diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-generic-conv3.C b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-conv3.C
new file mode 100644
index 000000000000..8ec6a2092d75
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-generic-conv3.C
@@ -0,0 +1,10 @@
+// PR c++/70942
+// { dg-do compile { target c++14 } }
+
+int main()
+{
+    int x = 0;
+    [](auto&& xv){
+        static_cast<decltype(xv)>(xv) = 1;
+    }(x);
+}