/// <summary>
/// Returns the better type amongst the two, with some possible modifications (dynamic/object or tuple names).
/// </summary>
private TypeSymbol Better(TypeSymbol type1, TypeSymbol type2, ref HashSet <DiagnosticInfo> useSiteDiagnostics)
{
// Anything is better than an error sym.
if (type1.IsErrorType())
{
return(type2);
}
if ((object)type2 == null || type2.IsErrorType())
{
return(type1);
}
var t1tot2 = _conversions.ClassifyImplicitConversionFromType(type1, type2, ref useSiteDiagnostics).Exists;
var t2tot1 = _conversions.ClassifyImplicitConversionFromType(type2, type1, ref useSiteDiagnostics).Exists;
if (t1tot2 && t2tot1)
{
if (type1.IsDynamic())
{
return(type1);
}
if (type2.IsDynamic())
{
return(type2);
}
if (type1.Equals(type2, TypeCompareKind.IgnoreDynamicAndTupleNames))
{
return(MethodTypeInferrer.MergeTupleNames(type1, type2, MethodTypeInferrer.MergeDynamic(type1, type2, type1, _conversions.CorLibrary), _conversions.CorLibrary));
}
return(null);
}
if (t1tot2)
{
return(type2);
}
if (t2tot1)
{
return(type1);
}
return(null);
}
