[cli] autofix via mops check --fix

[rvanasa]

Implements LANG-1136.

mops check --fix: autofix Motoko diagnostics

Add a --fix flag to mops check that automatically applies machine-applicable fixes suggested by moc (e.g. M0223, M0236, M0237). Fixes are applied iteratively (up to 10 rounds) to handle cascading diagnostics, including transitively imported files.

Changes

• --fix flag — new CLI option on mops check that invokes the autofix pipeline
• autofix-motoko — new helper that parses moc --error-format=json output, extracts MachineApplicable edit suggestions, and applies them via vscode-languageserver-textdocument
• --all-libs — automatically passed to moc >= 1.3.0 for richer diagnostics with edit suggestions
• Toolchain integration — check and build now resolve moc through toolchain.bin() instead of getMocPath()
• getMocSemVer() — new utility that consolidates version resolution (config toolchain → installed binary)
• Tests — snapshot-based test suite covering M0223, M0236, M0237 fixes, transitive imports, and a no-dfx build test

[github-actions]

Benchmark Results

bench/1-buffer-vector-add.bench.mo $({\color{green}-8.22\%})$

Add (second)

Add items one-by-one (second)

Instructions: ${\color{green}-8.22\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

	10	10000	1000000
Buffer	9_557 $({\color{green}-29.67\%})$	5_687_594 $({\color{green}-8.33\%})$	525_783_888 $({\color{green}-8.25\%})$
Vector	13_525 $({\color{red}+18.47\%})$	4_378_612 $({\color{green}-10.82\%})$	417_864_498 $({\color{green}-10.74\%})$

Heap

	10	10000	1000000
Buffer	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$
Vector	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$

Garbage Collection

	10	10000	1000000
Buffer	1.09 KiB $({\color{gray}0\%})$	143.28 KiB $({\color{gray}0\%})$	12.02 MiB $({\color{gray}0\%})$
Vector	1.09 KiB $({\color{gray}0\%})$	45.65 KiB $({\color{gray}0\%})$	3.86 MiB $({\color{gray}0\%})$

bench/2-vector-buffer-add.bench.mo $({\color{green}-10.02\%})$

Add

Add items one-by-one

Instructions: ${\color{green}-10.02\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

	10	10000	1000000
Vector	13_525 $({\color{green}-12.27\%})$	4_378_966 $({\color{green}-10.82\%})$	417_886_092 $({\color{green}-10.74\%})$
Buffer	9_557 $({\color{green}-9.75\%})$	5_686_886 $({\color{green}-8.33\%})$	525_781_056 $({\color{green}-8.25\%})$

Heap

	10	10000	1000000
Vector	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$
Buffer	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$	272 B $({\color{gray}0\%})$

Garbage Collection

	10	10000	1000000
Vector	1.09 KiB $({\color{gray}0\%})$	45.65 KiB $({\color{gray}0\%})$	3.86 MiB $({\color{gray}0\%})$
Buffer	1.09 KiB $({\color{gray}0\%})$	143.28 KiB $({\color{gray}0\%})$	12.02 MiB $({\color{gray}0\%})$

bench/array.bench.mo $({\color{green}-17.47\%})$

Array

arr arr

Instructions: ${\color{green}-17.47\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

	100k x1	reset1	100k x3	reset2	100k x4	reset3
Array	13_502_096 $({\color{green}-10.00\%})$	3_335 $({\color{green}-25.14\%})$	27_003_270 $({\color{green}-10.00\%})$	3_809 $({\color{green}-24.92\%})$	54_004_127 $({\color{green}-10.00\%})$	4_283 $({\color{green}-24.74\%})$

Heap

	100k x1	reset1	100k x3	reset2	100k x4	reset3
Array	390.9 KiB $({\color{gray}0\%})$	-390.37 KiB $({\color{gray}0\%})$	390.9 KiB $({\color{gray}0\%})$	-390.37 KiB $({\color{gray}0\%})$	390.9 KiB $({\color{gray}0\%})$	-390.37 KiB $({\color{gray}0\%})$

Garbage Collection

	100k x1	reset1	100k x3	reset2	100k x4	reset3
Array	360 B $({\color{gray}0\%})$	390.97 KiB $({\color{gray}0\%})$	391 KiB $({\color{gray}0\%})$	390.97 KiB $({\color{gray}0\%})$	1.14 MiB $({\color{gray}0\%})$	390.97 KiB $({\color{gray}0\%})$

No previous results found "/home/runner/work/mops/mops/.bench/prng.bench.json"

bench/prng.bench.mo $({\color{gray}0\%})$

Prng

Benchmark N next calls for different PRNGs

Instructions: ${\color{gray}0\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

	10	100	1000	10000
Seiran128	1_694	15_194	150_194	1_500_194
SFC64	2_802	28_962	288_557	2_882_655
SFC32	2_383	23_825	237_026	2_379_333

Heap

	10	100	1000	10000
Seiran128	272 B	272 B	272 B	272 B
SFC64	308 B	272 B	272 B	272 B
SFC32	280 B	280 B	272 B	272 B

Garbage Collection

	10	100	1000	10000
Seiran128	296 B	296 B	296 B	296 B
SFC64	536 B	4.98 KiB	47.16 KiB	469.04 KiB
SFC32	376 B	1.78 KiB	15.39 KiB	156.11 KiB

bench/removeLast.bench.mo $({\color{green}-10.90\%})$

Remove items using removeLast

Vector and buffer are initialized with 100k items and then 70k items are removed one-by-one.

Instructions: ${\color{green}-10.90\%}$
Heap: ${\color{gray}0\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{gray}0\%}$

Instructions

	remove 70k
Vector	27_707_716 $({\color{green}-13.98\%})$
Buffer	29_236_977 $({\color{green}-7.82\%})$

Heap

	remove 70k
Vector	-136.8 KiB $({\color{gray}0\%})$
Buffer	-269.76 KiB $({\color{gray}0\%})$

Garbage Collection

	remove 70k
Vector	139.45 KiB $({\color{gray}0\%})$
Buffer	540.43 KiB $({\color{gray}0\%})$

bench/stable-memory.bench.mo $({\color{green}-134.03\%})$

Stable Memory and Region

Grow Region and store blobs in it

Instructions: ${\color{green}-66.97\%}$
Heap: ${\color{green}-6.10\%}$
Stable Memory: ${\color{gray}0\%}$
Garbage Collection: ${\color{green}-60.97\%}$

Instructions

	Region (fill 1/100)	Region (fill 1/50)	StableMemory
10 pages	2_626_997 $({\color{green}-95.97\%})$	10_496_230 $({\color{green}-95.97\%})$	2_693 $({\color{green}-5.87\%})$
100 pages	52_466_953 $({\color{green}-95.97\%})$	104_914_314 $({\color{green}-95.97\%})$	2_698 $({\color{green}-8.67\%})$
256 pages	134_273_534 $({\color{green}-95.97\%})$	268_574_815 $({\color{green}-95.97\%})$	3_246 $({\color{green}-12.37\%})$

Heap

	Region (fill 1/100)	Region (fill 1/50)	StableMemory
10 pages	272 B $({\color{green}-8.11\%})$	272 B $({\color{gray}0\%})$	276 B $({\color{gray}0\%})$
100 pages	272 B $({\color{green}-11.69\%})$	272 B $({\color{green}-11.69\%})$	272 B $({\color{gray}0\%})$
256 pages	272 B $({\color{green}-11.69\%})$	272 B $({\color{green}-11.69\%})$	276 B $({\color{gray}0\%})$

Garbage Collection

	Region (fill 1/100)	Region (fill 1/50)	StableMemory
10 pages	208.34 KiB $({\color{green}-91.44\%})$	832.38 KiB $({\color{green}-91.45\%})$	336 B $({\color{gray}0\%})$
100 pages	4.06 MiB $({\color{green}-91.46\%})$	8.13 MiB $({\color{green}-91.46\%})$	340 B $({\color{gray}0\%})$
256 pages	10.4 MiB $({\color{green}-91.46\%})$	20.8 MiB $({\color{green}-91.46\%})$	340 B $({\color{gray}0\%})$

Stable Memory

	Region (fill 1/100)	Region (fill 1/50)	StableMemory
10 pages	8 MiB $({\color{gray}0\%})$	8 MiB $({\color{gray}0\%})$	8 MiB $({\color{gray}0\%})$
100 pages	8 MiB $({\color{gray}0\%})$	8 MiB $({\color{gray}0\%})$	0 B $({\color{gray}0\%})$
256 pages	16 MiB $({\color{gray}0\%})$	16 MiB $({\color{gray}0\%})$	16 MiB $({\color{gray}0\%})$

[Kamirus]

Ideally we should just have mops check, but it is ok for now to explicitly provide the entrypoint.
It is important to note that this command will also check all transitively imported files.

[rvanasa]

LGTM, thank you!

@Kamirus, it looks like you'll need to approve it since I originally opened the PR.