diff --git a/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.errors.txt b/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.errors.txt
new file mode 100644
index 0000000000..8fa0624416
--- /dev/null
+++ b/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.errors.txt
@@ -0,0 +1,13 @@
+tests/cases/compiler/propertyAccessOfReadonlyIndexSignature.ts(6,1): error TS2542: Index signature in type 'Test' only permits reading.
+
+
+==== tests/cases/compiler/propertyAccessOfReadonlyIndexSignature.ts (1 errors) ====
+    interface Test {
+        readonly [key: string]: string;
+    }
+    
+    declare var a: Test;
+    a.foo = 'baz';
+    ~~~~~
+!!! error TS2542: Index signature in type 'Test' only permits reading.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.js b/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.js
new file mode 100644
index 0000000000..a1069eca55
--- /dev/null
+++ b/tests/baselines/reference/propertyAccessOfReadonlyIndexSignature.js
@@ -0,0 +1,11 @@
+//// [propertyAccessOfReadonlyIndexSignature.ts]
+interface Test {
+    readonly [key: string]: string;
+}
+
+declare var a: Test;
+a.foo = 'baz';
+
+
+//// [propertyAccessOfReadonlyIndexSignature.js]
+a.foo = 'baz';
diff --git a/tests/cases/compiler/propertyAccessOfReadonlyIndexSignature.ts b/tests/cases/compiler/propertyAccessOfReadonlyIndexSignature.ts
new file mode 100644
index 0000000000..c5f28c5b09
--- /dev/null
+++ b/tests/cases/compiler/propertyAccessOfReadonlyIndexSignature.ts
@@ -0,0 +1,6 @@
+interface Test {
+    readonly [key: string]: string;
+}
+
+declare var a: Test;
+a.foo = 'baz';