Hello everyone,

I do not understand what the compiler is unhappy about and how to fix it:

let myExpression= <@ fun a - > a @>

Error 1 Value restriction. Type inference has inferred the signature val myExpression : Quotations.Expr<('_a -> '_a)> Either define 'myExpression' as a simple data term, make it a function, or add a type constraint to instantiate the type parameters.

Value restriction is actually independent of quotations, though it seems some extra constraints are in place in this case. It's basically a limitation of type inference in the presence of side-effects.

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let g = id >> id

Produces a similar error. You have typically a few ways of getting around the value restriction, as the error message explains. ("Either define...").It's kind of complex and some of it I don't reallly understand myself yet, so I'll put a link here ;)[link:www.strangelights.com]

I think you want e.g.

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let f<'a> = <@ (fun (x:'a) -> x) @>