From 96e5fab77f20d12c3c160646092eeb4ddc489152 Mon Sep 17 00:00:00 2001
From: Joseph Ferano <joseph@ferano.io>
Date: Thu, 17 Sep 2026 22:12:54 +0700
Subject: [PATCH] flan run does not offer --dev, and says so rather than
 building one

--dev builds a program whose call sites go through indirection cells so
something can attach and redefine through them. Nothing can attach to a
process this command builds, execs, waits for and deletes, so the flag had no
meaning here -- and an --x86 --dev route through run would have falsified
Build's own statement that flan dev never reaches that fork because --x86 is
read only by flan build. It falls into the refusal arm with a sentence
instead.
---
 bin/main.ml | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/bin/main.ml b/bin/main.ml
index 5801d72..4f8455c 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -704,8 +704,18 @@ let () =
        one's own that wants [-v] has [--] to ask for it. Plain arguments need
        no ceremony: they were never ambiguous and they still go straight
        through, so [flan run calc-me.flan "1+2"] is unchanged. *)
-    let run_flags = [ no_checks_flag; dev_flag; debug_flag; sanitize_flag;
-                      x86_flag ] @ opt_levels in
+    (* --dev is deliberately not on this list, and its absence is the point:
+       a dev build's indirection cells exist so that something can attach and
+       redefine through them, and nothing can attach to a process this command
+       builds, execs, waits for and deletes. Leaving it off means it lands in
+       the refusal below with a sentence, rather than quietly producing a
+       spelling [Build] says does not exist — [flan build]'s --x86 arm records
+       that `flan dev` never reaches its fork because --x86 is read only by
+       [flan build], and an --x86 --dev route through here would have made that
+       sentence false. *)
+    let run_flags =
+      [ no_checks_flag; debug_flag; sanitize_flag; x86_flag ] @ opt_levels
+    in
     let build_args, prog_args =
       let rec split acc = function
         | "--" :: rest -> (List.rev acc, rest)
@@ -727,7 +737,6 @@ let () =
       split [] args
     in
     let checks = not (List.mem no_checks_flag build_args) in
-    let dev = List.mem dev_flag build_args in
     let debug = List.mem debug_flag build_args in
     let sanitize = List.mem sanitize_flag build_args in
     let x86 = List.mem x86_flag build_args in
@@ -740,9 +749,9 @@ let () =
       in
       let l = load path in
       let p = Flan.Check.program_all l.decls in
-      let p, csrcs, lflags = Flan.Reach.link ~dev l p in
+      let p, csrcs, lflags = Flan.Reach.link l p in
       ignore (Flan.Build.executable
-                ~opts:{ Flan.Build.default with checks; dev; debug; sanitize;
+                ~opts:{ Flan.Build.default with checks; debug; sanitize;
                                                 x86;
                                                 opt = Option.value opt
                                                     ~default:Flan.Build.default.Flan.Build.opt }