refactor(transformer/class-properties): simplify to get constructor method only once (#10493)

Benefit from #10495, we can move getting `instance_inits_scope_id` and `instance_inits_constructor_scope_id` part to after all instance properties transformed. So that we can avoid to get `constructor` twice due to borrow checker.

Author: Dunqing

crates/oxc_transformer/src/es2022/class_properties/class.rs

@@ -78,7 +78,6 @@ impl<'a> ClassProperties<'a, '_> {
         let mut has_static_private_method_or_static_block = false;
         // TODO: Store `FxIndexMap`s in a pool and re-use them
         let mut private_props = FxIndexMap::default();
-        let mut constructor = None;
         for element in &mut body.body {
             match element {
                 ClassElement::PropertyDefinition(prop) => {
@@ -107,11 +106,7 @@ impl<'a> ClassProperties<'a, '_> {
                     }
                 }
                 ClassElement::MethodDefinition(method) => {
-                    if method.kind == MethodDefinitionKind::Constructor {
-                        if method.value.body.is_some() {
-                            constructor = Some(method);
-                        }
-                    } else if let PropertyKey::PrivateIdentifier(ident) = &method.key {
+                    if let PropertyKey::PrivateIdentifier(ident) = &method.key {
                         if method.r#static {
                             has_static_private_method_or_static_block = true;
                         } else {
@@ -239,51 +234,6 @@ impl<'a> ClassProperties<'a, '_> {
             return;
         }
 
-        // Scope that instance property initializers will be inserted into.
-        // This is usually class constructor, but can also be a `_super` function which is created.
-        let instance_inits_scope_id;
-        // Scope of class constructor, if instance property initializers will be inserted into constructor.
-        // Used for checking for variable name clashes.
-        // e.g. `class C { prop = x(); constructor(x) {} }`
-        // - `x` in constructor needs to be renamed when `x()` is moved into constructor body.
-        // `None` if class has no existing constructor, as then there can't be any clashes.
-        let mut instance_inits_constructor_scope_id = None;
-
-        // Determine where to insert instance property initializers in constructor
-        let instance_inits_insert_location = if let Some(constructor) = constructor {
-            // Existing constructor
-            let constructor = constructor.value.as_mut();
-            if has_super_class {
-                let (insert_scopes, insert_location) =
-                    Self::replace_super_in_constructor(constructor, ctx);
-                instance_inits_scope_id = insert_scopes.insert_in_scope_id;
-                instance_inits_constructor_scope_id = insert_scopes.constructor_scope_id;
-                insert_location
-            } else {
-                let constructor_scope_id = constructor.scope_id();
-                instance_inits_scope_id = constructor_scope_id;
-                // Only record `constructor_scope_id` if constructor's scope has some bindings.
-                // If it doesn't, no need to check for shadowed symbols in instance prop initializers,
-                // because no bindings to clash with.
-                instance_inits_constructor_scope_id =
-                    if ctx.scoping().get_bindings(constructor_scope_id).is_empty() {
-                        None
-                    } else {
-                        Some(constructor_scope_id)
-                    };
-                InstanceInitsInsertLocation::ExistingConstructor(0)
-            }
-        } else {
-            // No existing constructor - create scope for one
-            let constructor_scope_id = ctx.scoping_mut().add_scope(
-                Some(class_scope_id),
-                NodeId::DUMMY,
-                ScopeFlags::Function | ScopeFlags::Constructor | ScopeFlags::StrictMode,
-            );
-            instance_inits_scope_id = constructor_scope_id;
-            InstanceInitsInsertLocation::NewConstructor
-        };
-
         // Extract instance properties initializers.
         //
         // We leave the properties themselves in place, but take the initializers.
@@ -326,6 +276,49 @@ impl<'a> ClassProperties<'a, '_> {
             }
         }
 
+        // Scope that instance property initializers will be inserted into.
+        // This is usually class constructor, but can also be a `_super` function which is created.
+        let instance_inits_scope_id;
+        // Scope of class constructor, if instance property initializers will be inserted into constructor.
+        // Used for checking for variable name clashes.
+        // e.g. `class C { prop = x(); constructor(x) {} }`
+        // - `x` in constructor needs to be renamed when `x()` is moved into constructor body.
+        // `None` if class has no existing constructor, as then there can't be any clashes.
+        let mut instance_inits_constructor_scope_id = None;
+
+        // Determine where to insert instance property initializers in constructor
+        let instance_inits_insert_location = if let Some(constructor) = constructor.as_deref_mut() {
+            if has_super_class {
+                let (insert_scopes, insert_location) =
+                    Self::replace_super_in_constructor(constructor, ctx);
+                instance_inits_scope_id = insert_scopes.insert_in_scope_id;
+                instance_inits_constructor_scope_id = insert_scopes.constructor_scope_id;
+                insert_location
+            } else {
+                let constructor_scope_id = constructor.scope_id();
+                instance_inits_scope_id = constructor_scope_id;
+                // Only record `constructor_scope_id` if constructor's scope has some bindings.
+                // If it doesn't, no need to check for shadowed symbols in instance prop initializers,
+                // because no bindings to clash with.
+                instance_inits_constructor_scope_id =
+                    if ctx.scoping().get_bindings(constructor_scope_id).is_empty() {
+                        None
+                    } else {
+                        Some(constructor_scope_id)
+                    };
+                InstanceInitsInsertLocation::ExistingConstructor(0)
+            }
+        } else {
+            // No existing constructor - create scope for one
+            let constructor_scope_id = ctx.scoping_mut().add_scope(
+                Some(class_scope_id),
+                NodeId::DUMMY,
+                ScopeFlags::Function | ScopeFlags::Constructor | ScopeFlags::StrictMode,
+            );
+            instance_inits_scope_id = constructor_scope_id;
+            InstanceInitsInsertLocation::NewConstructor
+        };
+
         // Reparent property initializers scope to `instance_inits_scope_id`.
         self.reparent_initializers_scope(
             instance_inits.as_slice(),