Tej Chajed authored Jul 21, 2020 and Robbert Krebbers committed Jul 21, 2020

When running `iDestruct "H" as (?) "H"`, use the name of the binder in
"H". For example, if "H" has type `∃ y, Φ y`,  we now use `y` as the
name of the variable after freshening. Previously the name was always
the equivalent of running `fresh H`.

The implementation achieves this by forwarding the desired identifier
name through the `IntoExist` typeclass. Identifiers are serialized in
Gallina by using them as the name of a function of type `ident_name :=
unit -> unit`.

Fixes #325.

Also added a tests for the various `iSpecialize` error cases involving
the `[%]` and `[//]` specialization patterns.

Fixes #307.

Notably this support relies on string to identifier conversion, which
works natively using Ltac2 in Coq 8.11+ and with a plugin
(https://github.com/ppedrot/coq-string-ident) in Coq 8.10. To use it,
you must replace intro_patterns.string_to_ident_hook with a real
implementation; see https://gitlab.mpi-sws.org/iris/string-ident for a
working implementation that works with Coq 8.11 (using Ltac2).

The syntax is %H (within a string intro pattern). This is technically
backwards-incompatible, because this was previously supported and parsed
as % and H separately. To restore the old behavior, separate with a
space, eg [% H].

- The error messages were wrong: the goal needs to be absorbing, not the hypothesis.
- The wrong failure number was used in `iAssumption`, which caused the error not
  to be propagated properly.

Also, rewrite `iIntoEmpValid`. Now, instead of using Ltac to traverse
the type of the term and generate goals for the premises, we repeatedly
apply a series of lemmas. This has the advantage that it works up to
convertability, and we no longer need the `eval ...` hacks.

This avoids weird Ltac behaviors like those in !272.

Also, change `before_tc` keyword into `as` to be consistent with other tactics.

Joseph Tassarotti authored May 24, 2019 and Robbert Krebbers committed May 24, 2019

Also fixes pre-existing bug in iCombine error messages.

It now supports the specialization pattern `(H spat1 .. spatn)`, which first
recursively specializes the hypothesis `H` using the specialization patterns
`spat1 .. spatn`.

Split it up into more logical parts.

Thanks to @Blaisorblade for reporting.

pm_reduce just reduces away proof mode terms using cbv; pm_prettify just prettifies user-visible connectors using cbn.
Most uses of pm_default are converted to default to keep the desired reduction behavior.

List literals reduce with a spurious `emp` at the end, which is not pretty.

With a pretty proof by Robbert

make pm_maybe_wand a BI connective; reduce BI connectives and option combinators in the proofmode with cbn