diff --git a/crates/oxc_isolated_declarations/src/class.rs b/crates/oxc_isolated_declarations/src/class.rs
index 4a8a4f2d33e12..8144cb30cfb3c 100644
--- a/crates/oxc_isolated_declarations/src/class.rs
+++ b/crates/oxc_isolated_declarations/src/class.rs
@@ -376,6 +376,8 @@ impl<'a> IsolatedDeclarations<'a> {
                         continue;
                     }
 
+                    let errors_length = self.errors.borrow().len();
+
                     let inferred_accessor_types = self.collect_inferred_accessor_types(decl);
                     let function = &method.value;
                     let params = if method.kind.is_set() {
@@ -404,6 +406,7 @@ impl<'a> IsolatedDeclarations<'a> {
                     }
 
                     if method.accessibility.is_some_and(TSAccessibility::is_private) {
+                        self.errors.borrow_mut().truncate(errors_length);
                         elements.push(self.transform_private_modifier_method(method));
                         continue;
                     }
diff --git a/crates/oxc_isolated_declarations/tests/fixtures/function-parameters.ts b/crates/oxc_isolated_declarations/tests/fixtures/function-parameters.ts
index e22af6aac55b9..9b7d93e5879b7 100644
--- a/crates/oxc_isolated_declarations/tests/fixtures/function-parameters.ts
+++ b/crates/oxc_isolated_declarations/tests/fixtures/function-parameters.ts
@@ -14,6 +14,10 @@ const x = 42;
 const y = '';
 export function fooGood3({a = x, b: [{c = y}]}: object): void {}
 
+export class Foo {
+  private good(a): void {}
+}
+
 // Incorrect
 export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
 export function fnDeclBad2<T>(p: T = [], r2: T): void { }
@@ -26,3 +30,7 @@ export function fooBad([a, b] = [1, 2]): number {
 export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
   return 2;
 }
+
+export class Bar {
+  public bad(a): void {}
+}
\ No newline at end of file
diff --git a/crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap b/crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap
index c006d77d4c613..4e65c510d2c9d 100644
--- a/crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap
+++ b/crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap
@@ -9,65 +9,80 @@ export declare function fnDeclGood2(p?: T, rParam?: number): void;
 export declare function fooGood([a, b]?: any[]): number;
 export declare const fooGood2: ({ a, b }?: object) => number;
 export declare function fooGood3({ a, b: [{ c }] }: object): void;
+export declare class Foo {
+	private good;
+}
 export declare function fnDeclBad<T>(p: T, rParam: T, r2: T): void;
 export declare function fnDeclBad2<T>(p: T, r2: T): void;
 export declare function fnDeclBad3<T>(p: T, rParam?: T, r2: T): void;
 export declare function fooBad(): number;
 export declare const fooBad2: () => number;
+export declare class Bar {
+	bad(a): void;
+}
 
 
 ==================== Errors ====================
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[18:30]
- 17 | // Incorrect
- 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+    ,-[22:30]
+ 21 | // Incorrect
+ 22 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
     :                              ^^^^^^^^^
- 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 23 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[18:41]
- 17 | // Incorrect
- 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+    ,-[22:41]
+ 21 | // Incorrect
+ 22 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
     :                                         ^^^^^^^^^^^^^^
- 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 23 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[19:31]
- 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
- 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+    ,-[23:31]
+ 22 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+ 23 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     :                               ^^^^^^^^^
- 20 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
+ 24 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[20:31]
- 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
- 20 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
+    ,-[24:31]
+ 23 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 24 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
     :                               ^^^^^^^^^
- 21 | 
+ 25 | 
     `----
 
   x TS9011: Parameter must have an explicit type annotation with
   | --isolatedDeclarations.
-    ,-[22:24]
- 21 | 
- 22 | export function fooBad([a, b] = [1, 2]): number {
+    ,-[26:24]
+ 25 | 
+ 26 | export function fooBad([a, b] = [1, 2]): number {
     :                        ^^^^^^^^^^^^^^^
- 23 |   return 2;
+ 27 |   return 2;
     `----
 
   x TS9011: Parameter must have an explicit type annotation with
   | --isolatedDeclarations.
-    ,-[26:25]
- 25 | 
- 26 | export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
+    ,-[30:25]
+ 29 | 
+ 30 | export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
     :                         ^^^^^^^^^^^^^^^^^^^^^^^
- 27 |   return 2;
+ 31 |   return 2;
+    `----
+
+  x TS9011: Parameter must have an explicit type annotation with
+  | --isolatedDeclarations.
+    ,-[35:14]
+ 34 | export class Bar {
+ 35 |   public bad(a): void {}
+    :              ^
+ 36 | }
     `----