2024-06-17 13:33.39: New job: test c-cube/iter https://github.com/c-cube/iter.git#refs/heads/main (fc69ce4c919cdd04fb5041410fd61d5a3f742702) (linux-arm64:debian-12-5.2_arm64_opam-2.1)Base: ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0eOpam project buildTo reproduce locally:git clone --recursive "https://github.com/c-cube/iter.git" -b "main" && cd "iter" && git reset --hard fc69ce4ccat > Dockerfile <<'END-OF-DOCKERFILE'FROM ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e# debian-12-5.2_arm64_opam-2.1USER 1000:1000ENV CLICOLOR_FORCE="1"ENV OPAMCOLOR="always"WORKDIR /srcRUN sudo ln -f /usr/bin/opam-2.1 /usr/bin/opamRUN opam init --reinit -niRUN uname -rs && opam exec -- ocaml -version && opam --versionWORKDIR /srcRUN sudo chown opam /srcRUN cd ~/opam-repository && (git cat-file -e a6069b9eebba0e2b70cdbbd834bc800eb6d671fb || git fetch origin master) && git reset -q --hard a6069b9eebba0e2b70cdbbd834bc800eb6d671fb && git log --no-decorate -n1 --oneline && opam update -uCOPY --chown=1000:1000 iter.opam ./RUN opam pin add -yn iter.dev './'ENV DEPS="astring.0.8.5 base-bigarray.base base-domains.base base-nnp.base base-threads.base base-unix.base camlp-streams.5.0.1 cmdliner.1.3.0 cppo.1.6.9 csexp.1.5.2 dune.3.16.0 fmt.0.9.0 host-arch-arm64.1 host-system-other.1 logs.0.7.0 mdx.2.4.1 ocaml.5.2.0 ocaml-base-compiler.5.2.0 ocaml-config.3 ocaml-options-vanilla.1 ocaml-version.3.6.7 ocamlbuild.0.14.3 ocamlfind.1.9.6 ounit2.2.2.7 qcheck-core.0.21.3 re.1.11.0 result.1.5 seq.base stdlib-shims.0.3.0 topkg.1.0.7"ENV CI="true"ENV OCAMLCI="true"RUN opam update --depexts && opam install --cli=2.1 --depext-only -y iter.dev $DEPSRUN opam install $DEPSCOPY --chown=1000:1000 . /srcRUN opam exec -- dune build @install @check @runtest && rm -rf _buildEND-OF-DOCKERFILEdocker build .END-REPRO-BLOCK2024-06-17 13:33.39: Using cache hint "c-cube/iter-ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e-debian-12-5.2_arm64_opam-2.1-a757e8590ddf80633ba05643a2e5b742"2024-06-17 13:33.39: Using OBuilder spec:((from ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e)(comment debian-12-5.2_arm64_opam-2.1)(user (uid 1000) (gid 1000))(env CLICOLOR_FORCE 1)(env OPAMCOLOR always)(workdir /src)(run (shell "sudo ln -f /usr/bin/opam-2.1 /usr/bin/opam"))(run (shell "opam init --reinit -ni"))(run (shell "uname -rs && opam exec -- ocaml -version && opam --version"))(workdir /src)(run (shell "sudo chown opam /src"))(run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "cd ~/opam-repository && (git cat-file -e a6069b9eebba0e2b70cdbbd834bc800eb6d671fb || git fetch origin master) && git reset -q --hard a6069b9eebba0e2b70cdbbd834bc800eb6d671fb && git log --no-decorate -n1 --oneline && opam update -u"))(copy (src iter.opam) (dst ./))(run (network host)(shell "opam pin add -yn iter.dev './'"))(env DEPS "astring.0.8.5 base-bigarray.base base-domains.base base-nnp.base base-threads.base base-unix.base camlp-streams.5.0.1 cmdliner.1.3.0 cppo.1.6.9 csexp.1.5.2 dune.3.16.0 fmt.0.9.0 host-arch-arm64.1 host-system-other.1 logs.0.7.0 mdx.2.4.1 ocaml.5.2.0 ocaml-base-compiler.5.2.0 ocaml-config.3 ocaml-options-vanilla.1 ocaml-version.3.6.7 ocamlbuild.0.14.3 ocamlfind.1.9.6 ounit2.2.2.7 qcheck-core.0.21.3 re.1.11.0 result.1.5 seq.base stdlib-shims.0.3.0 topkg.1.0.7")(env CI true)(env OCAMLCI true)(run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "opam update --depexts && opam install --cli=2.1 --depext-only -y iter.dev $DEPS"))(run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "opam install $DEPS"))(copy (src .) (dst /src))(run (shell "opam exec -- dune build @install @check @runtest && rm -rf _build")))2024-06-17 13:33.39: Waiting for resource in pool OCluster2024-06-17 14:07.46: Waiting for worker…2024-06-17 14:22.28: Got resource from pool OClusterBuilding on ainia.caelum.ci.devAll commits already cachedHEAD is now at fc69ce4 faster doc build(from ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e)Unable to find image 'ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e' locallydocker.io/ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e: Pulling from ocaml/opamDigest: sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0eStatus: Downloaded newer image for ocaml/opam@sha256:235eb731e29a67e24c9eedaf8e671404ee3be4f47a484b0ed5dadb5666a2ba0e2024-06-17 14:22.32 ---> using "8b5c5b0c2bbbe95e82d214251274078fdbc9b88871776c4818ff6bcf5c970bf4" from cache/: (comment debian-12-5.2_arm64_opam-2.1)/: (user (uid 1000) (gid 1000))/: (env CLICOLOR_FORCE 1)/: (env OPAMCOLOR always)/: (workdir /src)/src: (run (shell "sudo ln -f /usr/bin/opam-2.1 /usr/bin/opam"))2024-06-17 14:22.32 ---> using "7ee9e221b04cfdec939618b6cf25c32f20144ff16202f4add1f634b2a4be1d0b" from cache/src: (run (shell "opam init --reinit -ni"))Configuring from /home/opam/.opamrc and then from built-in defaults.Checking for available remotes: rsync and local, git.- you won't be able to use mercurial repositories unless you install the hg command on your system.- you won't be able to use darcs repositories unless you install the darcs command on your system.This version of opam requires an update to the layout of /home/opam/.opam from version 2.0 to version 2.1, which can't be reverted.You may want to back it up before going further.Continue? [Y/n] yFormat upgrade done.<><> Updating repositories ><><><><><><><><><><><><><><><><><><><><><><><><><><>[default] synchronised from file:///home/opam/opam-repository2024-06-17 14:22.32 ---> using "0ff152ef8ca2c71f91ea179720b83b455c7403d00f76cdce29c83ffe79c43457" from cache/src: (run (shell "uname -rs && opam exec -- ocaml -version && opam --version"))Linux 5.15.0-112-genericThe OCaml toplevel, version 5.2.02.1.62024-06-17 14:22.32 ---> using "fd7db85fe01e2582f2355861e6a577f30e20f2d228d8d7026c9c436dab01476c" from cache/src: (workdir /src)/src: (run (shell "sudo chown opam /src"))2024-06-17 14:22.32 ---> using "1d59ae71f20988933fe9313ef7387cd274f00d61e91420049e08c6cfdc59c21c" from cache/src: (run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "cd ~/opam-repository && (git cat-file -e a6069b9eebba0e2b70cdbbd834bc800eb6d671fb || git fetch origin master) && git reset -q --hard a6069b9eebba0e2b70cdbbd834bc800eb6d671fb && git log --no-decorate -n1 --oneline && opam update -u"))From https://github.com/ocaml/opam-repository* branch master -> FETCH_HEADc45f5bab71..e06bf2b8c3 master -> origin/mastera6069b9eeb [new release] dune (15 packages) (3.16.0)<><> Updating package repositories ><><><><><><><><><><><><><><><><><><><><><><>[default] synchronised from file:///home/opam/opam-repositoryThe following actions will be performed:- install host-system-other 1- recompile ocaml-options-vanilla 1 [upstream or system changes]- recompile ocaml-base-compiler 5.2.0* [upstream or system changes]- install host-arch-arm64 1- recompile ocaml-config 3 [uses ocaml-base-compiler]- recompile ocaml 5.2.0 [uses ocaml-base-compiler]- recompile opam-depext 1.2.1-1 [uses ocaml]- recompile base-domains base [uses ocaml]- recompile base-nnp base [uses base-domains]===== 2 to install | 7 to recompile =====<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>-> retrieved ocaml-config.3 (cached)-> removed ocaml-options-vanilla.1-> installed host-arch-arm64.1-> installed host-system-other.1-> installed ocaml-options-vanilla.1-> retrieved opam-depext.1.2.1-1 (cached)-> retrieved ocaml-base-compiler.5.2.0 (cached)-> removed base-nnp.base-> removed base-domains.base-> removed opam-depext.1.2.1-1-> removed ocaml.5.2.0-> removed ocaml-config.3-> removed ocaml-base-compiler.5.2.0-> installed ocaml-base-compiler.5.2.0-> installed ocaml-config.3-> installed ocaml.5.2.0-> installed base-domains.base-> installed base-nnp.base-> installed opam-depext.1.2.1-1Done.<><> opam-depext.1.2.1-1 installed successfully <><><><><><><><><><><><><><><><>=> opam-depext is unnecessary when used with opam >= 2.1. Please use opam install directly instead# Run eval $(opam env) to update the current shell environment2024-06-17 14:22.32 ---> using "cf4e578b76825eb376f4bad62c97cfa6c9375e2899fbe212b8d6a41f20819675" from cache/src: (copy (src iter.opam) (dst ./))2024-06-17 14:22.34 ---> saved as "3dbe06b37309e16fa0b5ce69045e173235e2db580c470f89bbd210770544e9a7"/src: (run (network host)(shell "opam pin add -yn iter.dev './'"))[iter.dev] synchronised (file:///src)iter is now pinned to file:///src (version dev)2024-06-17 14:22.41 ---> saved as "8f38c742c87c26816c93015924d06360b11f678ca6bbd6ca03961e96fbadd771"/src: (env DEPS "astring.0.8.5 base-bigarray.base base-domains.base base-nnp.base base-threads.base base-unix.base camlp-streams.5.0.1 cmdliner.1.3.0 cppo.1.6.9 csexp.1.5.2 dune.3.16.0 fmt.0.9.0 host-arch-arm64.1 host-system-other.1 logs.0.7.0 mdx.2.4.1 ocaml.5.2.0 ocaml-base-compiler.5.2.0 ocaml-config.3 ocaml-options-vanilla.1 ocaml-version.3.6.7 ocamlbuild.0.14.3 ocamlfind.1.9.6 ounit2.2.2.7 qcheck-core.0.21.3 re.1.11.0 result.1.5 seq.base stdlib-shims.0.3.0 topkg.1.0.7")/src: (env CI true)/src: (env OCAMLCI true)/src: (run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "opam update --depexts && opam install --cli=2.1 --depext-only -y iter.dev $DEPS"))+ /usr/bin/sudo "apt-get" "update"- Hit:1 http://deb.debian.org/debian bookworm InRelease- Get:2 http://deb.debian.org/debian bookworm-updates InRelease [55.4 kB]- Get:3 http://deb.debian.org/debian-security bookworm-security InRelease [48.0 kB]- Get:4 http://deb.debian.org/debian-security bookworm-security/main arm64 Packages [157 kB]- Fetched 261 kB in 2s (104 kB/s)- Reading package lists...-<><> Synchronising pinned packages ><><><><><><><><><><><><><><><><><><><><><><>[iter.dev] synchronised (no changes)[NOTE] Package ocaml-options-vanilla is already installed (current version is 1).[NOTE] Package ocaml-config is already installed (current version is 3).[NOTE] Package ocaml-base-compiler is already installed (current version is 5.2.0).[NOTE] Package ocaml is already installed (current version is 5.2.0).[NOTE] Package host-system-other is already installed (current version is 1).[NOTE] Package host-arch-arm64 is already installed (current version is 1).[NOTE] Package base-unix is already installed (current version is base).[NOTE] Package base-threads is already installed (current version is base).[NOTE] Package base-nnp is already installed (current version is base).[NOTE] Package base-domains is already installed (current version is base).[NOTE] Package base-bigarray is already installed (current version is base).2024-06-17 14:23.14 ---> saved as "fd2f0c026e0f9a4ed2c73c341610d8d6f14d5bbf501bd19373661ec2a1a0fd8d"/src: (run (cache (opam-archives (target /home/opam/.opam/download-cache)))(network host)(shell "opam install $DEPS"))[NOTE] Package ocaml-options-vanilla is already installed (current version is 1).[NOTE] Package ocaml-config is already installed (current version is 3).[NOTE] Package ocaml-base-compiler is already installed (current version is 5.2.0).[NOTE] Package ocaml is already installed (current version is 5.2.0).[NOTE] Package host-system-other is already installed (current version is 1).[NOTE] Package host-arch-arm64 is already installed (current version is 1).[NOTE] Package base-unix is already installed (current version is base).[NOTE] Package base-threads is already installed (current version is base).[NOTE] Package base-nnp is already installed (current version is base).[NOTE] Package base-domains is already installed (current version is base).[NOTE] Package base-bigarray is already installed (current version is base).The following actions will be performed:- install ocamlbuild 0.14.3- install dune 3.16.0- install ocamlfind 1.9.6- install cmdliner 1.3.0- install seq base- install stdlib-shims 0.3.0- install result 1.5- install qcheck-core 0.21.3- install ocaml-version 3.6.7- install csexp 1.5.2- install cppo 1.6.9- install camlp-streams 5.0.1- install topkg 1.0.7- install re 1.11.0- install ounit2 2.2.7- install fmt 0.9.0- install astring 0.8.5- install logs 0.7.0- install mdx 2.4.1===== 19 to install =====<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>-> retrieved camlp-streams.5.0.1 (cached)-> retrieved astring.0.8.5 (cached)-> retrieved cmdliner.1.3.0 (cached)-> retrieved cppo.1.6.9 (cached)-> retrieved csexp.1.5.2 (cached)-> retrieved dune.3.16.0 (cached)-> retrieved fmt.0.9.0 (cached)-> retrieved logs.0.7.0 (cached)-> retrieved mdx.2.4.1 (cached)-> retrieved ocaml-version.3.6.7 (cached)-> retrieved ocamlbuild.0.14.3 (cached)-> retrieved ocamlfind.1.9.6 (cached)-> retrieved ounit2.2.2.7 (cached)-> retrieved qcheck-core.0.21.3 (cached)-> retrieved seq.base (cached)-> installed seq.base-> retrieved re.1.11.0 (cached)-> retrieved result.1.5 (cached)-> retrieved stdlib-shims.0.3.0 (cached)-> retrieved topkg.1.0.7 (cached)-> installed cmdliner.1.3.0-> installed ocamlfind.1.9.6-> installed ocamlbuild.0.14.3-> installed topkg.1.0.7-> installed fmt.0.9.0-> installed astring.0.8.5-> installed logs.0.7.0-> installed dune.3.16.0-> installed stdlib-shims.0.3.0-> installed result.1.5-> installed csexp.1.5.2-> installed ocaml-version.3.6.7-> installed camlp-streams.5.0.1-> installed qcheck-core.0.21.3-> installed re.1.11.0-> installed cppo.1.6.9-> installed ounit2.2.2.7-> installed mdx.2.4.1Done.# Run eval $(opam env) to update the current shell environment2024-06-17 14:25.08 ---> saved as "3ff9ec23289718cdd818d7424d85939d679216cf425ee7d223ebfdce1f791066"/src: (copy (src .) (dst /src))2024-06-17 14:25.37 ---> saved as "4e75042665db68a41d59310230c2c9e2e6d379c879015ec45e4d28152841f1a6"/src: (run (shell "opam exec -- dune build @install @check @runtest && rm -rf _build"))File "benchs/dune", line 3, characters 17-26:3 | (libraries iter benchmark)^^^^^^^^^Error: Library "benchmark" not found.-> required by_build/default/benchs/.bench_persistent_read.eobjs/byte/dune__exe__Bench_persistent.cmi-> required by alias benchs/check(cd _build/default && /home/opam/.opam/5.2/bin/ocamlc.opt -w @1..3@5..28@30..39@43@46..47@49..57@61..62-40 -strict-sequence -strict-formats -short-paths -keep-locs -w +a -warn-error -a+8 -strict-sequence -w +a -warn-error -a+8 -nolabels -g -bin-annot -bin-annot-occurrences -I src/.iter.objs/byte -intf-suffix .ml -no-alias-deps -opaque -o src/.iter.objs/byte/iter.cmo -c -impl src/Iter.ml)File "src/Iter.ml", lines 204-209, characters 6-33:204 | ......match !acc with205 | | Nil -> acc := !cur206 | | _ ->207 | (match !tail with208 | | Nil -> ()209 | | Cons r -> r.tl <- !cur)Warning 4 [fragile-match]: this pattern-matching is fragile.It will remain exhaustive when constructors are added to type node.File "src/Iter.ml", line 1043, characters 8-15:1043 | let of_list l = of_iter_ (of_list l)^^^^^^^Warning 32 [unused-value-declaration]: unused value of_list.File "src/Iter.ml", line 1044, characters 8-15:1044 | let to_list x = to_list (to_iter_ x)^^^^^^^Warning 32 [unused-value-declaration]: unused value to_list.File "README.md", line 1, characters 0-0:/usr/bin/git --no-pager diff --no-index --color=always -u _build/default/README.md _build/default/README.md.correcteddiff --git a/_build/default/README.md b/_build/default/README.md.correctedindex 4c8f158..03bc0c7 100644--- a/_build/default/README.md+++ b/_build/default/README.md.corrected@@ -5,9 +5,17 @@ Clean and efficient loop fusion for all your iterating needs!```ocaml# #require "iter";;+/src/_build/install/default/lib/iter: added to search path+/src/_build/install/default/lib/iter/iter.cma: loaded+Cannot find file /src/_build/install/default/lib/iter/iter.cma.+[125]# let p x = x mod 5 = 0 inIter.(1 -- 5_000 |> filter p |> map (fun x -> x * x) |> fold (+) 0);;-- : int = 8345837500+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?````Iter` is a simple abstraction over `iter` functions@@ -52,16 +60,32 @@ With iter, if the source structure provides a# let q : int Queue.t = Queue.create();;val q : int Queue.t = <abstr># Iter.( 1 -- 10 |> to_queue q);;-- : unit = ()+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# Iter.of_queue q |> Iter.to_list ;;-- : int list = [1; 2; 3; 4; 5; 6; 7; 8; 9; 10]+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# let s : int Stack.t = Stack.create();;val s : int Stack.t = <abstr># Iter.(of_queue q |> to_stack s);;-- : unit = ()+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# Iter.of_stack s |> Iter.to_list ;;-- : int list = [10; 9; 8; 7; 6; 5; 4; 3; 2; 1]+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?```Note how the list of elements is reversed when we transfer them@@ -84,7 +108,11 @@ val h : (int, string) Hashtbl.t = <abstr># (* now to get the values *)Iter.of_hashtbl h |> Iter.map snd |> Iter.to_list;;-- : string list = ["6"; "2"; "8"; "7"; "3"; "5"; "4"; "9"; "0"; "10"; "1"]+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?```### Replacing `for` loops@@ -95,7 +123,11 @@ use `Iter.(--) : int -> int -> int Iter.t`.```ocaml# Iter.(1 -- 10_000_000 |> fold (+) 0);;-- : int = 50000005000000+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# let p x = x mod 5 = 0 inIter.(1 -- 5_000@@ -103,7 +135,11 @@ use `Iter.(--) : int -> int -> int Iter.t`.|> map (fun x -> x * x)|> fold (+) 0);;-- : int = 8345837500+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?```**NOTE**: with _flambda_ under sufficiently strong@@ -131,20 +167,27 @@ type term = Var of string | App of term * term | Lambda of term| App (a,b) ->Iter.append (subterms a) (subterms b));;-val subterms : term -> term Iter.t = <fun>+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# (* Now we can define many other functions easily! *)let vars t =Iter.filter_map(function Var s -> Some s | _ -> None)(subterms t) ;;-val vars : term -> string Iter.t = <fun>+Line 5, characters 8-16:+Error: Unbound value subterms# let size t = Iter.length (subterms t) ;;-val size : term -> int = <fun>+Line 1, characters 27-35:+Error: Unbound value subterms# let vars_list l = Iter.(of_list l |> flat_map vars);;-val vars_list : term list -> string Iter.t = <fun>+Line 1, characters 47-51:+Error: Unbound value vars```### Permutations@@ -163,15 +206,21 @@ enumerating the ways we can insert an element in a list.Iter.append(insert x tl >|= fun tl' -> y :: tl')(Iter.return (x :: l)) ;;-val insert : 'a -> 'a list -> 'a list Iter.t = <fun>+File "_none_", line 1:+Error: Reference to undefined compilation unit `Iter'+Hint: This means that the interface of a module is loaded, but its implementation is not.+ Did you mean to load a compiled implementation of the module+ using #load or by passing it as an argument to the toplevel?# let rec permute l = match l with| [] -> Iter.return []| x :: tl -> permute tl >>= insert x ;;-val permute : 'a list -> 'a list Iter.t = <fun>+Line 3, characters 31-37:+Error: Unbound value insert# permute [1;2;3;4] |> Iter.take 2 |> Iter.to_list ;;-- : int list list = [[4; 3; 2; 1]; [4; 3; 1; 2]]+Line 1, characters 1-8:+Error: Unbound value permute```### Advanced example(cd _build/default && /home/opam/.opam/5.2/bin/ocamlopt.opt -w @1..3@5..28@30..39@43@46..47@49..57@61..62-40 -strict-sequence -strict-formats -short-paths -keep-locs -w +a -warn-error -a+8 -strict-sequence -w +a -warn-error -a+8 -nolabels -g -O3 -unbox-closures -unbox-closures-factor 20 -I src/.iter.objs/byte -I src/.iter.objs/native -intf-suffix .ml -no-alias-deps -opaque -o src/.iter.objs/native/iter.cmx -c -impl src/Iter.ml)File "src/Iter.ml", lines 204-209, characters 6-33:204 | ......match !acc with205 | | Nil -> acc := !cur206 | | _ ->207 | (match !tail with208 | | Nil -> ()209 | | Cons r -> r.tl <- !cur)Warning 4 [fragile-match]: this pattern-matching is fragile.It will remain exhaustive when constructors are added to type node.File "src/Iter.ml", line 1043, characters 8-15:1043 | let of_list l = of_iter_ (of_list l)^^^^^^^Warning 32 [unused-value-declaration]: unused value of_list.File "src/Iter.ml", line 1044, characters 8-15:1044 | let to_list x = to_list (to_iter_ x)^^^^^^^Warning 32 [unused-value-declaration]: unused value to_list.(cd _build/default/tests/unit && ./t_iter.exe)random seed: 414446290================================================================================success (ran 4 tests)"/bin/bash" "-c" "opam exec -- dune build @install @check @runtest && rm -rf _build" failed with exit status 12024-06-17 14:25.50: Job failed: Failed: Build failed