fix(transformer): remove an AstBuilder::copy call for TS AssignmentTarget transform

crates/oxc_ast/src/ast_impl/js.rs

@@ -626,6 +626,10 @@ impl<'a> AssignmentTarget<'a> {
     pub fn get_expression(&self) -> Option<&Expression<'a>> {
         self.as_simple_assignment_target().and_then(SimpleAssignmentTarget::get_expression)
     }
+
+    pub fn get_expression_mut(&mut self) -> Option<&mut Expression<'a>> {
+        self.as_simple_assignment_target_mut().and_then(SimpleAssignmentTarget::get_expression_mut)
+    }
 }
 
 impl<'a> SimpleAssignmentTarget<'a> {

crates/oxc_transformer/src/typescript/annotations.rs

@@ -250,10 +250,14 @@ impl<'a> TypeScriptAnnotations<'a> {
     }
 
     pub fn transform_assignment_target(&mut self, target: &mut AssignmentTarget<'a>) {
-        if let Some(expr) = target.get_expression() {
-            if let Some(member_expr) = expr.get_inner_expression().as_member_expression() {
-                // SAFETY: `ast.copy` is unsound! We need to fix.
-                *target = AssignmentTarget::from(unsafe { self.ctx.ast.copy(member_expr) });
+        if let Some(expr) = target.get_expression_mut() {
+            let inner_expr = expr.get_inner_expression_mut();
+            if inner_expr.is_member_expression() {
+                let inner_expr = self.ctx.ast.move_expression(inner_expr);
+                let Ok(member_expr) = MemberExpression::try_from(inner_expr) else {
+                    unreachable!();
+                };
+                *target = AssignmentTarget::from(member_expr);
             }
         }
     }