source: stable/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Parser/mcs/dynamic.cs @ 11937

//
// dynamic.cs: support for dynamic expressions
//
// Authors: Marek Safar (marek.safar@gmail.com)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2009 Novell, Inc
// Copyright 2011 Xamarin Inc.
//

using System;
using System.Linq;
using SLE = System.Linq.Expressions;

#if NET_4_0 || MOBILE_DYNAMIC
using System.Dynamic;
#endif

namespace Mono.CSharp
{
  //
  // A copy of Microsoft.CSharp/Microsoft.CSharp.RuntimeBinder/CSharpBinderFlags.cs
  // has to be kept in sync
  //
  [Flags]
  public enum CSharpBinderFlags
  {
    None = 0,
    CheckedContext = 1,
    InvokeSimpleName = 1 << 1,
    InvokeSpecialName = 1 << 2,
    BinaryOperationLogical = 1 << 3,
    ConvertExplicit = 1 << 4,
    ConvertArrayIndex = 1 << 5,
    ResultIndexed = 1 << 6,
    ValueFromCompoundAssignment = 1 << 7,
    ResultDiscarded = 1 << 8
  }

  //
  // Type expression with internal dynamic type symbol
  //
  class DynamicTypeExpr : TypeExpr
  {
    public DynamicTypeExpr (Location loc)
    {
      this.loc = loc;
    }

    public override TypeSpec ResolveAsType (IMemberContext ec, bool allowUnboundTypeArguments)
    {
      eclass = ExprClass.Type;
      type = ec.Module.Compiler.BuiltinTypes.Dynamic;
      return type;
    }
  }

  #region Dynamic runtime binder expressions

  //
  // Expression created from runtime dynamic object value by dynamic binder
  //
  public class RuntimeValueExpression : Expression, IDynamicAssign, IMemoryLocation
  {
#if !NET_4_0 && !MOBILE_DYNAMIC
    public class DynamicMetaObject
    {
      public TypeSpec RuntimeType;
      public TypeSpec LimitType;
      public SLE.Expression Expression;
    }
#endif

    readonly DynamicMetaObject obj;

    public RuntimeValueExpression (DynamicMetaObject obj, TypeSpec type)
    {
      this.obj = obj;
      this.type = type;
      this.eclass = ExprClass.Variable;
    }

    #region Properties

    public bool IsSuggestionOnly { get; set; }

    public DynamicMetaObject MetaObject {
      get { return obj; }
    }

    #endregion

    public void AddressOf (EmitContext ec, AddressOp mode)
    {
      throw new NotImplementedException ();
    }

    public override bool ContainsEmitWithAwait ()
    {
      throw new NotSupportedException ();
    }

    public override Expression CreateExpressionTree (ResolveContext ec)
    {
      throw new NotSupportedException ();
    }

    protected override Expression DoResolve (ResolveContext ec)
    {
      return this;
    }

    public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
    {
      return this;
    }

    public override void Emit (EmitContext ec)
    {
      throw new NotImplementedException ();
    }

    #region IAssignMethod Members

    public void Emit (EmitContext ec, bool leave_copy)
    {
      throw new NotImplementedException ();
    }

    public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
    {
      throw new NotImplementedException ();
    }

    #endregion

    public SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
    {
      return obj.Expression;
    }

    public override SLE.Expression MakeExpression (BuilderContext ctx)
    {
#if STATIC
      return base.MakeExpression (ctx);
#else

#if NET_4_0 || MOBILE_DYNAMIC
        if (type.IsStruct && !obj.Expression.Type.IsValueType)
          return SLE.Expression.Unbox (obj.Expression, type.GetMetaInfo ());

        if (obj.Expression.NodeType == SLE.ExpressionType.Parameter) {
          if (((SLE.ParameterExpression) obj.Expression).IsByRef)
            return obj.Expression;
        }
  #endif

        return SLE.Expression.Convert (obj.Expression, type.GetMetaInfo ());
#endif
    }
  }

  //
  // Wraps runtime dynamic expression into expected type. Needed
  // to satify expected type check by dynamic binder and no conversion
  // is required (ResultDiscarded).
  //
  public class DynamicResultCast : ShimExpression
  {
    public DynamicResultCast (TypeSpec type, Expression expr)
      : base (expr)
    {
      this.type = type;
    }

    protected override Expression DoResolve (ResolveContext ec)
    {
      expr = expr.Resolve (ec);
      eclass = ExprClass.Value;
      return this;
    }

#if NET_4_0 || MOBILE_DYNAMIC
    public override SLE.Expression MakeExpression (BuilderContext ctx)
    {
#if STATIC
      return base.MakeExpression (ctx);
#else
      return SLE.Expression.Block (expr.MakeExpression (ctx), SLE.Expression.Default (type.GetMetaInfo ()));
#endif
    }
#endif
  }

  #endregion

  //
  // Creates dynamic binder expression
  //
  interface IDynamicBinder
  {
    Expression CreateCallSiteBinder (ResolveContext ec, Arguments args);
  }

  //
  // Extends standard assignment interface for expressions
  // supported by dynamic resolver
  //
  interface IDynamicAssign : IAssignMethod
  {
    SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source);
  }

  //
  // Base dynamic expression statement creator
  //
  class DynamicExpressionStatement : ExpressionStatement
  {
    //
    // Binder flag dynamic constant, the value is combination of
    // flags known at resolve stage and flags known only at emit
    // stage
    //
    protected class BinderFlags : EnumConstant
    {
      readonly DynamicExpressionStatement statement;
      readonly CSharpBinderFlags flags;

      public BinderFlags (CSharpBinderFlags flags, DynamicExpressionStatement statement)
        : base (statement.loc)
      {
        this.flags = flags;
        this.statement = statement;
        eclass = 0;
      }

      protected override Expression DoResolve (ResolveContext ec)
      {
        Child = new IntConstant (ec.BuiltinTypes, (int) (flags | statement.flags), statement.loc);

        type = ec.Module.PredefinedTypes.BinderFlags.Resolve ();
        eclass = Child.eclass;
        return this;
      }
    }

    readonly Arguments arguments;
    protected IDynamicBinder binder;
    protected Expression binder_expr;

    // Used by BinderFlags
    protected CSharpBinderFlags flags;

    TypeSpec binder_type;
    TypeParameters context_mvars;

    public DynamicExpressionStatement (IDynamicBinder binder, Arguments args, Location loc)
    {
      this.binder = binder;
      this.arguments = args;
      this.loc = loc;
    }

    public Arguments Arguments {
      get {
        return arguments;
      }
    }

    public override bool ContainsEmitWithAwait ()
    {
      return arguments.ContainsEmitWithAwait ();
    }

    public override Expression CreateExpressionTree (ResolveContext ec)
    {
      ec.Report.Error (1963, loc, "An expression tree cannot contain a dynamic operation");
      return null;
    }

    protected override Expression DoResolve (ResolveContext rc)
    {
      if (DoResolveCore (rc))
        binder_expr = binder.CreateCallSiteBinder (rc, arguments);

      return this;
    }

    protected bool DoResolveCore (ResolveContext rc)
    {
      if (rc.CurrentTypeParameters != null && rc.CurrentTypeParameters[0].IsMethodTypeParameter)
        context_mvars = rc.CurrentTypeParameters;

      int errors = rc.Report.Errors;
      var pt = rc.Module.PredefinedTypes;

      binder_type = pt.Binder.Resolve ();
      pt.CallSite.Resolve ();
      pt.CallSiteGeneric.Resolve ();

      eclass = ExprClass.Value;

      if (type == null)
        type = rc.BuiltinTypes.Dynamic;

      if (rc.Report.Errors == errors)
        return true;

      rc.Report.Error (1969, loc,
        "Dynamic operation cannot be compiled without `Microsoft.CSharp.dll' assembly reference");
      return false;
    }

    public override void Emit (EmitContext ec)
    {
      EmitCall (ec, binder_expr, arguments,  false);
    }

    public override void EmitStatement (EmitContext ec)
    {
      EmitCall (ec, binder_expr, arguments, true);
    }

    protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
    {
      //
      // This method generates all internal infrastructure for a dynamic call. The
      // reason why it's quite complicated is the mixture of dynamic and anonymous
      // methods. Dynamic itself requires a temporary class (ContainerX) and anonymous
      // methods can generate temporary storey as well (AnonStorey). Handling MVAR
      // type parameters rewrite is non-trivial in such case as there are various
      // combinations possible therefore the mutator is not straightforward. Secondly
      // we need to keep both MVAR(possibly VAR for anon storey) and type VAR to emit
      // correct Site field type and its access from EmitContext.
      //

      int dyn_args_count = arguments == null ? 0 : arguments.Count;
      int default_args = isStatement ? 1 : 2;
      var module = ec.Module;

      bool has_ref_out_argument = false;
      var targs = new TypeExpression[dyn_args_count + default_args];
      targs[0] = new TypeExpression (module.PredefinedTypes.CallSite.TypeSpec, loc);

      TypeExpression[] targs_for_instance = null;
      TypeParameterMutator mutator;

      var site_container = ec.CreateDynamicSite ();

      if (context_mvars != null) {
        TypeParameters tparam;
        TypeContainer sc = site_container;
        do {
          tparam = sc.CurrentTypeParameters;
          sc = sc.Parent;
        } while (tparam == null);

        mutator = new TypeParameterMutator (context_mvars, tparam);

        if (!ec.IsAnonymousStoreyMutateRequired) {
          targs_for_instance = new TypeExpression[targs.Length];
          targs_for_instance[0] = targs[0];
        }
      } else {
        mutator = null;
      }

      for (int i = 0; i < dyn_args_count; ++i) {
        Argument a = arguments[i];
        if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
          has_ref_out_argument = true;

        var t = a.Type;

        // Convert any internal type like dynamic or null to object
        if (t.Kind == MemberKind.InternalCompilerType)
          t = ec.BuiltinTypes.Object;

        if (targs_for_instance != null)
          targs_for_instance[i + 1] = new TypeExpression (t, loc);

        if (mutator != null)
          t = t.Mutate (mutator);

        targs[i + 1] = new TypeExpression (t, loc);
      }

      TypeExpr del_type = null;
      TypeExpr del_type_instance_access = null;
      if (!has_ref_out_argument) {
        string d_name = isStatement ? "Action" : "Func";

        TypeSpec te = null;
        Namespace type_ns = module.GlobalRootNamespace.GetNamespace ("System", true);
        if (type_ns != null) {
          te = type_ns.LookupType (module, d_name, dyn_args_count + default_args, LookupMode.Normal, loc);
        }

        if (te != null) {
          if (!isStatement) {
            var t = type;
            if (t.Kind == MemberKind.InternalCompilerType)
              t = ec.BuiltinTypes.Object;

            if (targs_for_instance != null)
              targs_for_instance[targs_for_instance.Length - 1] = new TypeExpression (t, loc);

            if (mutator != null)
              t = t.Mutate (mutator);

            targs[targs.Length - 1] = new TypeExpression (t, loc);
          }

          del_type = new GenericTypeExpr (te, new TypeArguments (targs), loc);
          if (targs_for_instance != null)
            del_type_instance_access = new GenericTypeExpr (te, new TypeArguments (targs_for_instance), loc);
          else
            del_type_instance_access = del_type;
        }
      }

      //
      // Create custom delegate when no appropriate predefined delegate has been found
      //
      Delegate d;
      if (del_type == null) {
        TypeSpec rt = isStatement ? ec.BuiltinTypes.Void : type;
        Parameter[] p = new Parameter[dyn_args_count + 1];
        p[0] = new Parameter (targs[0], "p0", Parameter.Modifier.NONE, null, loc);

        var site = ec.CreateDynamicSite ();
        int index = site.Containers == null ? 0 : site.Containers.Count;

        if (mutator != null)
          rt = mutator.Mutate (rt);

        for (int i = 1; i < dyn_args_count + 1; ++i) {
          p[i] = new Parameter (targs[i], "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
        }

        d = new Delegate (site, new TypeExpression (rt, loc),
          Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
          new MemberName ("Container" + index.ToString ("X")),
          new ParametersCompiled (p), null);

        d.CreateContainer ();
        d.DefineContainer ();
        d.Define ();
        d.PrepareEmit ();

        site.AddTypeContainer (d);

        //
        // Add new container to inflated site container when the
        // member cache already exists
        //
        if (site.CurrentType is InflatedTypeSpec && index > 0)
          site.CurrentType.MemberCache.AddMember (d.CurrentType);

        del_type = new TypeExpression (d.CurrentType, loc);
        if (targs_for_instance != null) {
          del_type_instance_access = null;
        } else {
          del_type_instance_access = del_type;
        }
      } else {
        d = null;
      }

      var site_type_decl = new GenericTypeExpr (module.PredefinedTypes.CallSiteGeneric.TypeSpec, new TypeArguments (del_type), loc);
      var field = site_container.CreateCallSiteField (site_type_decl, loc);
      if (field == null)
        return;

      if (del_type_instance_access == null) {
        var dt = d.CurrentType.DeclaringType.MakeGenericType (module, context_mvars.Types);
        del_type_instance_access = new TypeExpression (MemberCache.GetMember (dt, d.CurrentType), loc);
      }

      var instanceAccessExprType = new GenericTypeExpr (module.PredefinedTypes.CallSiteGeneric.TypeSpec,
        new TypeArguments (del_type_instance_access), loc);

      if (instanceAccessExprType.ResolveAsType (ec.MemberContext) == null)
        return;

      bool inflate_using_mvar = context_mvars != null && ec.IsAnonymousStoreyMutateRequired;

      TypeSpec gt;
      if (inflate_using_mvar || context_mvars == null) {
        gt = site_container.CurrentType;
      } else {
        gt = site_container.CurrentType.MakeGenericType (module, context_mvars.Types);
      }

      // When site container already exists the inflated version has to be
      // updated manually to contain newly created field
      if (gt is InflatedTypeSpec && site_container.AnonymousMethodsCounter > 1) {
        var tparams = gt.MemberDefinition.TypeParametersCount > 0 ? gt.MemberDefinition.TypeParameters : TypeParameterSpec.EmptyTypes;
        var inflator = new TypeParameterInflator (module, gt, tparams, gt.TypeArguments);
        gt.MemberCache.AddMember (field.InflateMember (inflator));
      }

      FieldExpr site_field_expr = new FieldExpr (MemberCache.GetMember (gt, field), loc);

      BlockContext bc = new BlockContext (ec.MemberContext, null, ec.BuiltinTypes.Void);

      Arguments args = new Arguments (1);
      args.Add (new Argument (binder));
      StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (instanceAccessExprType, "Create"), args)));

      using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
        if (s.Resolve (bc)) {
          Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc)), s, loc);
          init.Emit (ec);
        }

        args = new Arguments (1 + dyn_args_count);
        args.Add (new Argument (site_field_expr));
        if (arguments != null) {
          int arg_pos = 1;
          foreach (Argument a in arguments) {
            if (a is NamedArgument) {
              // Name is not valid in this context
              args.Add (new Argument (a.Expr, a.ArgType));
            } else {
              args.Add (a);
            }

            if (inflate_using_mvar && a.Type != targs[arg_pos].Type)
              a.Expr.Type = targs[arg_pos].Type;

            ++arg_pos;
          }
        }

        Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, false, loc).Resolve (bc);
        if (target != null)
          target.Emit (ec);
      }
    }

    public override void FlowAnalysis (FlowAnalysisContext fc)
    {
      arguments.FlowAnalysis (fc);
    }

    public static MemberAccess GetBinderNamespace (Location loc)
    {
      return new MemberAccess (new MemberAccess (
        new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
    }

    protected MemberAccess GetBinder (string name, Location loc)
    {
      return new MemberAccess (new TypeExpression (binder_type, loc), name, loc);
    }
  }

  //
  // Dynamic member access compound assignment for events
  //
  class DynamicEventCompoundAssign : ExpressionStatement
  {
    class IsEvent : DynamicExpressionStatement, IDynamicBinder
    {
      string name;

      public IsEvent (string name, Arguments args, Location loc)
        : base (null, args, loc)
      {
        this.name = name;
        binder = this;
      }

      public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
      {
        type = ec.BuiltinTypes.Bool;

        Arguments binder_args = new Arguments (3);

        binder_args.Add (new Argument (new BinderFlags (0, this)));
        binder_args.Add (new Argument (new StringLiteral (ec.BuiltinTypes, name, loc)));
        binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));

        return new Invocation (GetBinder ("IsEvent", loc), binder_args);
      }
    }

    Expression condition;
    ExpressionStatement invoke, assign;

    public DynamicEventCompoundAssign (string name, Arguments args, ExpressionStatement assignment, ExpressionStatement invoke, Location loc)
    {
      condition = new IsEvent (name, args, loc);
      this.invoke = invoke;
      this.assign = assignment;
      this.loc = loc;
    }

    public override Expression CreateExpressionTree (ResolveContext ec)
    {
      return condition.CreateExpressionTree (ec);
    }

    protected override Expression DoResolve (ResolveContext rc)
    {
      type = rc.BuiltinTypes.Dynamic;
      eclass = ExprClass.Value;
      condition = condition.Resolve (rc);
      return this;
    }

    public override void Emit (EmitContext ec)
    {
      var rc = new ResolveContext (ec.MemberContext);
      var expr = new Conditional (new BooleanExpression (condition), invoke, assign, loc).Resolve (rc);
      expr.Emit (ec);
    }

    public override void EmitStatement (EmitContext ec)
    {
      var stmt = new If (condition, new StatementExpression (invoke), new StatementExpression (assign), loc);
      using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
        stmt.Emit (ec);
      }
    }

    public override void FlowAnalysis (FlowAnalysisContext fc)
    {
      invoke.FlowAnalysis (fc);
    }
  }

  class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
  {
    public DynamicConversion (TypeSpec targetType, CSharpBinderFlags flags, Arguments args, Location loc)
      : base (null, args, loc)
    {
      type = targetType;
      base.flags = flags;
      base.binder = this;
    }

    public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
    {
      Arguments binder_args = new Arguments (3);

      flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;

      binder_args.Add (new Argument (new BinderFlags (flags, this)));
      binder_args.Add (new Argument (new TypeOf (type, loc)));
      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
      return new Invocation (GetBinder ("Convert", loc), binder_args);
    }
  }

  class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
  {
    public DynamicConstructorBinder (TypeSpec type, Arguments args, Location loc)
      : base (null, args, loc)
    {
      this.type = type;
      base.binder = this;
    }

    public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
    {
      Arguments binder_args = new Arguments (3);

      binder_args.Add (new Argument (new BinderFlags (0, this)));
      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
      binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

      return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
    }
  }

  class DynamicIndexBinder : DynamicMemberAssignable
  {
    bool can_be_mutator;

    public DynamicIndexBinder (Arguments args, Location loc)
      : base (args, loc)
    {
    }

    public DynamicIndexBinder (CSharpBinderFlags flags, Arguments args, Location loc)
      : this (args, loc)
    {
      base.flags = flags;
    }

    protected override Expression DoResolve (ResolveContext ec)
    {
      can_be_mutator = true;
      return base.DoResolve (ec);
    }

    protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
    {
      Arguments binder_args = new Arguments (3);

      binder_args.Add (new Argument (new BinderFlags (flags, this)));
      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
      binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

      isSet |= (flags & CSharpBinderFlags.ValueFromCompoundAssignment) != 0;
      return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
    }

    protected override Arguments CreateSetterArguments (ResolveContext rc, Expression rhs)
    {
      //
      // Indexer has arguments which complicates things as the setter and getter
      // are called in two steps when unary mutator is used. We have to make a
      // copy of all variable arguments to not duplicate any side effect.
      //
      // ++d[++arg, Foo ()]
      //

      if (!can_be_mutator)
        return base.CreateSetterArguments (rc, rhs);

      var setter_args = new Arguments (Arguments.Count + 1);
      for (int i = 0; i < Arguments.Count; ++i) {
        var expr = Arguments[i].Expr;

        if (expr is Constant || expr is VariableReference || expr is This) {
          setter_args.Add (Arguments [i]);
          continue;
        }

        LocalVariable temp = LocalVariable.CreateCompilerGenerated (expr.Type, rc.CurrentBlock, loc);
        expr = new SimpleAssign (temp.CreateReferenceExpression (rc, expr.Location), expr).Resolve (rc);
        Arguments[i].Expr = temp.CreateReferenceExpression (rc, expr.Location).Resolve (rc);
        setter_args.Add (Arguments [i].Clone (expr));
      }

      setter_args.Add (new Argument (rhs));
      return setter_args;
    }
  }

  class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
  {
    readonly ATypeNameExpression member;

    public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
      : base (null, args, loc)
    {
      base.binder = this;
      this.member = member;
    }

    public static DynamicInvocation CreateSpecialNameInvoke (ATypeNameExpression member, Arguments args, Location loc)
    {
      return new DynamicInvocation (member, args, loc) {
        flags = CSharpBinderFlags.InvokeSpecialName
      };
    }

    public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
    {
      Arguments binder_args = new Arguments (member != null ? 5 : 3);
      bool is_member_access = member is MemberAccess;

      CSharpBinderFlags call_flags;
      if (!is_member_access && member is SimpleName) {
        call_flags = CSharpBinderFlags.InvokeSimpleName;
        is_member_access = true;
      } else {
        call_flags = 0;
      }

      binder_args.Add (new Argument (new BinderFlags (call_flags, this)));

      if (is_member_access)
        binder_args.Add (new Argument (new StringLiteral (ec.BuiltinTypes, member.Name, member.Location)));

      if (member != null && member.HasTypeArguments) {
        TypeArguments ta = member.TypeArguments;
        if (ta.Resolve (ec)) {
          var targs = new ArrayInitializer (ta.Count, loc);
          foreach (TypeSpec t in ta.Arguments)
            targs.Add (new TypeOf (t, loc));

          binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (targs, loc)));
        }
      } else if (is_member_access) {
        binder_args.Add (new Argument (new NullLiteral (loc)));
      }

      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));

      Expression real_args;
      if (args == null) {
        // Cannot be null because .NET trips over
        real_args = new ArrayCreation (
          new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc),
          new ArrayInitializer (0, loc), loc);
      } else {
        real_args = new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc);
      }

      binder_args.Add (new Argument (real_args));

      return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
    }

    public override void EmitStatement (EmitContext ec)
    {
      flags |= CSharpBinderFlags.ResultDiscarded;
      base.EmitStatement (ec);
    }
  }

  class DynamicMemberBinder : DynamicMemberAssignable
  {
    readonly string name;

    public DynamicMemberBinder (string name, Arguments args, Location loc)
      : base (args, loc)
    {
      this.name = name;
    }

    public DynamicMemberBinder (string name, CSharpBinderFlags flags, Arguments args, Location loc)
      : this (name, args, loc)
    {
      base.flags = flags;
    }

    protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
    {
      Arguments binder_args = new Arguments (4);

      binder_args.Add (new Argument (new BinderFlags (flags, this)));
      binder_args.Add (new Argument (new StringLiteral (ec.BuiltinTypes, name, loc)));
      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
      binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

      isSet |= (flags & CSharpBinderFlags.ValueFromCompoundAssignment) != 0;
      return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
    }
  }

  //
  // Any member binder which can be source and target of assignment
  //
  abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
  {
    Expression setter;
    Arguments setter_args;

    protected DynamicMemberAssignable (Arguments args, Location loc)
      : base (null, args, loc)
    {
      base.binder = this;
    }

    public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
    {
      //
      // DoResolve always uses getter
      //
      return CreateCallSiteBinder (ec, args, false);
    }

    protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);

    protected virtual Arguments CreateSetterArguments (ResolveContext rc, Expression rhs)
    {
      var setter_args = new Arguments (Arguments.Count + 1);
      setter_args.AddRange (Arguments);
      setter_args.Add (new Argument (rhs));
      return setter_args;
    }

    public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
    {
      if (right_side == EmptyExpression.OutAccess) {
        right_side.DoResolveLValue (rc, this);
        return null;
      }

      if (DoResolveCore (rc)) {
        setter_args = CreateSetterArguments (rc, right_side);
        setter = CreateCallSiteBinder (rc, setter_args, true);
      }

      eclass = ExprClass.Variable;
      return this;
    }

    public override void Emit (EmitContext ec)
    {
      // It's null for ResolveLValue used without assignment
      if (binder_expr == null)
        EmitCall (ec, setter, Arguments, false);
      else
        base.Emit (ec);
    }

    public override void EmitStatement (EmitContext ec)
    {
      // It's null for ResolveLValue used without assignment
      if (binder_expr == null)
        EmitCall (ec, setter, Arguments, true);
      else
        base.EmitStatement (ec);
    }

    #region IAssignMethod Members

    public void Emit (EmitContext ec, bool leave_copy)
    {
      throw new NotImplementedException ();
    }

    public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
    {
      EmitCall (ec, setter, setter_args, !leave_copy);
    }

    #endregion
  }

  class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
  {
    readonly string name;

    public DynamicUnaryConversion (string name, Arguments args, Location loc)
      : base (null, args, loc)
    {
      this.name = name;
      base.binder = this;
    }

    public static DynamicUnaryConversion CreateIsTrue (ResolveContext rc, Arguments args, Location loc)
    {
      return new DynamicUnaryConversion ("IsTrue", args, loc) { type = rc.BuiltinTypes.Bool };
    }

    public static DynamicUnaryConversion CreateIsFalse (ResolveContext rc, Arguments args, Location loc)
    {
      return new DynamicUnaryConversion ("IsFalse", args, loc) { type = rc.BuiltinTypes.Bool };
    }

    public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
    {
      Arguments binder_args = new Arguments (4);

      MemberAccess sle = new MemberAccess (new MemberAccess (
        new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);

      var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;

      binder_args.Add (new Argument (new BinderFlags (flags, this)));
      binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
      binder_args.Add (new Argument (new TypeOf (ec.CurrentType, loc)));
      binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

      return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
    }
  }

  sealed class DynamicSiteClass : HoistedStoreyClass
  {
    public DynamicSiteClass (TypeDefinition parent, MemberBase host, TypeParameters tparams)
      : base (parent, MakeMemberName (host, "DynamicSite", parent.DynamicSitesCounter, tparams, Location.Null), tparams, Modifiers.STATIC, MemberKind.Class)
    {
      parent.DynamicSitesCounter++;
    }

    public FieldSpec CreateCallSiteField (FullNamedExpression type, Location loc)
    {
      int index = AnonymousMethodsCounter++;
      Field f = new HoistedField (this, type, Modifiers.PUBLIC | Modifiers.STATIC, "Site" + index.ToString ("X"), null, loc);
      f.Define ();

      AddField (f);
      return f.Spec;
    }
  }
}