,
-        fuzzer: &F,
         state: &mut S,
         executor: &mut E,
         manager: &mut EM,
@@ -28,28 +38,33 @@ pub trait StagesTuple<E, EM, F, S> {
     ) -> Result<(), Error>;
 }
 
-impl<E, EM, F, S> StagesTuple<E, EM, F, S> for () {
-    fn perform_all(&self, _: &F, _: &mut S, _: &mut E, _: &mut EM, _: usize) -> Result<(), Error> {
+impl<E, EM, I, S> StagesTuple<E, EM, I, S> for ()
+where
+    EM: EventManager<I, S>,
+    E: Executor<I>,
+    I: Input,
+{
+    fn perform_all(&self, _: &mut S, _: &mut E, _: &mut EM, _: usize) -> Result<(), Error> {
         Ok(())
     }
 }
 
-impl<Head, Tail, E, EM, F, S> StagesTuple<E, EM, F, S> for (Head, Tail)
+impl<Head, Tail, E, EM, I, S> StagesTuple<E, EM, I, S> for (Head, Tail)
 where
-    Head: Stage<E, EM, F, S>,
-    Tail: StagesTuple<E, EM, F, S> + TupleList,
+    Head: Stage<E, EM, I, S>,
+    Tail: StagesTuple<E, EM, I, S> + TupleList,
+    EM: EventManager<I, S>,
+    E: Executor<I>,
+    I: Input,
 {
     fn perform_all(
         &self,
-        fuzzer: &F,
         state: &mut S,
         executor: &mut E,
         manager: &mut EM,
         corpus_idx: usize,
     ) -> Result<(), Error> {
-        self.0
-            .perform(fuzzer, state, executor, manager, corpus_idx)?;
-        self.1
-            .perform_all(fuzzer, state, executor, manager, corpus_idx)
+        self.0.perform(state, executor, manager, corpus_idx)?;
+        self.1.perform_all(state, executor, manager, corpus_idx)
     }
 }
diff --git a/libafl/src/stages/mutational.rs b/libafl/src/stages/mutational.rs
index d69c2e3600..59a283f893 100644
--- a/libafl/src/stages/mutational.rs
+++ b/libafl/src/stages/mutational.rs
@@ -18,9 +18,9 @@ use crate::{
 /// A Mutational stage is the stage in a fuzzing run that mutates inputs.
 /// Mutational stages will usually have a range of mutations that are
 /// being applied to the input one by one, between executions.
-pub trait MutationalStage<C, E, EM, F, I, M, OT, S>: Stage<E, EM, F, S>
+pub trait MutationalStage<C, E, EM, I, M, OT, S>: Stage<E, EM, I, S>
 where
-    M: Mutator<F, I, S>,
+    M: Mutator<I, S>,
     I: Input,
     S: HasCorpus<C, I> + Evaluator<I>,
     C: Corpus<I>,
@@ -40,7 +40,6 @@ where
     /// Runs this (mutational) stage for the given testcase
     fn perform_mutational(
         &self,
-        fuzzer: &F,
         state: &mut S,
         executor: &mut E,
         manager: &mut EM,
@@ -54,12 +53,11 @@ where
                 .borrow_mut()
                 .load_input()?
                 .clone();
-            self.mutator()
-                .mutate(fuzzer, state, &mut input_mut, i as i32)?;
+            self.mutator().mutate(state, &mut input_mut, i as i32)?;
 
             let fitness = state.evaluate_input(input_mut, executor, manager)?;
 
-            self.mutator().post_exec(fuzzer, state, fitness, i as i32)?;
+            self.mutator().post_exec(state, fitness, i as i32)?;
         }
         Ok(())
     }
@@ -69,9 +67,9 @@ pub static DEFAULT_MUTATIONAL_MAX_ITERATIONS: u64 = 128;
 
 /// The default mutational stage
 #[derive(Clone, Debug)]
-pub struct StdMutationalStage<C, E, EM, F, I, M, OT, R, S>
+pub struct StdMutationalStage<C, E, EM, I, M, OT, R, S>
 where
-    M: Mutator<F, I, S>,
+    M: Mutator<I, S>,
     I: Input,
     S: HasCorpus<C, I> + Evaluator<I> + HasRand<R>,
     C: Corpus<I>,
@@ -81,13 +79,13 @@ where
     R: Rand,
 {
     mutator: M,
-    phantom: PhantomData<(C, E, EM, F, I, OT, R, S)>,
+    phantom: PhantomData<(C, E, EM, I, OT, R, S)>,
 }
 
-impl<C, E, EM, F, I, M, OT, R, S> MutationalStage<C, E, EM, F, I, M, OT, S>
-    for StdMutationalStage<C, E, EM, F, I, M, OT, R, S>
+impl<C, E, EM, I, M, OT, R, S> MutationalStage<C, E, EM, I, M, OT, S>
+    for StdMutationalStage<C, E, EM, I, M, OT, R, S>
 where
-    M: Mutator<F, I, S>,
+    M: Mutator<I, S>,
     I: Input,
     S: HasCorpus<C, I> + Evaluator<I> + HasRand<R>,
     C: Corpus<I>,
@@ -114,10 +112,9 @@ where
     }
 }
 
-impl<C, E, EM, F, I, M, OT, R, S> Stage<E, EM, F, S>
-    for StdMutationalStage<C, E, EM, F, I, M, OT, R, S>
+impl<C, E, EM, I, M, OT, R, S> Stage<E, EM, I, S> for StdMutationalStage<C, E, EM, I, M, OT, R, S>
 where
-    M: Mutator<F, I, S>,
+    M: Mutator<I, S>,
     I: Input,
     S: HasCorpus<C, I> + Evaluator<I> + HasRand<R>,
     C: Corpus<I>,
@@ -129,19 +126,18 @@ where
     #[inline]
     fn perform(
         &self,
-        fuzzer: &F,
         state: &mut S,
         executor: &mut E,
         manager: &mut EM,
         corpus_idx: usize,
     ) -> Result<(), Error> {
-        self.perform_mutational(fuzzer, state, executor, manager, corpus_idx)
+        self.perform_mutational(state, executor, manager, corpus_idx)
     }
 }
 
-impl<C, E, EM, F, I, M, OT, R, S> StdMutationalStage<C, E, EM, F, I, M, OT, R, S>
+impl<C, E, EM, I, M, OT, R, S> StdMutationalStage<C, E, EM, I, M, OT, R, S>
 where
-    M: Mutator<F, I, S>,
+    M: Mutator<I, S>,
     I: Input,
     S: HasCorpus<C, I> + Evaluator<I> + HasRand<R>,
     C: Corpus<I>,