Instantiating a generative type provider twice results in invalid IL

[KevinRansom]

[from fsbugs]

If one defines a generative type provider with some fields/properties, then creates 2 identical versions of that provided type:

type T2 = Samples.ShareInfo.TPTest.TPTestType
type T  = Samples.ShareInfo.TPTest.TPTestType

the resulting assembly contains invalid IL.

file attachments

• reproSln.zip

comments latkin wrote Mar 24, 2014 at 4:22 PM [x]

[investigation from Vlad] It looks like a bug in type relocation code in fsc.fs around ~1531.

Here we have 2 type reference T and T2 that point to one actual type definition so the final copy-and-update expression below will create 2 different ILTypeDefs that originate from the same ILTypeDef => they will share same set of members (up to reference equality) => later it will lead to unexpected consequences in codegen because we'll generate normal type T2 and type T where property definition uses metadata token of getter from the type T2 => invalid IL.

 let generatedILTypeDefs = 
    let rec buildRelocatedGeneratedType (ProviderGeneratedType(ilOrigTyRef, ilTgtTyRef, ch)) = 
        let isNested = ilTgtTyRef.Enclosing |> nonNil
        if allTypeDefsInProviderGeneratedAssemblies.ContainsKey ilOrigTyRef then 
            let ilOrigTypeDef = allTypeDefsInProviderGeneratedAssemblies.[ilOrigTyRef]
            if debugStaticLinking then printfn "Relocating %s to %s " ilOrigTyRef.QualifiedName ilTgtTyRef.QualifiedName
            { ilOrigTypeDef with 
                  Name = ilTgtTyRef.Name
                  Access = (match ilOrigTypeDef.Access with 
                            | ILTypeDefAccess.Public when isNested -> ILTypeDefAccess.Nested ILMemberAccess.Public 
                            | ILTypeDefAccess.Private when isNested -> ILTypeDefAccess.Nested ILMemberAccess.Assembly 
                            | x -> x)
                  NestedTypes = mkILTypeDefs (List.map buildRelocatedGeneratedType ch) }

[enricosada]

additional info/repro in @7Sharp9 https://github.com/Microsoft/visualfsharp/issues/905#issue-129416759

[7sharp9]

@enricosada I was going to add a comment, got distracted though :-)

[enricosada]

@7sharp9 np, it's a nice bug report and useful info, better not lose it