protected override Expr VisitCAST(ExprCast pExpr) { Debug.Assert(pExpr != null); Expr pArgument = pExpr.Argument; // If we have generated an identity cast or reference cast to a base class // we can omit the cast. if (pArgument.Type == pExpr.Type || SymbolLoader.IsBaseClassOfClass(pArgument.Type, pExpr.Type) || CConversions.FImpRefConv(GetSymbolLoader(), pArgument.Type, pExpr.Type)) { return(Visit(pArgument)); } // If we have a cast to PredefinedType.PT_G_EXPRESSION and the thing that we're casting is // a EXPRBOUNDLAMBDA that is an expression tree, then just visit the expression tree. if (pExpr.Type != null && pExpr.Type.isPredefType(PredefinedType.PT_G_EXPRESSION) && pArgument is ExprBoundLambda) { return(Visit(pArgument)); } Expr result = GenerateConversion(pArgument, pExpr.Type, pExpr.isChecked()); if ((pExpr.Flags & EXPRFLAG.EXF_UNBOXRUNTIME) != 0) { // Propagate the unbox flag to the call for the ExpressionTreeCallRewriter. result.Flags |= EXPRFLAG.EXF_UNBOXRUNTIME; } return(result); }
private bool bindExplicitConversionFromArrayToArray(ArrayType arraySrc, ArrayType arrayDest) { // 13.2.2 // // The explicit reference conversions are: // // * From an array-type S with an element type SE to an array-type T with an element type // TE, provided all of the following are true: // // * S and T differ only in element type. (In other words, S and T have the same number // of dimensions.) // // * An explicit reference conversion exists from SE to TE. if (arraySrc.rank != arrayDest.rank || arraySrc.IsSZArray != arrayDest.IsSZArray) { return(false); // Ranks do not match. } if (CConversions.FExpRefConv(GetSymbolLoader(), arraySrc.GetElementType(), arrayDest.GetElementType())) { if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_REFCHECK); } return(true); } return(false); }
private AggCastResult bindExplicitConversionBetweenAggregates(AggregateType aggTypeDest) { // 13.2.3 // // The explicit reference conversions are: // // * From object to any reference-type. // * From any class-type S to any class-type T, provided S is a base class of T. // * From any class-type S to any interface-type T, provided S is not sealed and // provided S does not implement T. // * From any interface-type S to any class-type T, provided T is not sealed or provided // T implements S. // * From any interface-type S to any interface-type T, provided S is not derived from T. Debug.Assert(_typeSrc != null); Debug.Assert(aggTypeDest != null); if (!(_typeSrc is AggregateType atSrc)) { return(AggCastResult.Failure); } AggregateSymbol aggSrc = atSrc.getAggregate(); AggregateSymbol aggDest = aggTypeDest.getAggregate(); if (GetSymbolLoader().HasBaseConversion(aggTypeDest, atSrc)) { if (_needsExprDest) { if (aggDest.IsValueType() && aggSrc.getThisType().fundType() == FUNDTYPE.FT_REF) { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_UNBOX); } else { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_REFCHECK | (_exprSrc?.Flags & EXPRFLAG.EXF_CANTBENULL ?? 0)); } } return(AggCastResult.Success); } if ((aggSrc.IsClass() && !aggSrc.IsSealed() && aggDest.IsInterface()) || (aggSrc.IsInterface() && aggDest.IsClass() && !aggDest.IsSealed()) || (aggSrc.IsInterface() && aggDest.IsInterface()) || CConversions.HasGenericDelegateExplicitReferenceConversion(GetSymbolLoader(), _typeSrc, aggTypeDest)) { if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_REFCHECK | (_exprSrc?.Flags & EXPRFLAG.EXF_CANTBENULL ?? 0)); } return(AggCastResult.Success); } return(AggCastResult.Failure); }
private bool bindExplicitConversionFromArrayToIList() { // 13.2.2 // // The explicit reference conversions are: // // * From a one-dimensional array-type S[] to System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyList<T> and // their base interfaces, provided there is an explicit reference conversion from S to T. Debug.Assert(_typeSrc != null); Debug.Assert(_typeDest != null); if (!(_typeSrc is ArrayType arrSrc) || !arrSrc.IsSZArray || !(_typeDest is AggregateType aggDest) || !aggDest.isInterfaceType() || aggDest.GetTypeArgsAll().Count != 1) { return(false); } AggregateSymbol aggIList = GetSymbolLoader().GetPredefAgg(PredefinedType.PT_G_ILIST); AggregateSymbol aggIReadOnlyList = GetSymbolLoader().GetPredefAgg(PredefinedType.PT_G_IREADONLYLIST); if ((aggIList == null || !GetSymbolLoader().IsBaseAggregate(aggIList, aggDest.getAggregate())) && (aggIReadOnlyList == null || !GetSymbolLoader().IsBaseAggregate(aggIReadOnlyList, aggDest.getAggregate()))) { return(false); } CType typeArr = arrSrc.GetElementType(); CType typeLst = aggDest.GetTypeArgsAll()[0]; if (!CConversions.FExpRefConv(GetSymbolLoader(), typeArr, typeLst)) { return(false); } if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_REFCHECK); } return(true); }
private bool bindExplicitConversionFromIListToArray(ArrayType arrayDest) { // 13.2.2 // // The explicit reference conversions are: // // * From System.Collections.Generic.IList<T>, System.Collections.Generic.IReadOnlyList<T> and their base interfaces // to a one-dimensional array-type S[], provided there is an implicit or explicit reference conversion from // S[] to System.Collections.Generic.IList<T> or System.Collections.Generic.IReadOnlyList<T>. This is precisely when either S and T // are the same type or there is an implicit or explicit reference conversion from S to T. if (!arrayDest.IsSZArray || !(_typeSrc is AggregateType aggSrc) || !aggSrc.isInterfaceType() || aggSrc.GetTypeArgsAll().Count != 1) { return(false); } AggregateSymbol aggIList = GetSymbolLoader().GetPredefAgg(PredefinedType.PT_G_ILIST); AggregateSymbol aggIReadOnlyList = GetSymbolLoader().GetPredefAgg(PredefinedType.PT_G_IREADONLYLIST); if ((aggIList == null || !GetSymbolLoader().IsBaseAggregate(aggIList, aggSrc.getAggregate())) && (aggIReadOnlyList == null || !GetSymbolLoader().IsBaseAggregate(aggIReadOnlyList, aggSrc.getAggregate()))) { return(false); } CType typeArr = arrayDest.GetElementType(); CType typeLst = aggSrc.GetTypeArgsAll()[0]; Debug.Assert(!typeArr.IsNeverSameType()); if (typeArr != typeLst && !CConversions.FExpRefConv(GetSymbolLoader(), typeArr, typeLst)) { return(false); } if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest, EXPRFLAG.EXF_REFCHECK); } return(true); }
private bool bindImplicitConversionFromNullable(NullableType nubSrc) { // We can convert T? using a boxing conversion, we can convert it to ValueType, and // we can convert it to any interface implemented by T. // // 13.1.5 Boxing Conversions // // A nullable-type has a boxing conversion to the same set of types to which the nullable-type's // underlying type has boxing conversions. A boxing conversion applied to a value of a nullable-type // proceeds as follows: // // * If the HasValue property of the nullable value evaluates to false, then the result of the // boxing conversion is the null reference of the appropriate type. // // Otherwise, the result is obtained by boxing the result of evaluating the Value property on // the nullable value. AggregateType atsNub = nubSrc.GetAts(); if (atsNub == _typeDest) { if (_needsExprDest) { _exprDest = _exprSrc; } return(true); } if (GetSymbolLoader().HasBaseConversion(nubSrc.GetUnderlyingType(), _typeDest) && !CConversions.FUnwrappingConv(nubSrc, _typeDest)) { if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _typeDest, out _exprDest, EXPRFLAG.EXF_BOX); if (!_typeDest.isPredefType(PredefinedType.PT_OBJECT)) { // The base type of a nullable is always a non-nullable value type, // therefore so is typeDest unless typeDest is PT_OBJECT. In this case the conversion // needs to be unboxed. We only need this if we actually will use the result. _binder.bindSimpleCast(_exprDest, _typeDest, out _exprDest, EXPRFLAG.EXF_FORCE_UNBOX); } } return(true); } return(0 == (_flags & CONVERTTYPE.NOUDC) && _binder.bindUserDefinedConversion(_exprSrc, nubSrc, _typeDest, _needsExprDest, out _exprDest, true)); }
/*************************************************************************************************** * Called by BindImplicitConversion when the destination type is Nullable<T>. The following * conversions are handled by this method: * * For S in { object, ValueType, interfaces implemented by underlying type} there is an explicit * unboxing conversion S => T? * System.Enum => T? there is an unboxing conversion if T is an enum type * null => T? implemented as default(T?) * * Implicit T?* => T?+ implemented by either wrapping or calling GetValueOrDefault the * appropriate number of times. * If imp/exp S => T then imp/exp S => T?+ implemented by converting to T then wrapping the * appropriate number of times. * If imp/exp S => T then imp/exp S?+ => T?+ implemented by calling GetValueOrDefault (m-1) times * then calling HasValue, producing a null if it returns false, otherwise calling Value, * converting to T then wrapping the appropriate number of times. * * The 3 rules above can be summarized with the following recursive rules: * * If imp/exp S => T? then imp/exp S? => T? implemented as * qs.HasValue ? (T?)(qs.Value) : default(T?) * If imp/exp S => T then imp/exp S => T? implemented as new T?((T)s) * * This method also handles calling bindUserDefinedConverion. This method does NOT handle * the following conversions: * * Implicit boxing conversion from S? to { object, ValueType, Enum, ifaces implemented by S }. (Handled by BindImplicitConversion.) * If imp/exp S => T then explicit S?+ => T implemented by calling Value the appropriate number * of times. (Handled by BindExplicitConversion.) * * The recursive equivalent is: * * If imp/exp S => T and T is not nullable then explicit S? => T implemented as qs.Value * * Some nullable conversion are NOT standard conversions. In particular, if S => T is implicit * then S? => T is not standard. Similarly if S => T is not implicit then S => T? is not standard. ***************************************************************************************************/ private bool BindNubConversion(NullableType nubDst) { // This code assumes that STANDARD and ISEXPLICIT are never both set. // bindUserDefinedConversion should ensure this! Debug.Assert(0 != (~_flags & (CONVERTTYPE.STANDARD | CONVERTTYPE.ISEXPLICIT))); Debug.Assert(_exprSrc == null || _exprSrc.Type == _typeSrc); Debug.Assert(!_needsExprDest || _exprSrc != null); Debug.Assert(_typeSrc != nubDst); // BindImplicitConversion should have taken care of this already. AggregateType atsDst = nubDst.GetAts(); // Check for the unboxing conversion. This takes precedence over the wrapping conversions. if (GetSymbolLoader().HasBaseConversion(nubDst.GetUnderlyingType(), _typeSrc) && !CConversions.FWrappingConv(_typeSrc, nubDst)) { // These should be different! Fix the caller if typeSrc is an AggregateType of Nullable. Debug.Assert(atsDst != _typeSrc); // typeSrc is a base type of the destination nullable type so there is an explicit // unboxing conversion. if (0 == (_flags & CONVERTTYPE.ISEXPLICIT)) { return(false); } if (_needsExprDest) { _binder.bindSimpleCast(_exprSrc, _typeDest, out _exprDest, EXPRFLAG.EXF_UNBOX); } return(true); } bool dstWasNullable; bool srcWasNullable; CType typeDstBase = nubDst.StripNubs(out dstWasNullable); CType typeSrcBase = _typeSrc.StripNubs(out srcWasNullable); ConversionFunc pfn = (_flags & CONVERTTYPE.ISEXPLICIT) != 0 ? (ConversionFunc)_binder.BindExplicitConversion : (ConversionFunc)_binder.BindImplicitConversion; if (!srcWasNullable) { Debug.Assert(_typeSrc == typeSrcBase); // The null type can be implicitly converted to T? as the default value. if (_typeSrc is NullType) { // If we have the constant null, generate it as a default value of T?. If we have // some crazy expression which has been determined to be always null, like (null??null) // keep it in its expression form and transform it in the nullable rewrite pass. if (_needsExprDest) { if (_exprSrc.isCONSTANT_OK()) { _exprDest = GetExprFactory().CreateZeroInit(nubDst); } else { _exprDest = GetExprFactory().CreateCast(_typeDest, _exprSrc); } } return(true); } Expr exprTmp = _exprSrc; // If there is an implicit/explicit S => T then there is an implicit/explicit S => T? if (_typeSrc == typeDstBase || pfn(_exprSrc, _typeSrc, typeDstBase, _needsExprDest, out exprTmp, _flags | CONVERTTYPE.NOUDC)) { if (_needsExprDest) { ExprUserDefinedConversion exprUDC = exprTmp as ExprUserDefinedConversion; if (exprUDC != null) { exprTmp = exprUDC.UserDefinedCall; } if (dstWasNullable) { ExprCall call = _binder.BindNubNew(exprTmp); exprTmp = call; call.NullableCallLiftKind = NullableCallLiftKind.NullableConversionConstructor; } if (exprUDC != null) { exprUDC.UserDefinedCall = exprTmp; exprTmp = exprUDC; } Debug.Assert(exprTmp.Type == nubDst); _exprDest = exprTmp; } return(true); } // No builtin conversion. Maybe there is a user defined conversion.... return(0 == (_flags & CONVERTTYPE.NOUDC) && _binder.bindUserDefinedConversion(_exprSrc, _typeSrc, nubDst, _needsExprDest, out _exprDest, 0 == (_flags & CONVERTTYPE.ISEXPLICIT))); } // Both are Nullable so there is only a conversion if there is a conversion between the base types. // That is, if there is an implicit/explicit S => T then there is an implicit/explicit S?+ => T?+. if (typeSrcBase != typeDstBase && !pfn(null, typeSrcBase, typeDstBase, false, out _exprDest, _flags | CONVERTTYPE.NOUDC)) { // No builtin conversion. Maybe there is a user defined conversion.... return(0 == (_flags & CONVERTTYPE.NOUDC) && _binder.bindUserDefinedConversion(_exprSrc, _typeSrc, nubDst, _needsExprDest, out _exprDest, 0 == (_flags & CONVERTTYPE.ISEXPLICIT))); } if (_needsExprDest) { MethWithInst mwi = new MethWithInst(null, null); ExprMemberGroup pMemGroup = GetExprFactory().CreateMemGroup(null, mwi); ExprCall exprDst = GetExprFactory().CreateCall(0, nubDst, _exprSrc, pMemGroup, null); // Here we want to first check whether or not the conversions work on the base types. Expr arg1 = _binder.mustCast(_exprSrc, typeSrcBase); bool convertible = (_flags & CONVERTTYPE.ISEXPLICIT) != 0 ? _binder.BindExplicitConversion( arg1, arg1.Type, typeDstBase, out arg1, _flags | CONVERTTYPE.NOUDC) : _binder.BindImplicitConversion( arg1, arg1.Type, typeDstBase, out arg1, _flags | CONVERTTYPE.NOUDC); if (!convertible) { Debug.Fail("bind(Im|Ex)plicitConversion failed unexpectedly"); return(false); } exprDst.CastOfNonLiftedResultToLiftedType = _binder.mustCast(arg1, nubDst, 0); exprDst.NullableCallLiftKind = NullableCallLiftKind.NullableConversion; exprDst.PConversions = exprDst.CastOfNonLiftedResultToLiftedType; _exprDest = exprDst; } return(true); }
/*************************************************************************************************** * Called by BindImplicitConversion when the destination type is Nullable<T>. The following * conversions are handled by this method: * * For S in { object, ValueType, interfaces implemented by underlying type} there is an explicit * unboxing conversion S => T? * System.Enum => T? there is an unboxing conversion if T is an enum type * null => T? implemented as default(T?) * * Implicit T?* => T?+ implemented by either wrapping or calling GetValueOrDefault the * appropriate number of times. * If imp/exp S => T then imp/exp S => T?+ implemented by converting to T then wrapping the * appropriate number of times. * If imp/exp S => T then imp/exp S?+ => T?+ implemented by calling GetValueOrDefault (m-1) times * then calling HasValue, producing a null if it returns false, otherwise calling Value, * converting to T then wrapping the appropriate number of times. * * The 3 rules above can be summarized with the following recursive rules: * * If imp/exp S => T? then imp/exp S? => T? implemented as * qs.HasValue ? (T?)(qs.Value) : default(T?) * If imp/exp S => T then imp/exp S => T? implemented as new T?((T)s) * * This method also handles calling bindUserDefinedConverion. This method does NOT handle * the following conversions: * * Implicit boxing conversion from S? to { object, ValueType, Enum, ifaces implemented by S }. (Handled by BindImplicitConversion.) * If imp/exp S => T then explicit S?+ => T implemented by calling Value the appropriate number * of times. (Handled by BindExplicitConversion.) * * The recursive equivalent is: * * If imp/exp S => T and T is not nullable then explicit S? => T implemented as qs.Value * * Some nullable conversion are NOT standard conversions. In particular, if S => T is implicit * then S? => T is not standard. Similarly if S => T is not implicit then S => T? is not standard. ***************************************************************************************************/ private bool BindNubConversion(NullableType nubDst) { // This code assumes that STANDARD and ISEXPLICIT are never both set. // bindUserDefinedConversion should ensure this! Debug.Assert(0 != (~flags & (CONVERTTYPE.STANDARD | CONVERTTYPE.ISEXPLICIT))); Debug.Assert(exprSrc == null || exprSrc.type == typeSrc); Debug.Assert(!needsExprDest || exprSrc != null); Debug.Assert(typeSrc != nubDst); // BindImplicitConversion should have taken care of this already. AggregateType atsDst = nubDst.GetAts(GetErrorContext()); if (atsDst == null) { return(false); } // Check for the unboxing conversion. This takes precedence over the wrapping conversions. if (GetSymbolLoader().HasBaseConversion(nubDst.GetUnderlyingType(), typeSrc) && !CConversions.FWrappingConv(typeSrc, nubDst)) { // These should be different! Fix the caller if typeSrc is an AggregateType of Nullable. Debug.Assert(atsDst != typeSrc); // typeSrc is a base type of the destination nullable type so there is an explicit // unboxing conversion. if (0 == (flags & CONVERTTYPE.ISEXPLICIT)) { return(false); } if (needsExprDest) { binder.bindSimpleCast(exprSrc, exprTypeDest, out exprDest, EXPRFLAG.EXF_UNBOX); } return(true); } int cnubDst; int cnubSrc; CType typeDstBase = nubDst.StripNubs(out cnubDst); EXPRCLASS exprTypeDstBase = GetExprFactory().MakeClass(typeDstBase); CType typeSrcBase = typeSrc.StripNubs(out cnubSrc); ConversionFunc pfn = (flags & CONVERTTYPE.ISEXPLICIT) != 0 ? (ConversionFunc)binder.BindExplicitConversion : (ConversionFunc)binder.BindImplicitConversion; if (cnubSrc == 0) { Debug.Assert(typeSrc == typeSrcBase); // The null type can be implicitly converted to T? as the default value. if (typeSrc.IsNullType()) { // If we have the constant null, generate it as a default value of T?. If we have // some crazy expression which has been determined to be always null, like (null??null) // keep it in its expression form and transform it in the nullable rewrite pass. if (needsExprDest) { if (exprSrc.isCONSTANT_OK()) { exprDest = GetExprFactory().CreateZeroInit(nubDst); } else { exprDest = GetExprFactory().CreateCast(0x00, typeDest, exprSrc); } } return(true); } EXPR exprTmp = exprSrc; // If there is an implicit/explicit S => T then there is an implicit/explicit S => T? if (typeSrc == typeDstBase || pfn(exprSrc, typeSrc, exprTypeDstBase, nubDst, needsExprDest, out exprTmp, flags | CONVERTTYPE.NOUDC)) { if (needsExprDest) { // UNDONE: This is a premature realization of the nullable conversion as // UNDONE: a constructor. Rather than flagging this, can we simply emit it // UNDONE: as a cast node and have the operator rewrite pass turn it into // UNDONE: a constructor call? EXPRUSERDEFINEDCONVERSION exprUDC = exprTmp.kind == ExpressionKind.EK_USERDEFINEDCONVERSION ? exprTmp.asUSERDEFINEDCONVERSION() : null; if (exprUDC != null) { exprTmp = exprUDC.UserDefinedCall; } // This logic is left over from the days when T?? was legal. However there are error/LAF cases that necessitates the loop. // typeSrc is not nullable so just wrap the required number of times. For legal code (cnubDst <= 0). for (int i = 0; i < cnubDst; i++) { exprTmp = binder.BindNubNew(exprTmp); exprTmp.asCALL().nubLiftKind = NullableCallLiftKind.NullableConversionConstructor; } if (exprUDC != null) { exprUDC.UserDefinedCall = exprTmp; exprUDC.setType((CType)exprTmp.type); exprTmp = exprUDC; } Debug.Assert(exprTmp.type == nubDst); exprDest = exprTmp; } return(true); } // No builtin conversion. Maybe there is a user defined conversion.... return(0 == (flags & CONVERTTYPE.NOUDC) && binder.bindUserDefinedConversion(exprSrc, typeSrc, nubDst, needsExprDest, out exprDest, 0 == (flags & CONVERTTYPE.ISEXPLICIT))); } // Both are Nullable so there is only a conversion if there is a conversion between the base types. // That is, if there is an implicit/explicit S => T then there is an implicit/explicit S?+ => T?+. if (typeSrcBase != typeDstBase && !pfn(null, typeSrcBase, exprTypeDstBase, nubDst, false, out exprDest, flags | CONVERTTYPE.NOUDC)) { // No builtin conversion. Maybe there is a user defined conversion.... return(0 == (flags & CONVERTTYPE.NOUDC) && binder.bindUserDefinedConversion(exprSrc, typeSrc, nubDst, needsExprDest, out exprDest, 0 == (flags & CONVERTTYPE.ISEXPLICIT))); } if (needsExprDest) { MethWithInst mwi = new MethWithInst(null, null); EXPRMEMGRP pMemGroup = GetExprFactory().CreateMemGroup(null, mwi); EXPRCALL exprDst = GetExprFactory().CreateCall(0, nubDst, exprSrc, pMemGroup, null); // Here we want to first check whether or not the conversions work on the base types. EXPR arg1 = binder.mustCast(exprSrc, typeSrcBase); EXPRCLASS arg2 = GetExprFactory().MakeClass(typeDstBase); bool convertible; if (0 != (flags & CONVERTTYPE.ISEXPLICIT)) { convertible = binder.BindExplicitConversion(arg1, arg1.type, arg2, typeDstBase, out arg1, flags | CONVERTTYPE.NOUDC); } else { convertible = binder.BindImplicitConversion(arg1, arg1.type, arg2, typeDstBase, out arg1, flags | CONVERTTYPE.NOUDC); } if (!convertible) { VSFAIL("bind(Im|Ex)plicitConversion failed unexpectedly"); return(false); } exprDst.castOfNonLiftedResultToLiftedType = binder.mustCast(arg1, nubDst, 0); exprDst.nubLiftKind = NullableCallLiftKind.NullableConversion; exprDst.pConversions = exprDst.castOfNonLiftedResultToLiftedType; exprDest = exprDst; } return(true); }