//------------------------------------------------------------
// FUNCBREC.HasIEnumerable (2)
//
/// <summary>
/// Rewrite HasIEnumerable for collection initializer.
/// Return the IEnumerable or IEnumerable<T> instance.
/// </summary>
/// <param name="collection"></param>
/// <param name="tree"></param>
/// <param name="badType"></param>
/// <param name="badMember"></param>
/// <returns></returns>
//------------------------------------------------------------
private AGGTYPESYM HasIEnumerable(
TYPESYM collectionTypeSym/*,
* BASENODE treeNode,
* TYPESYM badTypeSym,
* PREDEFNAME badMemberName*/
)
{
AGGTYPESYM ifaceCandidateAts = null;
// First try the generic interfaces
AGGSYM gEnumAggSym
= Compiler.GetOptPredefAgg(PREDEFTYPE.G_IENUMERABLE, true);
TypeArray allIfacesTypeArray = null;
AGGTYPESYM baseAts = null;
// If generics don't exist or the type isn't an AGGTYPESYM
// then we can't check the interfaces (and base-class interfaces)
// for IEnumerable<T> so immediately try the non-generic IEnumerable
if (gEnumAggSym == null)
{
goto NO_GENERIC;
}
if (collectionTypeSym.IsAGGTYPESYM)
{
if (collectionTypeSym.GetAggregate() == gEnumAggSym ||
collectionTypeSym.IsPredefType(PREDEFTYPE.IENUMERABLE))
{
DebugUtil.Assert(false, "IEnumerable/ator types are bad!");
goto LERROR;
}
AGGTYPESYM tempAts = collectionTypeSym as AGGTYPESYM;
allIfacesTypeArray = tempAts.GetIfacesAll();
baseAts = tempAts.GetBaseClass();
}
else if (collectionTypeSym.IsTYVARSYM)
{
// Note:
// we'll search the interface list before the class constraint,
// but it doesn't matter since we require a unique instantiation of IEnumerable<T>.
// Note:
// The pattern search will usually find the interface constraint
// - but if the class constraint has a non-public or non-applicable
// or non-method GetEnumerator,
// the interfaces are hidden in which case we will find them here.
TYVARSYM tempTvSym = collectionTypeSym as TYVARSYM;
allIfacesTypeArray = tempTvSym.AllInterfaces;
baseAts = tempTvSym.BaseClassSym;
}
else
{
goto NO_GENERIC;
}
DebugUtil.Assert(allIfacesTypeArray != null);
// If the type implements exactly one instantiation of
// IEnumerable<T> then it's the one.
//
// If it implements none then try the non-generic interface.
//
// If it implements more than one, then it's an error.
//
// Search the direct and indirect interfaces via allIfacesTypeArray,
// going up the base chain...
// Work up the base chain
for (; ;)
{
// Now work across all the interfaces
for (int i = 0; i < allIfacesTypeArray.Count; ++i)
{
AGGTYPESYM iface = allIfacesTypeArray[i] as AGGTYPESYM;
if (iface.GetAggregate() == gEnumAggSym)
{
if (ifaceCandidateAts == null)
{
// First implementation
ifaceCandidateAts = iface;
}
else if (iface != ifaceCandidateAts)
{
// If this really is a different instantiation report an error
Compiler.Error(
treeNode,
CSCERRID.ERR_MultipleIEnumOfT,
new ErrArgRef(collectionTypeSym),
new ErrArg(gEnumAggSym.GetThisType()));
return(null);
}
}
}
// Check the base class.
if (baseAts == null)
{
break;
}
allIfacesTypeArray = baseAts.GetIfacesAll();
baseAts = baseAts.GetBaseClass();
}
// Report the one and only generic interface
if (ifaceCandidateAts != null)
{
DebugUtil.Assert(
CanConvert(collectionTypeSym, ifaceCandidateAts, ConvertTypeEnum.NOUDC));
return(ifaceCandidateAts);
}
NO_GENERIC:
if (collectionTypeSym.IsPredefType(PREDEFTYPE.IENUMERABLE))
{
DebugUtil.VsFail("Why didn't IEnumerator match the pattern?");
goto LERROR;
}
// No errors, no generic interfaces, try the non-generic interface
ifaceCandidateAts = GetRequiredPredefinedType(PREDEFTYPE.IENUMERABLE);
if (CanConvert(collectionTypeSym, ifaceCandidateAts, ConvertTypeEnum.NOUDC))
{
return(ifaceCandidateAts);
}
LERROR:
return(null);
}
