Detect and warn about overly complex expressions

Test/TrickyTests.cpp

@@ -38,6 +38,6 @@ TEST_CASE( "succeeding/Tricky/complex lhs", "Where the LHS is not a simple value
     int a = 1;
     int b = 2;
 
-    // !TBD: This only captures part of the expression
+    // This only captures part of the expression, but issues a warning about the rest
-    EXPECT( a == 2 || b == 2 );
+    EXPECT( a == 2 || b == 1 );
 }

internal/catch_capture.hpp

@@ -63,7 +63,7 @@ public:
     template<typename RhsT>
     MutableResultInfo& operator ||( const RhsT& rhs )
     {
-        // !TBD: set message to say we haven't captured all parts
+        m_expressionIncomplete = true;
         return *this;
     }
     

internal/catch_resultinfo.hpp

@@ -40,7 +40,8 @@ namespace Catch
         ResultInfo()
         :   m_result( ResultWas::Unknown ),
             m_isNot( false ),
-            m_line( 0 )
+            m_line( 0 ),
+            m_expressionIncomplete( false )
         {}
         
         ResultInfo( const std::string& expr, ResultWas::OfType result, bool isNot, const std::string& filename, size_t line, const std::string& macroName )
@@ -50,7 +51,8 @@ namespace Catch
             m_op( m_expr[0] == '!' ? "!" : "" ),
             m_filename( filename ),
             m_line( line ), 
-            m_macroName( macroName )
+            m_macroName( macroName ),
+            m_expressionIncomplete( false )
         {
         }
         
@@ -78,12 +80,9 @@ namespace Catch
         }
         std::string getExpandedExpression() const
         {
-            if( m_op == "" || m_isNot )
+            return m_expressionIncomplete
-                return m_lhs.empty() ? m_expr : m_op + m_lhs;
+                ? getExpandedExpressionInternal() + " {can't expand the rest of the expression - consider rewriting it}"
-            else if( m_op != "!" )
+                : getExpandedExpressionInternal();
-                return m_lhs + " " + m_op + " " + m_rhs;
-            else
-                return "{can't expand - use " + m_macroName + "_NOT( " + m_expr.substr(1) + " ) instead of " + m_macroName + "( " + m_expr + " ) for better diagnostics}";
         }
         
         std::string getMessage() const
@@ -106,6 +105,17 @@ namespace Catch
             return m_macroName;
         }
 
+    protected:
+        std::string getExpandedExpressionInternal() const
+        {
+            if( m_op == "" || m_isNot )
+                return m_lhs.empty() ? m_expr : m_op + m_lhs;
+            else if( m_op != "!" )
+                return m_lhs + " " + m_op + " " + m_rhs;
+            else
+                return "{can't expand - use " + m_macroName + "_NOT( " + m_expr.substr(1) + " ) instead of " + m_macroName + "( " + m_expr + " ) for better diagnostics}";
+        }
+        
     protected:
         std::string m_macroName;
         std::string m_filename;
@@ -114,6 +124,7 @@ namespace Catch
         std::string m_message;
         ResultWas::OfType m_result;
         bool m_isNot;
+        bool m_expressionIncomplete;
     };
     
 } // end namespace Catch