/// <summary>
/// Gets the best common type (C# 4.0 spec: §7.5.2.14) of a set of expressions.
/// </summary>
public IType GetBestCommonType(IList <ResolveResult> expressions, out bool success)
{
if (expressions == null)
{
throw new ArgumentNullException("expressions");
}
if (expressions.Count == 1)
{
success = (expressions[0].Type.Kind != TypeKind.Unknown);
return(expressions[0].Type);
}
Log.WriteCollection("GetBestCommonType() for ", expressions);
try {
ITypeParameter tp = DummyTypeParameter.GetMethodTypeParameter(0);
this.typeParameters = new TP[1] {
new TP(tp)
};
foreach (ResolveResult r in expressions)
{
MakeOutputTypeInference(r, tp);
}
success = Fix(typeParameters[0]);
return(typeParameters[0].FixedTo ?? SpecialType.UnknownType);
} finally {
Reset();
}
}
public override IType VisitTypeParameter(ITypeParameter type)
{
if (type.OwnerType == EntityType.Method)
{
return(DummyTypeParameter.GetMethodTypeParameter(type.Index));
}
else
{
return(base.VisitTypeParameter(type));
}
}
public ITypeParameter GetMethodTypeParameter(int index)
{
if (index < MethodTypeParameters?.Count)
{
return(MethodTypeParameters[index]);
}
else
{
return(DummyTypeParameter.GetMethodTypeParameter(index));
}
}
public override IType VisitTypeParameter(ITypeParameter type)
{
if (type.OwnerType == SymbolKind.Method && ReplaceMethodTypeParametersWithDummy)
{
return(DummyTypeParameter.GetMethodTypeParameter(type.Index));
}
else if (type.OwnerType == SymbolKind.TypeDefinition && ReplaceClassTypeParametersWithDummy)
{
return(DummyTypeParameter.GetClassTypeParameter(type.Index));
}
else
{
return(base.VisitTypeParameter(type));
}
}
public override IType VisitTypeParameter(ITypeParameter type)
{
if (type.OwnerType == SymbolKind.Method && ReplaceMethodTypeParametersWithDummy)
{
return(DummyTypeParameter.GetMethodTypeParameter(type.Index));
}
else if (type.OwnerType == SymbolKind.TypeDefinition && ReplaceClassTypeParametersWithDummy)
{
return(DummyTypeParameter.GetClassTypeParameter(type.Index));
}
else if (RemoveNullability && type is NullabilityAnnotatedTypeParameter natp)
{
return(natp.TypeWithoutAnnotation.AcceptVisitor(this));
}
else
{
return(base.VisitTypeParameter(type));
}
}