tlaplus/tlaplus

View on GitHub

TLC is a model checker for specifications written in TLA+. The TLA+Toolbox is an IDE for TLA+.

Stars: 3.1k
Forks: 264
Open beginner issues: 0
Indexed issues: 208
Avg merge: 3d 4h
Merged PRs (30d): 16

Dominant language: Java
License: MIT
Last GitHub push: Sep 17, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted good first issue

Beginner friendly Everything

Open All

208 open issues indexed

Warn when TLA+ specifications directly use `TLC!Assert` Open

enhancement SANY

Difficulty 4/5 3-5 days Newbie friendliness 58/100

tlaplus/tlaplus#1437 · 1 comment · Opened Sep 15, 2026
IntervalValue enumeration wraps after MaxInt Open

bug soundness \/ completeness Tools

Difficulty 3/5 1-2 days Newbie friendliness 72/100

tlaplus/tlaplus#1433 · Opened Sep 14, 2026
Empty interval-domain functions disagree on compareTo and equals Open

bug soundness \/ completeness Tools

Difficulty 4/5 3-5 days Newbie friendliness 52/100

tlaplus/tlaplus#1432 · Opened Sep 14, 2026
Parser rejects a RECURSIVE definition of the prefix `-.` operator applied to itself Open

bug SANY

tlaplus/tlaplus#1418 · 2 comments · 1 reaction · 2 assignees · Opened Sep 9, 2026
XML Exporter (and possibly SANY's semantic model) drops the containment relationship between a module and a module nested in its body Open

tlaplus/tlaplus#1410 · 1 reaction · 2 assignees · Opened Sep 2, 2026
SANY throws while formatting a level error for % Open

bug SANY

Difficulty 3/5 1-2 days Newbie friendliness 76/100

tlaplus/tlaplus#1406 · 1 comment · Opened Aug 25, 2026
Rev Release on JAR change Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1399 · 1 comment · Opened Aug 7, 2026
Feature request: TLC should accept named theorems as properties & invariants Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

tlaplus/tlaplus#1394 · 1 reaction · Opened Jun 8, 2026
Feature request: TLC should accept [] properties for INVARIANT Open

Difficulty 3/5 1-2 days Newbie friendliness 58/100

tlaplus/tlaplus#1393 · 1 reaction · Opened Jun 8, 2026
TLC Parser throws NullPointerException on ARM64 (Raspberry Pi 5, aarch64) Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1392 · Opened May 23, 2026
Recursive operators cannot be used to define a property Open

enhancement Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1389 · 7 comments · Opened May 15, 2026
TLC -continue reports success despite invariant violations Open

soundness \/ completeness Tools

Difficulty 3/5 1-2 days Newbie friendliness 65/100

tlaplus/tlaplus#1385 · 1 comment · Opened May 3, 2026
Different message codes for different messages Open

enhancement Tools usability

Difficulty 5/5 Over a week Newbie friendliness 35/100

tlaplus/tlaplus#1382 · 1 comment · Opened Apr 27, 2026
Version 1.8 reported as damaged when trying to execute Apple Silicon version Open

Toolbox

Difficulty 4/5 3-5 days Newbie friendliness 38/100

tlaplus/tlaplus#1381 · 1 comment · Opened Apr 26, 2026
Feature request: SANY should automatically include root spec directory in search path Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

tlaplus/tlaplus#1372 · Opened Apr 5, 2026
VIEW with SYMMETRY depend on variable naming. Open

Difficulty 4/5 3-5 days Newbie friendliness 50/100

tlaplus/tlaplus#1368 · 2 reactions · Opened Apr 1, 2026
TLC: replace generic/runtime failures with structured, source-aware diagnostics Open

enhancement refactoring Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1363 · 2 comments · Opened Mar 25, 2026
Simulation trace length statistics are incorrect Open

Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1357 · 1 comment · Opened Mar 19, 2026
TLC fails to evaluate ENABLED (x') when the body of ENABLED is a primed variable Open

bug Tools

Difficulty 3/5 1-2 days Newbie friendliness 48/100

tlaplus/tlaplus#1336 · 2 comments · Opened Mar 3, 2026
Noteworthy commits, issues, and pull requests not announced or back-ported to 1.7 maintenance branch Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

tlaplus/tlaplus#1332 · 1 comment · Opened Feb 25, 2026
Flaky unit test in tlc2.tool.DumpLoadTraceTest Open

bug DevEnvironment Tools

Difficulty 4/5 3-5 days Newbie friendliness 42/100

tlaplus/tlaplus#1325 · 2 comments · Opened Feb 23, 2026
Feedback & updates to the XML output format from TLAPM work Open

refactoring SANY

Difficulty 5/5 Over a week Newbie friendliness 35/100

tlaplus/tlaplus#1313 · Opened Feb 16, 2026
We need to update `current-tools.md` Open

DevEnvironment enhancement Tools

Difficulty 4/5 3-5 days Newbie friendliness 42/100

tlaplus/tlaplus#1311 · 1 comment · Opened Feb 14, 2026
Add compact output mode to XMLExporter. Open

AI enhancement help wanted Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1299 · Opened Feb 3, 2026
Include `tlc2.REPL` class in upcoming stable release Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

tlaplus/tlaplus#1272 · 4 comments · 1 reaction · Opened Jan 2, 2026
Replace custom data structures with `java.util` equivalents Open

refactoring Tools

Difficulty 5/5 Over a week Newbie friendliness 25/100

tlaplus/tlaplus#1258 · 4 comments · Opened Nov 21, 2025
`Trace` operator fails to evaluate for last state of counterexample Open

bug Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1253 · Opened Oct 24, 2025
Support verification of complex specs with numerous strong fairness constraints Open

enhancement Tools

Difficulty 5/5 Over a week Newbie friendliness 45/100

tlaplus/tlaplus#1251 · 4 comments · Opened Oct 22, 2025
Upgrade to Java 25 LTS Open

enhancement Tools

Difficulty 4/5 3-5 days Newbie friendliness 35/100

tlaplus/tlaplus#1246 · 6 comments · 1 reaction · Opened Sep 17, 2025
Question: How does TLC determine which action name to display instead of “Next”? Open

enhancement question Tools

Difficulty 4/5 3-5 days Newbie friendliness 25/100

tlaplus/tlaplus#1243 · 12 comments · Opened Sep 11, 2025
Dangling comment merges with succeeding definition's pre-comment in TLA+ modules Open

AI bug SANY

Difficulty 3/5 1-2 days Newbie friendliness 38/100

tlaplus/tlaplus#1238 · Opened Aug 29, 2025
Add convention for *module* comments Open

AI enhancement SANY

Difficulty 5/5 Over a week Newbie friendliness 25/100

tlaplus/tlaplus#1237 · 2 reactions · Opened Aug 28, 2025
Remove SANY syntax parser "pragma" construct Open

refactoring SANY

Difficulty 4/5 3-5 days Newbie friendliness 38/100

tlaplus/tlaplus#1227 · 2 comments · Opened Aug 11, 2025
PlusCal translator incorrectly renames bound variable Open

bug PlusCal Tools

Difficulty 4/5 3-5 days Newbie friendliness 35/100

tlaplus/tlaplus#1224 · 1 reaction · Opened Aug 5, 2025
Using `-dump` option to produce state dumps in machine readable format Open

enhancement help wanted Tools

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1216 · 2 comments · Opened Jul 24, 2025
TLCEval can silently fail due to how a constant operator is referenced Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

tlaplus/tlaplus#1212 · 16 comments · Opened Jul 17, 2025
Decide on & commit to code style guide Open

DevEnvironment

Difficulty 5/5 Over a week Newbie friendliness 20/100

tlaplus/tlaplus#1198 · 13 comments · Opened Jun 13, 2025
Create and curate a TLA+ Dataset for LLM Training and Evaluation Open

AI enhancement good first issue help wanted

Difficulty 5/5 Over a week Newbie friendliness 25/100

tlaplus/tlaplus#1196 · 4 comments · 2 reactions · Opened Jun 11, 2025
Feature proposal: add `EXPECT` statements to model config files Open

enhancement Tools

Difficulty 5/5 Over a week Newbie friendliness 35/100

tlaplus/tlaplus#1192 · 2 comments · Opened Jun 3, 2025
Feature request: Mapping errors in the generated TLA+ code Open

enhancement SANY Tools

Difficulty 5/5 Over a week Newbie friendliness 25/100

tlaplus/tlaplus#1187 · 3 comments · Opened May 13, 2025
REPL should not use short-circuit evaluation for infix disjunction Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

tlaplus/tlaplus#1168 · 1 comment · Opened Apr 14, 2025
Support finding relevant facts and definitions in TLA+ proofs Open

enhancement help wanted TLA+ Foundation Funding TLAPS

Difficulty 5/5 Over a week Newbie friendliness 20/100

tlaplus/tlaplus#1166 · Opened Apr 2, 2025
Bring back regular releases and maintenance branches Open

DevEnvironment enhancement TLA+ Foundation Funding

Difficulty 5/5 Over a week Newbie friendliness 25/100

tlaplus/tlaplus#1165 · 3 comments · 8 reactions · Opened Apr 1, 2025
SANY allows writing stuttering-sensitive expressions Open

SANY

Difficulty 5/5 Over a week Newbie friendliness 35/100

tlaplus/tlaplus#1160 · 2 comments · Opened Mar 15, 2025
SANY allows @ in odd locations Open

bug good first issue SANY Tools

Difficulty 3/5 1-2 days Newbie friendliness 48/100

tlaplus/tlaplus#1153 · 1 comment · Opened Feb 25, 2025
Wrong module location reported in error when substituting constant operator of wrong arity Open

bug SANY

Difficulty 4/5 3-5 days Newbie friendliness 45/100

tlaplus/tlaplus#1152 · Opened Feb 25, 2025
SANY semantic checking throws exception when declaring nested module in recursive section Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

tlaplus/tlaplus#1149 · 1 comment · Opened Feb 21, 2025
SANY allows temporal-level expressions as record values Open

SANY

Difficulty 4/5 3-5 days Newbie friendliness 35/100

tlaplus/tlaplus#1138 · 2 comments · Opened Feb 4, 2025
SANY fails to attach pre-comment to negative operator Open

SANY

Difficulty 4/5 3-5 days Newbie friendliness 38/100

tlaplus/tlaplus#1130 · Opened Jan 25, 2025
SANY (and other tools) incorrectly discover commented-out modules Open

bug SANY Tools

Difficulty 3/5 1-2 days Newbie friendliness 35/100

tlaplus/tlaplus#1104 · 3 comments · Opened Dec 23, 2024

tlaplus/tlaplus

Get new issues in your inbox