CHANGELOG.md 62.5 KB
Newer Older
Ralf Jung's avatar
Ralf Jung committed
1
In this changelog, we document "large-ish" changes to Iris that affect even the
Ralf Jung's avatar
Ralf Jung committed
2
3
4
way the logic is used on paper.  We also document changes in the Coq
development; every API-breaking change should be listed, but not every new
lemma.
5

6
7
8
9
## Iris master

**Changes in `algebra`:**

10
11
12
13
14
* Generalize the authorative elements of the `view`, `auth` and `gset_bij`
  cameras to be parameterized by a [discardable fraction](iris/algebra/dfrac.v)
  (`dfrac`) instead of a fraction (`frac`). Normal fractions are now denoted
  `●{#q} a` and `●V{#q} a`. Lemmas affected by this have been renamed such that
  the "frac" in their name has been changed into "dfrac".
Ralf Jung's avatar
Ralf Jung committed
15
16
17
18
19
20
21
22
23
24
* Generalize `namespace_map` to `reservation_map` which enhances `gmap positive
  A` with a notion of 'tokens' that enable allocating a particular name in the
  map. See [algebra.reservation_map](iris/algebra/reservation_map.v) for further
  information.
* Add `dyn_reservation_map` which further extends `reservation_map` with the
  ability to dynamically allocate an infinite set of tokens. This is useful to
  perform synchronized allocation of the same name in two maps/APIs without
  dedicated support from one of the involved maps/APIs. See
  [algebra.dyn_reservation_map](iris/algebra/dyn_reservation_map.v) for further
  information.
Ralf Jung's avatar
Ralf Jung committed
25
26
* Demote the Camera structure on `list` to `iris_staging` since its composition
  is not very well-behaved.
27

Ralf Jung's avatar
Ralf Jung committed
28
29
30
31
32
33
**Changes in `proof_mode`:**

* Add support for pure names `%H` in intro patterns. This is now natively
  supported whereas the previous experimental support required installing
  https://gitlab.mpi-sws.org/iris/string-ident.

Ralf Jung's avatar
Ralf Jung committed
34
35
36
37
**Changes in `base_logic`:**

* Add `ghost_map`, a logic-level library for a `gmap K V` with an authoritative
  view and per-element points-to facts written `k ↪[γ] w`.
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
38
39
* Generalize the soundness lemma of the base logic `step_fupdN_soundness`.
  It applies even if invariants stay open accross an arbitrary number of laters.
40
41
42

**Changes in `program_logic`:**

Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
43
44
45
46
47
48
* Change definition of weakest precondition to use a variable number of laters
  (i.e., logical steps) for each physical step of the operational semantics,
  depending on the number of physical steps executed since the begining of the
  execution of the program. See merge request [!595](https://gitlab.mpi-sws.org/iris/iris/-/merge_requests/595).
  This implies several API-breaking changes, which can be easily fixed in client
  formalizations in a backward compatible manner as follows:
49
50
51
52
53
54
55
56
   - Ignore the new parameter `ns` in the state interpretation, which
     corresponds to a step counter.
   - Use the constant function "0" for the new field `num_laters_per_step` of
     `irisG`.
   - Use `fupd_intro _ _` for the new field `state_interp_mono` of `irisG`.
   - Some proofs using lifting lemmas and adequacy theorems need to be adapted
     to ignore the new step counter.

Ralf Jung's avatar
Ralf Jung committed
57
58
59
60
**Changes in `heap_lang`:**

* Rename `Build_loc` constructor for `loc` type to `Loc`.

Ralf Jung's avatar
Ralf Jung committed
61
62
63
64
65
66
67
68
69
70
71
72
73
The following `sed` script helps adjust your code to the renaming (on macOS,
replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`).
Note that the script is not idempotent, do not run it twice.
```
sed -i -E -f- $(find theories -name "*.v") <<EOF
# auth and view renames from frac to dfrac
s/\b(auth|view)_(auth|both|update)_frac_(is_op|op_invN|op_inv|inv_L|validN|op_validN|valid|op_valid|valid_2|valid_discrete|includedN|included|alloc|validI|validI_2|validI_1|validI|)\b/\1_\2_dfrac_\3/g
s/\bgset_bij_auth_frac_(\w*)\b/gset_bij_auth_dfrac_\1/g
s/\bgset_bij_auth_empty_frac_valid\b/gset_bij_auth_empty_dfrac_valid/g
s/\bbij_both_frac_valid\b/bij_both_dfrac_valid/g
EOF
```

Ralf Jung's avatar
Ralf Jung committed
74
## Iris 3.4.0
75

Ralf Jung's avatar
Ralf Jung committed
76
77
78
79
The highlights and most notable changes of this release are as follows:
* Coq 8.13 is now supported; the old Coq 8.9 and Coq 8.10 are not supported any
  more.
* The new `view` RA construction generalizes `auth` to user-defined abstraction
Ralf Jung's avatar
Ralf Jung committed
80
  relations. (thanks to Gregory Malecha for the inspiration)
Ralf Jung's avatar
Ralf Jung committed
81
82
83
84
* The new `dfrac` RA extends `frac` (fractions `0 < q ≤ 1`) with support for
  "discarding" some part of the fraction in exchange for a persistent witness
  that discarding has happened. This can be used to easily generalize fractional
  permissions with support for persistently owning "any part" of the resource.
85
  (by Simon Friis Vindum)
Ralf Jung's avatar
Ralf Jung committed
86
* The new `gmap_view` RA provides convenient lemmas for ghost ownership
Ralf Jung's avatar
Ralf Jung committed
87
88
89
90
91
92
93
94
  of heap-like structures with an "authoritative" view. Thanks to `dfrac`, it
  supports both exclusive (mutable) and persistent (immutable) ownership of
  individual map elements.
* With this release we are beginning to provide logic-level abstractions for
  ghost state, which have the advantage that the user does not have to directly
  interact with RAs to use them.
  - `ghost_var` provides a logic-level abstraction of ghost variables: a mutable
    "variable" with fractional ownership.
Ralf Jung's avatar
Ralf Jung committed
95
  - `mono_nat` provides a "monotone counter" with a persistent witnesses
96
    representing a lower bound of the current counter value. (by Tej Chajed)
Ralf Jung's avatar
Ralf Jung committed
97
98
99
100
  - `gset_bij` provides a monotonically growing partial bijection; this is
    useful in particular when building binary logical relations for languages
    with a heap.
* HeapLang provides a persistent read-only points-to assertion `l ↦□ v`.
101
  (by Simon Friis Vindum)
Ralf Jung's avatar
Ralf Jung committed
102
103
104
105
* We split Iris into multiple opam packages: `coq-iris` no longer contains
  HeapLang, which is now in a separate package `coq-iris-heap-lang`. The two
  packages `coq-iris-deprecated` (for old modules that we eventually plan to
  remove entirely) and `coq-iris-staging` (for new modules that are not yet
Ralf Jung's avatar
Ralf Jung committed
106
  ready for prime time) exist only as development versions, so they are not part
Ralf Jung's avatar
Ralf Jung committed
107
108
109
  of this release.
* The proofmode now does a better job at picking reasonable names when moving
  variables into the Coq context without a name being explicitly given by the
110
  user. However, the exact variable names remain unspecified. (by Tej Chajed)
Ralf Jung's avatar
Ralf Jung committed
111

Ralf Jung's avatar
Ralf Jung committed
112
113
Further details are given in the changelog below.

114
115
116
117
This release of Iris was managed by Ralf Jung and Robbert Krebbers, with
contributions by Arthur Azevedo de Amorim, Dan Frumin, Enrico Tassi, Hai Dang,
Michael Sammler, Paolo G. Giarrusso, Rodolphe Lepigre, Simon Friis Vindum, Tej
Chajed, and Yusuke Matsushita.  Thanks a lot to everyone involved!
118

119
120
**Changes in `algebra`:**

121
* Add constructions to define a camera through restriction of the validity predicate
Robbert Krebbers's avatar
Robbert Krebbers committed
122
  (`iso_cmra_mixin_restrict`) and through an isomorphism (`iso_cmra_mixin`).
123
124
* Add a `frac_agree` library which encapsulates `frac * agree A` for some OFE
  `A`, and provides some useful lemmas.
Ralf Jung's avatar
Ralf Jung committed
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
* Add the view camera `view`, which generalizes the authoritative camera
  `auth` by being parameterized by a relation that relates the authoritative
  element with the fragments.
* Add the camera of discardable fractions `dfrac`. This is a generalization of
  the normal fractional camera.
  See [algebra.dfrac](iris/algebra/dfrac.v) for further information.
* Add `gmap_view`, a camera providing a "view of a `gmap`". The authoritative
  element is any `gmap`; the fragment provides fractional ownership of a single
  key, including support for persistent read-only ownership through `dfrac`.
  See [algebra.lib.gmap_view](iris/algebra/lib/gmap_view.v) for further information.
* Add `mono_nat`, a wrapper for `auth max_nat`. The result is an authoritative
  `nat` where a fragment is a lower bound whose ownership is persistent.
  See [algebra.lib.mono_nat](iris/algebra/lib/mono_nat.v) for further information.
* Add the `gset_bij` resource algebra for monotone partial bijections.
  See [algebra.lib.gset_bij](iris/algebra/lib/gset_bij.v) for further information.
* Rename `agree_op_inv'``to_agree_op_inv`,
  `agree_op_invL'``to_agree_op_inv_L`, and add `to_agree_op_invN`.
* Rename `auth_auth_frac_op_invL``auth_auth_frac_op_inv_L`,
  `excl_auth_agreeL``excl_auth_agree_L`,
  `frac_auth_agreeL``frac_auth_agree_L`, and
  `ufrac_auth_agreeL``ufrac_auth_agree_L`.
146
147
* Fix direction of `auth_auth_validN` to make it consistent with similar lemmas,
  e.g., `auth_auth_valid`. The direction is now `✓{n} (● a) ↔ ✓{n} a`.
148
149
150
* Rename `auth_both_valid` to `auth_both_valid_discrete` and
  `auth_both_frac_valid` to `auth_both_frac_valid_discrete`. The old name is
  used for new, stronger lemmas that do not assume discreteness.
Robbert Krebbers's avatar
Robbert Krebbers committed
151
152
153
154
155
* Redefine the authoritative camera in terms of the view camera. As part of this
  change, we have removed lemmas that leaked implementation details. Hence, the
  only way to construct elements of `auth` is via the elements `●{q} a` and
  `◯ b`. The constructor `Auth`, and the projections `auth_auth_proj` and
  `auth_frag_proj` no longer exist. Lemmas that referred to these constructors
Ralf Jung's avatar
Ralf Jung committed
156
157
158
  have been removed, in particular: `auth_equivI`, `auth_validI`,
  `auth_included`, `auth_valid_discrete`, and `auth_both_op`.  For validity, use
  `auth_auth_valid*`, `auth_frag_valid*`, or `auth_both_valid*` instead.
Robbert Krebbers's avatar
Robbert Krebbers committed
159
* Rename `auth_update_core_id` into `auth_update_frac_alloc`.
Robbert Krebbers's avatar
Robbert Krebbers committed
160
161
* Rename `cmra_monotone_valid` into `cmra_morphism_valid` (this rename was
  forgotten in !56).
Ralf Jung's avatar
Ralf Jung committed
162
163
164
* Move the `*_validI` and `*_equivI` lemmas to a new module, `base_logic.algebra`.
  That module is exported by `base_logic.base_logic` so it should usually be
  available everywhere without further changes.
Robbert Krebbers's avatar
Robbert Krebbers committed
165
166
* The authoritative fragment `✓ (◯ b : auth A)` is no longer definitionally
  equal to `✓ b`.
167
* Change `*_valid` lemma statements involving fractions to use `Qp` addition and
168
169
  inequality instead of RA composition and validity (also in `base_logic` and
  the higher layers).
Ralf Jung's avatar
Ralf Jung committed
170
* Move `algebra.base` module to `prelude.prelude`.
Ralf Jung's avatar
Ralf Jung committed
171
172
* Strengthen `cmra_op_discrete` to assume only `✓{0} (x1 ⋅ x2)` instead of `✓
  (x1 ⋅ x2)`.
173
* Rename the types `ofeT``ofe`, `cmraT``cmra`, `ucmraT``ucmra`, and the
Robbert Krebbers's avatar
Robbert Krebbers committed
174
175
176
  constructors `OfeT``Ofe`, `CmraT``Cmra`, and `UcmraT``Ucmra` since the `T`
  suffix is not needed. This change makes these names consistent with `bi`,
  which also does not have a `T` suffix.
Ralf Jung's avatar
Ralf Jung committed
177
178
179
* Rename typeclass instances of CMRA operational typeclasses (`Op`, `Core`,
  `PCore`, `Valid`, `ValidN`, `Unit`) to have a `_instance` suffix, so that
  their original names are available to use as lemma names.
180
* Rename `frac_valid'``frac_valid`, `frac_op'``frac_op`,
181
182
183
184
185
  `ufrac_op'``ufrac_op`, `coPset_op_union``coPset_op`, `coPset_core_self`
  `coPset_core`, `gset_op_union``gset_op`, `gset_core_self``gset_core`,
  `gmultiset_op_disj_union``gmultiset_op`, `gmultiset_core_empty`
  `gmultiset_core`, `nat_op_plus``nat_op`, `max_nat_op_max`
  `max_nat_op`. Those names were previously blocked by typeclass instances.
186

Ralf Jung's avatar
Ralf Jung committed
187
188
189
190
**Changes in `bi`:**

* Add big op lemmas `big_op{L,L2,M,M2,S}_intuitionistically_forall` and
  `big_sepL2_forall`, `big_sepMS_forall`, `big_sepMS_impl`, and `big_sepMS_dup`.
Ralf Jung's avatar
Ralf Jung committed
191
192
193
194
195
* Add lemmas to big-ops that provide ownership of a single element and permit
  changing the quantified-over predicate when re-assembling the big-op:
  `big_sepL_lookup_acc_impl`, `big_sepL2_lookup_acc_impl`,
  `big_sepM_lookup_acc_impl`, `big_sepM2_lookup_acc_impl`,
  `big_sepS_elem_of_acc_impl`, `big_sepMS_elem_of_acc_impl`.
Ralf Jung's avatar
Ralf Jung committed
196
197
* Add lemmas `big_sepM_filter'` and `big_sepM_filter` matching the corresponding
  `big_sepS` lemmas.
Ralf Jung's avatar
Ralf Jung committed
198
199
* Add lemmas for big-ops of magic wands: `big_sepL_wand`, `big_sepL2_wand`,
  `big_sepM_wand`, `big_sepM2_wand`, `big_sepS_wand`, `big_sepMS_wand`.
Ralf Jung's avatar
Ralf Jung committed
200
* Add notation `¬ P` for `P → False` to `bi_scope`.
Ralf Jung's avatar
Ralf Jung committed
201
202
203
204
205
206
207
208
209
210
211
212
213
* Add `fupd_mask_intro` which can be conveniently `iApply`ed to goals of the
  form `|={E1,E2}=>` to get rid of the `fupd` in the goal if `E2 ⊆ E1`. The
  lemma `fupd_mask_weaken Enew` can be `iApply`ed to shrink the first mask to
  `Enew` without getting rid of the modality; the same effect can also be
  obtained slightly more conveniently by using `iMod` with `fupd_mask_subseteq
  Enew`. To make the new names work, rename some existing lemmas:
  `fupd_intro_mask``fupd_mask_intro_subseteq`,
  `fupd_intro_mask'``fupd_mask_subseteq` (implicit arguments also changed
  here), `fupd_mask_weaken``fupd_mask_intro_discard`. Remove `fupd_mask_same`
  since it was unused and obscure.  In the `BiFUpd` axiomatization, rename
  `bi_fupd_mixin_fupd_intro_mask` to `bi_fupd_mixin_fupd_mask_subseteq` and
  weaken the lemma to be specifically about `emp` (the stronger version can be
  derived).
214
215
216
217
218
219
220
221
222
223
224
225
* Remove `bi.tactics` with tactics that predate the proofmode (and that have not
  been working properly for quite some time).
* Strengthen `persistent_sep_dup` to support propositions that are persistent
  and either affine or absorbing.
* Fix the statement of the lemma `fupd_plainly_laterN`; the old lemma was a
  duplicate of `fupd_plain_laterN`.
* Strengthen `big_sepL2_app_inv` by weakening a premise (it is sufficient for
  one of the two pairs of lists to have equal length).
* Rename `equiv_entails``equiv_entails_1_1`,
  `equiv_entails_sym``equiv_entails_1_2`, and `equiv_spec``equiv_entails`.
* Remove the laws `pure_forall_2 : (∀ a, ⌜ φ a ⌝) ⊢ ⌜ ∀ a, φ a ⌝` from the BI
  interface and factor it into a type class `BiPureForall`.
Ralf Jung's avatar
Ralf Jung committed
226

227
228
229
230
231
232
233
234
235
**Changes in `proofmode`:**

* The proofmode now preserves user-supplied names for existentials when using
  `iDestruct ... as (?) "..."`. This is backwards-incompatible if you were
  relying on the previous automatic names (which were always "H", possibly
  freshened). It also requires some changes if you were implementing `IntoExist`
  yourself, since the typeclass now forwards names. If your instance transforms
  one `IntoExist` into another, you can generally just forward the name from the
  premise.
236
237
238
239
240
* The proofmode also preserves user-supplied names in `iIntros`, for example
  with `iIntros (?)` and `iIntros "%"`, as described for destructing
  existentials above. As part of this change, it now uses a base name of `H` for
  pure facts rather than the previous default of `a`. This also requires some
  changes if you were implementing `FromForall`, in order to forward names.
Robbert Krebbers's avatar
Robbert Krebbers committed
241
242
243
244
245
* Make `iFrame` "less" smart w.r.t. clean up of modalities. It now consistently
  removes the modalities `<affine>`, `<absorbing>`, `<persistent>` and `□` only
  if the result after framing is `True` or `emp`. In particular, it no longer
  removes `<affine>` if the result after framing is affine, and it no longer
  removes `□` if the result after framing is intuitionistic.
Robbert Krebbers's avatar
Robbert Krebbers committed
246
247
248
* Allow framing below an `<affine>` modality if the hypothesis that is framed is
  affine. (Previously, framing below `<affine>` was only possible if the
  hypothesis that is framed resides in the intuitionistic context.)
Robbert Krebbers's avatar
Robbert Krebbers committed
249
250
* Add Coq side-condition `φ` to class `ElimAcc` (similar to what we already had
  for `ElimInv` and `ElimModal`).
251
252
* Add a tactic `iSelect pat tac` (similar to `select` in std++) which runs the
  tactic `tac H` with the name `H` of the last hypothesis of the intuitionistic
253
  or spatial context matching `pat`. The tactic `iSelect` is used to implement:
254
255
256
257
258
  + `iRename select (pat)%I into name` which renames the matching hypothesis,
  + `iDestruct select (pat)%I as ...` which destructs the matching hypothesis,
  + `iClear select (pat)%I` which clears the matching hypothesis,
  + `iRevert select (pat)%I` which reverts the matching hypothesis,
  + `iFrame select (pat)%I` which cancels the matching hypothesis.
259

260
261
262
263
**Changes in `base_logic`:**

* Add a `ghost_var` library that provides (fractional) ownership of a ghost
  variable of arbitrary `Type`.
Ralf Jung's avatar
Ralf Jung committed
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
* Define a ghost state library on top of the `mono_nat` resource algebra.
  See [base_logic.lib.mono_nat](iris/base_logic/lib/mono_nat.v) for further
  information.
* Define a ghost state library on top of the `gset_bij` resource algebra.
  See [base_logic.lib.gset_bij](iris/base_logic/lib/gset_bij.v) for further
  information.
* Extend the `gen_heap` library with read-only points-to assertions using
  [discardable fractions](iris/algebra/dfrac.v).
  + The `mapsto` connective now takes a `dfrac` rather than a `frac` (i.e.,
    positive rational number `Qp`).
  + The notation `l ↦{ dq } v` is generalized to discardable fractions
    `dq : dfrac`.
  + The new notation `l ↦{# q} v` is used for a concrete fraction `q : frac`
    (e.g., to enable writing `l ↦{# 1/2} v`).
  + The new notation `l ↦□ v` is used for the discarded fraction. This
    persistent proposition provides read-only access to `l`.
  + The lemma `mapsto_persist : l ↦{dq} v ==∗ l ↦□ v` is used for making the
    location `l` read-only.
  + See the [changes to HeapLang](https://gitlab.mpi-sws.org/iris/iris/-/merge_requests/554)
    for an indication on how to adapt your language.
  + See the [changes to iris-examples](https://gitlab.mpi-sws.org/iris/examples/-/commit/a8425b708ec51d918d5cf6eb3ab6fde88f4e2c2a)
    for an indication on how to adapt your development. In particular, instead
    of `∃ q, l ↦{q} v` you likely want to use `l ↦□ v`, which has the advantage
    of being persistent (rather than just duplicable).
Ralf Jung's avatar
Ralf Jung committed
288
289
290
291
292
293
294
295
* Change type of some ghost state lemmas (mostly about allocation) to use `∗`
  instead of `∧` (consistent with our usual style).  This affects the following
  lemmas: `own_alloc_strong_dep`, `own_alloc_cofinite_dep`, `own_alloc_strong`,
  `own_alloc_cofinite`, `own_updateP`, `saved_anything_alloc_strong`,
  `saved_anything_alloc_cofinite`, `saved_prop_alloc_strong`,
  `saved_prop_alloc_cofinite`, `saved_pred_alloc_strong`,
  `saved_pred_alloc_cofinite`, `auth_alloc_strong`, `auth_alloc_cofinite`,
  `auth_alloc`.
Ralf Jung's avatar
Ralf Jung committed
296
* Change `uPred_mono` to only require inclusion at the smaller step-index.
Robbert Krebbers's avatar
Robbert Krebbers committed
297
298
299
300
301
302
* Put `iProp`/`iPreProp`-isomorphism into the `own` construction. This affects
  clients that define higher-order ghost state constructions. Concretely, when
  defining an `inG`, the functor no longer needs to be applied to `iPreProp`,
  but should be applied to `iProp`. This avoids clients from having to push
  through the `iProp`/`iPreProp`-isomorphism themselves, which is now handled
  once and for all by the `own` construction.
303
304
305
306
* Rename `gen_heap_ctx` to `gen_heap_interp`, since it is meant to be used in
  the state interpretation of WP and since `_ctx` is elsewhere used as a suffix
  indicating "this is a persistent assumption that clients should always have in
  their context". Likewise, rename `proph_map_ctx` to `proph_map_interp`.
Ralf Jung's avatar
Ralf Jung committed
307
308
309
310
* Move `uPred.prod_validI`, `uPred.option_validI`, and
  `uPred.discrete_fun_validI` to the new `base_logic.algebra` module. That
  module is exported by `base_logic.base_logic` so these names are now usually
  available everywhere, and no longer inside the `uPred` module.
Ralf Jung's avatar
Ralf Jung committed
311
312
313
314
* Remove the `gen_heap` notations `l ↦ -` and `l ↦{q} -`. They were barely used
  and looked very confusing in context: `l ↦ - ∗ P` looks like a magic wand.
* Change `gen_inv_heap` notation `l ↦□ I` to `l ↦_I □`, so that `↦□` can be used
  by `gen_heap`.
Ralf Jung's avatar
Ralf Jung committed
315
316
* Strengthen `mapsto_valid_2` conclusion from `✓ (q1 + q2)%Qp` to
  `⌜✓ (q1 + q2)%Qp ∧ v1 = v2⌝`.
Ralf Jung's avatar
Ralf Jung committed
317
318
* Change `gen_heap_init` to also return ownership of the points-to facts for the
  initial heap.
319
320
* Rename `mapsto_mapsto_ne` to `mapsto_frac_ne`, and add a simpler
  `mapsto_ne` that does not require reasoning about fractions.
Ralf Jung's avatar
Ralf Jung committed
321
322
323
324
325
326
327
* Deprecate the `auth` and `sts` modules. These were logic-level wrappers around
  the underlying RAs; as far as we know, they are unused since they were not
  flexible enough for practical use.
* Deprecate the `viewshift` module, which defined a binary view-shift connective
  with an implicit persistence modality. It was unused and too easily confused
  with `={_}=∗`, the binary view-shift (fancy update) *without* a persistence
  modality.
328

329
330
331
332
333
**Changes in `program_logic`:**

* `wp_strong_adequacy` now applies to an initial state with multiple
  threads instead of only a single thread. The derived adequacy lemmas
  are unchanged.
Ralf Jung's avatar
Ralf Jung committed
334
335
* `pure_exec_fill` is no longer registered as an instance for `PureExec`, to
  avoid TC search attempting to apply this instance all the time.
Ralf Jung's avatar
Ralf Jung committed
336
* Merge `wp_value_inv`/`wp_value_inv'` into `wp_value_fupd`/`wp_value_fupd'` by
Ralf Jung's avatar
Ralf Jung committed
337
  making the lemmas bidirectional.
Robbert Krebbers's avatar
Robbert Krebbers committed
338
339
340
* Generalize HeapLang's `mapsto` (`↦`), `array` (`↦∗`), and atomic heap
  connectives to discardable fractions. See the CHANGELOG entry in the category
  `base_logic` for more information.
Robbert Krebbers's avatar
Robbert Krebbers committed
341
* Opening an invariant or eliminating a mask-changing update modality around a
342
343
  non-atomic weakest precondition creates a side-condition `Atomic ...`.
  Before, this would fail with the unspecific error "iMod: cannot eliminate
Robbert Krebbers's avatar
Robbert Krebbers committed
344
  modality (|={E1,E2}=> ...) in (WP ...)".
Ralf Jung's avatar
Ralf Jung committed
345
346
* In `Ectx_step` and `step_atomic`, mark the parameters that are determined by
  the goal as implicit.
Ralf Jung's avatar
Ralf Jung committed
347
348
* Deprecate the `hoare` module to prevent accidental usage; the recommended way
  to write Hoare-style specifications is to use Texan triples.
349

Ralf Jung's avatar
Ralf Jung committed
350
351
352
**Changes in `heap_lang`:**

* `wp_pures` now turns goals of the form `WP v {{ Φ }}` into `Φ v`.
Ralf Jung's avatar
Ralf Jung committed
353
354
* Fix `wp_bind` in case of a NOP (i.e., when the given expression pattern is
  already at the top level).
Ralf Jung's avatar
Ralf Jung committed
355
356
* The `wp_` tactics now preserve the possibility of doing a fancy update when
  the expression reduces to a value.
Robbert Krebbers's avatar
Robbert Krebbers committed
357
358
359
360
* Move `IntoVal`, `AsVal`, `Atomic`, `AsRecV`, and `PureExec` instances to their
  own file [heap_lang.class_instances](iris_heap_lang/class_instances.v).
* Move `inv_head_step` tactic and `head_step` auto hints (now part of new hint
  database `head_step`) to [heap_lang.tactics](iris_heap_lang/tactics.v).
Robbert Krebbers's avatar
Robbert Krebbers committed
361
362
363
* The tactic `wp_apply` no longer performs `wp_pures` before applying the given
  lemma. The new tactic `wp_smart_apply` repeatedly performs single `wp_pure`
  steps until the lemma matches the goal.
Ralf Jung's avatar
Ralf Jung committed
364

Ralf Jung's avatar
Ralf Jung committed
365
366
367
368
369
370
The following `sed` script helps adjust your code to the renaming (on macOS,
replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`).
Note that the script is not idempotent, do not run it twice.
```
sed -i -E -f- $(find theories -name "*.v") <<EOF
# agree and L suffix renames
Ralf Jung's avatar
Ralf Jung committed
371
372
s/\bagree_op_inv'/to_agree_op_inv/g
s/\bagree_op_invL'/to_agree_op_inv_L/g
Ralf Jung's avatar
Ralf Jung committed
373
374
s/\bauth_auth_frac_op_invL\b/auth_auth_frac_op_inv_L/g
s/\b(excl|frac|ufrac)_auth_agreeL/\1_auth_agree_L/g
375
376
377
# auth_both_valid
s/\bauth_both_valid\b/auth_both_valid_discrete/g
s/\bauth_both_frac_valid\b/auth_both_frac_valid_discrete/g
378
379
380
# gen_heap_ctx and proph_map_ctx
s/\bgen_heap_ctx\b/gen_heap_interp/g
s/\bproph_map_ctx\b/proph_map_interp/g
381
382
# other gen_heap changes
s/\bmapsto_mapsto_ne\b/mapsto_frac_ne/g
383
384
385
386
387
# remove Ts in algebra
s/\bofeT\b/ofe/g
s/\bOfeT\b/Ofe/g
s/\bcmraT\b/cmra/g
s/\bCmraT\b/Cmra/g
Robbert Krebbers's avatar
Robbert Krebbers committed
388
389
s/\bucmraT\b/ucmra/g
s/\bUcmraT\b/Ucmra/g
390
# _op/valid/core lemmas
391
s/\b(u?frac_(op|valid))'/\1/g
392
393
394
395
396
397
s/\b((coPset|gset)_op)_union\b/\1/g
s/\b((coPset|gset)_core)_self\b/\1/g
s/\b(gmultiset_op)_disj_union\b/\1/g
s/\b(gmultiset_core)_empty\b/\1/g
s/\b(nat_op)_plus\b/\1/g
s/\b(max_nat_op)_max\b/\1/g
398
399
400
401
# equiv_spec
s/\bequiv_entails\b/equiv_entails_1_1/g
s/\bequiv_entails_sym\b/equiv_entails_1_2/g
s/\bequiv_spec\b/equiv_entails/g
Ralf Jung's avatar
Ralf Jung committed
402
403
404
EOF
```

Ralf Jung's avatar
Ralf Jung committed
405
## Iris 3.3.0 (released 2020-07-15)
Robbert Krebbers's avatar
Robbert Krebbers committed
406

Ralf Jung's avatar
Ralf Jung committed
407
This release does not have any outstanding highlights, but contains a large
Ralf Jung's avatar
Ralf Jung committed
408
number of improvements all over the board.  For instance:
Ralf Jung's avatar
Ralf Jung committed
409
410

* `heap_lang` now supports deallocation as well as better reasoning about
Ralf Jung's avatar
Ralf Jung committed
411
412
  "invariant locations" (locations that perpetually satisfy some Coq-level
  invariant).
Ralf Jung's avatar
Ralf Jung committed
413
414
415
416
417
* Invariants (`inv N P`) are more flexible, now also supporting splitting
  and merging of invariants with respect to separating conjunction.
* Performance of the proofmode for BIs constructed on top of other BIs (e.g.,
  `monPred`) was greatly improved, leading to up to 70% speedup in individual
  files. As part of this refactoring, the proofmode can now also be instantiated
Ralf Jung's avatar
Ralf Jung committed
418
419
420
421
422
  with entirely "logical" notion of BIs that do not have a (non-trivial) metric
  structure, and still support reasoning about ▷.
* The proof mode now provides experimental support for naming pure facts in
  intro patterns.  See
  [iris/string-ident](https://gitlab.mpi-sws.org/iris/string-ident) for details.
Ralf Jung's avatar
Ralf Jung committed
423
424
425
426
427
428
429
430
* Iris now provides official ASCII notation. We still recommend using the
  Unicode notation for better consistency and interoperability with other Iris
  libraries, but provide ASCII notation for when Unicode is not an option.
* We removed several coercions, fixing "ambiguous coercion path" warnings and
  solving some readability issues.
* Coq 8.10, 8.11, and 8.12 are newly supported by this release, and Coq 8.7 and
  8.8 are no longer supported.

Ralf Jung's avatar
Ralf Jung committed
431
432
Further details are given in the changelog below. We always first list the
potentially breaking changes, then (some of) the additions.
Ralf Jung's avatar
Ralf Jung committed
433
434
435
436
437
438

This release of Iris received contributions by Abel Nieto, Amin Timany, Dan
Frumin, Derek Dreyer, Dmitry Khalanskiy, Gregory Malecha, Jacques-Henri Jourdan,
Jonas Kastberg, Jules Jacobs, Matthieu Sozeau, Maxime Dénès, Michael Sammler,
Paolo G. Giarrusso, Ralf Jung, Robbert Krebbers, Simon Friis Vindum, Simon
Spies, and Tej Chajed.  Thanks a lot to everyone involved!
Ralf Jung's avatar
Ralf Jung committed
439

440
**Changes in `heap_lang`:**
Ralf Jung's avatar
Ralf Jung committed
441

Ralf Jung's avatar
Ralf Jung committed
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
* Remove global `Open Scope Z_scope` from `heap_lang.lang`, and leave it up to
  reverse dependencies if they want to `Open Scope Z_scope` or not.
* Fix all binary operators performing pointer arithmetic (instead of just the
  dedicated `OffsetOp` operator doing that).
* Rename `heap_lang.lifting` to `heap_lang.primitive_laws`. There now also
  exists `heap_lang.derived_laws`.
* Make lemma names for `fill` more consistent
  - Use the `_inv` suffix for the the backwards directions:
   `reducible_fill``reducible_fill_inv`,
   `reducible_no_obs_fill``reducible_no_obs_fill_inv`,
   `not_stuck_fill``not_stuck_fill_inv`.
  - Use the non-`_inv` names (that freed up) for the forwards directions:
   `reducible_fill`, `reducible_no_obs_fill`, `irreducible_fill_inv`.
* Remove namespace `N` from `is_lock`.

Ralf Jung's avatar
Ralf Jung committed
457
458
459
* Add support for deallocation of locations via the `Free` operation.
* Add a fraction to the heap_lang `array` assertion.
* Add `lib.array` module for deallocating, copying and cloning arrays.
Ralf Jung's avatar
Ralf Jung committed
460
461
462
463
* Add TWP (total weakest-pre) lemmas for arrays.
* Add a library for "invariant locations": heap locations that will not be
  deallocated (i.e., they are GC-managed) and satisfy some pure, Coq-level
  invariant.  See `iris.base_logic.lib.gen_inv_heap` for details.
Ralf Jung's avatar
Ralf Jung committed
464
* Add the ghost state for "invariant locations" to `heapG`.  This affects the
Ralf Jung's avatar
Ralf Jung committed
465
466
  statement of `heap_adequacy`, which is now responsible for initializing the
  "invariant locations" invariant.
467
* Add lemma `mapsto_mapsto_ne : ¬ ✓(q1 + q2)%Qp → l1 ↦{q1} v1 -∗ l2 ↦{q2} v2 -∗ ⌜l1 ≠ l2⌝`.
Ralf Jung's avatar
Ralf Jung committed
468
* Add lemma `is_lock_iff` and show that `is_lock` is contractive.
Ralf Jung's avatar
Ralf Jung committed
469

470
**Changes in `program_logic`:**
Ralf Jung's avatar
Ralf Jung committed
471
472
473
474
475

* In the axiomatization of ectx languages, 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
476
**Changes in the logic (`base_logic`, `bi`):**
Robbert Krebbers's avatar
Robbert Krebbers committed
477

Ralf Jung's avatar
Ralf Jung committed
478
* Rename some accessor-style lemmas to consistently use the suffix `_acc`
Ralf Jung's avatar
Ralf Jung committed
479
  instead of `_open`:
480
481
482
483
484
  `inv_open``inv_acc`, `inv_open_strong``inv_acc_strong`,
  `inv_open_timeless``inv_acc_timeless`, `na_inv_open``na_inv_acc`,
  `cinv_open``cinv_acc`, `cinv_open_strong``cinv_acc_strong`,
  `auth_open``auth_acc`, `sts_open``sts_acc`.
  To make this work, also rename `inv_acc``inv_alter`.
Ralf Jung's avatar
Ralf Jung committed
485
486
  (Most developments should be unaffected as the typical way to invoke these
  lemmas is through `iInv`, and that does not change.)
Robbert Krebbers's avatar
Robbert Krebbers committed
487
488
489
490
* Change `inv_iff`, `cinv_iff` and `na_inv_iff` to make order of arguments
  consistent and more convenient for `iApply`. They are now of the form
  `inv N P -∗ ▷ □ (P ↔ Q) -∗ inv N Q` and (similar for `na_inv_iff` and
  `cinv_iff`), following e.g., `inv_alter` and `wp_wand`.
Ralf Jung's avatar
Ralf Jung committed
491
492
* Rename `inv_sep_1``inv_split_1`, `inv_sep_2``inv_split_2`, and
  `inv_sep``inv_split` to be consistent with the naming convention in boxes.
Ralf Jung's avatar
Ralf Jung committed
493
494
495
496
* Update the strong variant of the accessor lemma for cancellable invariants to
  match that of regular invariants, where you can pick the mask at a later time.
  (The other part that makes it strong is that you get back the token for the
  invariant immediately, not just when the invariant is closed again.)
Ralf Jung's avatar
Ralf Jung committed
497
498
* 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
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
* Flatten the BI hierarchy by merging the `bi` and `sbi` canonical structures.
  This gives significant performance benefits on developments that construct BIs
  from BIs (e.g., use `monPred`). For, example it gives a performance gain of 37%
  overall on lambdarust-weak, with improvements for individual files up to 72%,
  see Iris issue #303. The concrete changes are as follows:
  + The `sbi` canonical structure has been removed.
  + The `bi` canonical structure contains the later modality. It does not
    require the later modality to be contractive or to satisfy the Löb rule, so
    we provide a smart constructor `bi_later_mixin_id` to get the later axioms
    "for free" if later is defined to be the identity function.
  + There is a separate class `BiLöb`, and a "free" instance of that class if
    the later modality is contractive. A `BiLöb` instance is required for the
    `iLöb` tactic, and for timeless instances of implication and wand.
  + There is a separate type class `BiInternalEq` for BIs with a notion of
    internal equality (internal equality was part of `sbi`). An instance of this
    class is needed for the `iRewrite` tactic, and the various lemmas about
    internal equality.
  + The class `SbiEmbed` has been removed and been replaced by classes
    `BiEmbedLater` and `BiEmbedInternalEq`.
  + The class `BiPlainly` has been generalized to BIs without internal equality.
    As a consequence, there is a separate class `BiPropExt` for BIs with
    propositional extensionality (i.e., `■ (P ∗-∗ Q) ⊢ P ≡ Q`).
  + The class `BiEmbedPlainly` is a bi-entailment (i.e., `⎡■ P⎤ ⊣⊢ ■ ⎡P⎤`
    instead of `■ ⎡P⎤ ⊢ ⎡■ P⎤`) as it has been generalized to BIs without a
    internal equality. In the past, the left-to-right direction was obtained for
    "free" using the rules of internal equality.
Ralf Jung's avatar
Ralf Jung committed
525
526
527
528
* Remove coercion from `iProp` (and other MoSeL propositions) to `Prop`.
  Instead, use the new unary notation `⊢ P`, or `⊢@{PROP} P` if the proposition
  type cannot be inferred. This also means that `%I` should not be necessary any
  more when stating lemmas, as `P` above is automatically parsed in scope `%I`.
Ralf Jung's avatar
Ralf Jung committed
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
* Some improvements to the `bi/lib/core` construction:
  + Rename `coreP_wand` into `coreP_entails` since it does not involve wands.
  + Generalize `coreP_entails` to non-affine BIs, and prove more convenient
    version `coreP_entails'` for `coreP P` with `P` affine.
  + Add instance `coreP_affine P : Affine P → Affine (coreP P)` and
    lemma `coreP_wand P Q : <affine> ■ (P -∗ Q) -∗ coreP P -∗ coreP Q`.
* Remove notation for 3-mask step-taking updates, and made 2-mask notation less
  confusing by distinguishing it better from mask-changing updates.
  Old: `|={Eo,Ei}▷=> P`. New: `|={Eo}[Ei]▷=> P`.
  Here, `Eo` is the "outer mask" (used at the beginning and end) and `Ei` the
  "inner mask" (used around the ▷ in the middle).
  As part of this, the lemmas about the 3-mask variant were changed to be about
  the 2-mask variant instead, and `step_fupd_mask_mono` now also has a more
  consistent argument order for its masks.

* Add a counterexample showing that sufficiently powerful cancellable invariants
  with a linear token subvert the linearity guarantee (see
  `bi.lib.counterexmples` for details).
* Redefine invariants as "semantic invariants" so that they support
  splitting and other forms of weakening.
* Add lemmas `inv_combine` and `inv_combine_dup_l` for combining invariants.
* Add the type `siProp` of "plain" step-indexed propositions, together with
  basic proofmode support.
Ralf Jung's avatar
Ralf Jung committed
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
* New ASCII versions of Iris notations. These are marked parsing only and
  can be made available using `Require Import iris.bi.ascii`. The new
  notations are (notations marked [†] are disambiguated using notation scopes):
  - entailment: `|-` for `⊢` and `-|-` for `⊣⊢`
  - logic[†]: `->` for `→`, `/\\` for `∧`, `\\/` for `∨`, and `<->` for `↔`
  - quantifiers[†]: `forall` for `∀` and `exists` for `∃`
  - separation logic: `**` for `∗`, `-*` for `-∗`, and `*-*` for `∗-∗`
  - step indexing: `|>` for `▷`
  - modalities: `<#>` for `□` and `<except_0>` for `◇`
  - most derived notations can be computed from previous notations using the
    substitutions above, e.g. replace `∗` with `*` and `▷` with `|>`. Examples
    include the following:
    - `|={E1,E2}=* P` for `|={E1,E2}=∗`
    - `P ={E}=* Q` for `P ={E}=∗ Q`
    - `P ={E1,E2}=* Q` for `P ={E1,E2}=∗ Q`
Ralf Jung's avatar
Ralf Jung committed
567
    - `|={E1}[E2]|>=> Q` for `|={E1}[E2]▷=> Q`
Ralf Jung's avatar
Ralf Jung committed
568
569
570
571
572
    The full list can be found in [theories/bi/ascii.v](theories/bi/ascii.v),
    where the ASCII notations are defined in terms of the unicode notations.
* Add affine, absorbing, persistent and timeless instances for telescopes.
* Add a construction `bi_rtc` to create reflexive transitive closures of
  PROP-level binary relations.
573
574
575
576
* Slightly strengthen the lemmas `big_sepL_nil'`, `big_sepL2_nil'`,
  `big_sepM_nil'` `big_sepM2_empty'`, `big_sepS_empty'`, and `big_sepMS_empty'`.
  They now only require that the argument `P` is affine instead of the whole BI
  being affine.
Ralf Jung's avatar
Ralf Jung committed
577
578
579
580
581
582
* Add `big_sepL_insert_acc`, a variant of `big_sepL_lookup_acc` which allows
  updating the value.
* Add many missing `Proper`/non-expansiveness lemmas for big-ops.
* Add `big_*_insert_delete` lemmas to split a `<[i:=x]> m` map into `i` and the rest.
* Seal the definitions of `big_opS`, `big_opMS`, `big_opM` and `big_sepM2`
  to prevent undesired simplification.
583
* Fix `big_sepM2_fmap*` only working for `nat` keys.
Ralf Jung's avatar
Ralf Jung committed
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605

**Changes in `proofmode`:**

* 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:
  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.
  2. Due to the use of `notypeclasses refine`, TC constraints are solved less
     eagerly, see <https://github.com/coq/coq/issues/6583>.
  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).
* Strengthen the tactics `iDestruct`, `iPoseProof`, and `iAssert`:
  - They succeed in certain cases where they used to fail.
  - They keep certain hypotheses in the intuitionistic context, where they were
    moved to the spatial context before.
  The latter can lead to stronger proof mode contexts, and therefore to
  backwards incompatibility. This can usually be fixed by manually clearing some
  hypotheses. A more detailed description of the changes can be found in
  <https://gitlab.mpi-sws.org/iris/iris/merge_requests/341>.
Ralf Jung's avatar
Ralf Jung committed
606
607
608
609
610
611
* Remove the long-deprecated `cofeT` alias (for `ofeT`) and `dec_agree` RA (use
  `agree` instead).

* Add `auto` hint for `∗-∗`.
* Add new tactic `iStopProof` to turn the proof mode entailment into an ordinary
  Coq goal `big star of context ⊢ proof mode goal`.
Ralf Jung's avatar
Ralf Jung committed
612
613
614
615
616
617
618
619
620
621
* Add new introduction pattern `-# pat` that moves a hypothesis from the
  intuitionistic context to the spatial context.
* The tactic `iAssumption` also recognizes assumptions `⊢ P` in the Coq context.
* Better support for telescopes in the proof mode, i.e., all tactics should
  recognize and distribute telescopes now.
* The proof mode now supports names for pure facts in intro patterns. Support
  requires implementing `string_to_ident`. Without this tactic such patterns
  will fail. We provide one implementation using Ltac2 which works with Coq 8.11
  and can be installed with opam; see
  [iris/string-ident](https://gitlab.mpi-sws.org/iris/string-ident) for details.
Ralf Jung's avatar
Ralf Jung committed
622

623
624
625
626
627
628
**Changes in `algebra`:**

* Remove `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.
* The functions `{o,r,ur}Functor_diag` are no longer coercions, and renamed into
629
630
  `{o,r,ur}Functor_apply` to better match their intent. This fixes "ambiguous
  coercion path" warnings.
631
632
* Rename `{o,r,ur}Functor_{ne,id,compose,contractive}` into
  `{o,r,ur}Functor_map_{ne,id,compose,contractive}`.
Ralf Jung's avatar
Ralf Jung committed
633
634
* Move derived camera constructions (`frac_auth` and `ufrac_auth`) to the folder
  `algebra/lib`.
635
636
637
638
639
640
641
642
643
644
645
646
647
648
* Rename `mnat` to `max_nat` and "box" it by creating a separate type for it.
* Move the RAs for `nat` and `positive` and the `mnat` RA into a separate
  module. They must now be imported from `From iris.algebra Require Import
  numbers`.
* Make names of `f_op`/`f_core` rewrite lemmas more consistent by always making
  `_core`/`_op` the suffix:
  `op_singleton``singleton_op`, `core_singleton``singleton_core`,
  `discrete_fun_op_singleton``discrete_fun_singleton_op`,
  `discrete_fun_core_singleton``discrete_fun_singleton_core`,
  `list_core_singletonM``list_singleton_core`,
  `list_op_singletonM``list_singleton_op`,
  `sts_op_auth_frag``sts_auth_frag_op`,
  `sts_op_auth_frag_up``sts_auth_frag_up_op`,
  `sts_op_frag``sts_frag_op`,
649
650
651
652
653
654
655
656
657
658
659
  `list_op_length``list_length_op`,
  `list_core_singletonM``list_singletonM_core`,
  `list_op_singletonM``list_singletonM_op`.
* All list "map singleton" lemmas consistently use `singletonM` in their name:
  `list_singleton_valid``list_singletonM_valid`,
  `list_singleton_core_id``list_singletonM_core_id`,
  `list_singleton_snoc``list_singletonM_snoc`,
  `list_singleton_updateP``list_singletonM_updateP`,
  `list_singleton_updateP'``list_singletonM_updateP'`,
  `list_singleton_update``list_singletonM_update`,
  `list_alloc_singleton_local_update``list_alloc_singletonM_local_update`.
Ralf Jung's avatar
Ralf Jung committed
660
* Remove `auth_both_op` and rename `auth_both_frac_op` into `auth_both_op`.
661
662
* Add lemma `singleton_included : {[ i := x ]} ≼ ({[ i := y ]} ↔ x ≡ y ∨ x ≼ y`,
  and rename existing asymmetric lemmas (with a singleton on just the LHS):
Ralf Jung's avatar
Ralf Jung committed
663
664
665
  `singleton_includedN``singleton_includedN_l`,
  `singleton_included``singleton_included_l`,
  `singleton_included_exclusive``singleton_included_exclusive_l`.
Ralf Jung's avatar
Ralf Jung committed
666
667
668
669
670
671
672
673
674

* Add notion `ofe_iso A B` that states that OFEs `A` and `B` are
  isomorphic. This is used in the COFE solver.
* Add `{o,r,ur}Functor_oFunctor_compose` for composition of functors.
* Add `pair_op_1` and `pair_op_2` to split a pair where one component is the unit.
* Add derived camera construction `excl_auth A` for `auth (option (excl A))`.
* Make lemma `Excl_included` a bi-implication.
* Make `auth_update_core_id` work with any fraction of the authoritative
  element.
Yusuke Matsushita's avatar
Yusuke Matsushita committed
675
* Add `min_nat`, an RA for natural numbers with `min` as the operation.
Ralf Jung's avatar
Ralf Jung committed
676
* Add many missing `Proper`/non-expansiveness lemmas for maps and lists.
Ralf Jung's avatar
Ralf Jung committed
677
678
679
680
* Add `list_singletonM_included` and `list_lookup_singletonM_{lt,gt}` lemmas
  about singletons in the list RA.
* Add `list_core_id'`, a stronger version of `list_core_id` which only talks
  about elements that are actually in the list.
681

682
683
684
The following `sed` script helps adjust your code to the renaming (on macOS,
replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`).
Note that the script is not idempotent, do not run it twice.
685
686
```
sed -i -E '
687
688
689
690
691
692
# functor renames
s/\b(o|r|ur)Functor_(ne|id|compose|contractive)\b/\1Functor_map_\2/g
# singleton_included renames
s/\bsingleton_includedN\b/singleton_includedN_l/g
s/\bsingleton_included\b/singleton_included_l/g
s/\bsingleton_included_exclusive\b/singleton_included_exclusive_l/g
693
694
695
696
# f_op/f_core renames
s/\b(op|core)_singleton\b/singleton_\1/g
s/\bdiscrete_fun_(op|core)_singleton\b/discrete_fun_singleton_\1/g
s/\bsts_op_(auth_frag|auth_frag_up|frag)\b/sts_\1_op/g
697
s/\blist_(op|core)_singletonM\b/list_singletonM_\1/g
698
s/\blist_op_length\b/list_length_op/g
699
700
701
702
703
704
705
# list "singleton map" renames
s/\blist_singleton_valid\b/list_singletonM_valid/g
s/\blist_singleton_core_id\b/list_singletonM_core_id/g
s/\blist_singleton_snoc\b/list_singletonM_snoc/g
s/\blist_singleton_updateP\b/list_singletonM_updateP/g
s/\blist_singleton_update\b/list_singletonM_update/g
s/\blist_alloc_singleton_local_update\b/list_alloc_singletonM_local_update/g
706
707
708
709
710
711
712
# inv renames
s/\binv_sep(|_1|_2)\b/inv_split\1/g
s/\binv_acc\b/inv_alter/g
s/\binv_open(|_strong|_timeless)\b/inv_acc\1/g
s/\bcinv_open(|_strong)\b/cinv_acc\1/g
s/\b(na_inv|auth|sts)_open\b/\1_acc/g
# miscellaneous
713
s/\bauth_both_frac_op\b/auth_both_op/g
714
s/\bmnat\b/max_nat/g
715
s/\bcoreP_wand\b/coreP_entails/g
716
717
718
' $(find theories -name "*.v")
```

Ralf Jung's avatar
Ralf Jung committed
719
## Iris 3.2.0 (released 2019-08-29)
Ralf Jung's avatar
Ralf Jung committed
720

Ralf Jung's avatar
Ralf Jung committed
721
722
723
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
724
725
726
727
728
729
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
730
731
732
733
734
735
736
737
738
739
740
741
742
743

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
744
745
746
747
748
749
750
751
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
752

753
* Change in the definition of WP, so that there is a fancy update between
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
754
755
  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
756
  "update that takes a step".
757
758
759
* 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
760
* Add the notion of an "observation" to the language interface, so that
Ralf Jung's avatar
Ralf Jung committed
761
762
  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
763
  future trace of observations from the beginning.
Ralf Jung's avatar
Ralf Jung committed
764
* The Löb rule is now a derived rule; it follows from later-intro, later
Ralf Jung's avatar
Ralf Jung committed
765
766
  being contractive and the fact that we can take fixpoints of contractive
  functions.
Ralf Jung's avatar
Ralf Jung committed
767
* Add atomic updates and logically atomic triples, including tactic support.
Ralf Jung's avatar
Ralf Jung committed
768
  See `heap_lang/lib/increment.v` for an example.
769
770
771
* 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
772
  `True`).
773
774
775
* 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.
776
777
778
* 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
779
**Changes in heap_lang:**
780

781
782
783
784
785
786
787
788
* 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
789
790
791
792
793
  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
794
795
* 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
796
  behavior) can be found [in the iris/examples repository][prophecy-erasure].
Ralf Jung's avatar
Ralf Jung committed
797
* heap_lang now uses right-to-left evaluation order. This makes it
Ralf Jung's avatar
Ralf Jung committed
798
  significantly easier to write specifications of curried functions.
Ralf Jung's avatar
Ralf Jung committed
799
* heap_lang values are now injected in heap_lang expressions via a specific
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
800
801
  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
802
  the reflection mechanism that was needed for proving closedness, atomicity and
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
803
804
  "valueness" of a term. The price to pay is the addition of new
  "administrative" reductions in the operational semantics of the language.
805
806
* heap_lang now has support for allocating, accessing and reasoning about arrays
  (continuously allocated regions of memory).
Robbert Krebbers's avatar
Robbert Krebbers committed
807
* One can now assign "meta" data to heap_lang locations.
Ralf Jung's avatar
Ralf Jung committed
808

Ralf Jung's avatar
Ralf Jung committed
809
810
[prophecy-erasure]: https://gitlab.mpi-sws.org/iris/examples/blob/3f33781fe6e19cfdb25259c8194d34403f1134d5/theories/logatom/proph_erasure.v

Ralf Jung's avatar
Ralf Jung committed
811
**Changes in Coq:**
812

Ralf Jung's avatar
Ralf Jung committed
813
* An all-new generalized proof mode that abstracts away from Iris!  Major new
Ralf Jung's avatar
Ralf Jung committed
814
815
816
817
818
819
  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
820
    an existing logic (see the paper for more details).
Ralf Jung's avatar
Ralf Jung committed
821
    Developments instantiating the proof mode typeclasses may need significant
Robbert Krebbers's avatar
Robbert Krebbers committed
822
823
    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
824
825
826
827
828
  - 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
829
    searching for the BI to use, which (due to Coq limitations) can lead to
Ralf Jung's avatar
Ralf Jung committed
830
831
832
833
    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
834
835
* 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
836
837
* Added support for defining derived connectives involving n-ary binders using
  telescopes.
Ralf Jung's avatar
Ralf Jung committed
838
839
840
* 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
841
* Improved pretty-printing of Iris connectives (in particular WP and fancy
Ralf Jung's avatar
Ralf Jung committed
842
843
844
  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.
845
* Rename `timelessP``timeless` (projection of the `Timeless` class)
Ralf Jung's avatar
Ralf Jung committed
846
847
* 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
848
  CMRA even for an infinite domain.
Robbert Krebbers's avatar
Robbert Krebbers committed
849
850
851
852
853
* 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`
854
855
* Rename:
  - `frag_auth_op``frac_auth_frag_op`
856
857
858
  - `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
859
* `namespaces` has been moved to std++.
860
861
* 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
862
* `wp_fork` is now written in curried form.
863
* `PureExec`/`wp_pure` now supports taking multiple steps at once.
Jacques-Henri Jourdan's avatar
Jacques-Henri Jourdan committed
864
865
866
* 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
867
* Add `big_sepM_insert_acc`.
868
869
870
871
* 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
872
873
874
* 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
875
876
877
* 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
878
* Export the fact that `iPreProp` is a COFE.
879
880
881
882
883
884
885
* 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.
886
887
* Add a COFE construction (and functor) on dependent pairs `sigTO`, dual to
  `discrete_funO`.
Hai Dang's avatar
Hai Dang committed
888
889
890
891
892
893
* 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
894
895
896
897
898
    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
899
900
  - `auth_both_valid``auth_both_valid_2`
  - `auth_valid_discrete_2``auth_both_valid`
Robbert Krebbers's avatar
Robbert Krebbers committed
901
902
903
* 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.
904
905
* Changed `frac_auth` notation from `●!`/`◯!` to `●F`/`◯F`. sed script:
  `s/◯!/◯F/g; s/●!/●F/g;`.
906
907
* Lemma `prop_ext` works in both directions; its default direction is the
  opposite of what it used to be.
908
* Make direction of `f_op` rewrite lemmas more consistent: Flip `pair_op`,
Paolo G. Giarrusso's avatar
Paolo G. Giarrusso committed
909
910
  `Cinl_op`, `Cinr_op`, `cmra_morphism_op`, `cmra_morphism_pcore`,
  `cmra_morphism_core`.
Robbert Krebbers's avatar
Robbert Krebbers committed
911
912
* 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`.
913
* Rename `C` suffixes into `O` since we no longer use COFEs but OFEs. Also
Ralf Jung's avatar
Ralf Jung committed
914
  rename `ofe_fun` into `discrete_fun` and the corresponding notation `-c>` into
Ralf Jung's avatar
Ralf Jung committed
915
916
  `-d>`. The renaming can be automatically done using the following script
  (on macOS, replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`):
917
```
918
sed -i '
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
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;
970
' $(find theories -name "*.v")
971
```
Hai Dang's avatar
Hai Dang committed
972

Ralf Jung's avatar
Ralf Jung committed
973
## Iris 3.1.0 (released 2017-12-19)
974

Ralf Jung's avatar
Ralf Jung committed
975
**Changes in and extensions of the theory:**
Ralf Jung's avatar
Ralf Jung committed
976

Ralf Jung's avatar
Ralf Jung committed
977
* Define `uPred` as a quotient on monotone predicates `M -> SProp`.
Ralf Jung's avatar
Ralf Jung committed
978
979
* Get rid of some primitive laws; they can be derived:
  `True ⊢ □ True` and `□ (P ∧ Q) ⊢ □ (P ∗ Q)`
980
* Camera morphisms have to be homomorphisms, not just monotone functions.
Ralf Jung's avatar
Ralf Jung committed
981
* Add a proof that `f` has a fixed point if `f^k` is contractive.
982
983
* 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
984
* Add a proof of the inverse of `wp_bind`.
Ralf Jung's avatar
Ralf Jung committed
985
* [Experimental feature] Add new modality: ■ ("plainly").
Ralf Jung's avatar
Ralf Jung committed
986
987
988
989
990
991
992
993
* [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
994

Ralf Jung's avatar
Ralf Jung committed
995
**Changes in Coq:**
Ralf Jung's avatar
Ralf Jung committed
996

997
998
* 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
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
* 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
1010
* Rename some things and change notation:
1011
  - The unit of a camera: `empty` -> `unit`, `∅` -> `ε`
1012
  - Disjointness: `⊥` -> `##`
Ralf Jung's avatar
Ralf Jung committed
1013
  - A proof mode type class `IntoOp` -> `IsOp`
1014
1015
1016
1017
1018
1019
  - 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`
1020
  - Adequacy for non-stuck weakestpre: `adequate_safe` -> `adequate_not_stuck`
Ralf Jung's avatar
Ralf Jung committed
1021
  - Consistently SnakeCase identifiers:
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
    + `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
1032
1033
  - Many lemmas also changed their name.  `always_*` became `persistently_*`,
    and furthermore: (the following list is not complete)
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
    + `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
1044
  The following `sed` snippet should get you most of the way (on macOS you will
1045
  have to replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`):
Ralf Jung's avatar
Ralf Jung committed
1046
```
1047
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
1048
```
Ralf Jung's avatar
Ralf Jung committed
1049
1050
* `PersistentL` and `TimelessL` (persistence and timelessness of lists of
  propositions) are replaces by `TCForall` from std++.
Ralf Jung's avatar
Ralf Jung committed
1051
1052
* Fix a bunch of consistency issues in the proof mode, and make it overall more
  usable.  In particular:
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
  - 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
1063
1064
1065
1066
1067
1068
1069
1070
  - 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
1071
* Make `ofe_fun` dependently typed, subsuming `iprod`.  The latter got removed.
Ralf Jung's avatar
Ralf Jung committed
1072
1073
1074
* 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
1075
1076
1077
1078
1079
* 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
1080
1081
* Restore the original, stronger notion of atomicity alongside the weaker
  notion. These are `Atomic a e` where the stuckness bit `s` indicates whether
1082
1083
  expression `e` is weakly (`a = WeaklyAtomic`) or strongly
  (`a = StronglyAtomic`) atomic.
1084
1085
1086
1087
* 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.
1088
* The rules `internal_eq_rewrite` and `internal_eq_rewrite_contractive` are now
Ralf Jung's avatar
Ralf Jung committed
1089
  stated in the logic, i.e., they are `iApply`-friendly.
1090

Ralf Jung's avatar
Ralf Jung committed
1091
## Iris 3.0.0 (released 2017-01-11)
1092

Ralf Jung's avatar
Ralf Jung committed
1093
1094
1095
* 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
1096
* View shifts are radically simplified to just internalize frame-preserving
1097
  updates.  Weakestpre is defined inside the logic, and invariants and view
Ralf Jung's avatar
Ralf Jung committed
1098
  shifts with masks are also coded up inside Iris.  Adequacy of weakestpre is
1099
  proven in the logic. The old ownership of the entire physical state is
Ralf Jung's avatar
Ralf Jung committed
1100
1101
  replaced by a user-selected predicate over physical state that is maintained
  by weakestpre.
1102
* Use OFEs instead of COFEs everywhere.  COFEs are only used for solving the
1103
1104
  recursive domain equation.  As a consequence, CMRAs no longer need a proof of
  completeness.  (The old `cofeT` is provided by `algebra.deprecated`.)
1105
* Implement a new agreement construction.  Unlike the old one, this one
1106
1107
  preserves discreteness.  dec_agree is thus no longer needed and has been moved
  to algebra.deprecated.
1108
1109
1110
* 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.
1111
1112
1113
1114
* 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
1115
1116
1117
* 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
1118
  ⌜φ⌝.  Also removed `=` and `⊥` from the Iris scope.  (The old notations are
Ralf Jung's avatar
Ralf Jung committed
1119
  provided in `base_logic.deprecated`.)
1120
* Up-closure of namespaces is now a notation (↑) instead of a coercion.
1121
1122
* 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
1123
* The language can now fork off multiple threads at once.
1124
1125
* 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
1126
1127
1128

## Iris 2.0

Ralf Jung's avatar
Ralf Jung committed
1129
1130
1131
1132
* [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.
1133
1134
* [program_logic/language] The language does not define its own "atomic"
  predicate.  Instead, atomicity is defined as reducing in one step to a value.
1135
1136
1137
1138
1139
* [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
1140
This version matches the final ICFP 2016 paper.
1141
1142

* [algebra] Make the core of an RA or CMRA a partial function.
Ralf Jung's avatar
Ralf Jung committed
1143
* [program_logic/lifting] Lifting lemmas no longer round-trip through a
Ralf Jung's avatar
Ralf Jung committed
1144
1145
1146
  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
1147
1148
1149

## Iris 2.0-rc1

Ralf Jung's avatar
Ralf Jung committed
1150
This is the Coq development and Iris Documentation as submitted to ICFP 2016.