Fix logic for indexer when parameter-type differs (#569)

Author: StefH

NuGet.txt

@@ -1,3 +1,9 @@
+Open Command Prompt
+
 System.Linq.Dynamic.Core\src>
 
+del /S *.nupkg
+
+VS rebuild
+
 dotnet nuget push **\*.nupkg --source https://api.nuget.org/v3/index.json --api-key x

src/System.Linq.Dynamic.Core/Parser/ExpressionParser.cs

@@ -1965,7 +1965,16 @@ Expression ParseElementAccess(Expression expr)
                     throw ParseError(errorPos, Res.NoApplicableIndexer,
                         TypeHelper.GetTypeName(expr.Type));
                 case 1:
-                    return Expression.Call(expr, (MethodInfo)mb, args);
+                    var indexMethod = (MethodInfo)mb;
+                    var indexParameterType = indexMethod.GetParameters().First().ParameterType;
+
+                    var indexArgumentExpression = args[0]; // Indexer only has 1 parameter, so we can use args[0] here
+                    if (indexParameterType != indexArgumentExpression.Type)
+                    {
+                        indexArgumentExpression = Expression.Convert(indexArgumentExpression, indexParameterType);
+                    }
+
+                    return Expression.Call(expr, indexMethod, indexArgumentExpression);
 
                 default:
                     throw ParseError(errorPos, Res.AmbiguousIndexerInvocation, TypeHelper.GetTypeName(expr.Type));

test/System.Linq.Dynamic.Core.Tests/QueryableTests.Select.cs

@@ -2,10 +2,12 @@
 using System.Collections.Generic;
 using System.Linq.Dynamic.Core.Exceptions;
 using System.Linq.Dynamic.Core.Tests.Helpers.Models;
+using FluentAssertions;
 using Linq.PropertyTranslator.Core;
 using QueryInterceptor.Core;
 using Xunit;
 using NFluent;
+using Newtonsoft.Json.Linq;
 #if EFCORE
 using Microsoft.AspNetCore.Identity;
 #else
@@ -348,6 +350,29 @@ public void Select_Dynamic_RenameParameterExpression_Is_True()
             Check.That(result).Equals("System.Int32[].Select(it => (it * it))");
         }
 
+        [Fact]
+        public void Select_Dynamic_JObject_With_Array_Should_Use_Correct_Indexer()
+        {
+            // Arrange
+            var j = new JObject
+            {
+                {"I", new JValue(9)},
+                {"A", new JArray(new[] {1,2,3}) } ,
+                {"L", new JValue(5)}
+            };
+            var queryable = new[] { j }.AsQueryable();
+
+            // Act
+            var result = queryable.Select("new (long(I) as I, (new [] { long(A[0]), long(A[1]), long(A[2])}) as A, long(L) as L)").ToDynamicArray().First();
+
+            // Assert
+            Assert.Equal(9, result.I);
+            Assert.Equal(5, result.L);
+            Assert.Equal(1, result.A[0]);
+            Assert.Equal(2, result.A[1]);
+            Assert.Equal(3, result.A[2]);
+        }
+
         [Fact]
         public void Select_Dynamic_ReservedKeyword()
         {