With Eigen3.5.x, unary/binary block expressions don't like the manipulated c from above

Author: EricaCMitchell

tests/expressions_impl.h

@@ -3047,10 +3047,11 @@ BOOST_FIXTURE_TEST_CASE_TEMPLATE(empty_trange1, F, Fixtures, F) {
 
   // unary/binary block expressions
   {
-    BOOST_CHECK_NO_THROW(c("a,b,c") = aC("a,b,c").block(lobound, upbound));
-    BOOST_CHECK_NO_THROW(c("a,b,c") +=
+    std::decay_t<decltype(c)> t3;
+    BOOST_CHECK_NO_THROW(t3("a,b,c") = aC("a,b,c").block(lobound, upbound));
+    BOOST_CHECK_NO_THROW(t3("a,b,c") +=
                          2 * aC("a,b,c").block(lobound, upbound).conj());
-    BOOST_CHECK_NO_THROW(c("a,b,c") =
+    BOOST_CHECK_NO_THROW(t3("a,b,c") =
                              2 * conj(aC("a,c,b").block(lobound, upbound)));
   }