Compiler allows us to box a byreflike type, leading to runtime crash

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Compiler allows us to box a byreflike type, leading to runtime crash #7114

Open cartermp opened 5 years ago

cartermp commented 5 years ago

Consider this program:

open System

[<EntryPoint>]
let main argv =
    let sp = Span<int>.Empty
    let x = sp.GetType()
    printfn "%b" x.IsValueType
    0 // return an integer exit code

Result:

Expected:

This should fail to compiler
IntelliSense should also not suggest things like GetType() in the completion list (ref: https://github.com/dotnet/roslyn/issues/35178)

TIHan commented 5 years ago

Yea, I've been aware of this for a while but never created an issue for it. Should be fairly straightforward to filter out the common functions of an object.