Compile-time error with generative type provider

Question

I've run into an issue with on a branch of FSharp.Data.SqlClient I am working on with the generative SqlEnumProvider type provider. When the test project attemps to use a provided type, I get the following compile-time error:

A problem occurred writing the binary 'C:\code\FSharp.Data.SqlClient\src\SqlClient.Tests\obj\Debug\net451\SqlClient.Tests.dll': Error in pass3 for type FSharp.Data.EnumTests, error: Error in GetMethodRefAsMethodDefIdx for mref = ("Parse", "TinyIntMapping"), error: Exception of type 'Microsoft.FSharp.Compiler.AbstractIL.ILBinaryWriter+MethodDefNotFound' was thrown.

At design time, everything appears to be working as expected. (I have intellisense on the provided types, etc.)

I attempted the workaround suggested here, but no joy.

score 1 · Answer 1 · answered Oct 22 '18 at 09:00

1

How about using the container approach where you place all of the provided types into a container, decanting each one you need?

I used this in quite a few of my type providers, have a look at the iOS designer type provider for reference: https://github.com/xamarin/fsharp-iOS-designer/blob/master/src/Xamarin.iOSProviders/iOSDesignerProvider.fs#L64-L86

answered Oct 22 '18 at 09:00

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Yes, this is very similar to what I've got now, thanks for the suggestion! – Sam Hanes Oct 23 '18 at 13:39

score 1 · Accepted Answer · answered Oct 23 '18 at 13:36

It turns out the answer was in the sample template in the SDK, I just wasn't reading it closely enough:

The provider type (e.g., SqlEnumProvider) should be added to the executing assembly.
The root types (e.g., SqlEnumProvider<"SELECT * FROM (VALUES(('One'), 1), ('Two', 2)) AS T(Tag, Value)">) should be added to the provided assembly.

In the failing code, we were adding the root types to both assemblies.

Compile-time error with generative type provider

2 Answers2