diff --git a/compiler/testData/diagnostics/tests/regressions/kt557.jet b/compiler/testData/diagnostics/tests/regressions/kt557.jet
new file mode 100644
index 00000000000..546965a6064
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/regressions/kt557.jet
@@ -0,0 +1,9 @@
+// KT-557 Wrong type inference near sure extension function
+
+fun Array<String>.length() : Int {
+    return 0;
+}
+
+fun test(array : Array<String?>?) {
+    array<!UNNECESSARY_SAFE_CALL!>?.<!>sure<Array<String?>>()<!UNSAFE_CALL!>.<!>length()
+}
\ No newline at end of file