bool MatchDisposeCheck(ILVariable objVar, ILInstruction checkInst, bool isReference, bool usingNull, out int numObjVarLoadsInCheck)
{
numObjVarLoadsInCheck = 2;
CallVirt callVirt;
if (objVar.Type.IsKnownType(KnownTypeCode.NullableOfT))
{
if (checkInst.MatchIfInstruction(out var condition, out var disposeInst))
{
if (!NullableLiftingTransform.MatchHasValueCall(condition, objVar))
{
return(false);
}
if (!(disposeInst is Block disposeBlock) || disposeBlock.Instructions.Count != 1)
{
return(false);
}
callVirt = disposeBlock.Instructions[0] as CallVirt;
}
else if (checkInst.MatchNullableRewrap(out disposeInst))
{
callVirt = disposeInst as CallVirt;
}
else
{
return(false);
}
if (callVirt == null)
{
return(false);
}
if (callVirt.Method.FullName != "System.IDisposable.Dispose")
{
return(false);
}
if (callVirt.Method.Parameters.Count > 0)
{
return(false);
}
if (callVirt.Arguments.Count != 1)
{
return(false);
}
var firstArg = callVirt.Arguments.FirstOrDefault();
if (!(firstArg.MatchUnboxAny(out var innerArg1, out var unboxType) && unboxType.IsKnownType(KnownTypeCode.IDisposable)))
{
if (!firstArg.MatchAddressOf(out var innerArg2, out _))
{
return(false);
}
return(NullableLiftingTransform.MatchGetValueOrDefault(innerArg2, objVar) ||
(innerArg2 is NullableUnwrap unwrap &&
unwrap.Argument.MatchLdLoc(objVar)));
}
else
{
if (!(innerArg1.MatchBox(out firstArg, out var boxType) && boxType.IsKnownType(KnownTypeCode.NullableOfT) &&
NullableType.GetUnderlyingType(boxType).Equals(NullableType.GetUnderlyingType(objVar.Type))))
{
return(false);
}
return(firstArg.MatchLdLoc(objVar));
}
}