1	# src/lint/plan: `bolt` (the lint) as a pure planner. It reads a World
2	# (src/lint/world.bend) and returns either the questions it still needs
3	# answered (`wants`) or the Plan: the lines to print and the exit status
4	# (`plan`). The interpreter (src/lint.bend) loops on `wants`, answering each
5	# question by IO, until nothing is wanted, then prints `plan`'s lines and
6	# exits with its status. The design is docs/rfc/bolt-lint-planner.md.
7	#
8	# With no files named, the planner walks the tree under `.` as a fold over the
9	# World's listings: a directory not listed yet reads as empty and is asked
10	# for, so each round of the loop lists one more level of the tree. Once every
11	# directory the walk reads is listed, it asks for the text of each source, of
12	# SPEC.md, and of every bolt.bend candidate of their directories, each once.
13	# A directory's candidates are taken once it is resolved against the World's
14	# working directory (Config.home), so a relative path is graded by the same
15	# bolt.bend wherever bolt runs from.
16	# `wants` never parses a file; `plan` parses and lints once, and reads the
17	# settings of each bolt.bend that grades a directory for `setting` (C011). Once every rule
18	# has run and each finding is graded, the noqa comments (src/noqa.bend)
19	# silence what they name, and then the `noqa` rule reports the comments that
20	# silenced nothing.
21	import Base
22	import ../lazy/lazy.bend as Lazy
23	import ./world.bend as W
24	import ../finding.bend as F
25	import ../src.bend as Src
26	import ../rules.bend as Rules
27	import ../rules/imports.bend as Imports
28	import ../config.bend as Config
29	import ../noqa.bend as Noqa
30	import ../rules/style/noqa.bend as NoqaRule
31	import ../rules/correctness/setting.bend as Setting
32	
33	# what `bolt` prints, in order, and the status it exits with
34	type Plan is Data:
35	  Plan{lines: List<&2, String>, exit: U32}
36	
37	# the lines a plan prints
38	def lines.of(pl: Plan) -> List<&2, String>:
39	  Plan{lines, _exit} = pl
40	  lines
41	
42	# the status a plan exits with
43	def exit.of(pl: Plan) -> U32:
44	  Plan{_lines, exit} = pl
45	  exit
46	
47	# ---------------------------------------------------------------------------
48	# the walk: every `.bend` file under `.`, sorted. A hidden name (`.git`,
49	# `.gate`, `.claude`) and `node_modules` are not descended into. The walk keeps
50	# a queue of directories rather than nesting, as Bend has no mutual recursion:
51	# one def shrinks one argument, the fuel, which bounds how many directories are
52	# read.
53	
54	# a directory the walk never descends into
55	def walk.skipped(+name: String) -> Bool:
56	  Bool.or(String.starts_with(name, "."), String.eq(name, "node_modules"))
57	
58	# an entry's name without the "/" that marks it a directory
59	def walk.bare(+name: String) -> String:
60	  String.take(name, Nat.sub(String.length(name), 1n))
61	
62	# a name directly under a directory, as a path
63	def walk.under(+dir: String, +name: String) -> String:
64	  dir ++ "/" ++ name
65	
66	# the sub-directories of a listing worth descending into, as paths
67	def walk.dirs(es: List<&2, String>, +dir: String) -> List<&2, String>:
68	  match es:
69	    case Nil{}:
70	      Nil{}
71	    case Con{+e, rest}:
72	      +more = walk.dirs(rest, dir)
73	      +keep = Bool.and(String.ends_with(e, "/"), Bool.not(walk.skipped(walk.bare(e))))
74	      Bool.pick(List<&2, String>, keep, walk.under(dir, walk.bare(e)) <> more, more)
75	
76	# the `.bend` files of a listing, as paths (a directory's name ends in "/")
77	def walk.bends(es: List<&2, String>, +dir: String) -> List<&2, String>:
78	  match es:
79	    case Nil{}:
80	      Nil{}
81	    case Con{+e, rest}:
82	      +more = walk.bends(rest, dir)
83	      Bool.pick(List<&2, String>, String.ends_with(e, ".bend"), walk.under(dir, e) <> more, more)
84	
85	# a walk once it stops: the `.bend` files it found, and every directory it
86	# read, the last one read first
87	type Walk is Data:
88	  Walk{found: List<&2, String>, read: List<&2, String>}
89	
90	# the files a walk found
91	def walk.found(wk: Walk) -> List<&2, String>:
92	  Walk{found, _read} = wk
93	  found
94	
95	# the directories a walk read, in the order it read them
96	def walk.read(wk: Walk) -> List<&2, String>:
97	  Walk{_found, read} = wk
98	  List.reverse(&2, String, read)
99	
100	# every `.bend` file under the directories still queued, the fuel bounding how
101	# many directories are read, each read through the World's listing. What is
102	# found is put in front of what came before, not after it, so the walk stays
103	# linear; `files` sorts at the end regardless.
104	def walk(
105	  fuel: Nat,
106	  +world: W.World,
107	  queue: List<&2, String>,
108	  acc: List<&2, String>,
109	  seen: List<&2, String>
110	) -> Walk:
111	  match fuel:
112	    case 0n:
113	      Walk{acc, seen}
114	    case 1n+f:
115	      match queue:
116	        case Nil{}:
117	          Walk{acc, seen}
118	        case Con{+dir, rest}:
119	          +es = W.listing(world, dir)
120	          walk(f, world, List.append(&2, String, rest, walk.dirs(es, dir)),
121	            List.append(&2, String, walk.bends(es, dir), acc), dir <> seen)
122	
123	# how many directories the walk reads at most; past it the walk stops,
124	# silently. A literal, not `U32.to_nat(100000)`: the checker keeps a literal
125	# whole and steps it one at a time, so BOLT-SCOPE-1's law can name the bound,
126	# where it would expand the call in unary and overflow. The compiler emits
127	# the same `U32.to_nat` for either.
128	def limit() -> Nat:
129	  100000n
130	
131	# the walk of the tree under `.`, reading at most `limit()` directories
132	def tree(+world: W.World) -> Walk:
133	  walk(limit(), world, ["."], [], [])
134	
135	# ---------------------------------------------------------------------------
136	# the files of the run
137	
138	# the files named, or every `.bend` file the walk finds when none were
139	def files.named(paths: List<&2, String>, +world: W.World) -> List<&2, String>:
140	  match paths:
141	    case Nil{}:
142	      +found = walk.found(tree(world))
143	      List.sort(~String, ~String.is_le, found)
144	    case Con{p, rest}:
145	      p <> rest
146	
147	# the files the lint runs over
148	def files(+world: W.World) -> List<&2, String>:
149	  files.named(W.paths.of(world), world)
150	
151	# a bolt.bend is configuration, not source
152	def is_config(+pp: String) -> Bool:
153	  Bool.or(String.eq(pp, "bolt.bend"), String.ends_with(pp, "/bolt.bend"))
154	
155	# the paths that are source
156	def sources(ps: List<&2, String>) -> List<&2, String>:
157	  match ps:
158	    case Nil{}:
159	      Nil{}
160	    case Con{+p, rest}:
161	      +more = sources(rest)
162	      Bool.pick(List<&2, String>, is_config(p), more, p <> more)
163	
164	# the source files of the run, in file-list order
165	def inputs(+world: W.World) -> List<&2, String>:
166	  sources(files(world))
167	
168	# ---------------------------------------------------------------------------
169	# what the plan reads
170	
171	# whether a path is among the paths
172	def seen.has(ps: List<&2, String>, +pp: String) -> Bool:
173	  match ps:
174	    case Nil{}:
175	      False{}
176	    case Con{p, rest}:
177	      Lazy.or_else(String.eq(p, pp), _u => seen.has(rest, pp))
178	
179	# each path once, where it first appears
180	def uniq(ps: List<&2, String>, +seen: List<&2, String>) -> List<&2, String>:
181	  match ps:
182	    case Nil{}:
183	      Nil{}
184	    case Con{+p, rest}:
185	      +dup = seen.has(seen, p)
186	      +more = uniq(rest, p <> seen)
187	      Bool.pick(List<&2, String>, dup, more, p <> more)
188	
189	# ---------------------------------------------------------------------------
190	# the packages (BOLT-SCOPE-6): every directory the walk reads but `.` whose
191	# listing names a main.bend, in the order the walk reads them; none when files
192	# were named
193	
194	# the directories the walk read that hold a main.bend, `.` left out
195	def roots.of(ds: List<&2, String>, +world: W.World) -> List<&2, String>:
196	  match ds:
197	    case Nil{}:
198	      Nil{}
199	    case Con{+d, rest}:
200	      +more = roots.of(rest, world)
201	      +root = Bool.and(Bool.not(String.eq(d, ".")), seen.has(W.listing(world, d), "main.bend"))
202	      Bool.pick(List<&2, String>, root, d <> more, more)
203	
204	# the package roots but `.`, as the walk names them (`./w3c`)
205	def roots.named(paths: List<&2, String>, +world: W.World) -> List<&2, String>:
206	  match paths:
207	    case Nil{}:
208	      roots.of(walk.read(tree(world)), world)
209	    case Con{_p, _rest}:
210	      Nil{}
211	
212	# the package roots but `.`
213	def roots(+world: W.World) -> List<&2, String>:
214	  roots.named(W.paths.of(world), world)
215	
216	# the SPEC.md of a package root
217	def spec.at(+root: String) -> String:
218	  root ++ "/SPEC.md"
219	
220	# the SPEC.md of each package root
221	def specs(rs: List<&2, String>) -> List<&2, String>:
222	  match rs:
223	    case Nil{}:
224	      Nil{}
225	    case Con{r, rest}:
226	      spec.at(r) <> specs(rest)
227	
228	# each package root as the project rules take it: its directory as a digest
229	# names one, its SPEC.md's path and what the World holds for it
230	def packages(rs: List<&2, String>, +world: W.World) -> List<&2, Rules.Package>:
231	  match rs:
232	    case Nil{}:
233	      Nil{}
234	    case Con{+r, rest}:
235	      Rules.Package{Imports.dir_of(spec.at(r)), spec.at(r), W.text(world, spec.at(r))} <> packages(rest, world)
236	
237	# the directory of each path
238	def dirs.of(ps: List<&2, String>) -> List<&2, String>:
239	  match ps:
240	    case Nil{}:
241	      Nil{}
242	    case Con{p, rest}:
243	      Config.dir_of(p) <> dirs.of(rest)
244	
245	# the directory of every source and of SPEC.md, each once: every finding's
246	# path is a source's or SPEC.md, so these are the directories grading needs
247	def conf.dirs(+ps: List<&2, String>) -> List<&2, String>:
248	  uniq(dirs.of(List.append(&2, String, ps, ["SPEC.md"])), [])
249	
250	# the bolt.bend candidates of a directory as a path names it, nearest first:
251	# the directory resolved against the working directory, then each parent up to
252	# the root
253	def conf.chain(+world: W.World, dir: String) -> List<&2, String>:
254	  Config.chain(Config.home(W.cwd.of(world), dir))
255	
256	# the bolt.bend candidates of each directory, nearest first
257	def conf.cands(ds: List<&2, String>, +world: W.World) -> List<&2, String>:
258	  match ds:
259	    case Nil{}:
260	      Nil{}
261	    case Con{d, rest}:
262	      List.append(&2, String, conf.chain(world, d), conf.cands(rest, world))
263	
264	# the listing of each directory, as a question
265	def asks.entries(ds: List<&2, String>) -> List<&2, W.Ask>:
266	  match ds:
267	    case Nil{}:
268	      Nil{}
269	    case Con{d, rest}:
270	      W.Entries{d} <> asks.entries(rest)
271	
272	# the text of each path, as a question
273	def asks.texts(ps: List<&2, String>) -> List<&2, W.Ask>:
274	  match ps:
275	    case Nil{}:
276	      Nil{}
277	    case Con{p, rest}:
278	      W.Contents{p} <> asks.texts(rest)
279	
280	# the directories the walk lists: every one it reads, none when files were
281	# named
282	def lists.named(paths: List<&2, String>, +world: W.World) -> List<&2, W.Ask>:
283	  match paths:
284	    case Nil{}:
285	      asks.entries(walk.read(tree(world)))
286	    case Con{_p, _rest}:
287	      Nil{}
288	
289	# the listings the plan reads
290	def lists(+world: W.World) -> List<&2, W.Ask>:
291	  lists.named(W.paths.of(world), world)
292	
293	# the texts the plan reads: each source, SPEC.md, the SPEC.md of every other
294	# package root, and every bolt.bend candidate of their directories, each once
295	def texts(+world: W.World) -> List<&2, W.Ask>:
296	  +ps = inputs(world)
297	  asks.texts(uniq(List.concat(&2, String, [ps, ["SPEC.md"], specs(roots(world)), conf.cands(conf.dirs(ps), world)]),
298	    []))
299	
300	# every question the plan reads the World through: the listings, then the
301	# texts
302	def looks(+world: W.World) -> List<&2, W.Ask>:
303	  List.append(&2, W.Ask, lists(world), texts(world))
304	
305	# the questions a World does not answer yet
306	def unanswered(asks: List<&2, W.Ask>, +world: W.World) -> List<&2, W.Ask>:
307	  match asks:
308	    case Nil{}:
309	      Nil{}
310	    case Con{+a, rest}:
311	      +more = unanswered(rest, world)
312	      Bool.pick(List<&2, W.Ask>, W.answered(world, a), more, a <> more)
313	
314	# the listings still open, or, once there are none, the texts still open
315	def wants.pick(ls: List<&2, W.Ask>, +world: W.World) -> List<&2, W.Ask>:
316	  match ls:
317	    case Nil{}:
318	      unanswered(texts(world), world)
319	    case Con{a, rest}:
320	      a <> rest
321	
322	# the questions a World still leaves open. The file list is known only once
323	# every directory the walk reads is listed, so the texts wait for the walk.
324	def wants(+world: W.World) -> List<&2, W.Ask>:
325	  wants.pick(unanswered(lists(world), world), world)
326	
327	# ---------------------------------------------------------------------------
328	# the findings
329	
330	# a source path and the text the World holds for it
331	type Got is Data:
332	  Got{path: String, text: Maybe<&2, String>}
333	
334	# each source with what the World answers for it
335	def gots(ps: List<&2, String>, +world: W.World) -> List<&2, Got>:
336	  match ps:
337	    case Nil{}:
338	      Nil{}
339	    case Con{+p, rest}:
340	      Got{p, W.text(world, p)} <> gots(rest, world)
341	
342	# one finding for each source that could not be read
343	def unread(gs: List<&2, Got>) -> List<&2, F.Finding>:
344	  match gs:
345	    case Nil{}:
346	      Nil{}
347	    case Con{Got{+path, None{}}, rest}:
348	      F.Finding{path, 0, 0, 0, "read", "Cannot read this file."} <> unread(rest)
349	    case Con{Got{_path, Some{_text}}, rest}:
350	      unread(rest)
351	
352	# every source that was read, parsed once for every rule
353	def srcs_of(gs: List<&2, Got>) -> List<&2, Src.Src>:
354	  match gs:
355	    case Nil{}:
356	      Nil{}
357	    case Con{Got{_path, None{}}, rest}:
358	      srcs_of(rest)
359	    case Con{Got{path, Some{text}}, rest}:
360	      Src.of(path, text) <> srcs_of(rest)
361	
362	# every source's findings from the per-file rules
363	def per_file(ss: List<&2, Src.Src>) -> List<&2, F.Finding>:
364	  match ss:
365	    case Nil{}:
366	      Nil{}
367	    case Con{s, rest}:
368	      List.concat(&2, F.Finding, [Rules.on(s), per_file(rest)])
369	
370	# the path of the first candidate the World holds a text for, as a list of
371	# one; none when it holds none
372	def conf.first(gs: List<&2, Got>) -> List<&2, String>:
373	  match gs:
374	    case Nil{}:
375	      Nil{}
376	    case Con{Got{path, Some{_text}}, _rest}:
377	      [path]
378	    case Con{Got{_path, None{}}, rest}:
379	      conf.first(rest)
380	
381	# the bolt.bend that grades each directory, in directory order: the first of
382	# its candidates the World read, as conf.near reads it; none for a directory
383	# graded by the defaults
384	def conf.used(ds: List<&2, String>, +world: W.World) -> List<&2, String>:
385	  match ds:
386	    case Nil{}:
387	      Nil{}
388	    case Con{d, rest}:
389	      List.append(&2, String, conf.first(gots(conf.chain(world, d), world)), conf.used(rest, world))
390	
391	# every bolt.bend grading reads, each once, in the order its directories come
392	def graders(+world: W.World) -> List<&2, String>:
393	  uniq(conf.used(conf.dirs(inputs(world)), world), [])
394	
395	# the `setting` rule's findings on each bolt.bend the World read, in order
396	def settings.at(gs: List<&2, Got>) -> List<&2, F.Finding>:
397	  match gs:
398	    case Nil{}:
399	      Nil{}
400	    case Con{Got{+path, Some{text}}, rest}:
401	      List.append(&2, F.Finding, Setting.check(path, text), settings.at(rest))
402	    case Con{Got{_path, None{}}, rest}:
403	      settings.at(rest)
404	
405	# the `setting` rule's findings: each unknown setting of every bolt.bend
406	# grading reads (src/rules/correctness/setting.bend)
407	def settings(+world: W.World) -> List<&2, F.Finding>:
408	  settings.at(gots(graders(world), world))
409	
410	# every finding of every rule, ungraded, from the sources and what the World
411	# answers for them: the read failures, the per-file findings of each source,
412	# then `setting`'s over each bolt.bend grading reads, then the project rules'
413	# over every source, told whether the run is the whole tree, SPEC.md's text
414	# and the other packages
415	def found.at(+world: W.World, +gs: List<&2, Got>, +ss: List<&2, Src.Src>) -> List<&2, F.Finding>:
416	  List.concat(&2, F.Finding, [unread(gs), per_file(ss), settings(world),
417	    Rules.project(ss, List.is_empty(&2, String, W.paths.of(world)), W.text(world, "SPEC.md"),
418	      packages(roots(world), world))])
419	
420	# every finding of every rule, ungraded
421	def found(+world: W.World) -> List<&2, F.Finding>:
422	  +gs = gots(inputs(world), world)
423	  found.at(world, gs, srcs_of(gs))
424	
425	# ---------------------------------------------------------------------------
426	# grading
427	
428	# a directory and the config its findings are graded by
429	type Conf is Data:
430	  Conf{dir: String, config: Config.Config}
431	
432	# what the World holds at each path
433	def texts.at(ps: List<&2, String>, +world: W.World) -> List<&2, Maybe<&2, String>>:
434	  match ps:
435	    case Nil{}:
436	      Nil{}
437	    case Con{p, rest}:
438	      W.text(world, p) <> texts.at(rest, world)
439	
440	# a directory's config: the nearest bolt.bend the World could read among its
441	# candidates, or the defaults
442	def conf.near(+world: W.World, dir: String) -> Config.Config:
443	  Config.nearest(texts.at(conf.chain(world, dir), world))
444	
445	# each directory's config
446	def confs.at(ds: List<&2, String>, +world: W.World) -> List<&2, Conf>:
447	  match ds:
448	    case Nil{}:
449	      Nil{}
450	    case Con{+d, rest}:
451	      Conf{d, conf.near(world, d)} <> confs.at(rest, world)
452	
453	# the config of every directory grading needs
454	def confs(+world: W.World) -> List<&2, Conf>:
455	  confs.at(conf.dirs(inputs(world)), world)
456	
457	# the config of a directory, from the table; one the table does not hold is
458	# worked out the same way (every finding's directory is in the table, so this
459	# never happens in a run)
460	def conf.find(cs: List<&2, Conf>, +world: W.World, +dir: String) -> Config.Config:
461	  match cs:
462	    case Nil{}:
463	      conf.near(world, dir)
464	    case Con{Conf{d, cfg}, rest}:
465	      Lazy.stop(Config.Config, String.eq(d, dir), cfg, _u => conf.find(rest, world, dir))
466	
467	# the config a finding at a path is graded by: its directory's
468	def config.at(+cs: List<&2, Conf>, +world: W.World, path: String) -> Config.Config:
469	  conf.find(cs, world, Config.dir_of(path))
470	
471	# every finding graded by the config of its directory, in order, the ones at
472	# off dropped
473	def grade(+cs: List<&2, Conf>, +world: W.World, fs: List<&2, F.Finding>) -> List<&2, F.Graded>:
474	  match fs:
475	    case Nil{}:
476	      Nil{}
477	    case Con{F.Finding{+path, line, col, len, rule, msg}, rest}:
478	      cfg = config.at(cs, world, path)
479	      List.append(&2, F.Graded, Rules.graded(cfg, [F.Finding{path, line, col, len, rule, msg}]), grade(cs, world, rest))
480	
481	# ---------------------------------------------------------------------------
482	# silencing, then the `noqa` rule
483	
484	# the `noqa` rule's findings on each file's marks, against the graded
485	# findings, each put at its file as a per-file rule's are
486	def noqa(ms: List<&2, Noqa.Marks>, +whole: Bool, +gs: List<&2, F.Graded>) -> List<&2, F.Finding>:
487	  match ms:
488	    case Nil{}:
489	      Nil{}
490	    case Con{Noqa.Marks{+path, mks}, rest}:
491	      List.append(&2, F.Finding, Rules.on.at(path, NoqaRule.check(mks, whole, path, gs)), noqa(rest, whole, gs))
492	
493	# the graded findings no mark silences, in order, then the `noqa` rule's,
494	# graded by the grader given: nothing silences what `noqa` reports
495	def after(
496	  +ms: List<&2, Noqa.Marks>,
497	  +whole: Bool,
498	  +gs: List<&2, F.Graded>,
499	  grader: List<&2, F.Finding> -> List<&2, F.Graded>
500	) -> List<&2, F.Graded>:
501	  List.append(&2, F.Graded, Noqa.keep(ms, gs), grader(noqa(ms, whole, gs)))
502	
503	# every finding of the run, graded, then silenced by the marks of the
504	# sources, then `noqa`'s own, which judges a project rule's code only when
505	# the run is the whole tree. The sources are parsed once for both.
506	def final(+world: W.World) -> List<&2, F.Graded>:
507	  +gs = gots(inputs(world), world)
508	  +ss = srcs_of(gs)
509	  +cs = confs(world)
510	  after(Noqa.of_srcs(ss), List.is_empty(&2, String, W.paths.of(world)), grade(cs, world, found.at(world, gs, ss)),
511	    fs => grade(cs, world, fs))
512	
513	# ---------------------------------------------------------------------------
514	# the plan
515	
516	# one more at error, or the count as it was
517	def errors.at(ll: Config.Level, more: U32) -> U32:
518	  match ll:
519	    case Config.Off{}:
520	      more
521	    case Config.Warn{}:
522	      more
523	    case Config.Error{}:
524	      U32.inc(more)
525	
526	# how many are errors
527	def errors(gs: List<&2, F.Graded>) -> U32:
528	  match gs:
529	    case Nil{}:
530	      0
531	    case Con{F.Graded{ll, _ff}, rest}:
532	      errors.at(ll, errors(rest))
533	
534	# one more below error, or the count as it was
535	def warnings.at(ll: Config.Level, more: U32) -> U32:
536	  match ll:
537	    case Config.Off{}:
538	      U32.inc(more)
539	    case Config.Warn{}:
540	      U32.inc(more)
541	    case Config.Error{}:
542	      more
543	
544	# how many are not errors
545	def warnings(gs: List<&2, F.Graded>) -> U32:
546	  match gs:
547	    case Nil{}:
548	      0
549	    case Con{F.Graded{ll, _ff}, rest}:
550	      warnings.at(ll, warnings(rest))
551	
552	# whether any is an error
553	def has_error(gs: List<&2, F.Graded>) -> Bool:
554	  match gs:
555	    case Nil{}:
556	      False{}
557	    case Con{F.Graded{ll, _ff}, rest}:
558	      +more = has_error(rest)
559	      Bool.or(Config.is_error(ll), more)
560	
561	# `1 error`, `2 errors`
562	def count(+nn: U32, +what: String) -> String:
563	  U32.show(nn) ++ " " ++ what ++ Bool.pick(String, U32.is_eq(nn, 1), "", "s")
564	
565	# `clean`, or the counts
566	def summary(+gs: List<&2, F.Graded>) -> String:
567	  Lazy.stop(String, List.is_empty(&2, F.Graded, gs), "clean",
568	    _u => count(errors(gs), "error") ++ ", " ++ count(warnings(gs), "warning"))
569	
570	# every graded finding as a line
571	def show_all(gs: List<&2, F.Graded>) -> List<&2, String>:
572	  match gs:
573	    case Nil{}:
574	      Nil{}
575	    case Con{g, rest}:
576	      F.show_graded(g) <> show_all(rest)
577	
578	# `bolt` over a World: every graded finding no mark silences as a line, then
579	# `noqa`'s, then the summary of those, and exit 1 exactly when one is an error
580	def plan(+world: W.World) -> Plan:
581	  +gs = final(world)
582	  Plan{List.append(&2, String, show_all(gs), [summary(gs)]), Bool.pick(U32, has_error(gs), 1, 0)}