Ensure we always read 32 bit seed from std::random_device

src/catch2/benchmark/detail/catch_stats.cpp

@@ -355,8 +355,6 @@ namespace Catch {
                                                unsigned int n_resamples,
                                                double* first,
                                                double* last) {
-                auto n = static_cast<int>(last - first); // seriously, one can't use integral types without hell in C++
-
                 auto mean = &Detail::mean;
                 auto stddev = &standard_deviation;
 
@@ -389,6 +387,7 @@ namespace Catch {
                 auto stddev_estimate = Estimate(stddev);
 #endif // CATCH_USE_ASYNC
 
+                auto n = static_cast<int>(last - first); // seriously, one can't use integral types without hell in C++
                 double outlier_variance = Detail::outlier_variance(mean_estimate, stddev_estimate, n);
 
                 return { mean_estimate, stddev_estimate, outlier_variance };

src/catch2/internal/catch_random_seed_generation.cpp

@@ -9,6 +9,7 @@
 #include <catch2/internal/catch_random_seed_generation.hpp>
 
 #include <catch2/internal/catch_enforce.hpp>
+#include <catch2/internal/catch_random_integer_helpers.hpp>
 
 #include <ctime>
 #include <random>
@@ -21,10 +22,10 @@ namespace Catch {
             return static_cast<std::uint32_t>( std::time( nullptr ) );
 
         case GenerateFrom::Default:
-        case GenerateFrom::RandomDevice:
-            // In theory, a platform could have random_device that returns just
-            // 16 bits. That is still some randomness, so we don't care too much
-            return static_cast<std::uint32_t>( std::random_device{}() );
+        case GenerateFrom::RandomDevice: {
+            std::random_device rd;
+            return Detail::fillBitsFrom<std::uint32_t>( rd );
+        }
 
         default:
             CATCH_ERROR("Unknown generation method");