diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 41d93ae0..a8d7799d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -72,6 +72,7 @@ set(INTERNAL_HEADERS
     ${SOURCES_DIR}/interfaces/catch_interfaces_runner.hpp
     ${SOURCES_DIR}/interfaces/catch_interfaces_tag_alias_registry.hpp
     ${SOURCES_DIR}/interfaces/catch_interfaces_testcase.hpp
+    ${SOURCES_DIR}/internal/catch_lazy_expr.hpp
     ${SOURCES_DIR}/internal/catch_leak_detector.hpp
     ${SOURCES_DIR}/internal/catch_list.hpp
     ${SOURCES_DIR}/matchers/catch_matchers.hpp
@@ -147,6 +148,7 @@ set(IMPL_SOURCES
     ${SOURCES_DIR}/generators/internal/catch_generators_combined_tu.cpp
     ${SOURCES_DIR}/interfaces/catch_interfaces_combined_tu.cpp
     ${SOURCES_DIR}/interfaces/catch_interfaces_reporter.cpp
+    ${SOURCES_DIR}/internal/catch_lazy_expr.cpp
     ${SOURCES_DIR}/internal/catch_list.cpp
     ${SOURCES_DIR}/matchers/catch_matchers_floating.cpp
     ${SOURCES_DIR}/matchers/catch_matchers_string.cpp
diff --git a/src/catch2/catch_all.hpp b/src/catch2/catch_all.hpp
index 3920e822..019c1bfe 100644
--- a/src/catch2/catch_all.hpp
+++ b/src/catch2/catch_all.hpp
@@ -54,6 +54,7 @@
 #include <catch2/internal/catch_errno_guard.hpp>
 #include <catch2/internal/catch_exception_translator_registry.hpp>
 #include <catch2/internal/catch_fatal_condition_handler.hpp>
+#include <catch2/internal/catch_lazy_expr.hpp>
 #include <catch2/internal/catch_leak_detector.hpp>
 #include <catch2/internal/catch_list.hpp>
 #include <catch2/internal/catch_message_info.hpp>
diff --git a/src/catch2/catch_assertion_result.cpp b/src/catch2/catch_assertion_result.cpp
index 4bbf0416..84bb94c9 100644
--- a/src/catch2/catch_assertion_result.cpp
+++ b/src/catch2/catch_assertion_result.cpp
@@ -7,8 +7,10 @@
  */
 
 #include <catch2/catch_assertion_result.hpp>
+#include <catch2/internal/catch_stream.hpp>
 
 namespace Catch {
+
     AssertionResultData::AssertionResultData(ResultWas::OfType _resultType, LazyExpression const & _lazyExpression):
         lazyExpression(_lazyExpression),
         resultType(_resultType) {}
diff --git a/src/catch2/catch_assertion_result.hpp b/src/catch2/catch_assertion_result.hpp
index 56b3d1cb..b39e71f7 100644
--- a/src/catch2/catch_assertion_result.hpp
+++ b/src/catch2/catch_assertion_result.hpp
@@ -13,7 +13,7 @@
 #include <catch2/internal/catch_result_type.hpp>
 #include <catch2/internal/catch_common.hpp>
 #include <catch2/internal/catch_stringref.hpp>
-#include <catch2/internal/catch_assertion_handler.hpp>
+#include <catch2/internal/catch_lazy_expr.hpp>
 
 namespace Catch {
 
diff --git a/src/catch2/internal/catch_assertion_handler.cpp b/src/catch2/internal/catch_assertion_handler.cpp
index 14036062..54153462 100644
--- a/src/catch2/internal/catch_assertion_handler.cpp
+++ b/src/catch2/internal/catch_assertion_handler.cpp
@@ -19,29 +19,6 @@
 
 namespace Catch {
 
-    namespace {
-        auto operator <<( std::ostream& os, ITransientExpression const& expr ) -> std::ostream& {
-            expr.streamReconstructedExpression( os );
-            return os;
-        }
-    }
-
-    auto operator << ( std::ostream& os, LazyExpression const& lazyExpr ) -> std::ostream& {
-        if( lazyExpr.m_isNegated )
-            os << "!";
-
-        if( lazyExpr ) {
-            if( lazyExpr.m_isNegated && lazyExpr.m_transientExpression->isBinaryExpression() )
-                os << "(" << *lazyExpr.m_transientExpression << ")";
-            else
-                os << *lazyExpr.m_transientExpression;
-        }
-        else {
-            os << "{** error - unchecked empty expression requested **}";
-        }
-        return os;
-    }
-
     AssertionHandler::AssertionHandler
         (   StringRef const& macroName,
             SourceLineInfo const& lineInfo,
diff --git a/src/catch2/internal/catch_assertion_handler.hpp b/src/catch2/internal/catch_assertion_handler.hpp
index 646f12f4..df687f5d 100644
--- a/src/catch2/internal/catch_assertion_handler.hpp
+++ b/src/catch2/internal/catch_assertion_handler.hpp
@@ -11,6 +11,7 @@
 #include <catch2/catch_assertion_info.hpp>
 #include <catch2/internal/catch_decomposer.hpp>
 #include <catch2/interfaces/catch_interfaces_capture.hpp>
+#include <catch2/internal/catch_lazy_expr.hpp>
 
 namespace Catch {
 
@@ -19,27 +20,6 @@ namespace Catch {
     struct IResultCapture;
     class RunContext;
 
-    class LazyExpression {
-        friend class AssertionHandler;
-        friend struct AssertionStats;
-        friend class RunContext;
-
-        ITransientExpression const* m_transientExpression = nullptr;
-        bool m_isNegated;
-    public:
-        LazyExpression( bool isNegated ):
-            m_isNegated(isNegated)
-        {}
-        LazyExpression(LazyExpression const& other) = default;
-        LazyExpression& operator = ( LazyExpression const& ) = delete;
-
-        explicit operator bool() const {
-            return m_transientExpression != nullptr;
-        }
-
-        friend auto operator << ( std::ostream& os, LazyExpression const& lazyExpr ) -> std::ostream&;
-    };
-
     struct AssertionReaction {
         bool shouldDebugBreak = false;
         bool shouldThrow = false;
diff --git a/src/catch2/internal/catch_lazy_expr.cpp b/src/catch2/internal/catch_lazy_expr.cpp
new file mode 100644
index 00000000..21a33cdc
--- /dev/null
+++ b/src/catch2/internal/catch_lazy_expr.cpp
@@ -0,0 +1,30 @@
+#include <catch2/internal/catch_lazy_expr.hpp>
+
+#include <catch2/internal/catch_decomposer.hpp>
+
+
+namespace Catch {
+
+    namespace {
+        auto operator <<(std::ostream& os, ITransientExpression const& expr) -> std::ostream& {
+            expr.streamReconstructedExpression(os);
+            return os;
+        }
+    }
+
+    auto operator << (std::ostream& os, LazyExpression const& lazyExpr) -> std::ostream& {
+        if (lazyExpr.m_isNegated)
+            os << "!";
+
+        if (lazyExpr) {
+            if (lazyExpr.m_isNegated && lazyExpr.m_transientExpression->isBinaryExpression())
+                os << "(" << *lazyExpr.m_transientExpression << ")";
+            else
+                os << *lazyExpr.m_transientExpression;
+        } else {
+            os << "{** error - unchecked empty expression requested **}";
+        }
+        return os;
+    }
+
+} // namespace Catch
diff --git a/src/catch2/internal/catch_lazy_expr.hpp b/src/catch2/internal/catch_lazy_expr.hpp
new file mode 100644
index 00000000..8efc24fc
--- /dev/null
+++ b/src/catch2/internal/catch_lazy_expr.hpp
@@ -0,0 +1,33 @@
+#ifndef CATCH_LAZY_EXPR_HPP_INCLUDED
+#define CATCH_LAZY_EXPR_HPP_INCLUDED
+
+#include <iosfwd>
+
+namespace Catch {
+        
+    struct ITransientExpression;
+
+    class LazyExpression {
+        friend class AssertionHandler;
+        friend struct AssertionStats;
+        friend class RunContext;
+
+        ITransientExpression const* m_transientExpression = nullptr;
+        bool m_isNegated;
+    public:
+        LazyExpression( bool isNegated ):
+            m_isNegated(isNegated)
+        {}
+        LazyExpression(LazyExpression const& other) = default;
+        LazyExpression& operator = ( LazyExpression const& ) = delete;
+
+        explicit operator bool() const {
+            return m_transientExpression != nullptr;
+        }
+
+        friend auto operator << ( std::ostream& os, LazyExpression const& lazyExpr ) -> std::ostream&;
+    };
+
+} // namespace Catch
+
+#endif // CATCH_LAZY_EXPR_HPP_INCLUDED
diff --git a/src/catch2/reporters/catch_reporter_bases.cpp b/src/catch2/reporters/catch_reporter_bases.cpp
index de302d18..f0343a19 100644
--- a/src/catch2/reporters/catch_reporter_bases.cpp
+++ b/src/catch2/reporters/catch_reporter_bases.cpp
@@ -9,6 +9,7 @@
 #include <catch2/interfaces/catch_interfaces_reporter.hpp>
 #include <catch2/internal/catch_errno_guard.hpp>
 #include <catch2/reporters/catch_reporter_bases.hpp>
+#include <catch2/internal/catch_stream.hpp>
 
 #include <cstring>
 #include <cfloat>
diff --git a/src/catch2/reporters/catch_reporter_console.cpp b/src/catch2/reporters/catch_reporter_console.cpp
index cb38318b..e9bea0ee 100644
--- a/src/catch2/reporters/catch_reporter_console.cpp
+++ b/src/catch2/reporters/catch_reporter_console.cpp
@@ -13,6 +13,7 @@
 #include <catch2/internal/catch_string_manip.hpp>
 #include <catch2/catch_version.hpp>
 #include <catch2/internal/catch_text.hpp>
+#include <catch2/internal/catch_stream.hpp>
 #include <catch2/internal/catch_stringref.hpp>
 
 #include <cfloat>