From 77762e774274c82977bbf4f0c3681c75b91c1d4d Mon Sep 17 00:00:00 2001 From: Sam Tobin-Hochstadt Date: Tue, 21 May 2013 07:53:43 +0100 Subject: [PATCH] Add comment. original commit: 9f659c7df30b42ec49e6da1d85b5a0e5605fdcd1 --- .../typed-racket-lib/typed-racket/infer/constraints.rkt | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/constraints.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/constraints.rkt index 564060de..0433c801 100644 --- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/constraints.rkt +++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/infer/constraints.rkt @@ -12,7 +12,8 @@ (import restrict^ dmap^) (export constraints^) - +;; It's hard to remove this use of exceptions +;; because there's no monadic version of `hash-union` etc (define-values (fail-sym exn:infer?) (let ([sym (gensym 'infer-fail)]) (values sym (λ (s) (and (pair? s) (eq? (car s) sym))))))