diff --git a/src/catch2/benchmark/catch_constructor.hpp b/src/catch2/benchmark/catch_constructor.hpp
index 59600f21..fe651f1c 100644
--- a/src/catch2/benchmark/catch_constructor.hpp
+++ b/src/catch2/benchmark/catch_constructor.hpp
@@ -11,6 +11,7 @@
 #define CATCH_CONSTRUCTOR_HPP_INCLUDED
 
 #include <type_traits>
+#include <utility>
 
 namespace Catch {
     namespace Benchmark {
diff --git a/src/catch2/benchmark/detail/catch_analyse.hpp b/src/catch2/benchmark/detail/catch_analyse.hpp
index 0a52a845..46382c62 100644
--- a/src/catch2/benchmark/detail/catch_analyse.hpp
+++ b/src/catch2/benchmark/detail/catch_analyse.hpp
@@ -11,8 +11,10 @@
 #define CATCH_ANALYSE_HPP_INCLUDED
 
 #include <catch2/benchmark/catch_clock.hpp>
+#include <catch2/benchmark/catch_environment.hpp>
 #include <catch2/benchmark/catch_sample_analysis.hpp>
 #include <catch2/benchmark/detail/catch_stats.hpp>
+#include <catch2/interfaces/catch_interfaces_config.hpp>
 
 #include <algorithm>
 #include <iterator>
diff --git a/src/catch2/catch_reporter_registrars.hpp b/src/catch2/catch_reporter_registrars.hpp
index e7375aa7..978d2925 100644
--- a/src/catch2/catch_reporter_registrars.hpp
+++ b/src/catch2/catch_reporter_registrars.hpp
@@ -9,11 +9,15 @@
 #define CATCH_REPORTER_REGISTRARS_HPP_INCLUDED
 
 #include <catch2/interfaces/catch_interfaces_registry_hub.hpp>
+#include <catch2/interfaces/catch_interfaces_reporter.hpp>
 #include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
 #include <catch2/internal/catch_unique_ptr.hpp>
 
 namespace Catch {
 
+    struct IStreamingReporter;
+    using IStreamingReporterPtr = Detail::unique_ptr<IStreamingReporter>;
+
     template <typename T>
     class ReporterFactory : public IReporterFactory {
 
diff --git a/src/catch2/interfaces/catch_interfaces_reporter_factory.hpp b/src/catch2/interfaces/catch_interfaces_reporter_factory.hpp
index 9bcf94f0..5a40d1bd 100644
--- a/src/catch2/interfaces/catch_interfaces_reporter_factory.hpp
+++ b/src/catch2/interfaces/catch_interfaces_reporter_factory.hpp
@@ -8,9 +8,16 @@
 #ifndef CATCH_INTERFACES_REPORTER_FACTORY_HPP_INCLUDED
 #define CATCH_INTERFACES_REPORTER_FACTORY_HPP_INCLUDED
 
+#include <catch2/internal/catch_unique_ptr.hpp>
+
+#include <string>
+
 namespace Catch {
 
     struct ReporterConfig;
+    struct IStreamingReporter;
+    using IStreamingReporterPtr = Detail::unique_ptr<IStreamingReporter>;
+
 
     struct IReporterFactory {
         virtual ~IReporterFactory(); // = default
diff --git a/src/catch2/internal/catch_container_nonmembers.hpp b/src/catch2/internal/catch_container_nonmembers.hpp
index f1dedeb6..d6f10eb5 100644
--- a/src/catch2/internal/catch_container_nonmembers.hpp
+++ b/src/catch2/internal/catch_container_nonmembers.hpp
@@ -10,6 +10,8 @@
 
 #include <catch2/internal/catch_compiler_capabilities.hpp>
 
+#include <cstddef>
+#include <initializer_list>
 
 // We want a simple polyfill over `std::empty`, `std::size` and so on
 // for C++14 or C++ libraries with incomplete support.