public Expression ResolveBinaryOperator(ResolveContext rc, BinaryOperatorType op, Expression lhs, Expression rhs) { // V# 4.0 spec: §7.3.4 Binary operator overload resolution string overloadableOperatorName = ResolveContext.GetOverloadableOperatorName(op); if (overloadableOperatorName == null) { // Handle logical and/or exactly as bitwise and/or: // - If the user overloads a bitwise operator, that implicitly creates the corresponding logical operator. // - If both inputs are compile-time constants, it doesn't matter that we don't short-circuit. // - If inputs aren't compile-time constants, we don't evaluate anything, so again it doesn't matter that we don't short-circuit if (op == BinaryOperatorType.LogicalAnd) { overloadableOperatorName = ResolveContext.GetOverloadableOperatorName(BinaryOperatorType.BitwiseAnd); } else if (op == BinaryOperatorType.LogicalOr) { overloadableOperatorName = ResolveContext.GetOverloadableOperatorName(BinaryOperatorType.BitwiseOr); } else if (op == BinaryOperatorType.NullCoalescing) { // null coalescing operator is not overloadable and needs to be handled separately return(ResolveNullCoalescingOperator(rc, lhs, rhs)); } else { return(ErrorExpression.UnknownError); } } // If the type is nullable, get the underlying type: bool isNullable = NullableType.IsNullable(lhs.Type) || NullableType.IsNullable(rhs.Type); IType lhsType = NullableType.GetUnderlyingType(lhs.Type); IType rhsType = NullableType.GetUnderlyingType(rhs.Type); // the operator is overloadable: OverloadResolution userDefinedOperatorOR = rc.CreateOverloadResolution(new[] { lhs, rhs }); HashSet <IParameterizedMember> userOperatorCandidates = new HashSet <IParameterizedMember>(); userOperatorCandidates.UnionWith(rc.GetUserDefinedOperatorCandidates(lhsType, overloadableOperatorName)); userOperatorCandidates.UnionWith(rc.GetUserDefinedOperatorCandidates(rhsType, overloadableOperatorName)); foreach (var candidate in userOperatorCandidates) { userDefinedOperatorOR.AddCandidate(candidate); } if (userDefinedOperatorOR.FoundApplicableCandidate) { return(SetUserDefinedOperationInformations(rc, userDefinedOperatorOR)); } if (lhsType.Kind == TypeKind.Null && rhsType.IsReferenceType == false || lhsType.IsReferenceType == false && rhsType.Kind == TypeKind.Null) { isNullable = true; } if (op == BinaryOperatorType.LeftShift || op == BinaryOperatorType.RightShift) { // special case: the shift operators allow "var x = null << null", producing int?. if (lhsType.Kind == TypeKind.Null && rhsType.Kind == TypeKind.Null) { isNullable = true; } // for shift operators, do unary promotion independently on both arguments lhs = UnaryNumericPromotion(rc, UnaryOperatorType.UnaryPlus, ref lhsType, isNullable, lhs); rhs = UnaryNumericPromotion(rc, UnaryOperatorType.UnaryPlus, ref rhsType, isNullable, rhs); } else { bool allowNullableConstants = op == BinaryOperatorType.Equality || op == BinaryOperatorType.Inequality; if (!BinaryNumericPromotion(rc, isNullable, ref lhs, ref rhs, allowNullableConstants)) { return(new ErrorExpression(lhs.Type)); } } // re-read underlying types after numeric promotion lhsType = NullableType.GetUnderlyingType(lhs.Type); rhsType = NullableType.GetUnderlyingType(rhs.Type); IEnumerable <VSharpOperators.OperatorMethod> methodGroup; VSharpOperators operators = VSharpOperators.Get(rc.compilation); switch (op) { case BinaryOperatorType.Multiply: methodGroup = operators.MultiplicationOperators; break; case BinaryOperatorType.Division: methodGroup = operators.DivisionOperators; break; case BinaryOperatorType.Modulus: methodGroup = operators.RemainderOperators; break; case BinaryOperatorType.Addition: methodGroup = operators.AdditionOperators; { if (lhsType.Kind == TypeKind.Enum) { // E operator +(E x, U y); IType underlyingType = MakeNullable(rc, ResolveContext.GetEnumUnderlyingType(lhsType), isNullable); if (rc.TryConvertEnum(ref rhs, underlyingType, ref isNullable, ref lhs)) { return(HandleEnumOperator(rc, isNullable, lhsType, op, lhs, rhs)); } } if (rhsType.Kind == TypeKind.Enum) { // E operator +(U x, E y); IType underlyingType = MakeNullable(rc, ResolveContext.GetEnumUnderlyingType(rhsType), isNullable); if (rc.TryConvertEnum(ref lhs, underlyingType, ref isNullable, ref rhs)) { return(HandleEnumOperator(rc, isNullable, rhsType, op, lhs, rhs)); } } if (lhsType.Kind == TypeKind.Delegate && rc.TryConvert(ref rhs, lhsType)) { return(SetOperationInformations(rc, lhsType, lhs, op, rhs)); } else if (rhsType.Kind == TypeKind.Delegate && rc.TryConvert(ref lhs, rhsType)) { return(SetOperationInformations(rc, rhsType, lhs, op, rhs)); } if (lhsType is PointerTypeSpec) { methodGroup = new[] { PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.Int32), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.UInt32), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.Int64), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.UInt64) }; } else if (rhsType is PointerTypeSpec) { methodGroup = new[] { PointerArithmeticOperator(rc, rhsType, KnownTypeCode.Int32, rhsType), PointerArithmeticOperator(rc, rhsType, KnownTypeCode.UInt32, rhsType), PointerArithmeticOperator(rc, rhsType, KnownTypeCode.Int64, rhsType), PointerArithmeticOperator(rc, rhsType, KnownTypeCode.UInt64, rhsType) }; } if (lhsType.Kind == TypeKind.Null && rhsType.Kind == TypeKind.Null) { return(new ErrorExpression(SpecialTypeSpec.NullType)); } } break; case BinaryOperatorType.Subtraction: methodGroup = operators.SubtractionOperators; { if (lhsType.Kind == TypeKind.Enum) { // U operator –(E x, E y); if (rc.TryConvertEnum(ref rhs, lhs.Type, ref isNullable, ref lhs, allowConversionFromConstantZero: false)) { return(HandleEnumSubtraction(rc, isNullable, lhsType, lhs, rhs)); } // E operator –(E x, U y); IType underlyingType = MakeNullable(rc, ResolveContext.GetEnumUnderlyingType(lhsType), isNullable); if (rc.TryConvertEnum(ref rhs, underlyingType, ref isNullable, ref lhs)) { return(HandleEnumOperator(rc, isNullable, lhsType, op, lhs, rhs)); } } if (rhsType.Kind == TypeKind.Enum) { // U operator –(E x, E y); if (rc.TryConvertEnum(ref lhs, rhs.Type, ref isNullable, ref rhs, allowConversionFromConstantZero: false)) { return(HandleEnumSubtraction(rc, isNullable, rhsType, lhs, rhs)); } // E operator -(U x, E y); IType underlyingType = MakeNullable(rc, ResolveContext.GetEnumUnderlyingType(rhsType), isNullable); if (rc.TryConvertEnum(ref lhs, underlyingType, ref isNullable, ref rhs)) { return(HandleEnumOperator(rc, isNullable, rhsType, op, lhs, rhs)); } } if (lhsType.Kind == TypeKind.Delegate && rc.TryConvert(ref rhs, lhsType)) { return(SetOperationInformations(rc, lhsType, lhs, op, rhs)); } else if (rhsType.Kind == TypeKind.Delegate && rc.TryConvert(ref lhs, rhsType)) { return(SetOperationInformations(rc, rhsType, lhs, op, rhs)); } if (lhsType is PointerTypeSpec) { if (rhsType is PointerTypeSpec) { IType int64 = rc.compilation.FindType(KnownTypeCode.Int64); if (lhsType.Equals(rhsType)) { return(SetOperationInformations(rc, int64, lhs, op, rhs)); } else { return(new ErrorExpression(int64)); } } methodGroup = new[] { PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.Int32), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.UInt32), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.Int64), PointerArithmeticOperator(rc, lhsType, lhsType, KnownTypeCode.UInt64) }; } if (lhsType.Kind == TypeKind.Null && rhsType.Kind == TypeKind.Null) { return(new ErrorExpression(SpecialTypeSpec.NullType)); } } break; case BinaryOperatorType.LeftShift: methodGroup = operators.ShiftLeftOperators; break; case BinaryOperatorType.RightShift: methodGroup = operators.ShiftRightOperators; break; case BinaryOperatorType.RotateRight: methodGroup = operators.RotateRightOperators; break; case BinaryOperatorType.RotateLeft: methodGroup = operators.RotateLeftOperators; break; case BinaryOperatorType.Equality: case BinaryOperatorType.Inequality: case BinaryOperatorType.LessThan: case BinaryOperatorType.GreaterThan: case BinaryOperatorType.LessThanOrEqual: case BinaryOperatorType.GreaterThanOrEqual: { if (lhsType.Kind == TypeKind.Enum && rc.TryConvert(ref rhs, lhs.Type)) { // bool operator op(E x, E y); return(HandleEnumComparison(rc, op, lhsType, isNullable, lhs, rhs)); } else if (rhsType.Kind == TypeKind.Enum && rc.TryConvert(ref lhs, rhs.Type)) { // bool operator op(E x, E y); return(HandleEnumComparison(rc, op, rhsType, isNullable, lhs, rhs)); } else if (lhsType is PointerTypeSpec && rhsType is PointerTypeSpec) { return(SetOperationInformations(rc, rc.compilation.FindType(KnownTypeCode.Boolean), lhs, op, rhs)); } if (op == BinaryOperatorType.Equality || op == BinaryOperatorType.Inequality) { if (lhsType.IsReferenceType == true && rhsType.IsReferenceType == true) { // If it's a reference comparison if (op == BinaryOperatorType.Equality) { methodGroup = operators.ReferenceEqualityOperators; } else { methodGroup = operators.ReferenceInequalityOperators; } break; } else if (lhsType.Kind == TypeKind.Null && IsNullableTypeOrNonValueType(rhs.Type) || IsNullableTypeOrNonValueType(lhs.Type) && rhsType.Kind == TypeKind.Null) { // compare type parameter or nullable type with the null literal return(SetOperationInformations(rc, rc.compilation.FindType(KnownTypeCode.Boolean), lhs, op, rhs)); } } switch (op) { case BinaryOperatorType.Equality: methodGroup = operators.ValueEqualityOperators; break; case BinaryOperatorType.Inequality: methodGroup = operators.ValueInequalityOperators; break; case BinaryOperatorType.LessThan: methodGroup = operators.LessThanOperators; break; case BinaryOperatorType.GreaterThan: methodGroup = operators.GreaterThanOperators; break; case BinaryOperatorType.LessThanOrEqual: methodGroup = operators.LessThanOrEqualOperators; break; case BinaryOperatorType.GreaterThanOrEqual: methodGroup = operators.GreaterThanOrEqualOperators; break; default: throw new InvalidOperationException(); } } break; case BinaryOperatorType.BitwiseAnd: case BinaryOperatorType.BitwiseOr: case BinaryOperatorType.ExclusiveOr: { if (lhsType.Kind == TypeKind.Enum) { // bool operator op(E x, E y); if (rc.TryConvertEnum(ref rhs, lhs.Type, ref isNullable, ref lhs)) { return(HandleEnumOperator(rc, isNullable, lhsType, op, lhs, rhs)); } } if (rhsType.Kind == TypeKind.Enum) { // bool operator op(E x, E y); if (rc.TryConvertEnum(ref lhs, rhs.Type, ref isNullable, ref rhs)) { return(HandleEnumOperator(rc, isNullable, rhsType, op, lhs, rhs)); } } switch (op) { case BinaryOperatorType.BitwiseAnd: methodGroup = operators.BitwiseAndOperators; break; case BinaryOperatorType.BitwiseOr: methodGroup = operators.BitwiseOrOperators; break; case BinaryOperatorType.ExclusiveOr: methodGroup = operators.BitwiseXorOperators; break; default: throw new InvalidOperationException(); } } break; case BinaryOperatorType.LogicalAnd: methodGroup = operators.LogicalAndOperators; break; case BinaryOperatorType.LogicalOr: methodGroup = operators.LogicalOrOperators; break; default: throw new InvalidOperationException(); } OverloadResolution builtinOperatorOR = rc.CreateOverloadResolution(new[] { lhs, rhs }); foreach (var candidate in methodGroup) { builtinOperatorOR.AddCandidate(candidate); } VSharpOperators.BinaryOperatorMethod m = (VSharpOperators.BinaryOperatorMethod)builtinOperatorOR.BestCandidate; IType resultType = m.ReturnType; if (builtinOperatorOR.BestCandidateErrors != OverloadResolutionErrors.None) { // If there are any user-defined operators, prefer those over the built-in operators. // It'll be a more informative error. if (userDefinedOperatorOR.BestCandidate != null) { return(SetUserDefinedOperationInformations(rc, userDefinedOperatorOR)); } else { return(new ErrorExpression(resultType)); } } else if (lhs.IsCompileTimeConstant && rhs.IsCompileTimeConstant && m.CanEvaluateAtCompileTime) { object val; try { val = m.Invoke(rc, lhs.ConstantValue, rhs.ConstantValue); } catch (ArithmeticException) { return(new ErrorExpression(resultType)); } return(Constant.CreateConstantFromValue(rc, resultType, val, loc)); } else { lhs = rc.Convert(lhs, m.Parameters[0].Type, builtinOperatorOR.ArgumentConversions[0]); rhs = rc.Convert(rhs, m.Parameters[1].Type, builtinOperatorOR.ArgumentConversions[1]); return(SetOperationInformations(rc, resultType, lhs, op, rhs, builtinOperatorOR.BestCandidate is OverloadResolution.ILiftedOperator)); } }