mcs/class/System.Core/System.Linq.Expressions/Expression.cs

   1 //
   2 // Expression.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //   Miguel de Icaza (miguel@novell.com)
   7 //
   8 // (C) 2008 Novell, Inc. (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Collections;
  32 using System.Collections.Generic;
  33 using System.Collections.ObjectModel;
  34 using System.Globalization;
  35 using System.Linq;
  36 using System.Reflection;
  37 using System.Reflection.Emit;
  38
  39 namespace System.Linq.Expressions {
  40
  41         public abstract class Expression {
  42
  43                 ExpressionType node_type;
  44                 Type type;
  45
  46                 internal const BindingFlags PublicInstance = BindingFlags.Public | BindingFlags.Instance | BindingFlags.FlattenHierarchy;
  47                 internal const BindingFlags NonPublicInstance = BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.FlattenHierarchy;
  48                 internal const BindingFlags PublicStatic = BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy;
  49                 internal const BindingFlags AllInstance = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.FlattenHierarchy;
  50                 internal const BindingFlags AllStatic = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.FlattenHierarchy;
  51                 internal const BindingFlags All = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance | BindingFlags.FlattenHierarchy;
  52
  53                 public ExpressionType NodeType {
  54                         get { return node_type; }
  55                 }
  56
  57                 public Type Type {
  58                         get { return type; }
  59                 }
  60
  61                 protected Expression (ExpressionType node_type, Type type)
  62                 {
  63                         this.node_type = node_type;
  64                         this.type = type;
  65                 }
  66
  67                 public override string ToString ()
  68                 {
  69                         return ExpressionPrinter.ToString (this);
  70                 }
  71
  72                 #region Binary Expressions
  73
  74                 static MethodInfo GetUnaryOperator (string oper_name, Type declaring, Type param)
  75                 {
  76                         return GetUnaryOperator (oper_name, declaring, param, null);
  77                 }
  78
  79                 static MethodInfo GetUnaryOperator (string oper_name, Type declaring, Type param, Type ret)
  80                 {
  81                         var methods = declaring.GetNotNullableType ().GetMethods (PublicStatic);
  82
  83                         foreach (var method in methods) {
  84                                 if (method.Name != oper_name)
  85                                         continue;
  86
  87                                 var parameters = method.GetParameters ();
  88                                 if (parameters.Length != 1)
  89                                         continue;
  90
  91                                 if (method.IsGenericMethod)
  92                                         continue;
  93
  94                                 if (!IsAssignableToParameterType (param.GetNotNullableType (), parameters [0]))
  95                                         continue;
  96
  97                                 if (ret != null && method.ReturnType != ret.GetNotNullableType ())
  98                                         continue;
  99
 100                                 return method;
 101                         }
 102
 103                         return null;
 104                 }
 105
 106                 internal static MethodInfo GetTrueOperator (Type self)
 107                 {
 108                         return GetBooleanOperator ("op_True", self);
 109                 }
 110
 111                 internal static MethodInfo GetFalseOperator (Type self)
 112                 {
 113                         return GetBooleanOperator ("op_False", self);
 114                 }
 115
 116                 static MethodInfo GetBooleanOperator (string op, Type self)
 117                 {
 118                         return GetUnaryOperator (op, self, self, typeof (bool));
 119                 }
 120
 121                 static bool IsAssignableToParameterType (Type type, ParameterInfo param)
 122                 {
 123                         var ptype = param.ParameterType;
 124                         if (ptype.IsByRef)
 125                                 ptype = ptype.GetElementType ();
 126
 127                         return type.GetNotNullableType ().IsAssignableTo (ptype);
 128                 }
 129
 130                 static MethodInfo CheckUnaryMethod (MethodInfo method, Type param)
 131                 {
 132                         if (method.ReturnType == typeof (void))
 133                                 throw new ArgumentException ("Specified method must return a value", "method");
 134
 135                         if (!method.IsStatic)
 136                                 throw new ArgumentException ("Method must be static", "method");
 137
 138                         var parameters = method.GetParameters ();
 139
 140                         if (parameters.Length != 1)
 141                                 throw new ArgumentException ("Must have only one parameters", "method");
 142
 143                         if (!IsAssignableToParameterType (param.GetNotNullableType (), parameters [0]))
 144                                 throw new InvalidOperationException ("left-side argument type does not match expression type");
 145
 146                         return method;
 147                 }
 148
 149                 static MethodInfo UnaryCoreCheck (string oper_name, Expression expression, MethodInfo method, Func<Type, bool> validator)
 150                 {
 151                         if (expression == null)
 152                                 throw new ArgumentNullException ("expression");
 153
 154                         if (method != null)
 155                                 return CheckUnaryMethod (method, expression.Type);
 156
 157                         var type = expression.Type.GetNotNullableType ();
 158
 159                                 if (validator (type))
 160                                         return null;
 161
 162                                 if (oper_name != null) {
 163                                         method = GetUnaryOperator (oper_name, type, expression.Type);
 164                                         if (method != null)
 165                                                 return method;
 166                                 }
 167
 168                                 throw new InvalidOperationException (
 169                                         string.Format ("Operation {0} not defined for {1}", oper_name != null ? oper_name.Substring (3) : "is", expression.Type));
 170                 }
 171
 172                 static MethodInfo GetBinaryOperator (string oper_name, Type on_type, Expression left, Expression right)
 173                 {
 174                         MethodInfo [] methods = on_type.GetMethods (PublicStatic);
 175
 176                         foreach (var method in methods) {
 177                                 if (method.Name != oper_name)
 178                                         continue;
 179
 180                                 var parameters = method.GetParameters ();
 181                                 if (parameters.Length != 2)
 182                                         continue;
 183
 184                                 if (method.IsGenericMethod)
 185                                         continue;
 186
 187                                 if (!IsAssignableToParameterType (left.Type, parameters [0]))
 188                                         continue;
 189
 190                                 if (!IsAssignableToParameterType (right.Type, parameters [1]))
 191                                         continue;
 192
 193                                 // Method has papers in order.
 194                                 return method;
 195                         }
 196
 197                         return null;
 198                 }
 199
 200                 //
 201                 // Performs basic checks on the incoming expressions for binary expressions
 202                 // and any provided MethodInfo.
 203                 //
 204                 static MethodInfo BinaryCoreCheck (string oper_name, Expression left, Expression right, MethodInfo method)
 205                 {
 206                         if (left == null)
 207                                 throw new ArgumentNullException ("left");
 208                         if (right == null)
 209                                 throw new ArgumentNullException ("right");
 210
 211                         if (method != null){
 212                                 if (method.ReturnType == typeof (void))
 213                                         throw new ArgumentException ("Specified method must return a value", "method");
 214
 215                                 if (!method.IsStatic)
 216                                         throw new ArgumentException ("Method must be static", "method");
 217
 218                                 var parameters = method.GetParameters ();
 219
 220                                 if (parameters.Length != 2)
 221                                         throw new ArgumentException ("Must have only two parameters", "method");
 222
 223                                 if (!IsAssignableToParameterType (left.Type, parameters [0]))
 224                                         throw new InvalidOperationException ("left-side argument type does not match left expression type");
 225
 226                                 if (!IsAssignableToParameterType (right.Type, parameters [1]))
 227                                         throw new InvalidOperationException ("right-side argument type does not match right expression type");
 228
 229                                 return method;
 230                         } else {
 231                                 Type ltype = left.Type;
 232                                 Type rtype = right.Type;
 233                                 Type ultype = ltype.GetNotNullableType ();
 234                                 Type urtype = rtype.GetNotNullableType ();
 235
 236                                 if (oper_name == "op_BitwiseOr" || oper_name == "op_BitwiseAnd") {
 237                                         if (ultype == typeof (bool)) {
 238                                                 if (ultype == urtype && ltype == rtype)
 239                                                         return null;
 240                                         }
 241                                 }
 242
 243                                 // Use IsNumber to avoid expensive reflection.
 244                                 if (IsNumber (ultype)){
 245                                         if (ultype == urtype && ltype == rtype)
 246                                                 return null;
 247
 248                                         if (oper_name != null){
 249                                                 method = GetBinaryOperator (oper_name, urtype, left, right);
 250                                                 if (method != null)
 251                                                         return method;
 252                                         }
 253                                 }
 254
 255                                 if (oper_name != null){
 256                                         method = GetBinaryOperator (oper_name, ultype, left, right);
 257                                         if (method != null)
 258                                                 return method;
 259                                 }
 260
 261                                 if (oper_name == "op_Equality" || oper_name == "op_Inequality") {
 262                                         //
 263                                         // == and != allow reference types without operators defined.
 264                                         //
 265                                         if (!ltype.IsValueType && !rtype.IsValueType)
 266                                                 return null;
 267
 268                                         if (ltype == rtype && ultype == typeof (bool))
 269                                                 return null;
 270                                 }
 271
 272                                 if (oper_name == "op_LeftShift" || oper_name == "op_RightShift") {
 273                                         if (IsInt (ultype) && urtype == typeof (int))
 274                                                 return null;
 275                                 }
 276
 277                                 throw new InvalidOperationException (
 278                                         String.Format ("Operation {0} not defined for {1} and {2}", oper_name != null ? oper_name.Substring (3) : "is", ltype, rtype));
 279                         }
 280                 }
 281
 282                 //
 283                 // This is like BinaryCoreCheck, but if no method is used adds the restriction that
 284                 // only ints and bools are allowed
 285                 //
 286                 static MethodInfo BinaryBitwiseCoreCheck (string oper_name, Expression left, Expression right, MethodInfo method)
 287                 {
 288                         if (left == null)
 289                                 throw new ArgumentNullException ("left");
 290                         if (right == null)
 291                                 throw new ArgumentNullException ("right");
 292
 293                         if (method == null) {
 294                                 // avoid reflection shortcut and catches Ints/bools before we check Numbers in general
 295                                 if (left.Type == right.Type && IsIntOrBool (left.Type))
 296                                         return null;
 297                         }
 298
 299                         method = BinaryCoreCheck (oper_name, left, right, method);
 300                         if (method == null) {
 301                                 // The check in BinaryCoreCheck allows a bit more than we do
 302                                 // (floats and doubles).  Catch this here
 303                                 if (left.Type == typeof (double) || left.Type == typeof (float))
 304                                         throw new InvalidOperationException ("Types not supported");
 305                         }
 306
 307                         return method;
 308                 }
 309
 310                 static BinaryExpression MakeSimpleBinary (ExpressionType et, Expression left, Expression right, MethodInfo method)
 311                 {
 312                         bool is_lifted;
 313                         Type type;
 314
 315                         if (method == null) {
 316                                 is_lifted = left.Type.IsNullable ();
 317                                 type = left.Type;
 318                         } else {
 319                                 var parameters = method.GetParameters ();
 320
 321                                 var lp = parameters [0];
 322                                 var rp = parameters [1];
 323
 324                                 if (IsAssignableToOperatorParameter (left, lp) && IsAssignableToOperatorParameter (right, rp)) {
 325                                         is_lifted = false;
 326                                         type = method.ReturnType;
 327                                 } else if (left.Type.IsNullable ()
 328                                         && right.Type.IsNullable ()
 329                                         && left.Type.GetNotNullableType () == lp.ParameterType
 330                                         && right.Type.GetNotNullableType () == rp.ParameterType
 331                                         && !method.ReturnType.IsNullable ()) {
 332
 333                                         is_lifted = true;
 334                                         type = method.ReturnType.MakeNullableType ();
 335                                 } else
 336                                         throw new InvalidOperationException ();
 337                         }
 338
 339                         return new BinaryExpression (et, type, left, right, is_lifted, is_lifted, method, null);
 340                 }
 341
 342                 static bool IsAssignableToOperatorParameter (Expression expression, ParameterInfo parameter)
 343                 {
 344                         if (expression.Type == parameter.ParameterType)
 345                                 return true;
 346
 347                         if ((!expression.Type.IsNullable () && !parameter.ParameterType.IsNullable ())
 348                                 && IsAssignableToParameterType (expression.Type, parameter))
 349                                 return true;
 350
 351                         return false;
 352                 }
 353
 354                 static UnaryExpression MakeSimpleUnary (ExpressionType et, Expression expression, MethodInfo method)
 355                 {
 356                         bool is_lifted;
 357                         Type type;
 358
 359                         if (method == null) {
 360                                 type = expression.Type;
 361                                 is_lifted = type.IsNullable ();
 362                         } else {
 363                                 var parameter = method.GetParameters () [0];
 364
 365                                 if (IsAssignableToOperatorParameter (expression, parameter)) {
 366                                         is_lifted = false;
 367                                         type = method.ReturnType;
 368                                 } else if (expression.Type.IsNullable ()
 369                                         && expression.Type.GetNotNullableType () == parameter.ParameterType
 370                                         && !method.ReturnType.IsNullable ()) {
 371
 372                                         is_lifted = true;
 373                                         type = method.ReturnType.MakeNullableType ();
 374                                 } else
 375                                         throw new InvalidOperationException ();
 376                         }
 377
 378                         return new UnaryExpression (et, expression, type, method, is_lifted);
 379                 }
 380
 381                 static BinaryExpression MakeBoolBinary (ExpressionType et, Expression left, Expression right, bool liftToNull, MethodInfo method)
 382                 {
 383                         bool is_lifted;
 384                         Type type;
 385
 386                         if (method == null) {
 387                                 if (!left.Type.IsNullable () && !right.Type.IsNullable ()) {
 388                                         is_lifted = false;
 389                                         liftToNull = false;
 390                                         type = typeof (bool);
 391                                 } else if (left.Type.IsNullable () && right.Type.IsNullable ()) {
 392                                         is_lifted = true;
 393                                         type = liftToNull ? typeof (bool?) : typeof (bool);
 394                                 } else
 395                                         throw new InvalidOperationException ();
 396                         } else {
 397                                 var parameters = method.GetParameters ();
 398
 399                                 var lp = parameters [0];
 400                                 var rp = parameters [1];
 401
 402                                 if (IsAssignableToOperatorParameter (left, lp) && IsAssignableToOperatorParameter (right, rp)) {
 403                                         is_lifted = false;
 404                                         liftToNull = false;
 405                                         type = method.ReturnType;
 406                                 } else if (left.Type.IsNullable ()
 407                                         && right.Type.IsNullable ()
 408                                         && left.Type.GetNotNullableType () == lp.ParameterType
 409                                         && right.Type.GetNotNullableType () == rp.ParameterType) {
 410
 411                                         is_lifted = true;
 412
 413                                         if (method.ReturnType == typeof (bool))
 414                                                 type = liftToNull ? typeof (bool?) : typeof (bool);
 415                                         else if (!method.ReturnType.IsNullable ()) {
 416                                                 //
 417                                                 // This behavior is not documented: what
 418                                                 // happens if the result is not typeof(bool), but
 419                                                 // the parameters are nullable: the result
 420                                                 // becomes nullable<returntype>
 421                                                 //
 422                                                 // See:
 423                                                 // https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=323139
 424
 425                                                 type = method.ReturnType.MakeNullableType ();
 426                                         } else
 427                                                 throw new InvalidOperationException ();
 428                                 } else
 429                                         throw new InvalidOperationException ();
 430                         }
 431
 432                         return new BinaryExpression (et, type, left, right, liftToNull, is_lifted, method, null);
 433                 }
 434
 435                 //
 436                 // Arithmetic
 437                 //
 438                 public static BinaryExpression Add (Expression left, Expression right)
 439                 {
 440                         return Add (left, right, null);
 441                 }
 442
 443                 public static BinaryExpression Add (Expression left, Expression right, MethodInfo method)
 444                 {
 445                         method = BinaryCoreCheck ("op_Addition", left, right, method);
 446
 447                         return MakeSimpleBinary (ExpressionType.Add, left, right, method);
 448                 }
 449
 450                 public static BinaryExpression AddChecked (Expression left, Expression right)
 451                 {
 452                         return AddChecked (left, right, null);
 453                 }
 454
 455                 public static BinaryExpression AddChecked (Expression left, Expression right, MethodInfo method)
 456                 {
 457                         method = BinaryCoreCheck ("op_Addition", left, right, method);
 458
 459                         // The check in BinaryCoreCheck allows a bit more than we do
 460                         // (byte, sbyte).  Catch that here
 461                         if (method == null) {
 462                                 if (left.Type == typeof (byte) || left.Type == typeof (sbyte))
 463                                         throw new InvalidOperationException (String.Format ("AddChecked not defined for {0} and {1}", left.Type, right.Type));
 464                         }
 465
 466                         return MakeSimpleBinary (ExpressionType.AddChecked, left, right, method);
 467                 }
 468
 469                 public static BinaryExpression Subtract (Expression left, Expression right)
 470                 {
 471                         return Subtract (left, right, null);
 472                 }
 473
 474                 public static BinaryExpression Subtract (Expression left, Expression right, MethodInfo method)
 475                 {
 476                         method = BinaryCoreCheck ("op_Subtraction", left, right, method);
 477
 478                         return MakeSimpleBinary (ExpressionType.Subtract, left, right, method);
 479                 }
 480
 481                 public static BinaryExpression SubtractChecked (Expression left, Expression right)
 482                 {
 483                         return SubtractChecked (left, right, null);
 484                 }
 485
 486                 public static BinaryExpression SubtractChecked (Expression left, Expression right, MethodInfo method)
 487                 {
 488                         method = BinaryCoreCheck ("op_Subtraction", left, right, method);
 489
 490                         // The check in BinaryCoreCheck allows a bit more than we do
 491                         // (byte, sbyte).  Catch that here
 492                         if (method == null) {
 493                                 if (left.Type == typeof (byte) || left.Type == typeof (sbyte))
 494                                         throw new InvalidOperationException (String.Format ("SubtractChecked not defined for {0} and {1}", left.Type, right.Type));
 495                         }
 496
 497                         return MakeSimpleBinary (ExpressionType.SubtractChecked, left, right, method);
 498                 }
 499
 500                 public static BinaryExpression Modulo (Expression left, Expression right)
 501                 {
 502                         return Modulo (left, right, null);
 503                 }
 504
 505                 public static BinaryExpression Modulo (Expression left, Expression right, MethodInfo method)
 506                 {
 507                         method = BinaryCoreCheck ("op_Modulus", left, right, method);
 508
 509                         return MakeSimpleBinary (ExpressionType.Modulo, left, right, method);
 510                 }
 511
 512                 public static BinaryExpression Multiply (Expression left, Expression right)
 513                 {
 514                         return Multiply (left, right, null);
 515                 }
 516
 517                 public static BinaryExpression Multiply (Expression left, Expression right, MethodInfo method)
 518                 {
 519                         method = BinaryCoreCheck ("op_Multiply", left, right, method);
 520
 521                         return MakeSimpleBinary (ExpressionType.Multiply, left, right, method);
 522                 }
 523
 524                 public static BinaryExpression MultiplyChecked (Expression left, Expression right)
 525                 {
 526                         return MultiplyChecked (left, right, null);
 527                 }
 528
 529                 public static BinaryExpression MultiplyChecked (Expression left, Expression right, MethodInfo method)
 530                 {
 531                         method = BinaryCoreCheck ("op_Multiply", left, right, method);
 532
 533                         return MakeSimpleBinary (ExpressionType.MultiplyChecked, left, right, method);
 534                 }
 535
 536                 public static BinaryExpression Divide (Expression left, Expression right)
 537                 {
 538                         return Divide (left, right, null);
 539                 }
 540
 541                 public static BinaryExpression Divide (Expression left, Expression right, MethodInfo method)
 542                 {
 543                         method = BinaryCoreCheck ("op_Division", left, right, method);
 544
 545                         return MakeSimpleBinary (ExpressionType.Divide, left, right, method);
 546                 }
 547
 548                 public static BinaryExpression Power (Expression left, Expression right)
 549                 {
 550                         return Power (left, right, null);
 551                 }
 552
 553                 public static BinaryExpression Power (Expression left, Expression right, MethodInfo method)
 554                 {
 555                         method = BinaryCoreCheck (null, left, right, method);
 556
 557                         if (left.Type.GetNotNullableType () != typeof (double))
 558                                 throw new InvalidOperationException ("Power only supports double arguments");
 559
 560                         return MakeSimpleBinary (ExpressionType.Power, left, right, method);
 561                 }
 562
 563                 //
 564                 // Bitwise
 565                 //
 566                 public static BinaryExpression And (Expression left, Expression right)
 567                 {
 568                         return And (left, right, null);
 569                 }
 570
 571                 public static BinaryExpression And (Expression left, Expression right, MethodInfo method)
 572                 {
 573                         method = BinaryBitwiseCoreCheck ("op_BitwiseAnd", left, right, method);
 574
 575                         return MakeSimpleBinary (ExpressionType.And, left, right, method);
 576                 }
 577
 578                 public static BinaryExpression Or (Expression left, Expression right)
 579                 {
 580                         return Or (left, right, null);
 581                 }
 582
 583                 public static BinaryExpression Or (Expression left, Expression right, MethodInfo method)
 584                 {
 585                         method = BinaryBitwiseCoreCheck ("op_BitwiseOr", left, right, method);
 586
 587                         return MakeSimpleBinary (ExpressionType.Or, left, right, method);
 588                 }
 589
 590                 public static BinaryExpression ExclusiveOr (Expression left, Expression right)
 591                 {
 592                         return ExclusiveOr (left, right, null);
 593                 }
 594
 595                 public static BinaryExpression ExclusiveOr (Expression left, Expression right, MethodInfo method)
 596                 {
 597                         method = BinaryBitwiseCoreCheck ("op_ExclusiveOr", left, right, method);
 598
 599                         return MakeSimpleBinary (ExpressionType.ExclusiveOr, left, right, method);
 600                 }
 601
 602                 public static BinaryExpression LeftShift (Expression left, Expression right)
 603                 {
 604                         return LeftShift (left, right, null);
 605                 }
 606
 607                 public static BinaryExpression LeftShift (Expression left, Expression right, MethodInfo method)
 608                 {
 609                         method = BinaryBitwiseCoreCheck ("op_LeftShift", left, right, method);
 610
 611                         return MakeSimpleBinary (ExpressionType.LeftShift, left, right, method);
 612                 }
 613
 614                 public static BinaryExpression RightShift (Expression left, Expression right)
 615                 {
 616                         return RightShift (left, right, null);
 617                 }
 618
 619                 public static BinaryExpression RightShift (Expression left, Expression right, MethodInfo method)
 620                 {
 621                         method = BinaryCoreCheck ("op_RightShift", left, right, method);
 622
 623                         return MakeSimpleBinary (ExpressionType.RightShift, left, right, method);
 624                 }
 625
 626                 //
 627                 // Short-circuit
 628                 //
 629                 public static BinaryExpression AndAlso (Expression left, Expression right)
 630                 {
 631                         return AndAlso (left, right, null);
 632                 }
 633
 634                 public static BinaryExpression AndAlso (Expression left, Expression right, MethodInfo method)
 635                 {
 636                         method = ConditionalBinaryCheck ("op_BitwiseAnd", left, right, method);
 637
 638                         return MakeBoolBinary (ExpressionType.AndAlso, left, right, true, method);
 639                 }
 640
 641                 static MethodInfo ConditionalBinaryCheck (string oper, Expression left, Expression right, MethodInfo method)
 642                 {
 643                         method = BinaryCoreCheck (oper, left, right, method);
 644
 645                         if (method == null) {
 646                                 if (left.Type.GetNotNullableType () != typeof (bool))
 647                                         throw new InvalidOperationException ("Only booleans are allowed");
 648                         } else {
 649                                 var type = left.Type.GetNotNullableType ();
 650
 651                                 // The method should have identical parameter and return types.
 652                                 if (left.Type != right.Type || method.ReturnType != type)
 653                                         throw new ArgumentException ("left, right and return type must match");
 654
 655                                 var optrue = GetTrueOperator (type);
 656                                 var opfalse = GetFalseOperator (type);
 657
 658                                 if (optrue == null || opfalse == null)
 659                                         throw new ArgumentException ("Operators true and false are required but not defined");
 660                         }
 661
 662                         return method;
 663                 }
 664
 665                 public static BinaryExpression OrElse (Expression left, Expression right)
 666                 {
 667                         return OrElse (left, right, null);
 668                 }
 669
 670                 public static BinaryExpression OrElse (Expression left, Expression right, MethodInfo method)
 671                 {
 672                         method = ConditionalBinaryCheck ("op_BitwiseOr", left, right, method);
 673
 674                         return MakeBoolBinary (ExpressionType.OrElse, left, right, true, method);
 675                 }
 676
 677                 //
 678                 // Comparison
 679                 //
 680                 public static BinaryExpression Equal (Expression left, Expression right)
 681                 {
 682                         return Equal (left, right, false, null);
 683                 }
 684
 685                 public static BinaryExpression Equal (Expression left, Expression right, bool liftToNull, MethodInfo method)
 686                 {
 687                         method = BinaryCoreCheck ("op_Equality", left, right, method);
 688
 689                         return MakeBoolBinary (ExpressionType.Equal, left, right, liftToNull, method);
 690                 }
 691
 692                 public static BinaryExpression NotEqual (Expression left, Expression right)
 693                 {
 694                         return NotEqual (left, right, false, null);
 695                 }
 696
 697
 698                 public static BinaryExpression NotEqual (Expression left, Expression right, bool liftToNull, MethodInfo method)
 699                 {
 700                         method = BinaryCoreCheck ("op_Inequality", left, right, method);
 701
 702                         return MakeBoolBinary (ExpressionType.NotEqual, left, right, liftToNull, method);
 703                 }
 704
 705                 public static BinaryExpression GreaterThan (Expression left, Expression right)
 706                 {
 707                         return GreaterThan (left, right, false, null);
 708                 }
 709
 710                 public static BinaryExpression GreaterThan (Expression left, Expression right, bool liftToNull, MethodInfo method)
 711                 {
 712                         method = BinaryCoreCheck ("op_GreaterThan", left, right, method);
 713
 714                         return MakeBoolBinary (ExpressionType.GreaterThan, left, right, liftToNull, method);
 715                 }
 716
 717                 public static BinaryExpression GreaterThanOrEqual (Expression left, Expression right)
 718                 {
 719                         return GreaterThanOrEqual (left, right, false, null);
 720                 }
 721
 722
 723                 public static BinaryExpression GreaterThanOrEqual (Expression left, Expression right, bool liftToNull, MethodInfo method)
 724                 {
 725                         method = BinaryCoreCheck ("op_GreaterThanOrEqual", left, right, method);
 726
 727                         return MakeBoolBinary (ExpressionType.GreaterThanOrEqual, left, right, liftToNull, method);
 728                 }
 729
 730                 public static BinaryExpression LessThan (Expression left, Expression right)
 731                 {
 732                         return LessThan (left, right, false, null);
 733                 }
 734
 735                 public static BinaryExpression LessThan (Expression left, Expression right, bool liftToNull, MethodInfo method)
 736                 {
 737                         method = BinaryCoreCheck ("op_LessThan", left, right, method);
 738
 739                         return MakeBoolBinary (ExpressionType.LessThan, left, right, liftToNull, method);
 740                 }
 741
 742                 public static BinaryExpression LessThanOrEqual (Expression left, Expression right)
 743                 {
 744                         return LessThanOrEqual (left, right, false, null);
 745                 }
 746
 747                 public static BinaryExpression LessThanOrEqual (Expression left, Expression right, bool liftToNull, MethodInfo method)
 748                 {
 749                         method = BinaryCoreCheck ("op_LessThanOrEqual", left, right, method);
 750
 751                         return MakeBoolBinary (ExpressionType.LessThanOrEqual, left, right, liftToNull, method);
 752                 }
 753
 754                 //
 755                 // Miscelaneous
 756                 //
 757
 758                 static void CheckArray (Expression array)
 759                 {
 760                         if (array == null)
 761                                 throw new ArgumentNullException ("array");
 762                         if (!array.Type.IsArray)
 763                                 throw new ArgumentException ("The array argument must be of type array");
 764                 }
 765
 766                 public static BinaryExpression ArrayIndex (Expression array, Expression index)
 767                 {
 768                         CheckArray (array);
 769
 770                         if (index == null)
 771                                 throw new ArgumentNullException ("index");
 772                         if (array.Type.GetArrayRank () != 1)
 773                                 throw new ArgumentException ("The array argument must be a single dimensional array");
 774                         if (index.Type != typeof (int))
 775                                 throw new ArgumentException ("The index must be of type int");
 776
 777                         return new BinaryExpression (ExpressionType.ArrayIndex, array.Type.GetElementType (), array, index);
 778                 }
 779
 780                 public static BinaryExpression Coalesce (Expression left, Expression right)
 781                 {
 782                         return Coalesce (left, right, null);
 783                 }
 784
 785                 static BinaryExpression MakeCoalesce (Expression left, Expression right)
 786                 {
 787                         Type result = null;
 788
 789                         if (left.Type.IsNullable ()) {
 790                                 Type lbase = left.Type.GetNotNullableType ();
 791
 792                                 if (!right.Type.IsNullable () && right.Type.IsAssignableTo (lbase))
 793                                         result = lbase;
 794                         }
 795
 796                         if (result == null && right.Type.IsAssignableTo (left.Type))
 797                                 result = left.Type;
 798
 799                         if (result == null) {
 800                                 if (left.Type.IsNullable () && left.Type.GetNotNullableType ().IsAssignableTo (right.Type))
 801                                         result = right.Type;
 802                         }
 803
 804                         if (result == null)
 805                                 throw new ArgumentException ("Incompatible argument types");
 806
 807                         return new BinaryExpression (ExpressionType.Coalesce, result, left, right, false, false, null, null);
 808                 }
 809
 810                 static BinaryExpression MakeConvertedCoalesce (Expression left, Expression right, LambdaExpression conversion)
 811                 {
 812                         var invoke = conversion.Type.GetInvokeMethod ();
 813
 814                         CheckNotVoid (invoke.ReturnType);
 815
 816                         if (invoke.ReturnType != right.Type)
 817                                 throw new InvalidOperationException ("Conversion return type doesn't march right type");
 818
 819                         var parameters = invoke.GetParameters ();
 820
 821                         if (parameters.Length != 1)
 822                                 throw new ArgumentException ("Conversion has wrong number of parameters");
 823
 824                         if (!IsAssignableToParameterType (left.Type, parameters [0]))
 825                                 throw new InvalidOperationException ("Conversion argument doesn't marcht left type");
 826
 827                         return new BinaryExpression (ExpressionType.Coalesce, right.Type, left, right, false, false, null, conversion);
 828                 }
 829
 830                 public static BinaryExpression Coalesce (Expression left, Expression right, LambdaExpression conversion)
 831                 {
 832                         if (left == null)
 833                                 throw new ArgumentNullException ("left");
 834                         if (right == null)
 835                                 throw new ArgumentNullException ("right");
 836
 837                         //
 838                         // First arg must ne nullable (either Nullable<T> or a reference type
 839                         //
 840                         if (left.Type.IsValueType && !left.Type.IsNullable ())
 841                                 throw new InvalidOperationException ("Left expression can never be null");
 842
 843                         if (conversion != null)
 844                                 return MakeConvertedCoalesce (left, right, conversion);
 845
 846                         return MakeCoalesce (left, right);
 847                 }
 848
 849                 //
 850                 // MakeBinary constructors
 851                 //
 852                 public static BinaryExpression MakeBinary (ExpressionType binaryType, Expression left, Expression right)
 853                 {
 854                         return MakeBinary (binaryType, left, right, false, null);
 855                 }
 856
 857                 public static BinaryExpression MakeBinary (ExpressionType binaryType, Expression left, Expression right, bool liftToNull, MethodInfo method)
 858                 {
 859                         return MakeBinary (binaryType, left, right, liftToNull, method, null);
 860                 }
 861
 862                 public static BinaryExpression MakeBinary (ExpressionType binaryType, Expression left, Expression right, bool liftToNull, MethodInfo method, LambdaExpression conversion)
 863                 {
 864                         switch (binaryType) {
 865                         case ExpressionType.Add:
 866                                 return Add (left, right, method);
 867                         case ExpressionType.AddChecked:
 868                                 return AddChecked (left, right, method);
 869                         case ExpressionType.AndAlso:
 870                                 return AndAlso (left, right);
 871                         case ExpressionType.Coalesce:
 872                                 return Coalesce (left, right, conversion);
 873                         case ExpressionType.Divide:
 874                                 return Divide (left, right, method);
 875                         case ExpressionType.Equal:
 876                                 return Equal (left, right, liftToNull, method);
 877                         case ExpressionType.ExclusiveOr:
 878                                 return ExclusiveOr (left, right, method);
 879                         case ExpressionType.GreaterThan:
 880                                 return GreaterThan (left, right, liftToNull, method);
 881                         case ExpressionType.GreaterThanOrEqual:
 882                                 return GreaterThanOrEqual (left, right, liftToNull, method);
 883                         case ExpressionType.LeftShift:
 884                                 return LeftShift (left, right, method);
 885                         case ExpressionType.LessThan:
 886                                 return LessThan (left, right, liftToNull, method);
 887                         case ExpressionType.LessThanOrEqual:
 888                                 return LessThanOrEqual (left, right, liftToNull, method);
 889                         case ExpressionType.Modulo:
 890                                 return Modulo (left, right, method);
 891                         case ExpressionType.Multiply:
 892                                 return Multiply (left, right, method);
 893                         case ExpressionType.MultiplyChecked:
 894                                 return MultiplyChecked (left, right, method);
 895                         case ExpressionType.NotEqual:
 896                                 return NotEqual (left, right, liftToNull, method);
 897                         case ExpressionType.OrElse:
 898                                 return OrElse (left, right);
 899                         case ExpressionType.Power:
 900                                 return Power (left, right, method);
 901                         case ExpressionType.RightShift:
 902                                 return RightShift (left, right, method);
 903                         case ExpressionType.Subtract:
 904                                 return Subtract (left, right, method);
 905                         case ExpressionType.SubtractChecked:
 906                                 return SubtractChecked (left, right, method);
 907                         case ExpressionType.And:
 908                                 return And (left, right, method);
 909                         case ExpressionType.Or:
 910                                 return Or (left, right, method);
 911                         }
 912
 913                         throw new ArgumentException ("MakeBinary expect a binary node type");
 914                 }
 915
 916                 #endregion
 917
 918                 public static MethodCallExpression ArrayIndex (Expression array, params Expression [] indexes)
 919                 {
 920                         return ArrayIndex (array, indexes as IEnumerable<Expression>);
 921                 }
 922
 923                 public static MethodCallExpression ArrayIndex (Expression array, IEnumerable<Expression> indexes)
 924                 {
 925                         CheckArray (array);
 926
 927                         if (indexes == null)
 928                                 throw new ArgumentNullException ("indexes");
 929
 930                         var args = indexes.ToReadOnlyCollection ();
 931                         if (array.Type.GetArrayRank () != args.Count)
 932                                 throw new ArgumentException ("The number of arguments doesn't match the rank of the array");
 933
 934                         foreach (var arg in args)
 935                                 if (arg.Type != typeof (int))
 936                                         throw new ArgumentException ("The index must be of type int");
 937
 938                         return Call (array, array.Type.GetMethod ("Get", PublicInstance), args);
 939                 }
 940
 941                 public static UnaryExpression ArrayLength (Expression array)
 942                 {
 943                         if (array == null)
 944                                 throw new ArgumentNullException ("array");
 945                         if (!array.Type.IsArray)
 946                                 throw new ArgumentException ("The type of the expression must me Array");
 947                         if (array.Type.GetArrayRank () != 1)
 948                                 throw new ArgumentException ("The array must be a single dimensional array");
 949
 950                         return new UnaryExpression (ExpressionType.ArrayLength, array, typeof (int));
 951                 }
 952
 953                 public static MemberAssignment Bind (MemberInfo member, Expression expression)
 954                 {
 955                         if (member == null)
 956                                 throw new ArgumentNullException ("member");
 957                         if (expression == null)
 958                                 throw new ArgumentNullException ("expression");
 959
 960                         Type type = null;
 961
 962                         var prop = member as PropertyInfo;
 963                         if (prop != null && prop.GetSetMethod (true) != null)
 964                                 type = prop.PropertyType;
 965
 966                         var field = member as FieldInfo;
 967                         if (field != null)
 968                                 type = field.FieldType;
 969
 970                         if (type == null)
 971                                 throw new ArgumentException ("member");
 972
 973                         if (!expression.Type.IsAssignableTo (type))
 974                                 throw new ArgumentException ("member");
 975
 976                         return new MemberAssignment (member, expression);
 977                 }
 978
 979                 public static MemberAssignment Bind (MethodInfo propertyAccessor, Expression expression)
 980                 {
 981                         if (propertyAccessor == null)
 982                                 throw new ArgumentNullException ("propertyAccessor");
 983                         if (expression == null)
 984                                 throw new ArgumentNullException ("expression");
 985
 986                         var prop = GetAssociatedProperty (propertyAccessor);
 987                         if (prop == null)
 988                                 throw new ArgumentException ("propertyAccessor");
 989
 990                         var setter = prop.GetSetMethod (true);
 991                         if (setter == null)
 992                                 throw new ArgumentException ("setter");
 993
 994                         if (!expression.Type.IsAssignableTo (prop.PropertyType))
 995                                 throw new ArgumentException ("member");
 996
 997                         return new MemberAssignment (prop, expression);
 998                 }
 999
1000                 public static MethodCallExpression Call (Expression instance, MethodInfo method)
1001                 {
1002                         return Call (instance, method, null as IEnumerable<Expression>);
1003                 }
1004
1005                 public static MethodCallExpression Call (MethodInfo method, params Expression [] arguments)
1006                 {
1007                         return Call (null, method, arguments as IEnumerable<Expression>);
1008                 }
1009
1010                 public static MethodCallExpression Call (Expression instance, MethodInfo method, params Expression [] arguments)
1011                 {
1012                         return Call (instance, method, arguments as IEnumerable<Expression>);
1013                 }
1014
1015                 public static MethodCallExpression Call (Expression instance, MethodInfo method, IEnumerable<Expression> arguments)
1016                 {
1017                         if (method == null)
1018                                 throw new ArgumentNullException ("method");
1019                         if (instance == null && !method.IsStatic)
1020                                 throw new ArgumentNullException ("instance");
1021                         if (method.IsStatic && instance != null)
1022                                 throw new ArgumentException ("instance");
1023                         if (!method.IsStatic && !instance.Type.IsAssignableTo (method.DeclaringType))
1024                                 throw new ArgumentException ("Type is not assignable to the declaring type of the method");
1025
1026                         var args = CheckMethodArguments (method, arguments);
1027
1028                         return new MethodCallExpression (instance, method, args);
1029                 }
1030
1031                 static Type [] CollectTypes (IEnumerable<Expression> expressions)
1032                 {
1033                         return (from arg in expressions select arg.Type).ToArray ();
1034                 }
1035
1036                 static MethodInfo TryMakeGeneric (MethodInfo method, Type [] args)
1037                 {
1038                         if (method == null)
1039                                 return null;
1040
1041                         if (!method.IsGenericMethod && args == null)
1042                                 return method;
1043
1044                         if (args.Length == method.GetGenericArguments ().Length)
1045                                 return method.MakeGenericMethod (args);
1046
1047                         return null;
1048                 }
1049
1050                 public static MethodCallExpression Call (Expression instance, string methodName, Type [] typeArguments, params Expression [] arguments)
1051                 {
1052                         if (instance == null)
1053                                 throw new ArgumentNullException ("instance");
1054                         if (methodName == null)
1055                                 throw new ArgumentNullException ("methodName");
1056
1057                         var method = TryGetMethod (instance.Type, methodName, AllInstance,
1058                                 CollectTypes (arguments), typeArguments);
1059
1060                         var args = CheckMethodArguments (method, arguments);
1061
1062                         return new MethodCallExpression (instance, method, args);
1063                 }
1064
1065                 static bool MethodMatch (MethodInfo method, string name, Type [] parameterTypes)
1066                 {
1067                         if (method.Name != name)
1068                                 return false;
1069
1070                         var parameters = method.GetParameters ();
1071
1072                         if (parameters.Length != parameterTypes.Length)
1073                                 return false;
1074
1075                         if (method.IsGenericMethod) // if it's a generic method, when can't compare its parameters
1076                                 return true;
1077
1078                         for (int i = 0; i < parameters.Length; i++)
1079                                 if (!IsAssignableToParameterType (parameterTypes [i], parameters [i]))
1080                                         return false;
1081
1082                         return true;
1083                 }
1084
1085                 static MethodInfo TryGetMethod (Type type, string methodName, BindingFlags flags, Type [] parameterTypes, Type [] argumentTypes)
1086                 {
1087                         var methods = from meth in type.GetMethods (flags)
1088                                                   where MethodMatch (meth, methodName, parameterTypes)
1089                                                   select meth;
1090
1091                         if (methods.Count () > 1)
1092                                 throw new InvalidOperationException ("Too much method candidates");
1093
1094                         var method = TryMakeGeneric (methods.FirstOrDefault (), argumentTypes);
1095                         if (method != null)
1096                                 return method;
1097
1098                         throw new InvalidOperationException ("No such method");
1099                 }
1100
1101                 public static MethodCallExpression Call (Type type, string methodName, Type [] typeArguments, params Expression [] arguments)
1102                 {
1103                         if (type == null)
1104                                 throw new ArgumentNullException ("type");
1105                         if (methodName == null)
1106                                 throw new ArgumentNullException ("methodName");
1107
1108                         var method = TryGetMethod (type, methodName, AllStatic,
1109                                 CollectTypes (arguments), typeArguments);
1110
1111                         var args = CheckMethodArguments (method, arguments);
1112
1113                         return new MethodCallExpression (method, args);
1114                 }
1115
1116                 public static ConditionalExpression Condition (Expression test, Expression ifTrue, Expression ifFalse)
1117                 {
1118                         if (test == null)
1119                                 throw new ArgumentNullException ("test");
1120                         if (ifTrue == null)
1121                                 throw new ArgumentNullException ("ifTrue");
1122                         if (ifFalse == null)
1123                                 throw new ArgumentNullException ("ifFalse");
1124                         if (test.Type != typeof (bool))
1125                                 throw new ArgumentException ("Test expression should be of type bool");
1126                         if (ifTrue.Type != ifFalse.Type)
1127                                 throw new ArgumentException ("The ifTrue and ifFalse type do not match");
1128
1129                         return new ConditionalExpression (test, ifTrue, ifFalse);
1130                 }
1131
1132                 public static ConstantExpression Constant (object value)
1133                 {
1134                         if (value == null)
1135                                 return new ConstantExpression (null, typeof (object));
1136
1137                         return Constant (value, value.GetType ());
1138                 }
1139
1140                 public static ConstantExpression Constant (object value, Type type)
1141                 {
1142                         if (type == null)
1143                                 throw new ArgumentNullException ("type");
1144
1145                         //
1146                         // value must be compatible with type, no conversions
1147                         // are allowed
1148                         //
1149                         if (value == null){
1150                                 if (type.IsValueType && !type.IsNullable ())
1151                                         throw new ArgumentException ();
1152                         } else {
1153                                 if (!(type.IsValueType && type.IsNullable ()) && !value.GetType ().IsAssignableTo (type))
1154                                         throw new ArgumentException ();
1155
1156                         }
1157
1158                         return new ConstantExpression (value, type);
1159                 }
1160
1161                 static bool IsConvertiblePrimitive (Type type)
1162                 {
1163                         var t = type.GetNotNullableType ();
1164
1165                         if (t == typeof (bool))
1166                                 return false;
1167
1168                         if (t.IsEnum)
1169                                 return true;
1170
1171                         return t.IsPrimitive;
1172                 }
1173
1174                 internal static bool IsPrimitiveConversion (Type type, Type target)
1175                 {
1176                         if (type == target)
1177                                 return true;
1178
1179                         if (type.IsNullable () && target == type.GetNotNullableType ())
1180                                 return true;
1181
1182                         if (target.IsNullable () && type == target.GetNotNullableType ())
1183                                 return true;
1184
1185                         if (IsConvertiblePrimitive (type) && IsConvertiblePrimitive (target))
1186                                 return true;
1187
1188                         return false;
1189                 }
1190
1191                 internal static bool IsReferenceConversion (Type type, Type target)
1192                 {
1193                         if (type == target)
1194                                 return true;
1195
1196                         if (type == typeof (object) || target == typeof (object))
1197                                 return true;
1198
1199                         if (type.IsInterface || target.IsInterface)
1200                                 return true;
1201
1202                         if (type.IsValueType || target.IsValueType)
1203                                 return false;
1204
1205                         if (type.IsAssignableTo (target) || target.IsAssignableTo (type))
1206                                 return true;
1207
1208                         return false;
1209                 }
1210
1211                 public static UnaryExpression Convert (Expression expression, Type type)
1212                 {
1213                         return Convert (expression, type, null);
1214                 }
1215
1216                 static MethodInfo GetUserConversionMethod (Type type, Type target)
1217                 {
1218                         var method = GetUnaryOperator ("op_Explicit", type, type, target);
1219                         if (method == null)
1220                                 method = GetUnaryOperator ("op_Implicit", type, type, target);
1221                         if (method == null)
1222                                 method = GetUnaryOperator ("op_Explicit", target, type, target);
1223                         if (method == null)
1224                                 method = GetUnaryOperator ("op_Implicit", target, type, target);
1225                         if (method == null)
1226                                 throw new InvalidOperationException ();
1227
1228                         return method;
1229                 }
1230
1231                 public static UnaryExpression Convert (Expression expression, Type type, MethodInfo method)
1232                 {
1233                         if (expression == null)
1234                                 throw new ArgumentNullException ("expression");
1235                         if (type == null)
1236                                 throw new ArgumentNullException ("type");
1237
1238                         var et = expression.Type;
1239
1240                         if (method != null)
1241                                 CheckUnaryMethod (method, et);
1242                         else if (!IsPrimitiveConversion (et, type) && !IsReferenceConversion (et, type))
1243                                 method = GetUserConversionMethod (et, type);
1244
1245                         return new UnaryExpression (ExpressionType.Convert,
1246                                 expression, type, method,
1247                                 IsConvertNodeLifted (method, expression, type));
1248                 }
1249
1250                 static bool IsConvertNodeLifted (MethodInfo method, Expression operand, Type target)
1251                 {
1252                         if (method == null)
1253                                 return operand.Type.IsNullable () || target.IsNullable ();
1254
1255                         if (operand.Type.IsNullable () && !ParameterMatch (method, operand.Type))
1256                                 return true;
1257
1258                         if (target.IsNullable () && !ReturnTypeMatch (method, target))
1259                                 return true;
1260
1261                         return false;
1262                 }
1263
1264                 static bool ParameterMatch (MethodInfo method, Type type)
1265                 {
1266                         return method.GetParameters () [0].ParameterType == type;
1267                 }
1268
1269                 static bool ReturnTypeMatch (MethodInfo method, Type type)
1270                 {
1271                         return method.ReturnType == type;
1272                 }
1273
1274                 public static UnaryExpression ConvertChecked (Expression expression, Type type)
1275                 {
1276                         return ConvertChecked (expression, type, null);
1277                 }
1278
1279                 public static UnaryExpression ConvertChecked (Expression expression, Type type, MethodInfo method)
1280                 {
1281                         if (expression == null)
1282                                 throw new ArgumentNullException ("expression");
1283                         if (type == null)
1284                                 throw new ArgumentNullException ("type");
1285
1286                         var et = expression.Type;
1287
1288                         if (method != null)
1289                                 CheckUnaryMethod (method, et);
1290                         else if (IsReferenceConversion (et, type))
1291                                 return Convert (expression, type, method);
1292                         else if (!IsPrimitiveConversion (et, type))
1293                                 method = GetUserConversionMethod (et, type);
1294
1295                         return new UnaryExpression (ExpressionType.ConvertChecked,
1296                                 expression, type, method,
1297                                 IsConvertNodeLifted (method, expression, type));
1298                 }
1299
1300                 public static ElementInit ElementInit (MethodInfo addMethod, params Expression [] arguments)
1301                 {
1302                         return ElementInit (addMethod, arguments as IEnumerable<Expression>);
1303                 }
1304
1305                 public static ElementInit ElementInit (MethodInfo addMethod, IEnumerable<Expression> arguments)
1306                 {
1307                         if (addMethod == null)
1308                                 throw new ArgumentNullException ("addMethod");
1309                         if (arguments == null)
1310                                 throw new ArgumentNullException ("arguments");
1311                         if (addMethod.Name.ToLower (CultureInfo.InvariantCulture) != "add")
1312                                 throw new ArgumentException ("addMethod");
1313                         if (addMethod.IsStatic)
1314                                 throw new ArgumentException ("addMethod must be an instance method", "addMethod");
1315
1316                         var args = CheckMethodArguments (addMethod, arguments);
1317
1318                         return new ElementInit (addMethod, args);
1319                 }
1320
1321                 public static MemberExpression Field (Expression expression, FieldInfo field)
1322                 {
1323                         if (field == null)
1324                                 throw new ArgumentNullException ("field");
1325                         if (!field.IsStatic) {
1326                                 if (expression == null)
1327                                         throw new ArgumentNullException ("expression");
1328                                 if (!expression.Type.IsAssignableTo (field.DeclaringType))
1329                                         throw new ArgumentException ("field");
1330                         } else if (expression != null)
1331                                 throw new ArgumentException ("expression");
1332
1333                         return new MemberExpression (expression, field, field.FieldType);
1334                 }
1335
1336                 public static MemberExpression Field (Expression expression, string fieldName)
1337                 {
1338                         if (expression == null)
1339                                 throw new ArgumentNullException ("expression");
1340
1341                         var field = expression.Type.GetField (fieldName, AllInstance);
1342                         if (field == null)
1343                                 throw new ArgumentException (string.Format ("No field named {0} on {1}", fieldName, expression.Type));
1344
1345                         return new MemberExpression (expression, field, field.FieldType);
1346                 }
1347
1348                 public static Type GetActionType (params Type [] typeArgs)
1349                 {
1350                         if (typeArgs == null)
1351                                 throw new ArgumentNullException ("typeArgs");
1352
1353                         if (typeArgs.Length > 4)
1354                                 throw new ArgumentException ("No Action type of this arity");
1355
1356                         if (typeArgs.Length == 0)
1357                                 return typeof (Action);
1358
1359                         Type action = null;
1360                         switch (typeArgs.Length) {
1361                         case 1:
1362                                 action = typeof (Action<>);
1363                                 break;
1364                         case 2:
1365                                 action = typeof (Action<,>);
1366                                 break;
1367                         case 3:
1368                                 action = typeof (Action<,,>);
1369                                 break;
1370                         case 4:
1371                                 action = typeof (Action<,,,>);
1372                                 break;
1373                         }
1374
1375                         return action.MakeGenericType (typeArgs);
1376                 }
1377
1378                 public static Type GetFuncType (params Type [] typeArgs)
1379                 {
1380                         if (typeArgs == null)
1381                                 throw new ArgumentNullException ("typeArgs");
1382
1383                         if (typeArgs.Length < 1 || typeArgs.Length > 5)
1384                                 throw new ArgumentException ("No Func type of this arity");
1385
1386                         Type func = null;
1387                         switch (typeArgs.Length) {
1388                         case 1:
1389                                 func = typeof (Func<>);
1390                                 break;
1391                         case 2:
1392                                 func = typeof (Func<,>);
1393                                 break;
1394                         case 3:
1395                                 func = typeof (Func<,,>);
1396                                 break;
1397                         case 4:
1398                                 func = typeof (Func<,,,>);
1399                                 break;
1400                         case 5:
1401                                 func = typeof (Func<,,,,>);
1402                                 break;
1403                         }
1404
1405                         return func.MakeGenericType (typeArgs);
1406                 }
1407
1408                 public static InvocationExpression Invoke (Expression expression, params Expression [] arguments)
1409                 {
1410                         return Invoke (expression, arguments as IEnumerable<Expression>);
1411                 }
1412
1413                 static Type GetInvokableType (Type t)
1414                 {
1415                         if (t.IsAssignableTo (typeof (Delegate)))
1416                                 return t;
1417
1418                         return GetGenericType (t, typeof (Expression<>));
1419                 }
1420
1421                 static Type GetGenericType (Type t, Type def)
1422                 {
1423                         if (t == null)
1424                                 return null;
1425
1426                         if (t.IsGenericType && t.GetGenericTypeDefinition () == def)
1427                                 return t;
1428
1429                         return GetGenericType (t.BaseType, def);
1430                 }
1431
1432                 public static InvocationExpression Invoke (Expression expression, IEnumerable<Expression> arguments)
1433                 {
1434                         if (expression == null)
1435                                 throw new ArgumentNullException ("expression");
1436
1437                         var type = GetInvokableType (expression.Type);
1438                         if (type == null)
1439                                 throw new ArgumentException ("The type of the expression is not invokable");
1440
1441                         var args = arguments.ToReadOnlyCollection ();
1442                         CheckForNull (args, "arguments");
1443
1444                         var invoke = type.GetInvokeMethod ();
1445                         if (invoke == null)
1446                                 throw new ArgumentException ("expression");
1447
1448                         if (invoke.GetParameters ().Length != args.Count)
1449                                 throw new InvalidOperationException ("Arguments count doesn't match parameters length");
1450
1451                         args = CheckMethodArguments (invoke, args);
1452
1453                         return new InvocationExpression (expression, invoke.ReturnType, args);
1454                 }
1455
1456                 static bool CanAssign (Type target, Type source)
1457                 {
1458                         // This catches object and value type mixage, type compatibility is handled later
1459                         if (target.IsValueType ^ source.IsValueType)
1460                                 return false;
1461
1462                         return source.IsAssignableTo (target);
1463                 }
1464
1465                 static Expression CheckLambda (Type delegateType, Expression body, ReadOnlyCollection<ParameterExpression> parameters)
1466                 {
1467                         if (!delegateType.IsSubclassOf (typeof (System.Delegate)))
1468                                 throw new ArgumentException ("delegateType");
1469
1470                         var invoke = delegateType.GetInvokeMethod ();
1471                         if (invoke == null)
1472                                 throw new ArgumentException ("delegate must contain an Invoke method", "delegateType");
1473
1474                         var invoke_parameters = invoke.GetParameters ();
1475                         if (invoke_parameters.Length != parameters.Count)
1476                                 throw new ArgumentException (string.Format ("Different number of arguments in delegate {0}", delegateType), "delegateType");
1477
1478                         for (int i = 0; i < invoke_parameters.Length; i++) {
1479                                 if (!CanAssign (parameters [i].Type, invoke_parameters [i].ParameterType))
1480                                         throw new ArgumentException (String.Format ("Can not assign a {0} to a {1}", invoke_parameters [i].ParameterType, parameters [i].Type));
1481                         }
1482
1483                         if (invoke.ReturnType != typeof (void)) {
1484                                 if (!CanAssign (invoke.ReturnType, body.Type)) {
1485                                         if (invoke.ReturnType.IsExpression ())
1486                                                 return Expression.Quote (body);
1487
1488                                         throw new ArgumentException (String.Format ("body type {0} can not be assigned to {1}", body.Type, invoke.ReturnType));
1489                                 }
1490                         }
1491                         return body;
1492                 }
1493
1494                 public static Expression<TDelegate> Lambda<TDelegate> (Expression body, params ParameterExpression [] parameters)
1495                 {
1496                         return Lambda<TDelegate> (body, parameters as IEnumerable<ParameterExpression>);
1497                 }
1498
1499                 public static Expression<TDelegate> Lambda<TDelegate> (Expression body, IEnumerable<ParameterExpression> parameters)
1500                 {
1501                         if (body == null)
1502                                 throw new ArgumentNullException ("body");
1503
1504                         var ps = parameters.ToReadOnlyCollection ();
1505
1506                         body = CheckLambda (typeof (TDelegate), body, ps);
1507
1508                         return new Expression<TDelegate> (body, ps);
1509                 }
1510
1511                 public static LambdaExpression Lambda (Expression body, params ParameterExpression [] parameters)
1512                 {
1513                         if (body == null)
1514                                 throw new ArgumentNullException ("body");
1515                         if (parameters.Length > 4)
1516                                 throw new ArgumentException ("Too many parameters");
1517
1518                         return Lambda (GetDelegateType (body.Type, parameters), body, parameters);
1519                 }
1520
1521                 static Type GetDelegateType (Type return_type, ParameterExpression [] parameters)
1522                 {
1523                         if (parameters == null)
1524                                 parameters = new ParameterExpression [0];
1525
1526                         if (return_type == typeof (void))
1527                                 return GetActionType (parameters.Select (p => p.Type).ToArray ());
1528
1529                         var types = new Type [parameters.Length + 1];
1530                         for (int i = 0; i < types.Length - 1; i++)
1531                                 types [i] = parameters [i].Type;
1532
1533                         types [types.Length - 1] = return_type;
1534                         return GetFuncType (types);
1535                 }
1536
1537                 public static LambdaExpression Lambda (Type delegateType, Expression body, params ParameterExpression [] parameters)
1538                 {
1539                         return Lambda (delegateType, body, parameters as IEnumerable<ParameterExpression>);
1540                 }
1541
1542                 static LambdaExpression CreateExpressionOf (Type type, Expression body, ReadOnlyCollection<ParameterExpression> parameters)
1543                 {
1544                         return (LambdaExpression) typeof (Expression<>).MakeGenericType (type).GetConstructor (
1545                                 NonPublicInstance, null, new [] { typeof (Expression), typeof (ReadOnlyCollection<ParameterExpression>) }, null).Invoke (new object [] { body, parameters } );
1546                 }
1547
1548                 public static LambdaExpression Lambda (Type delegateType, Expression body, IEnumerable<ParameterExpression> parameters)
1549                 {
1550                         if (delegateType == null)
1551                                 throw new ArgumentNullException ("delegateType");
1552                         if (body == null)
1553                                 throw new ArgumentNullException ("body");
1554
1555                         var ps = parameters.ToReadOnlyCollection ();
1556
1557                         body = CheckLambda (delegateType, body, ps);
1558
1559                         return CreateExpressionOf (delegateType, body, ps);
1560                 }
1561
1562                 public static MemberListBinding ListBind (MemberInfo member, params ElementInit [] initializers)
1563                 {
1564                         return ListBind (member, initializers as IEnumerable<ElementInit>);
1565                 }
1566
1567                 static void CheckIsAssignableToIEnumerable (Type t)
1568                 {
1569                         if (!t.IsAssignableTo (typeof (IEnumerable)))
1570                                 throw new ArgumentException (string.Format ("Type {0} doesn't implemen IEnumerable", t));
1571                 }
1572
1573                 public static MemberListBinding ListBind (MemberInfo member, IEnumerable<ElementInit> initializers)
1574                 {
1575                         if (member == null)
1576                                 throw new ArgumentNullException ("member");
1577                         if (initializers == null)
1578                                 throw new ArgumentNullException ("initializers");
1579
1580                         var inits = initializers.ToReadOnlyCollection ();
1581                         CheckForNull (inits, "initializers");
1582
1583                         member.OnFieldOrProperty (
1584                                 field => CheckIsAssignableToIEnumerable (field.FieldType),
1585                                 prop => CheckIsAssignableToIEnumerable (prop.PropertyType));
1586
1587                         return new MemberListBinding (member, inits);
1588                 }
1589
1590                 public static MemberListBinding ListBind (MethodInfo propertyAccessor, params ElementInit [] initializers)
1591                 {
1592                         return ListBind (propertyAccessor, initializers as IEnumerable<ElementInit>);
1593                 }
1594
1595                 static void CheckForNull<T> (ReadOnlyCollection<T> collection, string name) where T : class
1596                 {
1597                         foreach (var t in collection)
1598                                 if (t == null)
1599                                         throw new ArgumentNullException (name);
1600                 }
1601
1602                 public static MemberListBinding ListBind (MethodInfo propertyAccessor, IEnumerable<ElementInit> initializers)
1603                 {
1604                         if (propertyAccessor == null)
1605                                 throw new ArgumentNullException ("propertyAccessor");
1606                         if (initializers == null)
1607                                 throw new ArgumentNullException ("initializers");
1608
1609                         var inits = initializers.ToReadOnlyCollection ();
1610                         CheckForNull (inits, "initializers");
1611
1612                         var prop = GetAssociatedProperty (propertyAccessor);
1613                         if (prop == null)
1614                                 throw new ArgumentException ("propertyAccessor");
1615
1616                         CheckIsAssignableToIEnumerable (prop.PropertyType);
1617
1618                         return new MemberListBinding (prop, inits);
1619                 }
1620
1621                 public static ListInitExpression ListInit (NewExpression newExpression, params ElementInit [] initializers)
1622                 {
1623                         return ListInit (newExpression, initializers as IEnumerable<ElementInit>);
1624                 }
1625
1626                 public static ListInitExpression ListInit (NewExpression newExpression, IEnumerable<ElementInit> initializers)
1627                 {
1628                         var inits = CheckListInit (newExpression, initializers);
1629
1630                         return new ListInitExpression (newExpression, inits);
1631                 }
1632
1633                 public static ListInitExpression ListInit (NewExpression newExpression, params Expression [] initializers)
1634                 {
1635                         return ListInit (newExpression, initializers as IEnumerable<Expression>);
1636                 }
1637
1638                 public static ListInitExpression ListInit (NewExpression newExpression, IEnumerable<Expression> initializers)
1639                 {
1640                         var inits = CheckListInit (newExpression, initializers);
1641
1642                         var add_method = GetAddMethod (newExpression.Type, inits [0].Type);
1643                         if (add_method == null)
1644                                 throw new InvalidOperationException ("No suitable add method found");
1645
1646                         return new ListInitExpression (newExpression, CreateInitializers (add_method, inits));
1647                 }
1648
1649                 static ReadOnlyCollection<ElementInit> CreateInitializers (MethodInfo add_method, ReadOnlyCollection<Expression> initializers)
1650                 {
1651                         return (from init in initializers select Expression.ElementInit (add_method, init)).ToReadOnlyCollection ();
1652                 }
1653
1654                 static MethodInfo GetAddMethod (Type type, Type arg)
1655                 {
1656                         return type.GetMethod ("Add", PublicInstance | BindingFlags.IgnoreCase, null, new [] { arg }, null);
1657                 }
1658
1659                 public static ListInitExpression ListInit (NewExpression newExpression, MethodInfo addMethod, params Expression [] initializers)
1660                 {
1661                         return ListInit (newExpression, addMethod, initializers as IEnumerable<Expression>);
1662                 }
1663
1664                 static ReadOnlyCollection<T> CheckListInit<T> (NewExpression newExpression, IEnumerable<T> initializers) where T : class
1665                 {
1666                         if (newExpression == null)
1667                                 throw new ArgumentNullException ("newExpression");
1668                         if (initializers == null)
1669                                 throw new ArgumentNullException ("initializers");
1670                         if (!newExpression.Type.IsAssignableTo (typeof (IEnumerable)))
1671                                 throw new InvalidOperationException ("The type of the new expression does not implement IEnumerable");
1672
1673                         var inits = initializers.ToReadOnlyCollection ();
1674                         if (inits.Count == 0)
1675                                 throw new ArgumentException ("Empty initializers");
1676
1677                         CheckForNull (inits, "initializers");
1678
1679                         return inits;
1680                 }
1681
1682                 public static ListInitExpression ListInit (NewExpression newExpression, MethodInfo addMethod, IEnumerable<Expression> initializers)
1683                 {
1684                         var inits = CheckListInit (newExpression, initializers);
1685
1686                         if (addMethod != null) {
1687                                 if (addMethod.Name.ToLower (CultureInfo.InvariantCulture) != "add")
1688                                         throw new ArgumentException ("addMethod");
1689
1690                                 var parameters = addMethod.GetParameters ();
1691                                 if (parameters.Length != 1)
1692                                         throw new ArgumentException ("addMethod");
1693
1694                                 foreach (var expression in inits)
1695                                         if (!IsAssignableToParameterType (expression.Type, parameters [0]))
1696                                                 throw new InvalidOperationException ("Initializer not assignable to the add method parameter type");
1697                         }
1698
1699                         if (addMethod == null)
1700                                 addMethod = GetAddMethod (newExpression.Type, inits [0].Type);
1701
1702                         if (addMethod == null)
1703                                 throw new InvalidOperationException ("No suitable add method found");
1704
1705                         return new ListInitExpression (newExpression, CreateInitializers (addMethod, inits));
1706                 }
1707
1708                 public static MemberExpression MakeMemberAccess (Expression expression, MemberInfo member)
1709                 {
1710                         if (expression == null)
1711                                 throw new ArgumentNullException ("expression");
1712                         if (member == null)
1713                                 throw new ArgumentNullException ("member");
1714
1715                         var field = member as FieldInfo;
1716                         if (field != null)
1717                                 return Field (expression, field);
1718
1719                         var property = member as PropertyInfo;
1720                         if (property != null)
1721                                 return Property (expression, property);
1722
1723                         throw new ArgumentException ("Member should either be a field or a property");
1724                 }
1725
1726                 public static UnaryExpression MakeUnary (ExpressionType unaryType, Expression operand, Type type)
1727                 {
1728                         return MakeUnary (unaryType, operand, type, null);
1729                 }
1730
1731                 public static UnaryExpression MakeUnary (ExpressionType unaryType, Expression operand, Type type, MethodInfo method)
1732                 {
1733                         switch (unaryType) {
1734                         case ExpressionType.ArrayLength:
1735                                 return ArrayLength (operand);
1736                         case ExpressionType.Convert:
1737                                 return Convert (operand, type, method);
1738                         case ExpressionType.ConvertChecked:
1739                                 return ConvertChecked (operand, type, method);
1740                         case ExpressionType.Negate:
1741                                 return Negate (operand, method);
1742                         case ExpressionType.NegateChecked:
1743                                 return NegateChecked (operand, method);
1744                         case ExpressionType.Not:
1745                                 return Not (operand, method);
1746                         case ExpressionType.Quote:
1747                                 return Quote (operand);
1748                         case ExpressionType.TypeAs:
1749                                 return TypeAs (operand, type);
1750                         case ExpressionType.UnaryPlus:
1751                                 return UnaryPlus (operand, method);
1752                         }
1753
1754                         throw new ArgumentException ("MakeUnary expect an unary operator");
1755                 }
1756
1757                 public static MemberMemberBinding MemberBind (MemberInfo member, params MemberBinding [] bindings)
1758                 {
1759                         return MemberBind (member, bindings as IEnumerable<MemberBinding>);
1760                 }
1761
1762                 public static MemberMemberBinding MemberBind (MemberInfo member, IEnumerable<MemberBinding> bindings)
1763                 {
1764                         if (member == null)
1765                                 throw new ArgumentNullException ("member");
1766
1767                         var type = member.OnFieldOrProperty (
1768                                 field => field.FieldType,
1769                                 prop => prop.PropertyType);
1770
1771                         return new MemberMemberBinding (member, CheckMemberBindings (type, bindings));
1772                 }
1773
1774                 public static MemberMemberBinding MemberBind (MethodInfo propertyAccessor, params MemberBinding [] bindings)
1775                 {
1776                         return MemberBind (propertyAccessor, bindings as IEnumerable<MemberBinding>);
1777                 }
1778
1779                 public static MemberMemberBinding MemberBind (MethodInfo propertyAccessor, IEnumerable<MemberBinding> bindings)
1780                 {
1781                         if (propertyAccessor == null)
1782                                 throw new ArgumentNullException ("propertyAccessor");
1783
1784                         var bds = bindings.ToReadOnlyCollection ();
1785                         CheckForNull (bds, "bindings");
1786
1787                         var prop = GetAssociatedProperty (propertyAccessor);
1788                         if (prop == null)
1789                                 throw new ArgumentException ("propertyAccessor");
1790
1791                         return new MemberMemberBinding (prop, CheckMemberBindings (prop.PropertyType, bindings));
1792                 }
1793
1794                 static ReadOnlyCollection<MemberBinding> CheckMemberBindings (Type type, IEnumerable<MemberBinding> bindings)
1795                 {
1796                         if (bindings == null)
1797                                 throw new ArgumentNullException ("bindings");
1798
1799                         var bds = bindings.ToReadOnlyCollection ();
1800                         CheckForNull (bds, "bindings");
1801
1802                         foreach (var binding in bds)
1803                                 if (!type.IsAssignableTo (binding.Member.DeclaringType))
1804                                         throw new ArgumentException ("Type not assignable to member type");
1805
1806                         return bds;
1807                 }
1808
1809                 public static MemberInitExpression MemberInit (NewExpression newExpression, params MemberBinding [] bindings)
1810                 {
1811                         return MemberInit (newExpression, bindings as IEnumerable<MemberBinding>);
1812                 }
1813
1814                 public static MemberInitExpression MemberInit (NewExpression newExpression, IEnumerable<MemberBinding> bindings)
1815                 {
1816                         if (newExpression == null)
1817                                 throw new ArgumentNullException ("newExpression");
1818
1819                         return new MemberInitExpression (newExpression, CheckMemberBindings (newExpression.Type, bindings));
1820                 }
1821
1822                 public static UnaryExpression Negate (Expression expression)
1823                 {
1824                         return Negate (expression, null);
1825                 }
1826
1827                 public static UnaryExpression Negate (Expression expression, MethodInfo method)
1828                 {
1829                         method = UnaryCoreCheck ("op_UnaryNegation", expression, method, type => IsSignedNumber (type));
1830
1831                         return MakeSimpleUnary (ExpressionType.Negate, expression, method);
1832                 }
1833
1834                 public static UnaryExpression NegateChecked (Expression expression)
1835                 {
1836                         return NegateChecked (expression, null);
1837                 }
1838
1839                 public static UnaryExpression NegateChecked (Expression expression, MethodInfo method)
1840                 {
1841                         method = UnaryCoreCheck ("op_UnaryNegation", expression, method, type => IsSignedNumber (type));
1842
1843                         return MakeSimpleUnary (ExpressionType.NegateChecked, expression, method);
1844                 }
1845
1846                 public static NewExpression New (ConstructorInfo constructor)
1847                 {
1848                         if (constructor == null)
1849                                 throw new ArgumentNullException ("constructor");
1850
1851                         if (constructor.GetParameters ().Length > 0)
1852                                 throw new ArgumentException ("Constructor must be parameter less");
1853
1854                         return new NewExpression (constructor, (null as IEnumerable<Expression>).ToReadOnlyCollection (), null);
1855                 }
1856
1857                 public static NewExpression New (Type type)
1858                 {
1859                         if (type == null)
1860                                 throw new ArgumentNullException ("type");
1861
1862                         CheckNotVoid (type);
1863
1864                         var args = (null as IEnumerable<Expression>).ToReadOnlyCollection ();
1865
1866                         if (type.IsValueType)
1867                                 return new NewExpression (type, args);
1868
1869                         var ctor = type.GetConstructor (Type.EmptyTypes);
1870                         if (ctor == null)
1871                                 throw new ArgumentException ("Type doesn't have a parameter less constructor");
1872
1873                         return new NewExpression (ctor, args, null);
1874                 }
1875
1876                 public static NewExpression New (ConstructorInfo constructor, params Expression [] arguments)
1877                 {
1878                         return New (constructor, arguments as IEnumerable<Expression>);
1879                 }
1880
1881                 public static NewExpression New (ConstructorInfo constructor, IEnumerable<Expression> arguments)
1882                 {
1883                         if (constructor == null)
1884                                 throw new ArgumentNullException ("constructor");
1885
1886                         var args = CheckMethodArguments (constructor, arguments);
1887
1888                         return new NewExpression (constructor, args, null);
1889                 }
1890
1891                 static IList<Expression> CreateArgumentList (IEnumerable<Expression> arguments)
1892                 {
1893                         if (arguments == null)
1894                                 return arguments.ToReadOnlyCollection ();
1895
1896                         return arguments.ToList ();
1897                 }
1898
1899                 static ReadOnlyCollection<Expression> CheckMethodArguments (MethodBase method, IEnumerable<Expression> args)
1900                 {
1901                         var arguments = CreateArgumentList (args);
1902                         var parameters = method.GetParameters ();
1903
1904                         if (arguments.Count != parameters.Length)
1905                                 throw new ArgumentException ("The number of arguments doesn't match the number of parameters");
1906
1907                         for (int i = 0; i < parameters.Length; i++) {
1908                                 if (arguments [i] == null)
1909                                         throw new ArgumentNullException ("arguments");
1910
1911                                 if (!IsAssignableToParameterType (arguments [i].Type, parameters [i])) {
1912                                         if (!parameters [i].ParameterType.IsExpression ())
1913                                                 throw new ArgumentException ("arguments");
1914
1915                                         arguments [i] = Expression.Quote (arguments [i]);
1916                                 }
1917                         }
1918
1919                         return arguments.ToReadOnlyCollection ();
1920                 }
1921
1922                 public static NewExpression New (ConstructorInfo constructor, IEnumerable<Expression> arguments, params MemberInfo [] members)
1923                 {
1924                         return New (constructor, arguments, members as IEnumerable<MemberInfo>);
1925                 }
1926
1927                 public static NewExpression New (ConstructorInfo constructor, IEnumerable<Expression> arguments, IEnumerable<MemberInfo> members)
1928                 {
1929                         if (constructor == null)
1930                                 throw new ArgumentNullException ("constructor");
1931
1932                         var args = arguments.ToReadOnlyCollection ();
1933                         var mmbs = members.ToReadOnlyCollection ();
1934
1935                         CheckForNull (args, "arguments");
1936                         CheckForNull (mmbs, "members");
1937
1938                         args = CheckMethodArguments (constructor, arguments);
1939
1940                         if (args.Count != mmbs.Count)
1941                                 throw new ArgumentException ("Arguments count does not match members count");
1942
1943                         for (int i = 0; i < mmbs.Count; i++) {
1944                                 var member = mmbs [i];
1945                                 Type type = null;
1946                                 switch (member.MemberType) {
1947                                 case MemberTypes.Field:
1948                                         type = (member as FieldInfo).FieldType;
1949                                         break;
1950                                 case MemberTypes.Method:
1951                                         type = (member as MethodInfo).ReturnType;
1952                                         break;
1953                                 case MemberTypes.Property:
1954                                         var prop = member as PropertyInfo;
1955                                         if (prop.GetGetMethod (true) == null)
1956                                                 throw new ArgumentException ("Property must have a getter");
1957
1958                                         type = (member as PropertyInfo).PropertyType;
1959                                         break;
1960                                 default:
1961                                         throw new ArgumentException ("Member type not allowed");
1962                                 }
1963
1964                                 if (!args [i].Type.IsAssignableTo (type))
1965                                         throw new ArgumentException ("Argument type not assignable to member type");
1966                         }
1967
1968                         return new NewExpression (constructor, args, mmbs);
1969                 }
1970
1971                 public static NewArrayExpression NewArrayBounds (Type type, params Expression [] bounds)
1972                 {
1973                         return NewArrayBounds (type, bounds as IEnumerable<Expression>);
1974                 }
1975
1976                 public static NewArrayExpression NewArrayBounds (Type type, IEnumerable<Expression> bounds)
1977                 {
1978                         if (type == null)
1979                                 throw new ArgumentNullException ("type");
1980                         if (bounds == null)
1981                                 throw new ArgumentNullException ("bounds");
1982
1983                         CheckNotVoid (type);
1984
1985                         var array_bounds = bounds.ToReadOnlyCollection ();
1986                         foreach (var expression in array_bounds)
1987                                 if (!IsInt (expression.Type))
1988                                         throw new ArgumentException ("The bounds collection can only contain expression of integers types");
1989
1990                         return new NewArrayExpression (ExpressionType.NewArrayBounds, type.MakeArrayType (array_bounds.Count), array_bounds);
1991                 }
1992
1993                 public static NewArrayExpression NewArrayInit (Type type, params Expression [] initializers)
1994                 {
1995                         return NewArrayInit (type, initializers as IEnumerable<Expression>);
1996                 }
1997
1998                 public static NewArrayExpression NewArrayInit (Type type, IEnumerable<Expression> initializers)
1999                 {
2000                         if (type == null)
2001                                 throw new ArgumentNullException ("type");
2002                         if (initializers == null)
2003                                 throw new ArgumentNullException ("initializers");
2004
2005                         CheckNotVoid (type);
2006
2007                         var inits = initializers.ToReadOnlyCollection ();
2008
2009                         foreach (var expression in inits) {
2010                                 if (expression == null)
2011                                         throw new ArgumentNullException ("initializers");
2012
2013                                 if (!expression.Type.IsAssignableTo (type))
2014                                         throw new InvalidOperationException (
2015                                                 string.Format ("{0} IsAssignableTo {1}, expression [ {2} ] : {3}", expression.Type, type, expression.NodeType, expression));
2016
2017                                 // TODO: Quote elements if type == typeof (Expression)
2018                         }
2019
2020                         return new NewArrayExpression (ExpressionType.NewArrayInit, type.MakeArrayType (), inits);
2021                 }
2022
2023                 public static UnaryExpression Not (Expression expression)
2024                 {
2025                         return Not (expression, null);
2026                 }
2027
2028                 public static UnaryExpression Not (Expression expression, MethodInfo method)
2029                 {
2030                         Func<Type, bool> validator = type => IsIntOrBool (type);
2031
2032                         method = UnaryCoreCheck ("op_LogicalNot", expression, method, validator);
2033
2034                         if (method == null)
2035                                 method = UnaryCoreCheck ("op_OnesComplement", expression, method, validator);
2036
2037                         return MakeSimpleUnary (ExpressionType.Not, expression, method);
2038                 }
2039
2040                 static void CheckNotVoid (Type type)
2041                 {
2042                         if (type == typeof (void))
2043                                 throw new ArgumentException ("Type can't be void");
2044                 }
2045
2046                 public static ParameterExpression Parameter (Type type, string name)
2047                 {
2048                         if (type == null)
2049                                 throw new ArgumentNullException ("type");
2050
2051                         CheckNotVoid (type);
2052
2053                         return new ParameterExpression (type, name);
2054                 }
2055
2056                 public static MemberExpression Property (Expression expression, MethodInfo propertyAccessor)
2057                 {
2058                         if (propertyAccessor == null)
2059                                 throw new ArgumentNullException ("propertyAccessor");
2060
2061                         if (!propertyAccessor.IsStatic) {
2062                                 if (expression == null)
2063                                         throw new ArgumentNullException ("expression");
2064                                 if (!expression.Type.IsAssignableTo (propertyAccessor.DeclaringType))
2065                                         throw new ArgumentException ("expression");
2066                         } else if (expression != null)
2067                                 throw new ArgumentException ("expression");
2068
2069                         var prop = GetAssociatedProperty (propertyAccessor);
2070                         if (prop == null)
2071                                 throw new ArgumentException (string.Format ("Method {0} has no associated property", propertyAccessor));
2072
2073                         return new MemberExpression (expression, prop, prop.PropertyType);
2074                 }
2075
2076                 static PropertyInfo GetAssociatedProperty (MethodInfo method)
2077                 {
2078                         if (method == null)
2079                                 return null;
2080
2081                         foreach (var prop in method.DeclaringType.GetProperties (All)) {
2082                                 if (method.Equals (prop.GetGetMethod (true)))
2083                                         return prop;
2084                                 if (method.Equals (prop.GetSetMethod (true)))
2085                                         return prop;
2086                         }
2087
2088                         return null;
2089                 }
2090
2091                 public static MemberExpression Property (Expression expression, PropertyInfo property)
2092                 {
2093                         if (property == null)
2094                                 throw new ArgumentNullException ("property");
2095
2096                         var getter = property.GetGetMethod (true);
2097                         if (getter == null)
2098                                 throw new ArgumentException ("getter");
2099
2100                         if (!getter.IsStatic) {
2101                                 if (expression == null)
2102                                         throw new ArgumentNullException ("expression");
2103                                 if (!expression.Type.IsAssignableTo (property.DeclaringType))
2104                                         throw new ArgumentException ("expression");
2105                         } else if (expression != null)
2106                                 throw new ArgumentException ("expression");
2107
2108                         return new MemberExpression (expression, property, property.PropertyType);
2109                 }
2110
2111                 public static MemberExpression Property (Expression expression, string propertyName)
2112                 {
2113                         if (expression == null)
2114                                 throw new ArgumentNullException ("expression");
2115
2116                         var prop = expression.Type.GetProperty (propertyName, AllInstance);
2117                         if (prop == null)
2118                                 throw new ArgumentException (string.Format ("No property named {0} on {1}", propertyName, expression.Type));
2119
2120                         return new MemberExpression (expression, prop, prop.PropertyType);
2121                 }
2122
2123                 public static MemberExpression PropertyOrField (Expression expression, string propertyOrFieldName)
2124                 {
2125                         if (expression == null)
2126                                 throw new ArgumentNullException ("expression");
2127                         if (propertyOrFieldName == null)
2128                                 throw new ArgumentNullException ("propertyOrFieldName");
2129
2130                         var prop = expression.Type.GetProperty (propertyOrFieldName, AllInstance);
2131                         if (prop != null)
2132                                 return new MemberExpression (expression, prop, prop.PropertyType);
2133
2134                         var field = expression.Type.GetField (propertyOrFieldName, AllInstance);
2135                         if (field != null)
2136                                 return new MemberExpression (expression, field, field.FieldType);
2137
2138                         throw new ArgumentException (string.Format ("No field or property named {0} on {1}", propertyOrFieldName, expression.Type));
2139                 }
2140
2141                 public static UnaryExpression Quote (Expression expression)
2142                 {
2143                         if (expression == null)
2144                                 throw new ArgumentNullException ("expression");
2145
2146                         return new UnaryExpression (ExpressionType.Quote, expression, expression.GetType ());
2147                 }
2148
2149                 public static UnaryExpression TypeAs (Expression expression, Type type)
2150                 {
2151                         if (expression == null)
2152                                 throw new ArgumentNullException ("expression");
2153                         if (type == null)
2154                                 throw new ArgumentNullException ("type");
2155                         if (type.IsValueType && !type.IsNullable ())
2156                                 throw new ArgumentException ("TypeAs expect a reference or a nullable type");
2157
2158                         return new UnaryExpression (ExpressionType.TypeAs, expression, type);
2159                 }
2160
2161                 public static TypeBinaryExpression TypeIs (Expression expression, Type type)
2162                 {
2163                         if (expression == null)
2164                                 throw new ArgumentNullException ("expression");
2165                         if (type == null)
2166                                 throw new ArgumentNullException ("type");
2167
2168                         CheckNotVoid (type);
2169
2170                         return new TypeBinaryExpression (ExpressionType.TypeIs, expression, type, typeof (bool));
2171                 }
2172
2173                 public static UnaryExpression UnaryPlus (Expression expression)
2174                 {
2175                         return UnaryPlus (expression, null);
2176                 }
2177
2178                 public static UnaryExpression UnaryPlus (Expression expression, MethodInfo method)
2179                 {
2180                         method = UnaryCoreCheck ("op_UnaryPlus", expression, method, type => IsNumber (type));
2181
2182                         return MakeSimpleUnary (ExpressionType.UnaryPlus, expression, method);
2183                 }
2184
2185                 static bool IsInt (Type t)
2186                 {
2187                         return t == typeof (byte) || t == typeof (sbyte) ||
2188                                 t == typeof (short) || t == typeof (ushort) ||
2189                                 t == typeof (int) || t == typeof (uint) ||
2190                                 t == typeof (long) || t == typeof (ulong);
2191                 }
2192
2193                 static bool IsIntOrBool (Type t)
2194                 {
2195                         return IsInt (t) || t == typeof (bool);
2196                 }
2197
2198                 static bool IsNumber (Type t)
2199                 {
2200                         if (IsInt (t))
2201                                 return true;
2202
2203                         return t == typeof (float) || t == typeof (double) || t == typeof (decimal);
2204                 }
2205
2206                 static bool IsSignedNumber (Type t)
2207                 {
2208                         return IsNumber (t) && !IsUnsigned (t);
2209                 }
2210
2211                 internal static bool IsUnsigned (Type t)
2212                 {
2213 #if !TARGET_JVM
2214                         if (t.IsPointer)
2215                                 return IsUnsigned (t.GetElementType ());
2216
2217 #endif
2218                         return t == typeof (ushort) ||
2219                                 t == typeof (uint) ||
2220                                 t == typeof (ulong) ||
2221                                 t == typeof (byte);
2222                 }
2223
2224                 //
2225                 // This method must be overwritten by derived classes to
2226                 // compile the expression
2227                 //
2228                 internal virtual void Emit (EmitContext ec)
2229                 {
2230                         throw new NotImplementedException ();
2231                 }
2232         }
2233 }