No longer omit the conversion expression when the return type is expl…

…icitly object.

Force the return type of a lambda expression to typeof(void) to prevent the emission of a conversion expresssion.
Fixes dynamicexpresso#185

src/DynamicExpresso.Core/Interpreter.cs

@@ -405,7 +405,16 @@ public Expression<TDelegate> ParseAsExpression<TDelegate>(string expressionText,
 
 		internal LambdaExpression ParseAsExpression(Type delegateType, string expressionText, params string[] parametersNames)
 		{
-			var lambda = ParseAs(delegateType, expressionText, parametersNames);
+			var delegateInfo = ReflectionExtensions.GetDelegateInfo(delegateType, parametersNames);
+
+			// return type is object means that we have no information beforehand
+			// => we force it to typeof(void) so that no conversion expression is emitted by the parser
+			//    and the actual expression type is preserved
+			var returnType = delegateInfo.ReturnType;
+			if (returnType == typeof(object))
+				returnType = typeof(void);
+
+			var lambda = ParseAsLambda(expressionText, returnType, delegateInfo.Parameters);
 			return lambda.LambdaExpression(delegateType);
 		}
 

src/DynamicExpresso.Core/Parsing/Parser.cs

@@ -101,7 +101,7 @@ private Expression ParseExpressionSegment(Type returnType)
 			int errorPos = _token.pos;
 			var expression = ParseExpressionSegment();
 
-			if (returnType != typeof(void) && returnType != typeof(object))
+			if (returnType != typeof(void))
 			{
 				return GenerateConversion(expression, returnType, errorPos);
 			}

test/DynamicExpresso.UnitTest/GithubIssues.cs

@@ -344,5 +344,17 @@ public void GitHub_Issue_169_quatro()
 			result = interpreter.Eval<string>("x?.ToString()");
 			Assert.AreEqual("56", result);
 		}
+
+		[Test]
+		public void GitHub_Issue_185()
+		{
+			var interpreter = new Interpreter().SetVariable("a", 123L);
+
+			// forcing the return type to object should work
+			// (ie a conversion expression should be emitted from long to object)
+			var del = interpreter.ParseAsDelegate<Func<object>>("a*2");
+			var result = del();
+			Assert.AreEqual(246, result);
+		}
 	}
 }