diff --git a/tests/baselines/reference/declarationEmitNoTypeParamLeak1.js b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.js
new file mode 100644
index 0000000000000..f9c445a69eb86
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.js
@@ -0,0 +1,25 @@
+//// [tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts] ////
+
+//// [declarationEmitNoTypeParamLeak1.ts]
+type BrokenType<T> = 'a' | 'b';
+
+class MyClass {
+    constructor(readonly arg?: BrokenType<any>) {}
+}
+
+//// [declarationEmitNoTypeParamLeak1.js]
+"use strict";
+var MyClass = /** @class */ (function () {
+    function MyClass(arg) {
+        this.arg = arg;
+    }
+    return MyClass;
+}());
+
+
+//// [declarationEmitNoTypeParamLeak1.d.ts]
+type BrokenType<T> = 'a' | 'b';
+declare class MyClass {
+    readonly arg?: BrokenType<any> | undefined;
+    constructor(arg?: BrokenType<any> | undefined);
+}
diff --git a/tests/baselines/reference/declarationEmitNoTypeParamLeak1.symbols b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.symbols
new file mode 100644
index 0000000000000..17c7fb65a4924
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.symbols
@@ -0,0 +1,14 @@
+//// [tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts] ////
+
+=== declarationEmitNoTypeParamLeak1.ts ===
+type BrokenType<T> = 'a' | 'b';
+>BrokenType : Symbol(BrokenType, Decl(declarationEmitNoTypeParamLeak1.ts, 0, 0))
+>T : Symbol(T, Decl(declarationEmitNoTypeParamLeak1.ts, 0, 16))
+
+class MyClass {
+>MyClass : Symbol(MyClass, Decl(declarationEmitNoTypeParamLeak1.ts, 0, 31))
+
+    constructor(readonly arg?: BrokenType<any>) {}
+>arg : Symbol(MyClass.arg, Decl(declarationEmitNoTypeParamLeak1.ts, 3, 16))
+>BrokenType : Symbol(BrokenType, Decl(declarationEmitNoTypeParamLeak1.ts, 0, 0))
+}
diff --git a/tests/baselines/reference/declarationEmitNoTypeParamLeak1.types b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.types
new file mode 100644
index 0000000000000..69a4caab088a8
--- /dev/null
+++ b/tests/baselines/reference/declarationEmitNoTypeParamLeak1.types
@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts] ////
+
+=== declarationEmitNoTypeParamLeak1.ts ===
+type BrokenType<T> = 'a' | 'b';
+>BrokenType : BrokenType<T>
+>           : ^^^^^^^^^^^^^
+
+class MyClass {
+>MyClass : MyClass
+>        : ^^^^^^^
+
+    constructor(readonly arg?: BrokenType<any>) {}
+>arg : BrokenType<T> | undefined
+>    : ^^^^^^^^^^^^^^^^^^^^^^^^^
+}
diff --git a/tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts b/tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts
new file mode 100644
index 0000000000000..1f5dd48efe8ba
--- /dev/null
+++ b/tests/cases/compiler/declarationEmitNoTypeParamLeak1.ts
@@ -0,0 +1,8 @@
+// @strict: true
+// @declaration: true
+
+type BrokenType<T> = 'a' | 'b';
+
+class MyClass {
+    constructor(readonly arg?: BrokenType<any>) {}
+}
\ No newline at end of file