CHANGELOG.md 24.7 KB
Newer Older
Ralf Jung's avatar
Ralf Jung committed
1 2 3
In this changelog, we document "large-ish" changes to Iris that affect even the
way the logic is used on paper.  We also mention some significant changes in the
Coq development, but not every API-breaking change is listed.  Changes marked
4
`[#]` still need to be ported to the Iris Documentation LaTeX file(s).
5

Robbert Krebbers's avatar
Robbert Krebbers committed
6 7
## Iris master

Ralf Jung's avatar
Ralf Jung committed
8 9 10 11
**Changes in the theory of Iris itself:**

* [#] Redefine invariants as "semantic invariants" so that they support
  splitting and other forms of weakening.
12 13
* Updated the strong variant of the opening lemma for cancellable invariants
  to match that of regular invariants, where you can pick the mask at a later time.
Amin Timany's avatar
Amin Timany committed
14 15 16 17 18 19
  
**Changes in program logic:**

* In the axiomatization of ectx languages we replace the axiom of positivity of
  context composition with an axiom that says if `fill K e` takes a head step,
  then either `K` is the empty evaluation context or `e` is a value.
Ralf Jung's avatar
Ralf Jung committed
20

Robbert Krebbers's avatar
Robbert Krebbers committed
21 22
**Changes in Coq:**

23
* Added support for Coq 8.10; dropped support for Coq 8.7.
Robbert Krebbers's avatar
Robbert Krebbers committed
24 25
* A new tactic `iStopProof` to turn the proof mode entailment into an ordinary
  Coq goal `big star of context ⊢ proof mode goal`.
Robbert Krebbers's avatar
Robbert Krebbers committed
26 27
* Rename `iProp`/`iPreProp` to `iPropO`/`iPrePropO` since they are `ofeT`s.
  Introduce `iProp` for the `Type` carrier of `iPropO`.
Robbert Krebbers's avatar
Robbert Krebbers committed
28 29 30
* Move derived camera constructions (`frac_auth` and `ufrac_auth`) to the folder
  `algebra/lib`.
* Add derived camera construction `excl_auth A` for `auth (option (excl A))`.
31 32 33
* Make use of `notypeclasses refine` in the implementation of `iPoseProof` and
  `iAssumption`, see https://gitlab.mpi-sws.org/iris/iris/merge_requests/329
  This has two consequences:
Ralf Jung's avatar
Ralf Jung committed
34 35
  1. Coq's "new" unification algorithm (the one in `refine`, not the "old" one
     in `apply`) is used more often by the proof mode tactics.
Robbert Krebbers's avatar
Robbert Krebbers committed
36 37
  2. Due to the use of `notypeclasses refine`, TC constraints are solved less
     eagerly, see https://github.com/coq/coq/issues/6583.
38 39 40 41
  In order to port your development, it is often needed to instantiate evars
  explicitly (since TC search is performed less eagerly), and in few cases it is
  needed to unfold definitions explicitly (due to new unification algorithm
  behaving differently).
Ralf Jung's avatar
Ralf Jung committed
42 43 44
* Removed `Core` type class for defining the total core; it is now always
  defined in terms of the partial core. The only user of this type class was the
  STS RA.
Robbert Krebbers's avatar
Robbert Krebbers committed
45 46
* Added the type `siProp` of "plain" step-indexed propositions, together with
  basic proofmode support.
Robbert Krebbers's avatar
Robbert Krebbers committed
47

Ralf Jung's avatar
Ralf Jung committed
48
## Iris 3.2.0 (released 2019-08-29)
Ralf Jung's avatar
Ralf Jung committed
49

Ralf Jung's avatar
Ralf Jung committed
50 51 52
The highlight of this release is the completely re-engineered interactive proof
mode.  Not only did many tactics become more powerful; the entire proof mode can
now be used not just for Iris but also for other separation logics satisfying
Ralf Jung's avatar
Ralf Jung committed
53 54 55 56 57 58
the proof mode interface (e.g., [Iron] and [GPFSL]). Also see the
[accompanying paper][MoSeL].

[Iron]: https://iris-project.org/iron/
[GPFSL]: https://gitlab.mpi-sws.org/iris/gpfsl/
[MoSeL]: https://iris-project.org/mosel/
Ralf Jung's avatar
Ralf Jung committed
59 60 61 62 63 64 65 66 67 68 69 70 71 72

Beyond that, the Iris program logic gained the ability to reason about
potentially stuck programs, and a significantly strengthened adequacy theorem
that unifies the three previously separately presented theorems.  There are now
also Hoare triples for total program correctness (but with very limited support
for invariants) and logical atomicity.

And finally, our example language HeapLang was made more realistic
(Compare-and-set got replaced by compare-exchange and limited to only compare
values that can actually be compared atomically) and more powerful, with added
support for arrays and prophecy variables.

Further details are given in the changelog below.

Ralf Jung's avatar
Ralf Jung committed
73 74 75 76 77 78 79 80
This release of Iris received contributions by Aleš Bizjak, Amin Timany, Dan
Frumin, Glen Mével, Hai Dang, Hugo Herbelin, Jacques-Henri Jourdan, Jan Menz,
Jan-Oliver Kaiser, Jonas Kastberg Hinrichsen, Joseph Tassarotti, Mackie Loeffel,
Marianna Rapoport, Maxime Dénès, Michael Sammler, Paolo G. Giarrusso,
Pierre-Marie Pédrot, Ralf Jung, Robbert Krebbers, Rodolphe Lepigre, and Tej
Chajed. Thanks a lot to everyone involved!

**Changes in the theory of Iris itself:**
Ralf Jung's avatar
Ralf Jung committed
81

82
* Change in the definition of WP, so that there is a fancy update between
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
83 84
  the quantification over the next states and the later modality. This makes it
  possible to prove more powerful lifting lemmas: The new versions feature an
Ralf Jung's avatar
Ralf Jung committed
85
  "update that takes a step".
86 87 88
* Add weakest preconditions for total program correctness.
* "(Potentially) stuck" weakest preconditions and the "plainly modality" are no
  longer considered experimental.
Ralf Jung's avatar
Ralf Jung committed
89
* Add the notion of an "observation" to the language interface, so that
Ralf Jung's avatar
Ralf Jung committed
90 91
  every reduction step can optionally be marked with an event, and an execution
  trace has a matching list of events.  Change WP so that it is told the entire
92
  future trace of observations from the beginning.
Ralf Jung's avatar
Ralf Jung committed
93
* The Löb rule is now a derived rule; it follows from later-intro, later
Ralf Jung's avatar
Ralf Jung committed
94 95
  being contractive and the fact that we can take fixpoints of contractive
  functions.
Ralf Jung's avatar
Ralf Jung committed
96
* Add atomic updates and logically atomic triples, including tactic support.
Ralf Jung's avatar
Ralf Jung committed
97
  See `heap_lang/lib/increment.v` for an example.
98 99 100
* Extend the state interpretation with a natural number that keeps track of
  the number of forked-off threads, and have a global fixed proposition that
  describes the postcondition of each forked-off thread (instead of it being
Robbert Krebbers's avatar
Robbert Krebbers committed
101
  `True`).
102 103 104
* A stronger adequacy statement for weakest preconditions that involves
  the final state, the post-condition of forked-off threads, and also applies if
  the main-thread has not terminated.
105 106 107
* The user-chosen functor used to instantiate the Iris logic now goes from
  COFEs to Cameras (it was OFEs to Cameras).

Ralf Jung's avatar
Ralf Jung committed
108
**Changes in heap_lang:**
109

110 111 112 113 114 115 116 117
* CAS (compare-and-set) got replaced by CmpXchg (compare-exchange).  The
  difference is that CmpXchg returns a pair consisting of the old value and a
  boolean indicating whether the comparison was successful and hence the
  exchange happened.  CAS can be obtained by simply projecting to the second
  component, but also providing the old value more closely models the primitive
  typically provided in systems languages (C, C++, Rust).
  The comparison by this operation also got weakened to be efficiently
  implementable: CmpXchg may only be used to compare "unboxed" values that can
Ralf Jung's avatar
Ralf Jung committed
118 119 120 121 122
  be represented in a single machine word. It is sufficient if one of the two
  compared values is unboxed.
* For consistency, the restrictions CmpXchg imposes on comparison also apply to
  the `=` binary operator. This also fixes the long-standing problem that that
  operator allowed compared closures with each other.
Ralf Jung's avatar
Ralf Jung committed
123 124
* Implement prophecy variables using the new support for "observations". The
  erasure theorem (showing that prophecy variables do not alter program
Ralf Jung's avatar
Ralf Jung committed
125
  behavior) can be found [in the iris/examples repository][prophecy-erasure].
Ralf Jung's avatar
Ralf Jung committed
126
* heap_lang now uses right-to-left evaluation order. This makes it
Ralf Jung's avatar
Ralf Jung committed
127
  significantly easier to write specifications of curried functions.
Ralf Jung's avatar
Ralf Jung committed
128
* heap_lang values are now injected in heap_lang expressions via a specific
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
129 130
  constructor of the expr inductive type. This simplifies much the tactical
  infrastructure around the language. In particular, this allow us to get rid
Robbert Krebbers's avatar
Robbert Krebbers committed
131
  the reflection mechanism that was needed for proving closedness, atomicity and
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
132 133
  "valueness" of a term. The price to pay is the addition of new
  "administrative" reductions in the operational semantics of the language.
134 135
* heap_lang now has support for allocating, accessing and reasoning about arrays
  (continuously allocated regions of memory).
Robbert Krebbers's avatar
Robbert Krebbers committed
136
* One can now assign "meta" data to heap_lang locations.
Ralf Jung's avatar
Ralf Jung committed
137

Ralf Jung's avatar
Ralf Jung committed
138 139
[prophecy-erasure]: https://gitlab.mpi-sws.org/iris/examples/blob/3f33781fe6e19cfdb25259c8194d34403f1134d5/theories/logatom/proph_erasure.v

Ralf Jung's avatar
Ralf Jung committed
140
**Changes in Coq:**
141

Ralf Jung's avatar
Ralf Jung committed
142
* An all-new generalized proof mode that abstracts away from Iris!  Major new
Ralf Jung's avatar
Ralf Jung committed
143 144 145 146 147 148
  features:
  - The proof mode can now be used with logics derived from Iris (like iGPS),
    with non-step-indexed logics and even with non-affine (i.e., linear) logics.
  - `iModIntro` is more flexible and more powerful, it now also subsumes
    `iNext` and `iAlways`.
  - General infrastructure for deriving a logic for monotone predicates over
Ralf Jung's avatar
Ralf Jung committed
149
    an existing logic (see the paper for more details).
Ralf Jung's avatar
Ralf Jung committed
150
    Developments instantiating the proof mode typeclasses may need significant
Robbert Krebbers's avatar
Robbert Krebbers committed
151 152
    changes.  For developments just using the proof mode tactics, porting should
    not be too much effort.  Notable things to port are:
Ralf Jung's avatar
Ralf Jung committed
153 154 155 156 157
  - All the BI laws moved from the `uPred` module to the `bi` module.  For
    example, `uPred.later_equivI` became `bi.later_equivI`.
  - Big-ops are automatically imported, imports of `iris.base_logic.big_op` have
    to be removed.
  - The ⊢ notation can sometimes infer different (but convertible) terms when
Robbert Krebbers's avatar
Robbert Krebbers committed
158
    searching for the BI to use, which (due to Coq limitations) can lead to
Ralf Jung's avatar
Ralf Jung committed
159 160 161 162
    failing rewrites, in particular when rewriting at function types.
* The `iInv` tactic can now be used without the second argument (the name for
  the closing update).  It will then instead add the obligation to close the
  invariant to the goal.
Ralf Jung's avatar
Ralf Jung committed
163 164
* The new `iEval` tactic can be used to execute a simplification or rewriting
  tactic on some specific part(s) of the proofmode goal.
Ralf Jung's avatar
Ralf Jung committed
165 166
* Added support for defining derived connectives involving n-ary binders using
  telescopes.
Ralf Jung's avatar
Ralf Jung committed
167 168 169
* The proof mode now more consistently "prettifies" the goal after each tactic.
  Prettification also simplifies some BI connectives, like conditional
  modalities and telescope quantifiers.
Ralf Jung's avatar
Ralf Jung committed
170
* Improved pretty-printing of Iris connectives (in particular WP and fancy
Ralf Jung's avatar
Ralf Jung committed
171 172 173
  updates) when Coq has to line-wrap the output.  This goes hand-in-hand with an
  improved test suite that also tests pretty-printing.
* Added a `gmultiset` RA.
174
* Rename `timelessP` -> `timeless` (projection of the `Timeless` class)
Ralf Jung's avatar
Ralf Jung committed
175 176
* The CMRA axiom `cmra_extend` is now stated in `Type`, using `sigT` instead of
  in `Prop` using `exists`. This makes it possible to define the function space
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
177
  CMRA even for an infinite domain.
Robbert Krebbers's avatar
Robbert Krebbers committed
178 179 180 181 182
* Rename proof mode type classes for laters:
  - `IntoLaterN``MaybeIntoLaterN` (this one _may_ strip a later)
  - `IntoLaterN'``IntoLaterN` (this one _should_ strip a later)
  - `IntoLaterNEnv``MaybeIntoLaterNEnv`
  - `IntoLaterNEnvs``MaybeIntoLaterNEnvs`
183 184
* Rename:
  - `frag_auth_op``frac_auth_frag_op`
185 186 187
  - `cmra_opM_assoc``cmra_op_opM_assoc`
  - `cmra_opM_assoc_L``cmra_op_opM_assoc_L`
  - `cmra_opM_assoc'``cmra_opM_opM_assoc`
Robbert Krebbers's avatar
Robbert Krebbers committed
188
* `namespaces` has been moved to std++.
189 190
* Changed `IntoVal` to be directly usable for rewriting `e` into `of_val v`, and
  changed `AsVal` to be usable for rewriting via the `[v <-]` destruct pattern.
Ralf Jung's avatar
Ralf Jung committed
191
* `wp_fork` is now written in curried form.
192
* `PureExec`/`wp_pure` now supports taking multiple steps at once.
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
193 194 195
* A new tactic, `wp_pures`, executes as many pure steps as possible, excluding
  steps that would require unlocking subterms. Every impure wp_ tactic executes
  this tactic before doing anything else.
Dan Frumin's avatar
Dan Frumin committed
196
* Add `big_sepM_insert_acc`.
197 198 199 200
* Add big separating conjunctions that operate on pairs of lists (`big_sepL2`)
  and on pairs of maps (`big_sepM2`). In the former case the lists are required
  to have the same length, and in the latter case the maps are required to
  have the same domains.
Dan Frumin's avatar
Dan Frumin committed
201 202 203
* The `_strong` lemmas (e.g. `own_alloc_strong`) work for all infinite
  sets, instead of just for cofinite sets. The versions with cofinite
  sets have been renamed to use the `_cofinite` suffix.
Robbert Krebbers's avatar
Robbert Krebbers committed
204 205 206
* Remove locked value lambdas. The value scope notations `rec: f x := e` and
  `(λ: x, e)` no longer add a `locked`. Instead, we made the `wp_` tactics
  smarter to no longer unfold lambdas/recs that occur behind definitions.
Ralf Jung's avatar
Ralf Jung committed
207
* Export the fact that `iPreProp` is a COFE.
208 209 210 211 212 213 214
* The CMRA `auth` now can have fractional authoritative parts. So now `auth` has
  3 types of elements: the fractional authoritative `●{q} a`, the full
  authoritative `● a ≡ ●{1} a`, and the non-authoritative `◯ a`. Updates are
  only possible with the full authoritative element `● a`, while fractional
  authoritative elements have agreement: `✓ (●{p} a ⋅ ●{q} b) ⇒ a ≡ b`. As a
  consequence, `auth` is no longer a COFE and does not preserve Leibniz
  equality.
215 216
* Add a COFE construction (and functor) on dependent pairs `sigTO`, dual to
  `discrete_funO`.
Hai Dang's avatar
Hai Dang committed
217 218 219 220 221 222
* Rename in `auth`:
  - Use `auth_auth_proj`/`auth_frag_proj` for the projections of `auth`:
    `authoritative``auth_auth_proj` and `auth_own``auth_frag_proj`.
  - Use `auth_auth` and `auth_frag` for the injections into authoritative
    elements and non-authoritative elements respectively.
  - Lemmas for the projections and injections are renamed accordingly.
Hai Dang's avatar
Hai Dang committed
223 224 225 226 227
    For examples:
    + `authoritative_validN``auth_auth_proj_validN`
    + `auth_own_validN``auth_frag_proj_validN`
    + `auth_auth_valid` was not renamed because it was already used for the
      authoritative injection.
Hai Dang's avatar
Hai Dang committed
228 229
  - `auth_both_valid``auth_both_valid_2`
  - `auth_valid_discrete_2``auth_both_valid`
Robbert Krebbers's avatar
Robbert Krebbers committed
230 231 232
* Add the camera `ufrac` for unbounded fractions (i.e. without fractions that
  can be `> 1`) and the camera `ufrac_auth` for a variant of the authoritative
  fractional camera (`frac_auth`) with unbounded fractions.
233 234
* Changed `frac_auth` notation from `●!`/`◯!` to `●F`/`◯F`. sed script:
  `s/◯!/◯F/g; s/●!/●F/g;`.
235 236
* Lemma `prop_ext` works in both directions; its default direction is the
  opposite of what it used to be.
237
* Make direction of `f_op` rewrite lemmas more consistent: Flip `pair_op`,
Paolo G. Giarrusso's avatar
Paolo G. Giarrusso committed
238 239
  `Cinl_op`, `Cinr_op`, `cmra_morphism_op`, `cmra_morphism_pcore`,
  `cmra_morphism_core`.
Robbert Krebbers's avatar
Robbert Krebbers committed
240 241
* Rename lemmas `fupd_big_sep{L,M,S,MS}` into `big_sep{L,M,S,MS}_fupd` to be
  consistent with other such big op lemmas. Also add such lemmas for `bupd`.
242
* Rename `C` suffixes into `O` since we no longer use COFEs but OFEs. Also
Ralf Jung's avatar
Ralf Jung committed
243 244
  rename `ofe_fun` into `discrete_fun` and the corresponding notation `-c>` into
  `-d>`. The renaming can be automatically done using the following script (on
245
  macOS, replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`):
246
```
247
sed -i '
248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298
s/\bCofeMor/OfeMor/g;
s/\-c>/\-d>/g;
s/\bcFunctor/oFunctor/g;
s/\bCFunctor/OFunctor/g;
s/\b\%CF/\%OF/g;
s/\bconstCF/constOF/g;
s/\bidCF/idOF/g
s/\bdiscreteC/discreteO/g;
s/\bleibnizC/leibnizO/g;
s/\bunitC/unitO/g;
s/\bprodC/prodO/g;
s/\bsumC/sumO/g;
s/\bboolC/boolO/g;
s/\bnatC/natO/g;
s/\bpositiveC/positiveO/g;
s/\bNC/NO/g;
s/\bZC/ZO/g;
s/\boptionC/optionO/g;
s/\blaterC/laterO/g;
s/\bofe\_fun/discrete\_fun/g;
s/\bdiscrete\_funC/discrete\_funO/g;
s/\bofe\_morC/ofe\_morO/g;
s/\bsigC/sigO/g;
s/\buPredC/uPredO/g;
s/\bcsumC/csumO/g;
s/\bagreeC/agreeO/g;
s/\bauthC/authO/g;
s/\bnamespace_mapC/namespace\_mapO/g;
s/\bcmra\_ofeC/cmra\_ofeO/g;
s/\bucmra\_ofeC/ucmra\_ofeO/g;
s/\bexclC/exclO/g;
s/\bgmapC/gmapO/g;
s/\blistC/listO/g;
s/\bvecC/vecO/g;
s/\bgsetC/gsetO/g;
s/\bgset\_disjC/gset\_disjO/g;
s/\bcoPsetC/coPsetO/g;
s/\bgmultisetC/gmultisetO/g;
s/\bufracC/ufracO/g
s/\bfracC/fracO/g;
s/\bvalidityC/validityO/g;
s/\bbi\_ofeC/bi\_ofeO/g;
s/\bsbi\_ofeC/sbi\_ofeO/g;
s/\bmonPredC/monPredO/g;
s/\bstateC/stateO/g;
s/\bvalC/valO/g;
s/\bexprC/exprO/g;
s/\blocC/locO/g;
s/\bdec\_agreeC/dec\_agreeO/g;
s/\bgnameC/gnameO/g;
s/\bcoPset\_disjC/coPset\_disjO/g;
299
' $(find theories -name "*.v")
300
```
Hai Dang's avatar
Hai Dang committed
301

Ralf Jung's avatar
Ralf Jung committed
302
## Iris 3.1.0 (released 2017-12-19)
303

Ralf Jung's avatar
Ralf Jung committed
304
**Changes in and extensions of the theory:**
Ralf Jung's avatar
Ralf Jung committed
305

Ralf Jung's avatar
Ralf Jung committed
306
* Define `uPred` as a quotient on monotone predicates `M -> SProp`.
Ralf Jung's avatar
Ralf Jung committed
307 308
* Get rid of some primitive laws; they can be derived:
  `True ⊢ □ True` and `□ (P ∧ Q) ⊢ □ (P ∗ Q)`
309
* Camera morphisms have to be homomorphisms, not just monotone functions.
Ralf Jung's avatar
Ralf Jung committed
310
* Add a proof that `f` has a fixed point if `f^k` is contractive.
311 312
* Constructions for least and greatest fixed points over monotone predicates
  (defined in the logic of Iris using impredicative quantification).
Ralf Jung's avatar
Ralf Jung committed
313
* Add a proof of the inverse of `wp_bind`.
Ralf Jung's avatar
Ralf Jung committed
314
* [Experimental feature] Add new modality: ■ ("plainly").
Ralf Jung's avatar
Ralf Jung committed
315 316 317 318 319 320 321 322
* [Experimental feature] Support verifying code that might get stuck by
  distinguishing "non-stuck" vs. "(potentially) stuck" weakest
  preconditions. (See [Swasey et al., OOPSLA '17] for examples.) The non-stuck
  `WP e @ E {{ Φ }}` ensures that, as `e` runs, it does not get stuck. The stuck
  `WP e @ E ?{{ Φ }}` ensures that, as usual, all invariants are preserved while
  `e` runs, but it permits execution to get stuck. The former implies the
  latter. The full judgment is `WP e @ s; E {{ Φ }}`, where non-stuck WP uses
  *stuckness bit* `s = NotStuck` while stuck WP uses `s = MaybeStuck`.
Ralf Jung's avatar
Ralf Jung committed
323

Ralf Jung's avatar
Ralf Jung committed
324
**Changes in Coq:**
Ralf Jung's avatar
Ralf Jung committed
325

Robbert's avatar
Robbert committed
326 327
* Move the `prelude` folder to its own project:
  [coq-std++](https://gitlab.mpi-sws.org/robbertkrebbers/coq-stdpp)
Ralf Jung's avatar
Ralf Jung committed
328 329 330 331 332 333 334 335 336 337 338
* Some extensions/improvements of heap_lang:
  - Improve handling of pure (non-state-dependent) reductions.
  - Add fetch-and-add (`FAA`) operation.
  - Add syntax for all Coq's binary operations on `Z`.
* Generalize `saved_prop` to let the user choose the location of the type-level
  later.  Rename the general form to `saved_anything`.  Provide `saved_prop` and
  `saved_pred` as special cases.
* Improved big operators:
  + They are no longer tied to cameras, but work on any monoid
  + The version of big operations over lists was redefined so that it enjoys
    more definitional equalities.
Ralf Jung's avatar
Ralf Jung committed
339
* Rename some things and change notation:
340
  - The unit of a camera: `empty` -> `unit`, `∅` -> `ε`
341
  - Disjointness: `⊥` -> `##`
Ralf Jung's avatar
Ralf Jung committed
342
  - A proof mode type class `IntoOp` -> `IsOp`
343 344 345 346 347 348
  - OFEs with all elements being discrete: `Discrete` -> `OfeDiscrete`
  - OFE elements whose equality is discrete: `Timeless` -> `Discrete`
  - Timeless propositions: `TimelessP` -> `Timeless`
  - Camera elements such that `core x = x`: `Persistent` -> `CoreId`
  - Persistent propositions: `PersistentP` -> `Persistent`
  - The persistent modality: `always` -> `persistently`
349
  - Adequacy for non-stuck weakestpre: `adequate_safe` -> `adequate_not_stuck`
Ralf Jung's avatar
Ralf Jung committed
350
  - Consistently SnakeCase identifiers:
351 352 353 354 355 356 357 358 359 360
    + `CMRAMixin` -> `CmraMixin`
    + `CMRAT` -> `CmraT`
    + `CMRATotal` -> `CmraTotal`
    + `CMRAMorphism` -> `CmraMorphism`
    + `CMRADiscrete` -> `CmraDiscrete`
    + `UCMRAMixin` -> `UcmraMixin`
    + `UCMRAT` -> `UcmraT`
    + `DRAMixin` -> `DraMixin`
    + `DRAT` -> `DraT`
    + `STS` -> `Sts`
Ralf Jung's avatar
Ralf Jung committed
361 362
  - Many lemmas also changed their name.  `always_*` became `persistently_*`,
    and furthermore: (the following list is not complete)
363 364 365 366 367 368 369 370 371 372
    + `impl_wand` -> `impl_wand_1` (it only involves one direction of the
      equivalent)
    + `always_impl_wand` -> `impl_wand`
    + `always_and_sep_l` -> `and_sep_l`
    + `always_and_sep_r` -> `and_sep_r`
    + `always_sep_dup` -> `sep_dup`
    + `wand_impl_always` -> `impl_wand_persistently` (additionally,
      the direction of this equivalence got swapped for consistency's sake)
    + `always_wand_impl` -> `persistently_impl_wand` (additionally, the
      direction of this equivalence got swapped for consistency's sake)
Ralf Jung's avatar
Ralf Jung committed
373
  The following `sed` snippet should get you most of the way (on macOS you will
374
  have to replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`):
Ralf Jung's avatar
Ralf Jung committed
375
```
376
sed -i 's/\bPersistentP\b/Persistent/g; s/\bTimelessP\b/Timeless/g; s/\bCMRADiscrete\b/CmraDiscrete/g; s/\bCMRAT\b/CmraT/g; s/\bCMRAMixin\b/CmraMixin/g; s/\bUCMRAT\b/UcmraT/g; s/\bUCMRAMixin\b/UcmraMixin/g; s/\bSTS\b/Sts/g' $(find -name "*.v")
Ralf Jung's avatar
Ralf Jung committed
377
```
Ralf Jung's avatar
Ralf Jung committed
378 379
* `PersistentL` and `TimelessL` (persistence and timelessness of lists of
  propositions) are replaces by `TCForall` from std++.
Ralf Jung's avatar
Ralf Jung committed
380 381
* Fix a bunch of consistency issues in the proof mode, and make it overall more
  usable.  In particular:
382 383 384 385 386 387 388 389 390 391
  - All proof mode tactics start the proof mode if necessary; `iStartProof` is
    no longer needed and should only be used for building custom proof mode
    tactics.
  - Change in the grammar of specialization patterns: `>[...]` -> `[> ...]`
  - Various new specification patterns for `done` and framing.
  - There is common machinery for symbolic execution of pure reductions. This
    is provided by the type classes `PureExec` and `IntoVal`.
  - There is a new connective `tc_opaque`, which can be used to make definitions
    opaque for type classes, and thus opaque for most tactics of the proof
    mode.
Ralf Jung's avatar
Ralf Jung committed
392 393 394 395 396 397 398 399
  - Define Many missing type class instances for distributing connectives.
  - Implement the tactics `iIntros (?)` and `iIntros "!#"` (i.e. `iAlways`)
    using type classes. This makes them more generic, e.g., `iIntros (?)` also
    works when the universal quantifier is below a modality, and `iAlways` also
    works for the plainness modality.  A breaking change, however, is that these
    tactics now no longer work when the universal quantifier or modality is
    behind a type class opaque definition.  Furthermore, this can change the
    name of anonymous identifiers introduced with the "%" pattern.
Ralf Jung's avatar
Ralf Jung committed
400
* Make `ofe_fun` dependently typed, subsuming `iprod`.  The latter got removed.
Ralf Jung's avatar
Ralf Jung committed
401 402 403
* Define the generic `fill` operation of the `ectxi_language` construct in terms
  of a left fold instead of a right fold. This gives rise to more definitional
  equalities.
Robbert Krebbers's avatar
Robbert Krebbers committed
404 405 406 407 408
* The language hierarchy (`language`, `ectx_language`, `ectxi_language`) is now
  fully formalized using canonical structures instead of using a mixture of
  type classes and canonical structures. Also, it now uses explicit mixins. The
  file `program_logic/ectxi_language` contains some documentation on how to
  setup Iris for your language.
Ralf Jung's avatar
Ralf Jung committed
409 410
* Restore the original, stronger notion of atomicity alongside the weaker
  notion. These are `Atomic a e` where the stuckness bit `s` indicates whether
411 412
  expression `e` is weakly (`a = WeaklyAtomic`) or strongly
  (`a = StronglyAtomic`) atomic.
413 414 415 416
* Various improvements to `solve_ndisj`.
* Use `Hint Mode` to prevent Coq from making arbitrary guesses in the presence
  of evars, which often led to divergence. There are a few places where type
  annotations are now needed.
417
* The rules `internal_eq_rewrite` and `internal_eq_rewrite_contractive` are now
Ralf Jung's avatar
Ralf Jung committed
418
  stated in the logic, i.e., they are `iApply`-friendly.
419

Ralf Jung's avatar
Ralf Jung committed
420
## Iris 3.0.0 (released 2017-01-11)
421

Ralf Jung's avatar
Ralf Jung committed
422 423 424
* There now is a deprecation process.  The modules `*.deprecated` contain
  deprecated notations and definitions that are provided for backwards
  compatibility and will be removed in a future version of Iris.
Ralf Jung's avatar
Ralf Jung committed
425
* View shifts are radically simplified to just internalize frame-preserving
426
  updates.  Weakestpre is defined inside the logic, and invariants and view
Ralf Jung's avatar
Ralf Jung committed
427
  shifts with masks are also coded up inside Iris.  Adequacy of weakestpre is
428
  proven in the logic. The old ownership of the entire physical state is
Ralf Jung's avatar
Ralf Jung committed
429 430
  replaced by a user-selected predicate over physical state that is maintained
  by weakestpre.
431
* Use OFEs instead of COFEs everywhere.  COFEs are only used for solving the
432 433
  recursive domain equation.  As a consequence, CMRAs no longer need a proof of
  completeness.  (The old `cofeT` is provided by `algebra.deprecated`.)
434
* Implement a new agreement construction.  Unlike the old one, this one
435 436
  preserves discreteness.  dec_agree is thus no longer needed and has been moved
  to algebra.deprecated.
437 438 439
* Renaming and moving things around: uPred and the rest of the base logic are in
  `base_logic`, while `program_logic` is for everything involving the general
  Iris notion of a language.
440 441 442 443
* Renaming in prelude.list: Rename `prefix_of` -> `prefix` and `suffix_of` ->
  `suffix` in lemma names, but keep notation ``l1 `prefix_of` l2`` and ``l1
  `suffix_of` l2``.  `` l1 `sublist` l2`` becomes ``l1 `sublist_of` l2``. Rename
  `contains` -> `submseteq` and change `` l1 `contains` l2`` to ``l1 ⊆+ l2``.
Ralf Jung's avatar
Ralf Jung committed
444 445 446
* Slightly weaker notion of atomicity: an expression is atomic if it reduces in
  one step to something that does not reduce further.
* Changed notation for embedding Coq assertions into Iris.  The new notation is
447
  ⌜φ⌝.  Also removed `=` and `⊥` from the Iris scope.  (The old notations are
Ralf Jung's avatar
Ralf Jung committed
448
  provided in `base_logic.deprecated`.)
449
* Up-closure of namespaces is now a notation (↑) instead of a coercion.
450 451
* With invariants and the physical state being handled in the logic, there is no
  longer any reason to demand the CMRA unit to be discrete.
Ralf Jung's avatar
Ralf Jung committed
452
* The language can now fork off multiple threads at once.
453 454
* Local Updates (for the authoritative monoid) are now a 4-way relation with
  syntax-directed lemmas proving them.
Ralf Jung's avatar
Ralf Jung committed
455 456 457

## Iris 2.0

Ralf Jung's avatar
Ralf Jung committed
458 459 460 461
* [heap_lang] No longer use dependent types for expressions.  Instead, values
  carry a proof of closedness.  Substitution, closedness and value-ness proofs
  are performed by computation after reflecting into a term langauge that knows
  about values and closed expressions.
462 463
* [program_logic/language] The language does not define its own "atomic"
  predicate.  Instead, atomicity is defined as reducing in one step to a value.
464 465 466 467 468
* [program_logic] Due to a lack of maintenance and usefulness, lifting lemmas
  for Hoare triples are removed.

## Iris 2.0-rc2

Ralf Jung's avatar
Ralf Jung committed
469
This version matches the final ICFP 2016 paper.
470 471

* [algebra] Make the core of an RA or CMRA a partial function.
Ralf Jung's avatar
Ralf Jung committed
472
* [program_logic/lifting] Lifting lemmas no longer round-trip through a
Ralf Jung's avatar
Ralf Jung committed
473 474 475
  user-chosen predicate to define the configurations we can reduce to; they
  directly relate to the operational semantics.  This is equivalent and
  much simpler to read.
Ralf Jung's avatar
Ralf Jung committed
476 477 478

## Iris 2.0-rc1

Ralf Jung's avatar
Ralf Jung committed
479
This is the Coq development and Iris Documentation as submitted to ICFP 2016.