An interesting bit of F# behaviour

In one assembly, define a public static class in C#:

	namespace ClassLibrary1
	{
	public static class Class1
	{
	public static string Hello()
	{
	return "Hello";
	}
	}
	}

view raw gistfile1.cs hosted with ❤ by GitHub

In another do something similar in F#:

	namespace ClassLibrary1
	module Module1 =
	let Hello () = "Hello"

view raw gistfile1.fs hosted with ❤ by GitHub

which Reflector tells us is equivalent to

	[CompilationMapping(SourceConstructFlags.Module)]
	public static class Module1
	{
	// Methods
	public static string Hello()
	{
	return "Hello";
	}
	}

view raw gistfile1.cs hosted with ❤ by GitHub

inside namespace ClassLibrary1. Now create another F# library referencing the previous two containing

	namespace ClassLibrary1
	module Module1 =
	let type1 = typeof<ClassLibrary1.Class1>
	let type2 = typeof<ClassLibrary1.Module1>

view raw gistfile1.fs hosted with ❤ by GitHub

The first line compiles; the second doesn't, failing with compile error error FS0039: The type 'Module1' is not defined.

Clearly the CompilationMapping is being sniffed by the typeof operation, because that is the only difference between the two.