Exemplo n.º 1
0
        public static Constant CreateFromExpression(ResolveContext ec, Expression e)
        {
            ec.Report.Warning(458, 2, e.Location, "The result of the expression is always `null' of type `{0}'",
                              TypeManager.CSharpName(e.Type));

            return(ReducedExpression.Create(Create(e.Type, e.Location), e));
        }
Exemplo n.º 2
0
        public static Constant CreateFromExpression(ResolveContext ec, Expression e)
        {
            ec.Report.Warning(458, 2, e.Location, "The result of the expression is always `null' of type `{0}'",
                              e.Type.GetSignatureForError());

            return(ReducedExpression.Create(Create(e.Type, e.Location), e));
        }
Exemplo n.º 3
0
        public static Constant CreateFromExpression(ResolveContext rc, Expression e)
        {
            if (!rc.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
                rc.Report.Warning (458, 2, e.Location, "The result of the expression is always `null' of type `{0}'",
                    e.Type.GetSignatureForError ());
            }

            return ReducedExpression.Create (Create (e.Type, e.Location), e);
        }
Exemplo n.º 4
0
        //
        // CSC 2 has this behavior, it allows structs to be compared
        // with the null literal *outside* of a generics context and
        // inlines that as true or false.
        //
        Constant CreateNullConstant(ResolveContext ec, Expression expr)
        {
            // FIXME: Handle side effect constants
            Constant c = new BoolConstant(ec.BuiltinTypes, Oper == Operator.Inequality, loc);

            if ((Oper & Operator.EqualityMask) != 0)
            {
                ec.Report.Warning(472, 2, loc, "The result of comparing value type `{0}' with null is `{1}'",
                                  TypeManager.CSharpName(expr.Type), c.GetValueAsLiteral());
            }
            else
            {
                ec.Report.Warning(464, 2, loc, "The result of comparing type `{0}' with null is always `{1}'",
                                  TypeManager.CSharpName(expr.Type), c.GetValueAsLiteral());
            }

            return(ReducedExpression.Create(c, this));
        }
Exemplo n.º 5
0
        //
        // CSC 2 has this behavior, it allows structs to be compared
        // with the null literal *outside* of a generics context and
        // inlines that as true or false.
        //
        Expression CreateNullConstant(ResolveContext ec, Expression expr)
        {
            // FIXME: Handle side effect constants
            Constant c = new BoolConstant(Oper == Operator.Inequality, loc);

            if ((Oper & Operator.EqualityMask) != 0)
            {
                ec.Report.Warning(472, 2, loc, "The result of comparing value type `{0}' with null is `{1}'",
                                  expr.GetSignatureForError(), c.AsString());
            }
            else
            {
                ec.Report.Warning(464, 2, loc, "The result of comparing type `{0}' with null is always `{1}'",
                                  expr.GetSignatureForError(), c.AsString());
            }

            return(ReducedExpression.Create(c, this));
        }
Exemplo n.º 6
0
        Expression ConvertExpression(ResolveContext ec)
        {
            // TODO: ImplicitConversionExists should take care of this
            if (left.eclass == ExprClass.MethodGroup)
            {
                return(null);
            }

            TypeSpec ltype = left.Type;

            //
            // If left is a nullable type and an implicit conversion exists from right to underlying type of left,
            // the result is underlying type of left
            //
            if (ltype.IsNullableType)
            {
                unwrap = Unwrap.Create(left, false);
                if (unwrap == null)
                {
                    return(null);
                }

                //
                // Reduce (left ?? null) to left
                //
                if (right.IsNull)
                {
                    return(ReducedExpression.Create(left, this));
                }

                Expression conv;
                if (right.Type.IsNullableType)
                {
                    conv = right.Type == ltype ? right : Convert.ImplicitNulableConversion(ec, right, ltype);
                    if (conv != null)
                    {
                        right = conv;
                        type  = ltype;
                        return(this);
                    }
                }
                else
                {
                    conv = Convert.ImplicitConversion(ec, right, unwrap.Type, loc);
                    if (conv != null)
                    {
                        left  = unwrap;
                        ltype = left.Type;

                        //
                        // If right is a dynamic expression, the result type is dynamic
                        //
                        if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
                        {
                            type = right.Type;

                            // Need to box underlying value type
                            left = Convert.ImplicitBoxingConversion(left, ltype, type);
                            return(this);
                        }

                        right = conv;
                        type  = ltype;
                        return(this);
                    }
                }
            }
            else if (TypeSpec.IsReferenceType(ltype))
            {
                if (Convert.ImplicitConversionExists(ec, right, ltype))
                {
                    //
                    // If right is a dynamic expression, the result type is dynamic
                    //
                    if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
                    {
                        type = right.Type;
                        return(this);
                    }

                    //
                    // Reduce ("foo" ?? expr) to expression
                    //
                    Constant lc = left as Constant;
                    if (lc != null && !lc.IsDefaultValue)
                    {
                        return(ReducedExpression.Create(lc, this, false));
                    }

                    //
                    // Reduce (left ?? null) to left OR (null-constant ?? right) to right
                    //
                    if (right.IsNull || lc != null)
                    {
                        //
                        // Special case null ?? null
                        //
                        if (right.IsNull && ltype == right.Type)
                        {
                            return(null);
                        }

                        return(ReducedExpression.Create(lc != null ? right : left, this, false));
                    }

                    right = Convert.ImplicitConversion(ec, right, ltype, loc);
                    type  = ltype;
                    return(this);
                }
            }
            else
            {
                return(null);
            }

            TypeSpec rtype = right.Type;

            if (!Convert.ImplicitConversionExists(ec, unwrap ?? left, rtype) || right.eclass == ExprClass.MethodGroup)
            {
                return(null);
            }

            //
            // Reduce (null ?? right) to right
            //
            if (left.IsNull)
            {
                return(ReducedExpression.Create(right, this, false).Resolve(ec));
            }

            left = Convert.ImplicitConversion(ec, unwrap ?? left, rtype, loc);
            type = rtype;
            return(this);
        }
Exemplo n.º 7
0
        Expression ConvertExpression(ResolveContext ec)
        {
            // TODO: ImplicitConversionExists should take care of this
            if (left.eclass == ExprClass.MethodGroup)
            {
                return(null);
            }

            Type ltype = left.Type;

            //
            // If left is a nullable type and an implicit conversion exists from right to underlying type of left,
            // the result is underlying type of left
            //
            if (TypeManager.IsNullableType(ltype))
            {
                unwrap = Unwrap.Create(left, false);
                if (unwrap == null)
                {
                    return(null);
                }

                if (Convert.ImplicitConversionExists(ec, right, unwrap.Type))
                {
                    left  = unwrap;
                    type  = left.Type;
                    right = Convert.ImplicitConversion(ec, right, type, loc);
                    return(this);
                }
            }
            else if (TypeManager.IsReferenceType(ltype))
            {
                if (Convert.ImplicitConversionExists(ec, right, ltype))
                {
                    //
                    // Reduce (constant ?? expr) to constant
                    //
                    Constant lc = left as Constant;
                    if (lc != null && !lc.IsDefaultValue)
                    {
                        return(new SideEffectConstant(lc, right, loc).Resolve(ec));
                    }

                    //
                    // Reduce (left ?? null) to left OR (null-constant ?? right) to right
                    //
                    if (right.IsNull || lc != null)
                    {
                        return(ReducedExpression.Create(lc != null ? right : left, this).Resolve(ec));
                    }

                    right = Convert.ImplicitConversion(ec, right, ltype, loc);
                    type  = left.Type;
                    return(this);
                }
            }
            else
            {
                return(null);
            }

            Type rtype = right.Type;

            if (!Convert.ImplicitConversionExists(ec, unwrap != null ? unwrap : left, rtype) || right.eclass == ExprClass.MethodGroup)
            {
                return(null);
            }

            //
            // Reduce (null ?? right) to right
            //
            if (left.IsNull)
            {
                return(ReducedExpression.Create(right, this).Resolve(ec));
            }

            left = Convert.ImplicitConversion(ec, unwrap != null ? unwrap : left, rtype, loc);
            type = rtype;
            return(this);
        }