Possible null reference return.

Possible null reference argument for parameter 'parser' in 'TokenListParser<PythonToken, PythonTypeSpec?> Combinators.OptionalOrDefault<PythonToken, PythonTypeSpec?>(TokenListParser<PythonToken, PythonTypeSpec?> parser, PythonTypeSpec? defaultValue = null)'.

Possible null reference argument for parameter 'parser' in 'TokenListParser<PythonToken, PythonTypeSpec?> Combinators.OptionalOrDefault<PythonToken, PythonTypeSpec?>(TokenListParser<PythonToken, PythonTypeSpec?> parser, PythonTypeSpec? defaultValue = null)'.

Possible null reference argument for parameter 'parser' in 'TokenListParser<PythonToken, PythonTypeSpec?[]> Combinators.ManyDelimitedBy<PythonToken, PythonTypeSpec?, Token<PythonToken>>(TokenListParser<PythonToken, PythonTypeSpec?> parser, TokenListParser<PythonToken, Token<PythonToken>> delimiter, TokenListParser<PythonToken, Token<PythonToken>>? end = null)'.

Argument of type 'TokenListParser<PythonToken, PythonTypeSpec?[]>' cannot be used for parameter 'parser' of type 'TokenListParser<PythonToken, PythonTypeSpec?[]?>' in 'TokenListParser<PythonToken, PythonTypeSpec?[]?> Combinators.OptionalOrDefault<PythonToken, PythonTypeSpec?[]?>(TokenListParser<PythonToken, PythonTypeSpec?[]?> parser, PythonTypeSpec?[]? defaultValue = null)' due to differences in the nullability of reference types.

Converting null literal or possible null value to non-nullable type.

Possible null reference return.

Parameter 'string version' is captured into the state of the enclosing type and its value is also passed to the base constructor. The value might be captured by the base class as well.

Possible null reference argument for parameter 'o' in 'PyObject PyObjectTypeConverter.ToPython(object o, ITypeDescriptorContext? context, CultureInfo? culture)'.