Handle UseParameterizedNamesInDynamicQuery when parsing dynamic OfType function (#723)

* Test UseParameterizedNamesInDynamicQuery TypeOf use-case

This test fails

* Handle case where expression is MemberExpression

This fixes #722

* Check TryUnwrapAsConstantExpression output before calling resolve

---------

Co-authored-by: Isaac Ouellet-Therrien <iotherrien@dns1.sherweb.com>

Author: yonguelink

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

@@ -2006,23 +2006,36 @@ private Expression ParseEnumerable(Expression instance, Type elementType, string
     private Type ResolveTypeFromArgumentExpression(string functionName, Expression argumentExpression, int? arguments = null)
     {
         string argument = arguments == null ? string.Empty : arguments == 1 ? "first " : "second ";
+
         switch (argumentExpression)
         {
             case ConstantExpression constantExpression:
-                switch (constantExpression.Value)
+                return ResolveTypeFromExpressionValue(functionName, constantExpression, argument);
+
+            case MemberExpression memberExpression:
+                if (_expressionHelper.TryUnwrapAsConstantExpression(memberExpression, out var unwrappedConstantExpression))
                 {
-                    case string typeName:
-                        return ResolveTypeStringFromArgument(typeName);
+                    return ResolveTypeFromExpressionValue(functionName, unwrappedConstantExpression, argument);
+                }
 
-                    case Type type:
-                        return type;
+                break;
+        }
 
-                    default:
-                        throw ParseError(_textParser.CurrentToken.Pos, Res.FunctionRequiresNotNullArgOfType, functionName, argument, "string or System.Type");
-                }
+        throw ParseError(_textParser.CurrentToken.Pos, Res.FunctionRequiresNotNullArgOfType, functionName, argument, "ConstantExpression");
+    }
+
+    private Type ResolveTypeFromExpressionValue(string functionName, ConstantExpression constantExpression, string argument)
+    {
+        switch (constantExpression.Value)
+        {
+            case string typeName:
+                return ResolveTypeStringFromArgument(typeName);
+
+            case Type type:
+                return type;
 
             default:
-                throw ParseError(_textParser.CurrentToken.Pos, Res.FunctionRequiresNotNullArgOfType, functionName, argument, "ConstantExpression");
+                throw ParseError(_textParser.CurrentToken.Pos, Res.FunctionRequiresNotNullArgOfType, functionName, argument, "string or System.Type");
         }
     }
 

test/System.Linq.Dynamic.Core.Tests/QueryableTests.Is,OfType,As,Cast.cs

@@ -66,6 +66,36 @@ public void OfType_Dynamic_WithFullName()
             Check.That(oftypeDynamic.Length).Equals(oftype.Length);
         }
 
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void OfType_Dynamic_WithFullName_UseParameterizedNamesInDynamicQuery(bool useParameterizedNamesInDynamicQuery)
+        {
+            // Assign
+            var qry = new[]
+            {
+                new CompanyWithBaseEmployees
+                {
+                    Employees = new BaseEmployee[]
+                    {
+                        new Worker { Name = "e" }, new Boss { Name = "e" }
+                    }
+                }
+            }.AsQueryable();
+
+            var parsingConfig = new ParsingConfig
+            {
+                UseParameterizedNamesInDynamicQuery = useParameterizedNamesInDynamicQuery
+            };
+
+            // Act
+            var oftype = qry.Select(c => c.Employees.OfType<Worker>().Where(e => e.Name == "e")).ToArray();
+            var oftypeDynamic = qry.Select(parsingConfig, "Employees.OfType(\"System.Linq.Dynamic.Core.Tests.Entities.Worker\").Where(Name == \"e\")").ToDynamicArray();
+
+            // Assert
+            Check.That(oftypeDynamic.Length).Equals(oftype.Length);
+        }
+
         internal class Base { }
 
         internal class DerivedA : Base { }