Method not fournd: SystemCollections.Generic IEqualityComparer'1

[KevinRansom]

Opened by jackfoxy on codeplex

12/18/14 daily build found this issue at runtime:

System.MissingMethodException : Method not fournd: SystemCollections.Generic IEqualityComparer'1

 let checkForColumnHeaderDifference (expected: seq<string>) (actual: seq<string>) =
    let expected = HashSet(expected, HashIdentity.StringIgnoreCase)

fails on "let expected = ..." 
 System.Collections.Generic.HashSet 

(Having problems getting the debugger to run to the affected line (VM issue) ...so I can't currently tell you the values of "expected" and "actual" coming into the function.)

comments
jackfoxy wrote Dec 23, 2014 at 7:55 PM [x]
Update: fixed my VM, and there is nothing remarkable about the data coming into the function, simply a string sequence of length 13.

latkin wrote Dec 23, 2014 at 10:20 PM [x]
Can you provide a ZIP of a repro solution?

A few other questions -- What version of FSharp.Core are you using? What .NET version/profile are you targeting? What is HashIdentity.StringIgnoreCase?

jackfoxy wrote Dec 24, 2014 at 10:13 AM [x]

I researched this issue on a VM on my work machine. I won't have access again until 1/5/15. If this issue is still open then I will attempt a repro solution.

The original app was built on FSharp.Core, 4.3.1.0. I simply changed the Target F# runtime to F#4.0 within the project property page of VS 2015 preview and rebuilt the solution within VS.

A repro app "should" just consist of the following:

open System.Collections.Generic

let checkForColumnHeaderDifference (expected: seq) (actual: seq) =
let expected = HashSet(expected, HashIdentity.StringIgnoreCase)
expected

>>>>vladima wrote Dec 24, 2014 at 11:14 AM [x] 

>>>>Given that FSharp.Core does not expose StringIgnoreCase on  HashIdentity module I suspect that repro should include something else (that presumably defines this extrinsic extension property)

>>>>>jackfoxy wrote Dec 24, 2014 at 11:33 AM [x] 

>>>>>@vladima right you are. I found this additional code:
````fsharp
module HashIdentity =
        let ByProjection (f: 'A -> 'B) (eq: IEqualityComparer<'B>) : IEqualityComparer<'A> =
            let hasher x = eq.GetHashCode(f x)
            let equality x y = eq.Equals(f x, f y)
            HashIdentity.FromFunctions hasher equality
        let StringIgnoreCase =
            HashIdentity.Structural<string>
            |> ByProjection (fun (x: string) -> x.ToLower())

vladima wrote Dec 24, 2014 at 11:51 AM [x]

Is this code located in the same project or in different dll? For the latter case - what version of FSharp.Core is referenced in this assembly?

vladima wrote Dec 24, 2014 at 12:01 PM [x]

Ok, I have a guess: can you check if autogeneration of binding redirects is enabled in the repro project (http://msdn.microsoft.com/en-us/library/2fc472t2%28v=vs.110%29.aspx), enable it if it is disabled and check if the problem still exists

jackfoxy wrote Dec 24, 2014 at 2:20 PM [x]
All the code is in the same project, and in fact in the same file.

There is no specified in the fsproj file, but there is true

Like I said above, I will not be able to work on the VM I have created for testing F#4.0 again until 1/5/15.

dsyme wrote Today at 1:23 AM [x]

It looks important to get to the bottom of this in case it is somehow related to the perf improvements for hash/compare/equality in F# 4.0 (though I think the likely solution is to add AutoGenerateBindingRedirects)

jackfoxy wrote Today at 5:00 PM [x]

My most recent research led me to suspect this issue involves the Target Framework .NET Portable Subset (.NET Framework 4.5, Windows 8) and Target F# runtime F# 4.0 (FSharp.Core, 3.7.4.0), but in attempting to set up a simple problem replication project that target framework is not available to me in VS2015, and the only target runtime available is F# 4.0 (FSharp.Core, 4.4.0.0).

As another issue in creating a replication project, my test environment somehow regressed to where I am failing on issue https://visualfsharp.codeplex.com/workitem/176, and I currently cannot replicate this reported issue. Fixing 176 should take precedence.

[jackfoxy]

Cannot replicate with Visual FSharp 4.0 Preview 01-15-2015, suggest closing this issue.

[dsyme]

OK, I'm closing this