I am still struggling with value restriction rules. When exactly the explicit type definition is necessary and when it is redundant. Here is my latest encounter:

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    type ValueListNode(nodeType, token: TextToken, location, values)  =
            
        let body = token.Text
            
    type TagNameNode (context: ParsingContext, token, location) =
        inherit ValueListNode
            (
                NodeType.TagName, 
                token,
                location,
                context.Tags
            )
            
    type KeywordNode (token:TextToken, location, values:string list) =
        inherit ValueListNode
            (
                NodeType.Keyword, 
                token,
                location,
                values
            )
            

The code here shows a base type (ValueListNode) and two derived types. Each one calls the constructor of the base type. But for some reason while the TagName node is prefectly happy without explicit type for token, but when I try to remove the type definition from the KeywordNode it complains with the following message:

"Value restriction. This member has been inferred to have generic type internal new : token:'_a * location:(int * int) * values:string list -> ParserNodes.KeywordNode when '_a :> TextToken Constructors and property getters/setters cannot be more generic than the enclosing type. Add a type annotation to indicate the exact types involved. C:\Hill30\NDjango\NDjangoParser\ParserNodes.fs 173 10 NDjangoParser