diff --git a/include/boost/math/special_functions/nonfinite_num_facets.hpp b/include/boost/math/special_functions/nonfinite_num_facets.hpp
index 697a35f98..d86162dc5 100644
--- a/include/boost/math/special_functions/nonfinite_num_facets.hpp
+++ b/include/boost/math/special_functions/nonfinite_num_facets.hpp
@@ -493,10 +493,10 @@ namespace boost {
               return;
             }
           }
-          break;
+          break;  // LCOV_EXCL_LINE  simple fallthrough not registered as covered.
 
         default:
-          break;
+          break;  // LCOV_EXCL_LINE  simple fallthrough not registered as covered.
         }
 
         state |= std::ios_base::failbit;
@@ -533,10 +533,10 @@ namespace boost {
                 val = positive_nan<ValType>();
                 return;
             }
-            break;
+            break;  // LCOV_EXCL_LINE  simple fallthrough not registered as covered.
 
           default:
-            break;
+            break;  // LCOV_EXCL_LINE  simple fallthrough not registered as covered.
           }
         }
 
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 6894dff27..66ab791ec 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -895,6 +895,7 @@ test-suite distribution_tests :
 
    [ run test_legacy_nonfinite.cpp /boost/test//boost_unit_test_framework ]
    [ run test_basic_nonfinite.cpp /boost/test//boost_unit_test_framework  ]
+   [ run test_nonfinite_io.cpp /boost/test//boost_unit_test_framework  ]
    [ run test_lexical_cast.cpp /boost/test//boost_unit_test_framework  ]
    [ run test_nonfinite_trap.cpp /boost/test//boost_unit_test_framework : : : <exception-handling>off:<build>no  ]
    [ run test_signed_zero.cpp /boost/test//boost_unit_test_framework  ]
diff --git a/test/test_basic_nonfinite.cpp b/test/test_basic_nonfinite.cpp
index 20f0e222c..c279be9ae 100644
--- a/test/test_basic_nonfinite.cpp
+++ b/test/test_basic_nonfinite.cpp
@@ -163,6 +163,19 @@ template<class CharType, class ValType> void basic_test_inf_impl()
     BOOST_CHECK(b2 == a2);
     BOOST_CHECK(b3 == std::numeric_limits<ValType>::infinity());
     BOOST_CHECK(ss.rdstate() == std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "ind";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "infinidy";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit);
+
 }
 
 //------------------------------------------------------------------------------
@@ -221,6 +234,56 @@ template<class CharType, class ValType> void basic_test_nan_impl()
     BOOST_CHECK(!(signbit)(b5));
 
     BOOST_CHECK(ss.rdstate() == std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "nad";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "nan(123";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "qnad";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
+
+    std::locale new_locale_2(tmp_locale, new nonfinite_num_get<CharType>(legacy));
+    ss.imbue(new_locale_2);
+    ss.clear();
+    ss.str(S_(""));
+    ss << "qnan";
+    ss >> b1;
+    BOOST_CHECK((boost::math::isnan)(b1));
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "qnad";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "1.#SNAD";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "1.#POP";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
+
+    ss.clear();
+    ss.str(S_(""));
+    ss << "1.#IMP";
+    ss >> b1;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit | std::ios_base::eofbit);
 }
 
 //------------------------------------------------------------------------------
diff --git a/test/test_nonfinite_io.cpp b/test/test_nonfinite_io.cpp
index 855843c71..9c50b4c25 100644
--- a/test/test_nonfinite_io.cpp
+++ b/test/test_nonfinite_io.cpp
@@ -22,6 +22,8 @@
 #include <sstream>
 #include <iomanip>
 
+#include "boost/math/tools/test.hpp"
+
 namespace {
 
 // Using an anonymous namespace resolves ambiguities on platforms
@@ -30,7 +32,7 @@ namespace {
 using namespace boost::math;
 using boost::math::signbit;
 using boost::math::changesign;
-using (boost::math::isnan)(;
+using boost::math::isnan;
 
 //------------------------------------------------------------------------------
 // Test nonfinite_num_put and nonfinite_num_get facets by checking
@@ -232,6 +234,15 @@ template<class CharType, class ValType> void trap_test_get_nan_impl()
     ss.clear();
     ss.str(S_(""));
 
+    ValType a3 = std::numeric_limits<ValType>::quiet_NaN();
+    ss << std::showpos << a3;
+    ValType b3;
+    ss >> b3;
+    BOOST_CHECK(ss.rdstate() == std::ios_base::failbit);
+
+    ss.clear();
+    ss.str(S_(""));
+
     ValType a2 = std::numeric_limits<ValType>::signaling_NaN();
     ss << a2;
     ValType b2;