Fix cargo clippy warnings

I found there were clippy warnings introduced in recent rust versions.

I fixed the following three types of warnings:
1. creating a mutable reference to mutable static is discouraged
rust-lang/rust#114447
2. initializer for `thread_local` value can be made `const`
 https://rust-lang.github.io/rust-clippy/master/index.html#thread_local_initializer_can_be_made_const
 3. unused imported libraries

hopper-core/src/config.rs

@@ -151,12 +151,12 @@ pub struct Config {
 
 use eyre::Context;
 use once_cell::sync::OnceCell;
-use std::io::BufRead;
+use std::{io::BufRead, ptr::{addr_of, addr_of_mut}};
 
 pub static mut CONFIG_INSTANCE: Option<Config> = None;
 
 pub fn get_config() -> &'static Config {
-    if let Some(c) = unsafe { &CONFIG_INSTANCE } {
+    if let Some(Some(c)) = unsafe { addr_of!(CONFIG_INSTANCE).as_ref() } {
         return c;
     }
     unsafe {
@@ -166,7 +166,7 @@ pub fn get_config() -> &'static Config {
 }
 
 pub fn get_config_mut() -> &'static mut Config {
-    if let Some(c) = unsafe { &mut CONFIG_INSTANCE } {
+    if let Some(Some(c)) = unsafe { addr_of_mut!(CONFIG_INSTANCE).as_mut() } {
         return c;
     }
     unsafe {

hopper-core/src/depot/mod.rs

@@ -8,7 +8,6 @@ use self::select::*;
 use crate::{execute::StatusType, FuzzProgram, FeedbackSummary};
 pub use io::*;
 use priority::PriorityWrap;
-pub use priority::*;
 
 /// Depot for saving all inputs, hangs, and crashes.
 pub struct Depot {

hopper-core/src/depot/select.rs

@@ -45,7 +45,7 @@ const SA_UNIQ_NEW: u64 = 3;
 const KEY_BONUS: u64 = 2;
 
 thread_local! {
-    static AVG_SCORE: Cell<(f64, u64)> = Cell::new((0_f64, 0_u64));
+    static AVG_SCORE: Cell<(f64, u64)> = const { Cell::new((0_f64, 0_u64)) };
 }
 
 impl Selector for SaSelector {

hopper-core/src/fuzz/flag.rs

@@ -3,25 +3,25 @@ use std::cell::Cell;
 
 thread_local! {
     // Deterministic generation in pilot phase
-    pub static PILOT_DET: Cell<bool> = Cell::new(false);
+    pub static PILOT_DET: Cell<bool> = const { Cell::new(false) };
     // Generate only single call
-    pub static SINGLE_CALL: Cell<bool> = Cell::new(true);
+    pub static SINGLE_CALL: Cell<bool> = const { Cell::new(true) };
     // Reuse statement in generation
-    pub static REUSE_STMT: Cell<bool> = Cell::new(false);
+    pub static REUSE_STMT: Cell<bool> = const { Cell::new(false) };
     // Only mutate argument inputs.
-    pub static INPUT_ONLY: Cell<bool> = Cell::new(false);
+    pub static INPUT_ONLY: Cell<bool> = const { Cell::new(false) };
     // Refine successful or not
-    pub static REFINE_SUC: Cell<bool> = Cell::new(false);
+    pub static REFINE_SUC: Cell<bool> = const { Cell::new(false) };
     // Mutate pointer or not
-    pub static MUTATE_PTR: Cell<bool> = Cell::new(false);
+    pub static MUTATE_PTR: Cell<bool> = const { Cell::new(false) };
     // deterministic mutation for call
-    pub static CALL_DET: Cell<bool> = Cell::new(false);
+    pub static CALL_DET: Cell<bool> = const { Cell::new(false) };
     // Generate an incomplete program
-    pub static INCOMPLETE_GEN: Cell<bool> = Cell::new(false);
+    pub static INCOMPLETE_GEN: Cell<bool> = const { Cell::new(false) };
     // Running in pilot infer phase
-    pub static PILOT_INFER: Cell<bool> = Cell::new(false);
+    pub static PILOT_INFER: Cell<bool> = const { Cell::new(false) };
     // u64 temp value
-    pub static TMP_U64: Cell<u64> = Cell::new(0);
+    pub static TMP_U64: Cell<u64> = const { Cell::new(0) };
 }
 
 pub fn is_pilot_det() -> bool {

hopper-core/src/fuzz/mod.rs

@@ -23,7 +23,6 @@ pub use constraints::*;
 pub use det::*;
 pub use flag::*;
 pub use generate::*;
-pub use mutate::*;
 pub use object::*;
 pub use operator::*;
 pub use rng::*;

hopper-core/src/fuzz/stmt/assert.rs

@@ -30,7 +30,7 @@ pub enum ExpectedValue {
 unsafe impl Sync for ExpectedValue {}
 
 thread_local! {
-    static ASSERTIONS: RefCell<Vec<Assertion>> = RefCell::new(vec![]);
+    static ASSERTIONS: RefCell<Vec<Assertion>> = const { RefCell::new(vec![]) };
 }
 
 pub fn add_assertion(assertion: Assertion) {

hopper-core/src/fuzz/stmt/mod.rs

@@ -1,5 +1,4 @@
 use crate::{impl_stmt_match, runtime::*};
-pub use call::*;
 use super::*;
 
 pub trait StmtMutate: WeightedItem {

hopper-core/src/runtime/object/mod.rs

@@ -15,7 +15,6 @@ mod bitfield;
 pub use builder::*;
 pub use canary::*;
 pub use layout::*;
-pub use pointer::*;
 pub use state::*;
 pub use void::*;
 pub use bitfield::*;