Fsharpc cannot generate fsi files - f#

Question

I am trying to generate the fsi file for a particular fs file.
Config.fs:
namespace Web2
open FSharp.Data
module Config =
type JsonConfig =
JsonProvider<Sample="./config.json">
let config =
JsonConfig.Load("./config.json")
Generating the signature file:
fsharpc --sig:Config.fsi Config.fs
Error:
Microsoft (R) F# Compiler version 10.2.3 for F# 4.5
Copyright (c) Microsoft Corporation. All Rights Reserved.
Config.fs(8,5): error FS0039: The type 'JsonProvider' is not defined.
Config.fs(8,5): error FS0039: The type 'JsonProvider' is not defined.
Config.fs(11,16): error FS0039: The field, constructor or member 'Load' is not defined.
Not sure what I am doing wrong.

Answer 1

The issue is that the code in Config.fs depends on JsonProvider which comes from the FSharp.Data.dll library - but when you invoke the compiler, you are not specifying the dependency.
You can do that by using the -r command line option:
fsharpc -r:whatever/folder/FSharp.Data.dll --sig:Config.fsi Config.fs
In general, if you are compiling a project, the references are specified in the project file and so you do not need to specify them elsewhere. But when you're invoking the compiler directly, you need to do that.