diff --git a/crates/oxc_isolated_declarations/src/class.rs b/crates/oxc_isolated_declarations/src/class.rs
index a6fd14ddf3cfb..109a293b6e297 100644
--- a/crates/oxc_isolated_declarations/src/class.rs
+++ b/crates/oxc_isolated_declarations/src/class.rs
@@ -15,7 +15,8 @@ use crate::{
 };
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn is_literal_key(&self, key: &PropertyKey<'a>) -> bool {
+    #[allow(clippy::unused_self)]
+    pub(crate) fn is_literal_key(&self, key: &PropertyKey<'a>) -> bool {
         match key {
             PropertyKey::StringLiteral(_)
             | PropertyKey::NumericLiteral(_)
@@ -32,7 +33,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn report_property_key(&self, key: &PropertyKey<'a>, computed: bool) -> bool {
+    pub(crate) fn report_property_key(&self, key: &PropertyKey<'a>, computed: bool) -> bool {
         if computed && !self.is_literal_key(key) {
             self.error(computed_property_name(key.span()));
             true
@@ -41,7 +42,8 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn transform_accessibility(
+    #[allow(clippy::unused_self)]
+    pub(crate) fn transform_accessibility(
         &self,
         accessibility: Option<TSAccessibility>,
     ) -> Option<TSAccessibility> {
@@ -328,7 +330,7 @@ impl<'a> IsolatedDeclarations<'a> {
         method_annotations
     }
 
-    pub fn transform_class(
+    pub(crate) fn transform_class(
         &self,
         decl: &Class<'a>,
         declare: Option<bool>,
@@ -557,7 +559,7 @@ impl<'a> IsolatedDeclarations<'a> {
         ))
     }
 
-    pub fn create_formal_parameters(
+    pub(crate) fn create_formal_parameters(
         &self,
         kind: BindingPatternKind<'a>,
     ) -> Box<'a, FormalParameters<'a>> {
diff --git a/crates/oxc_isolated_declarations/src/declaration.rs b/crates/oxc_isolated_declarations/src/declaration.rs
index ad88e1f0b11c8..2c4d2eb49050d 100644
--- a/crates/oxc_isolated_declarations/src/declaration.rs
+++ b/crates/oxc_isolated_declarations/src/declaration.rs
@@ -21,7 +21,7 @@ use crate::{
 };
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_variable_declaration(
+    pub(crate) fn transform_variable_declaration(
         &self,
         decl: &VariableDeclaration<'a>,
         check_binding: bool,
@@ -37,7 +37,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn transform_variable_declaration_with_new_declarations(
+    pub(crate) fn transform_variable_declaration_with_new_declarations(
         &self,
         decl: &VariableDeclaration<'a>,
         declarations: oxc_allocator::Vec<'a, VariableDeclarator<'a>>,
@@ -50,7 +50,7 @@ impl<'a> IsolatedDeclarations<'a> {
         )
     }
 
-    pub fn transform_variable_declarator(
+    pub(crate) fn transform_variable_declarator(
         &self,
         decl: &VariableDeclarator<'a>,
         check_binding: bool,
@@ -117,31 +117,6 @@ impl<'a> IsolatedDeclarations<'a> {
         Some(self.ast.variable_declarator(decl.span, decl.kind, id, init, decl.definite))
     }
 
-    pub fn transform_using_declaration(
-        &self,
-        decl: &VariableDeclaration<'a>,
-        check_binding: bool,
-    ) -> Box<'a, VariableDeclaration<'a>> {
-        let declarations =
-            self.ast.vec_from_iter(decl.declarations.iter().filter_map(|declarator| {
-                self.transform_variable_declarator(declarator, check_binding)
-            }));
-        self.transform_using_declaration_with_new_declarations(decl, declarations)
-    }
-
-    pub fn transform_using_declaration_with_new_declarations(
-        &self,
-        decl: &VariableDeclaration<'a>,
-        declarations: oxc_allocator::Vec<'a, VariableDeclarator<'a>>,
-    ) -> Box<'a, VariableDeclaration<'a>> {
-        self.ast.alloc_variable_declaration(
-            decl.span,
-            VariableDeclarationKind::Const,
-            declarations,
-            self.is_declare(),
-        )
-    }
-
     fn transform_ts_module_block(
         &mut self,
         block: &Box<'a, TSModuleBlock<'a>>,
@@ -154,7 +129,7 @@ impl<'a> IsolatedDeclarations<'a> {
         self.ast.alloc_ts_module_block(SPAN, self.ast.vec(), stmts)
     }
 
-    pub fn transform_ts_module_declaration(
+    pub(crate) fn transform_ts_module_declaration(
         &mut self,
         decl: &Box<'a, TSModuleDeclaration<'a>>,
     ) -> Box<'a, TSModuleDeclaration<'a>> {
@@ -194,7 +169,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn transform_declaration(
+    pub(crate) fn transform_declaration(
         &mut self,
         decl: &Declaration<'a>,
         check_binding: bool,
diff --git a/crates/oxc_isolated_declarations/src/function.rs b/crates/oxc_isolated_declarations/src/function.rs
index 743f2fccefe41..d506ef367693d 100644
--- a/crates/oxc_isolated_declarations/src/function.rs
+++ b/crates/oxc_isolated_declarations/src/function.rs
@@ -13,7 +13,7 @@ use crate::{
 };
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_function(
+    pub(crate) fn transform_function(
         &mut self,
         func: &Function<'a>,
         declare: Option<bool>,
@@ -45,7 +45,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn transform_formal_parameter(
+    pub(crate) fn transform_formal_parameter(
         &self,
         param: &FormalParameter<'a>,
         is_remaining_params_have_required: bool,
@@ -124,7 +124,7 @@ impl<'a> IsolatedDeclarations<'a> {
         Some(self.ast.formal_parameter(param.span, self.ast.vec(), pattern, None, false, false))
     }
 
-    pub fn transform_formal_parameters(
+    pub(crate) fn transform_formal_parameters(
         &self,
         params: &FormalParameters<'a>,
     ) -> Box<'a, FormalParameters<'a>> {
diff --git a/crates/oxc_isolated_declarations/src/inferrer.rs b/crates/oxc_isolated_declarations/src/inferrer.rs
index 21856c09b846f..67eca4b22b018 100644
--- a/crates/oxc_isolated_declarations/src/inferrer.rs
+++ b/crates/oxc_isolated_declarations/src/inferrer.rs
@@ -12,11 +12,11 @@ use crate::{
 };
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn can_infer_unary_expression(expr: &UnaryExpression<'a>) -> bool {
+    pub(crate) fn can_infer_unary_expression(expr: &UnaryExpression<'a>) -> bool {
         expr.operator.is_arithmetic() && expr.argument.is_number_literal()
     }
 
-    pub fn infer_type_from_expression(&self, expr: &Expression<'a>) -> Option<TSType<'a>> {
+    pub(crate) fn infer_type_from_expression(&self, expr: &Expression<'a>) -> Option<TSType<'a>> {
         match expr {
             Expression::BooleanLiteral(_) => Some(self.ast.ts_type_boolean_keyword(SPAN)),
             Expression::NullLiteral(_) => Some(self.ast.ts_type_null_keyword(SPAN)),
@@ -84,7 +84,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn infer_type_from_formal_parameter(
+    pub(crate) fn infer_type_from_formal_parameter(
         &self,
         param: &FormalParameter<'a>,
     ) -> Option<TSType<'a>> {
@@ -106,7 +106,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn infer_function_return_type(
+    pub(crate) fn infer_function_return_type(
         &self,
         function: &Function<'a>,
     ) -> Option<Box<'a, TSTypeAnnotation<'a>>> {
@@ -125,7 +125,7 @@ impl<'a> IsolatedDeclarations<'a> {
         })
     }
 
-    pub fn infer_arrow_function_return_type(
+    pub(crate) fn infer_arrow_function_return_type(
         &self,
         function: &ArrowFunctionExpression<'a>,
     ) -> Option<Box<'a, TSTypeAnnotation<'a>>> {
@@ -150,7 +150,7 @@ impl<'a> IsolatedDeclarations<'a> {
             .map(|type_annotation| self.ast.alloc_ts_type_annotation(SPAN, type_annotation))
     }
 
-    pub fn is_need_to_infer_type_from_expression(expr: &Expression<'a>) -> bool {
+    pub(crate) fn is_need_to_infer_type_from_expression(expr: &Expression<'a>) -> bool {
         match expr {
             Expression::NumericLiteral(_)
             | Expression::BigIntLiteral(_)
diff --git a/crates/oxc_isolated_declarations/src/lib.rs b/crates/oxc_isolated_declarations/src/lib.rs
index 89fdf38fee2d3..06a7ea70e3ec0 100644
--- a/crates/oxc_isolated_declarations/src/lib.rs
+++ b/crates/oxc_isolated_declarations/src/lib.rs
@@ -131,7 +131,7 @@ impl<'a> IsolatedDeclarations<'a> {
 }
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_program(
+    fn transform_program(
         &mut self,
         program: &Program<'a>,
     ) -> oxc_allocator::Vec<'a, Statement<'a>> {
@@ -152,7 +152,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn transform_program_without_module_declaration(
+    fn transform_program_without_module_declaration(
         &mut self,
         stmts: &oxc_allocator::Vec<'a, Statement<'a>>,
     ) -> oxc_allocator::Vec<'a, Statement<'a>> {
@@ -175,7 +175,7 @@ impl<'a> IsolatedDeclarations<'a> {
     }
 
     #[allow(clippy::missing_panics_doc)]
-    pub fn transform_statements_on_demand(
+    fn transform_statements_on_demand(
         &mut self,
         stmts: &oxc_allocator::Vec<'a, Statement<'a>>,
     ) -> oxc_allocator::Vec<'a, Statement<'a>> {
@@ -421,7 +421,7 @@ impl<'a> IsolatedDeclarations<'a> {
         new_stm
     }
 
-    pub fn remove_function_overloads_implementation(
+    fn remove_function_overloads_implementation(
         stmts: &mut oxc_allocator::Vec<'a, &Statement<'a>>,
     ) {
         let mut last_function_name: Option<Atom<'a>> = None;
@@ -556,7 +556,7 @@ impl<'a> IsolatedDeclarations<'a> {
         assignable_properties_for_namespace
     }
 
-    pub fn report_error_for_expando_function(&self, stmts: &oxc_allocator::Vec<'a, Statement<'a>>) {
+    fn report_error_for_expando_function(&self, stmts: &oxc_allocator::Vec<'a, Statement<'a>>) {
         let assignable_properties_for_namespace =
             IsolatedDeclarations::get_assignable_properties_for_namespaces(stmts);
 
@@ -644,7 +644,7 @@ impl<'a> IsolatedDeclarations<'a> {
         }
     }
 
-    pub fn is_declare(&self) -> bool {
+    fn is_declare(&self) -> bool {
         // If we are in a module block, we don't need to add declare
         !self.scope.is_ts_module_block()
     }
diff --git a/crates/oxc_isolated_declarations/src/literal.rs b/crates/oxc_isolated_declarations/src/literal.rs
index 319ba48286f5d..b36109eb8971c 100644
--- a/crates/oxc_isolated_declarations/src/literal.rs
+++ b/crates/oxc_isolated_declarations/src/literal.rs
@@ -4,7 +4,7 @@ use oxc_ast::ast::{StringLiteral, TemplateLiteral};
 use crate::IsolatedDeclarations;
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_template_to_string(
+    pub(crate) fn transform_template_to_string(
         &self,
         lit: &TemplateLiteral<'a>,
     ) -> Option<Box<'a, StringLiteral<'a>>> {
diff --git a/crates/oxc_isolated_declarations/src/module.rs b/crates/oxc_isolated_declarations/src/module.rs
index b8247021abbb2..a048f6fe6d459 100644
--- a/crates/oxc_isolated_declarations/src/module.rs
+++ b/crates/oxc_isolated_declarations/src/module.rs
@@ -7,7 +7,7 @@ use oxc_span::{Atom, GetSpan, SPAN};
 use crate::{diagnostics::default_export_inferred, IsolatedDeclarations};
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_export_named_declaration(
+    pub(crate) fn transform_export_named_declaration(
         &mut self,
         prev_decl: &ExportNamedDeclaration<'a>,
     ) -> Option<ExportNamedDeclaration<'a>> {
@@ -23,7 +23,7 @@ impl<'a> IsolatedDeclarations<'a> {
         ))
     }
 
-    pub fn create_unique_name(&mut self, name: &str) -> Atom<'a> {
+    pub(crate) fn create_unique_name(&mut self, name: &str) -> Atom<'a> {
         let mut binding = self.ast.atom(name);
         let mut i = 1;
         while self.scope.has_reference(&binding) {
@@ -33,7 +33,7 @@ impl<'a> IsolatedDeclarations<'a> {
         binding
     }
 
-    pub fn transform_export_default_declaration(
+    pub(crate) fn transform_export_default_declaration(
         &mut self,
         decl: &ExportDefaultDeclaration<'a>,
     ) -> Option<(Option<VariableDeclaration<'a>>, ExportDefaultDeclaration<'a>)> {
@@ -91,7 +91,7 @@ impl<'a> IsolatedDeclarations<'a> {
         })
     }
 
-    pub fn transform_import_declaration(
+    pub(crate) fn transform_import_declaration(
         &self,
         decl: &ImportDeclaration<'a>,
     ) -> Option<Box<'a, ImportDeclaration<'a>>> {
diff --git a/crates/oxc_isolated_declarations/src/types.rs b/crates/oxc_isolated_declarations/src/types.rs
index 8ee3b0daa5574..3f5a3b150a86c 100644
--- a/crates/oxc_isolated_declarations/src/types.rs
+++ b/crates/oxc_isolated_declarations/src/types.rs
@@ -18,7 +18,7 @@ use crate::{
 };
 
 impl<'a> IsolatedDeclarations<'a> {
-    pub fn transform_function_to_ts_type(&self, func: &Function<'a>) -> Option<TSType<'a>> {
+    pub(crate) fn transform_function_to_ts_type(&self, func: &Function<'a>) -> Option<TSType<'a>> {
         let return_type = self.infer_function_return_type(func);
         if return_type.is_none() {
             self.error(function_must_have_explicit_return_type(get_function_span(func)));
@@ -39,7 +39,7 @@ impl<'a> IsolatedDeclarations<'a> {
         })
     }
 
-    pub fn transform_arrow_function_to_ts_type(
+    pub(crate) fn transform_arrow_function_to_ts_type(
         &self,
         func: &ArrowFunctionExpression<'a>,
     ) -> Option<TSType<'a>> {
@@ -148,7 +148,7 @@ impl<'a> IsolatedDeclarations<'a> {
         self.ast.ts_type_type_literal(SPAN, members)
     }
 
-    pub fn transform_array_expression_to_ts_type(
+    pub(crate) fn transform_array_expression_to_ts_type(
         &self,
         expr: &ArrayExpression<'a>,
         is_const: bool,
@@ -181,7 +181,10 @@ impl<'a> IsolatedDeclarations<'a> {
     }
 
     // https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-4.html#const-assertions
-    pub fn transform_expression_to_ts_type(&self, expr: &Expression<'a>) -> Option<TSType<'a>> {
+    pub(crate) fn transform_expression_to_ts_type(
+        &self,
+        expr: &Expression<'a>,
+    ) -> Option<TSType<'a>> {
         match expr {
             Expression::BooleanLiteral(lit) => Some(self.ast.ts_type_literal_type(
                 SPAN,