Fix testing build errors in Errata.

Author: SolidWallOfCode

code/include/swoc/DiscreteRange.h

@@ -1267,7 +1267,7 @@ DiscreteSpace<METRIC, PAYLOAD>::blend(DiscreteSpace::range_type const& range, U
                                       , F&& blender) -> self_type& {
   // Do a base check for the color to use on unmapped values. If self blending on @a color
   // is @c false, then do not color currently unmapped values.
-  PAYLOAD plain_color; // color to paint uncolored metrics.
+  [[maybe_unused]] PAYLOAD plain_color{}; // color to paint uncolored metrics.
   bool plain_color_p = blender(plain_color, color); // start with default and blend in @a color.
 
   auto node_cleaner = [&](Node *ptr) -> void { _fa.destroy(ptr); };

code/include/swoc/Errata.h

@@ -955,3 +955,7 @@ get(swoc::Rv<R> const& rv) {
 }
 
 }} // namespace swoc
+
+namespace std {
+  using swoc::get; // Import specialized overloads to standard namespace.
+}

unit_tests/test_Errata.cc

@@ -102,17 +102,19 @@ TEST_CASE("Rv", "[libswoc][Errata]")
   REQUIRE(result == 17); // Local copy binding, no update.
 
   auto &[r_result, r_erratum] = zret;
+  REQUIRE(r_erratum.is_ok() == false);
 
   REQUIRE(r_result == 38);
   zret = 56;
   REQUIRE(r_result == 56); // reference binding, update.
 
   auto const &[cr_result, cr_erratum] = zret;
   REQUIRE(cr_result == 56);
+  REQUIRE(cr_erratum.is_ok() == false);
 
   auto test = [](Rv<int> const &rvc) {
-    auto const &[cv_result, cv_erratum] = rvc;
-    REQUIRE(cv_result == 56);
+    auto n = std::get<0>(rvc);
+    REQUIRE(n == 56);
   };
 
   test(zret); // invoke it.
@@ -142,4 +144,5 @@ TEST_CASE("Rv", "[libswoc][Errata]")
 
   auto &&[tr2, te2]{maker()};
   REQUIRE(tr2->s == "made"sv);
+  REQUIRE(te2.is_ok() == true);
 };

unit_tests/test_ip.cc

@@ -756,6 +756,7 @@ TEST_CASE("IP Space Int", "[libswoc][ip][ipspace]") {
   // Verify that earlier ranges are still valid after the double blend.
   for (auto &&[text, value] : r2) {
     IPRange range{text};
+    static_cast<void>(value);
     REQUIRE(space.end() != space.find(range.min()));
     REQUIRE(space.end() != space.find(range.max()));
   }
@@ -765,6 +766,7 @@ TEST_CASE("IP Space Int", "[libswoc][ip][ipspace]") {
   // Verify all the data is in the ranges.
   for (auto &&[text, value] : r2) {
     IPRange range{text};
+    static_cast<void>(value);
     REQUIRE(space.end() != space.find(range.min()));
     REQUIRE(space.end() != space.find(range.max()));
   }
@@ -777,6 +779,7 @@ TEST_CASE("IP Space Int", "[libswoc][ip][ipspace]") {
   }
   {
     auto && [ r, p ] = *space.find(IPAddr{"2001:4997:58:400::1E"});
+    static_cast<void>(p);
     REQUIRE(true == r.empty());
   }
 }
@@ -808,8 +811,10 @@ TEST_CASE("IPSpace bitset", "[libswoc][ipspace][bitset]") {
 
   // Check that if an IPv4 lookup misses, it doesn't pass on to the first IPv6
   auto && [ r1, p1 ] = *(space.find(IP4Addr{"172.28.56.100"}));
+  static_cast<void>(p1);
   REQUIRE(true == r1.empty());
   auto && [ r2, p2 ] = *(space.find(IPAddr{"172.28.56.100"}));
+  static_cast<void>(p2);
   REQUIRE(true == r2.empty());
 }
 
@@ -864,6 +869,7 @@ TEST_CASE("IPSpace docJJ", "[libswoc][ipspace][docJJ]") {
 
   idx = 0;
   for (auto const&[range, bits] : space) {
+    static_cast<void>(range);
     REQUIRE(idx < results.size());
     CHECK(bits == make_bits(results[idx]));
     ++idx;
@@ -872,6 +878,7 @@ TEST_CASE("IPSpace docJJ", "[libswoc][ipspace][docJJ]") {
   idx = results.size();
   for (auto spot = space.end(); spot != space.begin();) {
     auto const&[range, bits]{*--spot};
+    static_cast<void>(range);
     REQUIRE(idx > 0);
     --idx;
     CHECK(bits == make_bits(results[idx]));
@@ -885,6 +892,7 @@ TEST_CASE("IPSpace docJJ", "[libswoc][ipspace][docJJ]") {
   for (auto spot = space.begin(); spot != space.end() ; ++spot) {
     iter = spot;
     std::tie(range, bits) = *iter;
+    static_cast<void>(range);
     REQUIRE(idx < results.size());
     CHECK(bits == make_bits(results[idx]));
     ++idx;
@@ -1500,10 +1508,14 @@ TEST_CASE("IPSpace Uthira", "[libswoc][ipspace][uthira]") {
       auto spot = space.begin();
       auto [ r1, p1 ] = *++spot;
       auto [ r2, p2 ] = *++spot;
+      static_cast<void>(p1);
+      static_cast<void>(p2);
       REQUIRE(r1.max() < r2.min()); // This is supposed to be an invariant! Make sure.
       auto back = space.end();
       auto [ br1, bp1 ] = *--back;
       auto [ br2, bp2 ] = *--back;
+      static_cast<void>(bp1);
+      static_cast<void>(bp2);
       REQUIRE(br2.max() < br1.min()); // This is supposed to be an invariant! Make sure.
     }
   }