protected virtual EXPR GenerateConversion(EXPR arg, CType CType, bool bChecked)
{
return GenerateConversionWithSource(Visit(arg), CType, bChecked || arg.isChecked());
}
protected virtual EXPR GenerateUserDefinedConversion(EXPR arg, CType CType, EXPR target, MethWithInst method)
{
// The user-defined explicit conversion from enum? to decimal or decimal? requires
// that we convert the enum? to its nullable underlying CType.
if (isEnumToDecimalConversion(arg.type, CType))
{
// Special case: If we have enum? to decimal? then we need to emit
// a conversion from enum? to its nullable underlying CType first.
// This is unfortunate; we ought to reorganize how conversions are
// represented in the EXPR tree so that this is more transparent.
// converting an enum to its underlying CType never fails, so no need to check it.
CType underlyingType = arg.type.StripNubs().underlyingEnumType();
CType nullableType = GetSymbolLoader().GetTypeManager().GetNullable(underlyingType);
EXPR typeofNubEnum = CreateTypeOf(nullableType);
target = GenerateCall(PREDEFMETH.PM_EXPRESSION_CONVERT, target, typeofNubEnum);
}
// If the methodinfo does not return the target CType AND this is not a lifted conversion
// from one value CType to another, then we need to wrap the whole thing in another conversion,
// e.g. if we have a user-defined conversion from int to S? and we have (S)myint, then we need to generate
// Convert(Convert(myint, typeof(S?), op_implicit), typeof(S))
CType pMethodReturnType = GetSymbolLoader().GetTypeManager().SubstType(method.Meth().RetType,
method.GetType(), method.TypeArgs);
bool fDontLiftReturnType = (pMethodReturnType == CType || (IsNullableValueType(arg.type) && IsNullableValueType(CType)));
EXPR typeofInner = CreateTypeOf(fDontLiftReturnType ? CType : pMethodReturnType);
EXPR methodInfo = GetExprFactory().CreateMethodInfo(method);
PREDEFMETH pdmInner = arg.isChecked() ? PREDEFMETH.PM_EXPRESSION_CONVERTCHECKED_USER_DEFINED : PREDEFMETH.PM_EXPRESSION_CONVERT_USER_DEFINED;
EXPR callUserDefinedConversion = GenerateCall(pdmInner, target, typeofInner, methodInfo);
if (fDontLiftReturnType)
{
return callUserDefinedConversion;
}
PREDEFMETH pdmOuter = arg.isChecked() ? PREDEFMETH.PM_EXPRESSION_CONVERTCHECKED : PREDEFMETH.PM_EXPRESSION_CONVERT;
EXPR typeofOuter = CreateTypeOf(CType);
return GenerateCall(pdmOuter, callUserDefinedConversion, typeofOuter);
}
protected virtual EXPR GenerateQuestionMarkOperand(EXPR pExpr)
{
Debug.Assert(pExpr != null);
// We must not optimize away compiler-generated reference casts because
// the expression tree API insists that the CType of both sides be identical.
if (pExpr.isCAST())
{
return GenerateConversion(pExpr.asCAST().GetArgument(), pExpr.type, pExpr.isChecked());
}
return Visit(pExpr);
}
