diff --git a/crates/libkoopa/src/raw/generator.rs b/crates/libkoopa/src/raw/generator.rs
index ee3012d..b6b1633 100644
--- a/crates/libkoopa/src/raw/generator.rs
+++ b/crates/libkoopa/src/raw/generator.rs
@@ -96,7 +96,7 @@ struct RawSliceIter<'a, T: Pointer> {
   phantom: PhantomData<T>,
 }
 
-impl<'a, T, E> RawSliceIter<'a, T>
+impl<T, E> RawSliceIter<'_, T>
 where
   T: Pointer + GenerateOnRaw<Entity = E>,
 {
@@ -109,7 +109,7 @@ where
   }
 }
 
-impl<'a, T: Pointer> Iterator for RawSliceIter<'a, T> {
+impl<T: Pointer> Iterator for RawSliceIter<'_, T> {
   type Item = T;
 
   fn next(&mut self) -> Option<Self::Item> {
@@ -196,7 +196,7 @@ impl GenerateOnRaw for *const c_char {
   }
 }
 
-impl<'rpb> GenerateOnRaw for RawProgram<'rpb> {
+impl GenerateOnRaw for RawProgram<'_> {
   type Entity = ();
 
   fn generate(&self, program: &mut Program, info: &mut ProgramInfo) -> Result<Self::Entity> {
diff --git a/src/back/koopa.rs b/src/back/koopa.rs
index ab60987..7e0e7f0 100644
--- a/src/back/koopa.rs
+++ b/src/back/koopa.rs
@@ -48,7 +48,7 @@ macro_rules! value {
   };
 }
 
-impl<'a, W: Write> VisitorImpl<'a, W> {
+impl<W: Write> VisitorImpl<'_, W> {
   /// Visits the program.
   fn visit(&mut self) -> Result<()> {
     for inst in self.program.inst_layout() {
diff --git a/src/back/llvm.rs b/src/back/llvm.rs
index 21f0ac0..e752b4c 100644
--- a/src/back/llvm.rs
+++ b/src/back/llvm.rs
@@ -60,7 +60,7 @@ macro_rules! value_ty {
   };
 }
 
-impl<'a, W: Write> VisitorImpl<'a, W> {
+impl<W: Write> VisitorImpl<'_, W> {
   /// Maximum length of LLVM IR identifier.
   const MAX_ID_LEN: usize = 512;
 
diff --git a/src/front/span.rs b/src/front/span.rs
index 20cfbbf..c54eb86 100644
--- a/src/front/span.rs
+++ b/src/front/span.rs
@@ -111,6 +111,7 @@ impl Span {
   const TAB_WIDTH: usize = 2;
 
   thread_local! {
+    #[allow(clippy::missing_const_for_thread_local)]
     static STATE: RefCell<GlobalState> = RefCell::new(GlobalState {
       file: FileType::Buffer,
       err_num: 0,
diff --git a/src/ir/builder.rs b/src/ir/builder.rs
index 5c372b9..fe715c9 100644
--- a/src/ir/builder.rs
+++ b/src/ir/builder.rs
@@ -494,20 +494,20 @@ pub struct LocalBuilder<'a> {
   pub(in crate::ir) dfg: &'a mut DataFlowGraph,
 }
 
-impl<'a> DfgBasedInfoQuerier for LocalBuilder<'a> {
+impl DfgBasedInfoQuerier for LocalBuilder<'_> {
   fn dfg(&self) -> &DataFlowGraph {
     self.dfg
   }
 }
 
-impl<'a> ValueInserter for LocalBuilder<'a> {
+impl ValueInserter for LocalBuilder<'_> {
   fn insert_value(&mut self, data: ValueData) -> Value {
     self.dfg.new_value_data(data)
   }
 }
 
-impl<'a> ValueBuilder for LocalBuilder<'a> {}
-impl<'a> LocalInstBuilder for LocalBuilder<'a> {}
+impl ValueBuilder for LocalBuilder<'_> {}
+impl LocalInstBuilder for LocalBuilder<'_> {}
 
 /// An basic block builder that builds a new basic block and inserts it
 /// to the data flow graph.
@@ -517,13 +517,13 @@ pub struct BlockBuilder<'a> {
   pub(in crate::ir) dfg: &'a mut DataFlowGraph,
 }
 
-impl<'a> ValueInserter for BlockBuilder<'a> {
+impl ValueInserter for BlockBuilder<'_> {
   fn insert_value(&mut self, data: ValueData) -> Value {
     self.dfg.new_value_data(data)
   }
 }
 
-impl<'a> BasicBlockBuilder for BlockBuilder<'a> {
+impl BasicBlockBuilder for BlockBuilder<'_> {
   fn insert_bb(&mut self, data: BasicBlockData) -> BasicBlock {
     self.dfg.new_bb_data(data)
   }
@@ -538,21 +538,21 @@ pub struct ReplaceBuilder<'a> {
   pub(in crate::ir) value: Value,
 }
 
-impl<'a> DfgBasedInfoQuerier for ReplaceBuilder<'a> {
+impl DfgBasedInfoQuerier for ReplaceBuilder<'_> {
   fn dfg(&self) -> &DataFlowGraph {
     self.dfg
   }
 }
 
-impl<'a> ValueInserter for ReplaceBuilder<'a> {
+impl ValueInserter for ReplaceBuilder<'_> {
   fn insert_value(&mut self, data: ValueData) -> Value {
     self.dfg.replace_value_with_data(self.value, data);
     self.value
   }
 }
 
-impl<'a> ValueBuilder for ReplaceBuilder<'a> {}
-impl<'a> LocalInstBuilder for ReplaceBuilder<'a> {}
+impl ValueBuilder for ReplaceBuilder<'_> {}
+impl LocalInstBuilder for ReplaceBuilder<'_> {}
 
 /// An value builder that builds a new global value and inserts it
 /// to the program.
@@ -562,7 +562,7 @@ pub struct GlobalBuilder<'a> {
   pub(in crate::ir) program: &'a mut Program,
 }
 
-impl<'a> EntityInfoQuerier for GlobalBuilder<'a> {
+impl EntityInfoQuerier for GlobalBuilder<'_> {
   fn value_type(&self, value: Value) -> Type {
     self
       .program
@@ -594,7 +594,7 @@ impl<'a> EntityInfoQuerier for GlobalBuilder<'a> {
   }
 }
 
-impl<'a> ValueInserter for GlobalBuilder<'a> {
+impl ValueInserter for GlobalBuilder<'_> {
   fn insert_value(&mut self, data: ValueData) -> Value {
     let is_inst = data.kind().is_global_alloc();
     let value = self.program.new_value_data(data);
@@ -605,5 +605,5 @@ impl<'a> ValueInserter for GlobalBuilder<'a> {
   }
 }
 
-impl<'a> ValueBuilder for GlobalBuilder<'a> {}
-impl<'a> GlobalInstBuilder for GlobalBuilder<'a> {}
+impl ValueBuilder for GlobalBuilder<'_> {}
+impl GlobalInstBuilder for GlobalBuilder<'_> {}
diff --git a/src/ir/entities.rs b/src/ir/entities.rs
index c6b62d3..fa5c476 100644
--- a/src/ir/entities.rs
+++ b/src/ir/entities.rs
@@ -591,7 +591,7 @@ pub struct ValueUses<'a> {
   index: usize,
 }
 
-impl<'a> Iterator for ValueUses<'a> {
+impl Iterator for ValueUses<'_> {
   type Item = Value;
 
   fn next(&mut self) -> Option<Self::Item> {
@@ -658,7 +658,7 @@ pub struct BasicBlockUses<'a> {
   index: usize,
 }
 
-impl<'a> Iterator for BasicBlockUses<'a> {
+impl Iterator for BasicBlockUses<'_> {
   type Item = BasicBlock;
 
   fn next(&mut self) -> Option<Self::Item> {
diff --git a/src/ir/idman.rs b/src/ir/idman.rs
index 1e542a4..a3f415c 100644
--- a/src/ir/idman.rs
+++ b/src/ir/idman.rs
@@ -15,7 +15,7 @@ pub(in crate::ir) type ValueId = NonZeroU32;
 /// memory layout optimization.
 const GLOBAL_VALUE_ID_STARTS_FROM: ValueId = unsafe { NonZeroU32::new_unchecked(1) };
 
-/// The value of `ValueId` (local value) should start from 1,
+/// The value of `ValueId` (local value) should start from 0x40000000,
 /// because we want to use `NonZeroU32` to enable some
 /// memory layout optimization.
 const LOCAL_VALUE_ID_STARTS_FROM: ValueId = unsafe { NonZeroU32::new_unchecked(0x40000000) };
@@ -42,12 +42,16 @@ const FUNC_ID_STARTS_FROM: FunctionId = unsafe { NonZeroU32::new_unchecked(1) };
 
 thread_local! {
   /// The next global value ID.
+  #[allow(clippy::missing_const_for_thread_local)]
   static NEXT_GLOBAL_VALUE_ID: Cell<ValueId> = Cell::new(GLOBAL_VALUE_ID_STARTS_FROM);
   /// The next local value ID.
+  #[allow(clippy::missing_const_for_thread_local)]
   static NEXT_LOCAL_VALUE_ID: Cell<ValueId> = Cell::new(LOCAL_VALUE_ID_STARTS_FROM);
   /// The next basic block ID.
+  #[allow(clippy::missing_const_for_thread_local)]
   static NEXT_BB_ID: Cell<BasicBlockId> = Cell::new(BB_ID_STARTS_FROM);
   /// The next function ID.
+  #[allow(clippy::missing_const_for_thread_local)]
   static NEXT_FUNC_ID: Cell<FunctionId> = Cell::new(FUNC_ID_STARTS_FROM);
 }
 
diff --git a/src/ir/layout.rs b/src/ir/layout.rs
index e5a876d..94e770a 100644
--- a/src/ir/layout.rs
+++ b/src/ir/layout.rs
@@ -106,18 +106,18 @@ impl Map<BasicBlock, BasicBlockNode> for BasicBlockMap {
     self.map.clear()
   }
 
-  fn get<Q: ?Sized>(&self, k: &Q) -> Option<&BasicBlockNode>
+  fn get<Q>(&self, k: &Q) -> Option<&BasicBlockNode>
   where
     BasicBlock: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     self.map.get(k)
   }
 
-  fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut BasicBlockNode>
+  fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut BasicBlockNode>
   where
     BasicBlock: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     self.map.get_mut(k)
   }
@@ -135,10 +135,10 @@ impl Map<BasicBlock, BasicBlockNode> for BasicBlockMap {
     }
   }
 
-  fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(BasicBlock, BasicBlockNode)>
+  fn remove_entry<Q>(&mut self, k: &Q) -> Option<(BasicBlock, BasicBlockNode)>
   where
     BasicBlock: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     self.map.remove_entry(k)
   }
@@ -225,18 +225,18 @@ impl Map<Value, InstNode> for InstMap {
     self.map.clear()
   }
 
-  fn get<Q: ?Sized>(&self, k: &Q) -> Option<&InstNode>
+  fn get<Q>(&self, k: &Q) -> Option<&InstNode>
   where
     Value: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     self.map.get(k)
   }
 
-  fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut InstNode>
+  fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut InstNode>
   where
     Value: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     self.map.get_mut(k)
   }
@@ -260,10 +260,10 @@ impl Map<Value, InstNode> for InstMap {
     }
   }
 
-  fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(Value, InstNode)>
+  fn remove_entry<Q>(&mut self, k: &Q) -> Option<(Value, InstNode)>
   where
     Value: Borrow<Q>,
-    Q: Hash + Eq,
+    Q: ?Sized + Hash + Eq,
   {
     let kv = self.map.remove_entry(k);
     if kv.is_some() {
diff --git a/src/ir/types.rs b/src/ir/types.rs
index fbbf079..d3cdb17 100644
--- a/src/ir/types.rs
+++ b/src/ir/types.rs
@@ -61,6 +61,7 @@ impl Type {
     static POOL: RefCell<HashMap<TypeKind, Type>> = RefCell::new(HashMap::new());
 
     /// Size of pointers.
+    #[allow(clippy::missing_const_for_thread_local)]
     static PTR_SIZE: Cell<usize> = Cell::new(mem::size_of::<*const ()>());
   }