C# ResolveContext.HasSet方法代码示例

		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);
		}

		/// <summary>
		///   Constant expression folder for binary operations.
		///
		///   Returns null if the expression can not be folded.
		/// </summary>
		static public Constant BinaryFold (ResolveContext ec, Binary.Operator oper,
						     Constant left, Constant right, Location loc)
		{
			Constant result = null;

			if (left is EmptyConstantCast)
				return BinaryFold (ec, oper, ((EmptyConstantCast)left).child, right, loc);

			if (left is SideEffectConstant) {
				result = BinaryFold (ec, oper, ((SideEffectConstant) left).value, right, loc);
				if (result == null)
					return null;
				return new SideEffectConstant (result, left, loc);
			}

			if (right is EmptyConstantCast)
				return BinaryFold (ec, oper, left, ((EmptyConstantCast)right).child, loc);

			if (right is SideEffectConstant) {
				result = BinaryFold (ec, oper, left, ((SideEffectConstant) right).value, loc);
				if (result == null)
					return null;
				return new SideEffectConstant (result, right, loc);
			}

			TypeSpec lt = left.Type;
			TypeSpec rt = right.Type;
			bool bool_res;

			if (lt.BuiltinType == BuiltinTypeSpec.Type.Bool && lt == rt) {
				bool lv = (bool) left.GetValue ();
				bool rv = (bool) right.GetValue ();			
				switch (oper) {
				case Binary.Operator.BitwiseAnd:
				case Binary.Operator.LogicalAnd:
					return new BoolConstant (ec.BuiltinTypes, lv && rv, left.Location);
				case Binary.Operator.BitwiseOr:
				case Binary.Operator.LogicalOr:
					return new BoolConstant (ec.BuiltinTypes, lv || rv, left.Location);
				case Binary.Operator.ExclusiveOr:
					return new BoolConstant (ec.BuiltinTypes, lv ^ rv, left.Location);
				case Binary.Operator.Equality:
					return new BoolConstant (ec.BuiltinTypes, lv == rv, left.Location);
				case Binary.Operator.Inequality:
					return new BoolConstant (ec.BuiltinTypes, lv != rv, left.Location);
				}
				return null;
			}

			//
			// During an enum evaluation, none of the rules are valid
			// Not sure whether it is bug in csc or in documentation
			//
			if (ec.HasSet (ResolveContext.Options.EnumScope)){
				if (left is EnumConstant)
					left = ((EnumConstant) left).Child;
				
				if (right is EnumConstant)
					right = ((EnumConstant) right).Child;
			} else if (left is EnumConstant && rt == lt) {
				switch (oper){
					///
					/// E operator |(E x, E y);
					/// E operator &(E x, E y);
					/// E operator ^(E x, E y);
					/// 
					case Binary.Operator.BitwiseOr:
					case Binary.Operator.BitwiseAnd:
					case Binary.Operator.ExclusiveOr:
						result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
						if (result != null)
							result = result.Reduce (ec, lt);
						return result;

					///
					/// U operator -(E x, E y);
					/// 
					case Binary.Operator.Subtraction:
						result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
						if (result != null)
							result = result.Reduce (ec, EnumSpec.GetUnderlyingType (lt));
						return result;

					///
					/// bool operator ==(E x, E y);
					/// bool operator !=(E x, E y);
					/// bool operator <(E x, E y);
					/// bool operator >(E x, E y);
					/// bool operator <=(E x, E y);
					/// bool operator >=(E x, E y);
					/// 
					case Binary.Operator.Equality:				
					case Binary.Operator.Inequality:
					case Binary.Operator.LessThan:				
					case Binary.Operator.GreaterThan:
//.........这里部分代码省略.........

		public BlockContext (ResolveContext rc, ExplicitBlock block, TypeSpec returnType)
			: this (rc.MemberContext, block, returnType)
		{
			if (rc.IsUnsafe)
				flags |= ResolveContext.Options.UnsafeScope;

			if (rc.HasSet (ResolveContext.Options.CheckedScope))
				flags |= ResolveContext.Options.CheckedScope;

			if (!rc.ConstantCheckState)
				flags &= ~Options.ConstantCheckState;

			if (rc.IsInProbingMode)
				flags |= ResolveContext.Options.ProbingMode;

			if (rc.HasSet (ResolveContext.Options.FieldInitializerScope))
				flags |= ResolveContext.Options.FieldInitializerScope;

			if (rc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
				flags |= ResolveContext.Options.ExpressionTreeConversion;

			if (rc.HasSet (ResolveContext.Options.BaseInitializer))
				flags |= ResolveContext.Options.BaseInitializer;
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			constructor_method = Delegate.GetConstructor (type);

			var invoke_method = Delegate.GetInvokeMethod (type);

			if (!ec.HasSet (ResolveContext.Options.ConditionalAccessReceiver)) {
				if (method_group.HasConditionalAccess ()) {
					conditional_access_receiver = true;
					ec.Set (ResolveContext.Options.ConditionalAccessReceiver);
				}
			}

			Arguments arguments = CreateDelegateMethodArguments (ec, invoke_method.Parameters, invoke_method.Parameters.Types, loc);
			method_group = method_group.OverloadResolve (ec, ref arguments, this, OverloadResolver.Restrictions.CovariantDelegate);

			if (conditional_access_receiver)
				ec.With (ResolveContext.Options.ConditionalAccessReceiver, false);

			if (method_group == null)
				return null;

			var delegate_method = method_group.BestCandidate;
			
			if (delegate_method.DeclaringType.IsNullableType) {
				ec.Report.Error (1728, loc, "Cannot create delegate from method `{0}' because it is a member of System.Nullable<T> type",
					delegate_method.GetSignatureForError ());
				return null;
			}		
			
			if (!AllowSpecialMethodsInvocation)
				Invocation.IsSpecialMethodInvocation (ec, delegate_method, loc);

			ExtensionMethodGroupExpr emg = method_group as ExtensionMethodGroupExpr;
			if (emg != null) {
				method_group.InstanceExpression = emg.ExtensionExpression;
				TypeSpec e_type = emg.ExtensionExpression.Type;
				if (TypeSpec.IsValueType (e_type)) {
					ec.Report.Error (1113, loc, "Extension method `{0}' of value type `{1}' cannot be used to create delegates",
						delegate_method.GetSignatureForError (), e_type.GetSignatureForError ());
				}
			}

			TypeSpec rt = method_group.BestCandidateReturnType;
			if (rt.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
				rt = ec.BuiltinTypes.Object;

			if (!Delegate.IsTypeCovariant (ec, rt, invoke_method.ReturnType)) {
				Expression ret_expr = new TypeExpression (delegate_method.ReturnType, loc);
				Error_ConversionFailed (ec, delegate_method, ret_expr);
			}

			if (method_group.IsConditionallyExcluded) {
				ec.Report.SymbolRelatedToPreviousError (delegate_method);
				MethodOrOperator m = delegate_method.MemberDefinition as MethodOrOperator;
				if (m != null && m.IsPartialDefinition) {
					ec.Report.Error (762, loc, "Cannot create delegate from partial method declaration `{0}'",
						delegate_method.GetSignatureForError ());
				} else {
					ec.Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute",
						TypeManager.CSharpSignature (delegate_method));
				}
			}

			var expr = method_group.InstanceExpression;
			if (expr != null && (expr.Type.IsGenericParameter || !TypeSpec.IsReferenceType (expr.Type)))
				method_group.InstanceExpression = new BoxedCast (expr, ec.BuiltinTypes.Object);

			eclass = ExprClass.Value;
			return this;
		}

		public AnonymousExpression Compatible (ResolveContext ec, AnonymousExpression ae)
		{
			if (block.Resolved)
				return this;

			// TODO: Implement clone
			BlockContext aec = new BlockContext (ec, block, ReturnType);
			aec.CurrentAnonymousMethod = ae;

			var am = this as AnonymousMethodBody;

			if (ec.HasSet (ResolveContext.Options.InferReturnType) && am != null) {
				am.ReturnTypeInference = new TypeInferenceContext ();
			}

			var bc = ec as BlockContext;

			if (bc != null) {
				aec.AssignmentInfoOffset = bc.AssignmentInfoOffset;
				aec.EnclosingLoop = bc.EnclosingLoop;
				aec.EnclosingLoopOrSwitch = bc.EnclosingLoopOrSwitch;
				aec.Switch = bc.Switch;
			}

			var errors = ec.Report.Errors;

			bool res = Block.Resolve (aec);

			if (res && errors == ec.Report.Errors) {
				MarkReachable (new Reachability ());

				if (!CheckReachableExit (ec.Report)) {
					return null;
				}

				if (bc != null)
					bc.AssignmentInfoOffset = aec.AssignmentInfoOffset;
			}

			if (am != null && am.ReturnTypeInference != null) {
				am.ReturnTypeInference.FixAllTypes (ec);
				ReturnType = am.ReturnTypeInference.InferredTypeArguments [0];
				am.ReturnTypeInference = null;

				//
				// If e is synchronous the inferred return type is T
				// If e is asynchronous and the body of F is either an expression classified as nothing
				// or a statement block where no return statements have expressions, the inferred return type is Task
				// If e is async and has an inferred result type T, the inferred return type is Task<T>
				//
				if (block.IsAsync && ReturnType != null) {
					ReturnType = ReturnType.Kind == MemberKind.Void ?
						ec.Module.PredefinedTypes.Task.TypeSpec :
						ec.Module.PredefinedTypes.TaskGeneric.TypeSpec.MakeGenericType (ec, new [] { ReturnType });
				}
			}

			if (res && errors != ec.Report.Errors)
				return null;

			return res ? this : null;
		}

		protected override Expression DoResolve (ResolveContext rc)
		{
			if (rc.HasSet (ResolveContext.Options.ConstantScope)) {
				rc.Report.Error (1706, loc, "Anonymous methods and lambda expressions cannot be used in the current context");
				return null;
			}

			//
			// Update top-level block generated duting parsing with actual top-level block
			//
			if (rc.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer) && rc.CurrentMemberDefinition.Parent.PartialContainer.PrimaryConstructorParameters != null) {
				var tb = rc.ConstructorBlock.ParametersBlock.TopBlock;
				if (Block.TopBlock != tb) {
					Block b = Block;
					while (b.Parent != Block.TopBlock && b != Block.TopBlock)
						b = b.Parent;

					b.Parent = tb;
					tb.IncludeBlock (Block, Block.TopBlock);
					b.ParametersBlock.TopBlock = tb;
				}
			}

			eclass = ExprClass.Value;

			//
			// This hack means `The type is not accessible
			// anywhere', we depend on special conversion
			// rules.
			// 
			type = InternalType.AnonymousMethod;

			if (!DoResolveParameters (rc))
				return null;

			return this;
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			right = right.Resolve (ec);
			if (right == null)
				return null;

			MemberAccess ma = target as MemberAccess;
			using (ec.Set (ResolveContext.Options.CompoundAssignmentScope)) {
				target = target.Resolve (ec);
			}
			
			if (target == null)
				return null;

			if (target is MethodGroupExpr){
				ec.Report.Error (1656, loc,
					"Cannot assign to `{0}' because it is a `{1}'",
					((MethodGroupExpr)target).Name, target.ExprClassName);
				return null;
			}

			var event_expr = target as EventExpr;
			if (event_expr != null) {
				source = Convert.ImplicitConversionRequired (ec, right, target.Type, loc);
				if (source == null)
					return null;

				Expression rside;
				if (op == Binary.Operator.Addition)
					rside = EmptyExpression.EventAddition;
				else if (op == Binary.Operator.Subtraction)
					rside = EmptyExpression.EventSubtraction;
				else
					rside = null;

				target = target.ResolveLValue (ec, rside);
				if (target == null)
					return null;

				eclass = ExprClass.Value;
				type = event_expr.Operator.ReturnType;
				return this;
			}

			//
			// Only now we can decouple the original source/target
			// into a tree, to guarantee that we do not have side
			// effects.
			//
			if (left == null)
				left = new TargetExpression (target);

			source = new Binary (op, left, right, true);

			if (target is DynamicMemberAssignable) {
				Arguments targs = ((DynamicMemberAssignable) target).Arguments;
				source = source.Resolve (ec);

				Arguments args = new Arguments (targs.Count + 1);
				args.AddRange (targs);
				args.Add (new Argument (source));

				var binder_flags = CSharpBinderFlags.ValueFromCompoundAssignment;

				//
				// Compound assignment does target conversion using additional method
				// call, set checked context as the binary operation can overflow
				//
				if (ec.HasSet (ResolveContext.Options.CheckedScope))
					binder_flags |= CSharpBinderFlags.CheckedContext;

				if (target is DynamicMemberBinder) {
					source = new DynamicMemberBinder (ma.Name, binder_flags, args, loc).Resolve (ec);

					// Handles possible event addition/subtraction
					if (op == Binary.Operator.Addition || op == Binary.Operator.Subtraction) {
						args = new Arguments (targs.Count + 1);
						args.AddRange (targs);
						args.Add (new Argument (right));
						string method_prefix = op == Binary.Operator.Addition ?
							Event.AEventAccessor.AddPrefix : Event.AEventAccessor.RemovePrefix;

						var invoke = DynamicInvocation.CreateSpecialNameInvoke (
							new MemberAccess (right, method_prefix + ma.Name, loc), args, loc).Resolve (ec);

						args = new Arguments (targs.Count);
						args.AddRange (targs);
						source = new DynamicEventCompoundAssign (ma.Name, args,
							(ExpressionStatement) source, (ExpressionStatement) invoke, loc).Resolve (ec);
					}
				} else {
					source = new DynamicIndexBinder (binder_flags, args, loc).Resolve (ec);
				}

				return source;
			}

			return base.DoResolve (ec);
		}