public ExprUserDefinedConversion CreateUserDefinedConversion(Expr arg, Expr call, MethWithInst mwi) { Debug.Assert(arg != null); Debug.Assert(call != null); ExprUserDefinedConversion rval = new ExprUserDefinedConversion(); rval.Argument = arg; rval.UserDefinedCall = call; rval.UserDefinedCallMethod = mwi; if (call.HasError) { rval.SetError(); } return(rval); }
private Expr GenerateUserDefinedConversion(ExprUserDefinedConversion pExpr, Expr pArgument) { Expr pCastCall = pExpr.UserDefinedCall; Expr pCastArgument = pExpr.Argument; Expr pConversionSource; if (!isEnumToDecimalConversion(pArgument.Type, pExpr.Type) && IsNullableValueAccess(pCastArgument, pArgument)) { // We have an implicit conversion of nullable CType to the value CType, generate a convert node for it. pConversionSource = GenerateValueAccessConversion(pArgument); } else { ExprCall call = pCastCall as ExprCall; Expr pUDConversion = call?.PConversions; if (pUDConversion != null) { if (pUDConversion is ExprCall convCall) { Expr pUDConversionArgument = convCall.OptionalArguments; if (IsNullableValueAccess(pUDConversionArgument, pArgument)) { pConversionSource = GenerateValueAccessConversion(pArgument); } else { pConversionSource = Visit(pUDConversionArgument); } return(GenerateConversionWithSource(pConversionSource, pCastCall.Type, call.isChecked())); } // This can happen if we have a UD conversion from C to, say, int, // and we have an explicit cast to decimal?. The conversion should // then be bound as two chained user-defined conversions. Debug.Assert(pUDConversion is ExprUserDefinedConversion); // Just recurse. return(GenerateUserDefinedConversion((ExprUserDefinedConversion)pUDConversion, pArgument)); } pConversionSource = Visit(pCastArgument); } return(GenerateUserDefinedConversion(pCastArgument, pExpr.Type, pConversionSource, pExpr.UserDefinedCallMethod)); }
public ExprUserDefinedConversion CreateUserDefinedConversion(Expr arg, Expr call, MethWithInst mwi) { Debug.Assert(arg != null); Debug.Assert(call != null); ExprUserDefinedConversion rval = new ExprUserDefinedConversion(); rval.Kind = ExpressionKind.EK_USERDEFINEDCONVERSION; rval.Type = call.Type; rval.Flags = 0; rval.Argument = arg; rval.UserDefinedCall = call; rval.UserDefinedCallMethod = mwi; if (call.HasError) { rval.SetError(); } Debug.Assert(rval != null); return(rval); }
protected override Expr VisitUSERDEFINEDCONVERSION(ExprUserDefinedConversion expr) { Debug.Assert(expr != null); return(GenerateUserDefinedConversion(expr, expr.Argument)); }
/*************************************************************************************************** * 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); }
protected virtual Expr VisitUSERDEFINEDCONVERSION(ExprUserDefinedConversion pExpr) { return(VisitEXPR(pExpr)); }