diff --git a/tests/baselines/reference/emitClassExpressionInDeclarationFile.js b/tests/baselines/reference/emitClassExpressionInDeclarationFile.js
index 423546bcd4e..ab64fe003be 100644
--- a/tests/baselines/reference/emitClassExpressionInDeclarationFile.js
+++ b/tests/baselines/reference/emitClassExpressionInDeclarationFile.js
@@ -95,18 +95,12 @@ export declare var simpleExample: {
     new (): {
         tags(): void;
     };
-    prototype: {
-        tags(): void;
-    };
     getTags(): void;
 };
 export declare var circularReference: {
     new (): {
         tags(c: any): any;
     };
-    prototype: {
-        tags(c: any): any;
-    };
     getTags(c: {
         tags(c: any): any;
     }): {
@@ -124,11 +118,6 @@ export declare function WithTags<T extends Constructor<FooItem>>(Base: T): {
         foo(): void;
         name?: string;
     };
-    prototype: {
-        tags(): void;
-        foo(): void;
-        name?: string;
-    };
     getTags(): void;
 } & T;
 declare const Test_base: {
@@ -137,11 +126,6 @@ declare const Test_base: {
         foo(): void;
         name?: string;
     };
-    prototype: {
-        tags(): void;
-        foo(): void;
-        name?: string;
-    };
     getTags(): void;
 } & typeof FooItem;
 export declare class Test extends Test_base {
diff --git a/tests/baselines/reference/emitClassExpressionInDeclarationFile2.errors.txt b/tests/baselines/reference/emitClassExpressionInDeclarationFile2.errors.txt
new file mode 100644
index 00000000000..4541cf2a58a
--- /dev/null
+++ b/tests/baselines/reference/emitClassExpressionInDeclarationFile2.errors.txt
@@ -0,0 +1,41 @@
+tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts(1,12): error TS4094: Property 'p' of exported class expression may not be private or protected.
+tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts(1,12): error TS4094: Property 'ps' of exported class expression may not be private or protected.
+tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts(16,17): error TS4094: Property 'property' of exported class expression may not be private or protected.
+
+
+==== tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts (3 errors) ====
+    export var noPrivates = class {
+               ~~~~~~~~~~
+!!! error TS4094: Property 'p' of exported class expression may not be private or protected.
+               ~~~~~~~~~~
+!!! error TS4094: Property 'ps' of exported class expression may not be private or protected.
+        static getTags() { }
+        tags() { }
+        private static ps = -1
+        private p = 12
+    }
+    
+    // altered repro from #15066 to add private property
+    export class FooItem {
+        foo(): void { }
+        name?: string;
+        private property = "capitalism"
+    }
+    
+    export type Constructor<T> = new(...args: any[]) => T;
+    export function WithTags<T extends Constructor<FooItem>>(Base: T) {
+                    ~~~~~~~~
+!!! error TS4094: Property 'property' of exported class expression may not be private or protected.
+        return class extends Base {
+            static getTags(): void { }
+            tags(): void { }
+        }
+    }
+    
+    export class Test extends WithTags(FooItem) {}
+    
+    const test = new Test();
+    
+    Test.getTags()
+    test.tags();
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/emitClassExpressionInDeclarationFile2.js b/tests/baselines/reference/emitClassExpressionInDeclarationFile2.js
new file mode 100644
index 00000000000..e3a0aa4cb99
--- /dev/null
+++ b/tests/baselines/reference/emitClassExpressionInDeclarationFile2.js
@@ -0,0 +1,87 @@
+//// [emitClassExpressionInDeclarationFile2.ts]
+export var noPrivates = class {
+    static getTags() { }
+    tags() { }
+    private static ps = -1
+    private p = 12
+}
+
+// altered repro from #15066 to add private property
+export class FooItem {
+    foo(): void { }
+    name?: string;
+    private property = "capitalism"
+}
+
+export type Constructor<T> = new(...args: any[]) => T;
+export function WithTags<T extends Constructor<FooItem>>(Base: T) {
+    return class extends Base {
+        static getTags(): void { }
+        tags(): void { }
+    }
+}
+
+export class Test extends WithTags(FooItem) {}
+
+const test = new Test();
+
+Test.getTags()
+test.tags();
+
+
+//// [emitClassExpressionInDeclarationFile2.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = Object.setPrototypeOf ||
+        ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+        function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+exports.noPrivates = (_a = (function () {
+        function class_1() {
+            this.p = 12;
+        }
+        class_1.getTags = function () { };
+        class_1.prototype.tags = function () { };
+        return class_1;
+    }()),
+    _a.ps = -1,
+    _a);
+// altered repro from #15066 to add private property
+var FooItem = (function () {
+    function FooItem() {
+        this.property = "capitalism";
+    }
+    FooItem.prototype.foo = function () { };
+    return FooItem;
+}());
+exports.FooItem = FooItem;
+function WithTags(Base) {
+    return (function (_super) {
+        __extends(class_2, _super);
+        function class_2() {
+            return _super !== null && _super.apply(this, arguments) || this;
+        }
+        class_2.getTags = function () { };
+        class_2.prototype.tags = function () { };
+        return class_2;
+    }(Base));
+}
+exports.WithTags = WithTags;
+var Test = (function (_super) {
+    __extends(Test, _super);
+    function Test() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return Test;
+}(WithTags(FooItem)));
+exports.Test = Test;
+var test = new Test();
+Test.getTags();
+test.tags();
+var _a;
diff --git a/tests/cases/compiler/emitClassExpressionInDeclarationFile.ts b/tests/cases/compiler/emitClassExpressionInDeclarationFile.ts
index 4268f237044..f99bcbd7efd 100644
--- a/tests/cases/compiler/emitClassExpressionInDeclarationFile.ts
+++ b/tests/cases/compiler/emitClassExpressionInDeclarationFile.ts
@@ -2,19 +2,12 @@
 export var simpleExample = class {
     static getTags() { }
     tags() { }
-    private static ps = -1
-    private p = 12
 }
 export var circularReference = class C {
     static getTags(c: C): C { return c }
     tags(c: C): C { return c }
 }
 
-class Base { }
-export function foo() {
-    return class extends Base { }
-}
-
 // repro from #15066
 export class FooItem {
     foo(): void { }
diff --git a/tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts b/tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts
new file mode 100644
index 00000000000..3175f2afce7
--- /dev/null
+++ b/tests/cases/compiler/emitClassExpressionInDeclarationFile2.ts
@@ -0,0 +1,29 @@
+// @declaration: true
+export var noPrivates = class {
+    static getTags() { }
+    tags() { }
+    private static ps = -1
+    private p = 12
+}
+
+// altered repro from #15066 to add private property
+export class FooItem {
+    foo(): void { }
+    name?: string;
+    private property = "capitalism"
+}
+
+export type Constructor<T> = new(...args: any[]) => T;
+export function WithTags<T extends Constructor<FooItem>>(Base: T) {
+    return class extends Base {
+        static getTags(): void { }
+        tags(): void { }
+    }
+}
+
+export class Test extends WithTags(FooItem) {}
+
+const test = new Test();
+
+Test.getTags()
+test.tags();