//------------------------------------------------------------
// FUNCBREC.BindNubNew
//
/// <summary>
/// Create an expr for new T?(exprSrc) where T is exprSrc->type.
/// </summary>
/// <param name="treeNode"></param>
/// <param name="srcExpr"></param>
/// <returns></returns>
//------------------------------------------------------------
private EXPR BindNubNew(BASENODE treeNode, EXPR srcExpr)
{
DebugUtil.Assert(srcExpr != null);
// Create a NUBSYM instance whose base bype is represented by srcExpr.TypeSym.
NUBSYM nubSym = Compiler.MainSymbolManager.GetNubType(srcExpr.TypeSym);
// Get a TYPESYM instance representing Nullable<> for nubSym.
AGGTYPESYM aggTypeSym = nubSym.GetAggTypeSym();
if (aggTypeSym == null)
{
return(NewError(treeNode, nubSym));
}
Compiler.EnsureState(aggTypeSym, AggStateEnum.Prepared);
METHSYM methSym = Compiler.MainSymbolManager.NullableCtorMethodSym;
if (methSym == null)
{
string name = Compiler.NameManager.GetPredefinedName(PREDEFNAME.CTOR);
for (SYM sym = Compiler.MainSymbolManager.LookupAggMember(name, aggTypeSym.GetAggregate(), SYMBMASK.ALL);
;
sym = sym.NextSameNameSym)
{
if (sym == null)
{
Compiler.Error(treeNode, CSCERRID.ERR_MissingPredefinedMember,
new ErrArg(aggTypeSym), new ErrArg(name));
return(NewError(treeNode, nubSym));
}
if (sym.IsMETHSYM)
{
methSym = sym as METHSYM;
if (methSym.ParameterTypes.Count == 1 && methSym.ParameterTypes[0].IsTYVARSYM &&
methSym.Access == ACCESS.PUBLIC)
{
break;
}
}
}
Compiler.MainSymbolManager.NullableCtorMethodSym = methSym;
}
EXPRCALL resExpr = NewExpr(treeNode, EXPRKIND.CALL, nubSym) as EXPRCALL;
resExpr.MethodWithInst.Set(methSym, aggTypeSym, BSYMMGR.EmptyTypeArray);
resExpr.ArgumentsExpr = srcExpr;
resExpr.ObjectExpr = null;
resExpr.Flags |= EXPRFLAG.NEWOBJCALL | EXPRFLAG.CANTBENULL;
return(resExpr);
}
//------------------------------------------------------------
// FUNCBREC.BindNubOpRes (1)
//
/// <summary>
/// <para>Combine the condition and value.</para>
/// <para>(In sscli, warOnNull has the default value false.)</para>
/// </summary>
/// <param name="treeNode"></param>
/// <param name="nubSym"></param>
/// <param name="dstTypeSym"></param>
/// <param name="valueExpr"></param>
/// <param name="nubInfo"></param>
/// <param name="warnOnNull"></param>
/// <returns></returns>
//------------------------------------------------------------
private EXPR BindNubOpRes(
BASENODE treeNode,
NUBSYM nubSym,
TYPESYM dstTypeSym,
EXPR valueExpr,
ref NubInfo nubInfo,
bool warnOnNull) // = false
{
if (nubInfo.FAlwaysNull() && warnOnNull)
{
Compiler.Error(treeNode, CSCERRID.WRN_AlwaysNull, new ErrArg(nubSym));
}
return(BindNubOpRes(
treeNode,
dstTypeSym,
valueExpr,
NewExprZero(treeNode, dstTypeSym.IsNUBSYM ? dstTypeSym : nubSym),
ref nubInfo));
}
//------------------------------------------------------------
// FUNCBREC.BindNubConversion
//
// 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.
//
/// <summary></summary>
/// <param name="treeNode"></param>
/// <param name="srcExpr"></param>
/// <param name="srcTypeSym"></param>
/// <param name="dstNubSym"></param>
/// <param name="dstExpr"></param>
/// <param name="flags"></param>
/// <returns></returns>
//------------------------------------------------------------
private bool BindNubConversion(
BASENODE treeNode,
EXPR srcExpr,
TYPESYM srcTypeSym,
NUBSYM dstNubSym,
ref EXPR dstExpr,
ConvertTypeEnum flags)
{
// This code assumes that STANDARD and ISEXPLICIT are never both set.
// bindUserDefinedConversion should ensure this!
DebugUtil.Assert((~flags & (ConvertTypeEnum.STANDARD | ConvertTypeEnum.ISEXPLICIT)) != 0);
DebugUtil.Assert(srcExpr == null || srcExpr.TypeSym == srcTypeSym);
DebugUtil.Assert(dstExpr == null || srcExpr != null);
DebugUtil.Assert(srcTypeSym != dstNubSym);
// bindImplicitConversion should have taken care of this already.
AGGTYPESYM dstAggTypeSym = dstNubSym.GetAggTypeSym();
if (dstAggTypeSym == null)
{
return(false);
}
// Check for the unboxing conversion. This takes precedence over the wrapping conversions.
if (Compiler.IsBaseType(dstNubSym.BaseTypeSym, srcTypeSym) && !FWrappingConv(srcTypeSym, dstNubSym))
{
// These should be different! Fix the caller if srcTypeSym is an AGGTYPESYM of Nullable.
DebugUtil.Assert(dstAggTypeSym != srcTypeSym);
// srcTypeSym is a base type of the destination nullable type so there is an explicit
// unboxing conversion.
if ((flags & ConvertTypeEnum.ISEXPLICIT) == 0)
{
return(false);
}
return(BindSimpleCast(treeNode, srcExpr, dstNubSym, ref dstExpr, EXPRFLAG.UNBOX));
}
int dstNubStripCount;
int srcNubStripCount;
TYPESYM dstBaseTypeSym = dstNubSym.StripNubs(out dstNubStripCount);
TYPESYM srcBaseTypeSym = srcTypeSym.StripNubs(out srcNubStripCount);
bindNubConversion_Convert fnConvert;
EXPR expr = null; // temp
if ((flags & ConvertTypeEnum.ISEXPLICIT) != 0)
{
fnConvert = new bindNubConversion_Convert(BindExplicitConversion);
}
else
{
fnConvert = new bindNubConversion_Convert(BindImplicitConversion);
}
//bool (FUNCBREC::*pfn)(BASENODE *, EXPR *, TYPESYM *, TYPESYM *, EXPR **, uint) =
// (flags & ISEXPLICIT) ? &FUNCBREC::bindExplicitConversion : &FUNCBREC::bindImplicitConversion;
if (srcNubStripCount == 0)
{
DebugUtil.Assert(srcTypeSym == srcBaseTypeSym);
// The null type can be implicitly converted to T? as the default value.
if (srcTypeSym.IsNULLSYM)
{
dstExpr = AddSideEffects(treeNode, NewExprZero(treeNode, dstNubSym), srcExpr, true, true);
return(true);
}
EXPR tempExpr = srcExpr;
// If there is an implicit/explicit S => T then there is an implicit/explicit S => T?
if (srcTypeSym == dstBaseTypeSym ||
fnConvert(
treeNode,
srcExpr,
srcTypeSym,
dstBaseTypeSym,
ref tempExpr,
flags | ConvertTypeEnum.NOUDC))
{
// srcTypeSym is not nullable so just wrap the required number of times.
for (int i = 0; i < dstNubStripCount; i++)
{
tempExpr = BindNubNew(treeNode, tempExpr);
}
DebugUtil.Assert(tempExpr.TypeSym == dstNubSym);
dstExpr = tempExpr;
return(true);
}
// No builtin conversion. Maybe there is a user defined conversion....
return(
(flags & ConvertTypeEnum.NOUDC) == 0 &&
BindUserDefinedConversion(
treeNode,
srcExpr,
srcTypeSym,
dstNubSym,
ref dstExpr,
(flags & ConvertTypeEnum.ISEXPLICIT) == 0));
}
// 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 (srcBaseTypeSym != dstBaseTypeSym &&
!fnConvert(treeNode, null, srcBaseTypeSym, dstBaseTypeSym, ref expr, flags | ConvertTypeEnum.NOUDC))
{
// No builtin conversion. Maybe there is a user defined conversion....
return(
(flags & ConvertTypeEnum.NOUDC) == 0 &&
BindUserDefinedConversion(
treeNode,
srcExpr,
srcTypeSym,
dstNubSym,
ref dstExpr,
(flags & ConvertTypeEnum.ISEXPLICIT) == 0));
}
// We need to go all the way down to the base types, do the conversion, then come all the way back up.
EXPR valExpr;
NubInfo nubInfo = new NubInfo();
BindNubCondValBin(
treeNode,
srcExpr,
null,
ref nubInfo,
LiftFlagsEnum.LiftBoth);
valExpr = nubInfo.Val(0);
DebugUtil.Assert(valExpr.TypeSym == srcBaseTypeSym);
if (!fnConvert(
treeNode,
valExpr,
valExpr.TypeSym,
dstBaseTypeSym,
ref valExpr,
flags | ConvertTypeEnum.NOUDC))
{
DebugUtil.Assert(false, "bind(Im|Ex)plicitConversion failed unexpectedly");
return(false);
}
for (int i = 0; i < dstNubStripCount; i++)
{
valExpr = BindNubNew(treeNode, valExpr);
}
DebugUtil.Assert(valExpr.TypeSym == dstNubSym);
dstExpr = BindNubOpRes(treeNode, dstNubSym, dstNubSym, valExpr, ref nubInfo, false);
return(true);
}