Add test for #10342 (#3567)

test/testfunctions.cpp

@@ -1510,6 +1510,9 @@ private:
 
         check("int f(int x) { if (x) return 1; else return bar({1}, {}); }");
         ASSERT_EQUALS("", errout.str());
+
+        check("auto f() -> void {}"); // #10342
+        ASSERT_EQUALS("", errout.str());
     }
 
     // NRVO check