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* Fixing #5460 (limitation in computing deps in pattern-matching compilation).Gravatar Hugo Herbelin2017-04-08
| | | | | | | This was assuming dependencies occurring in configurations of the form x:A, y:B x, z:C x y |- match x, y, z with ... end". But still work to do for better management of dependencies in general...
* Fixing bugs in typing "match" (regressions #5322 and #5324 + bugs with let-ins).Gravatar Hugo Herbelin2017-01-22
| | | | | | | | | | | | A cleaning done in ade2363e35 (Dec 2015) was hinting at bugs in typing a matching over a "catch-all" variable, when let-ins occur in the arity. However ade2363e35 failed to understand what was the correct fix, introducing instead the regressions mentioned in #5322 and #5324. This fixes all of #5322 and #5324, as well as the handling of let-ins in the arity. Thanks to Jason for helping in diagnosing the problem.
* Document changesGravatar Matthieu Sozeau2016-12-02
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* Fix UGraph.check_eq!Gravatar Matthieu Sozeau2016-11-30
| | | | | | | | | | | | | | | | | Universes are kept in normal form w.r.t. equality but not the <= relation, so the previous check worked almost always but was actually too strict! In cases like (max(Set,u) = u) when u is declared >= Set it was failing to find an equality. Applying the KISS principle: u = v <-> u <= v /\ v <= u. Fix invariant breakage that triggered the discovery of the check_eq bug as well. No algebraic universes should appear in a term position (on the left of a colon in a typing judgment), this was not the case when an algebraic universe instantiated an evar that appeared in the term. We force their universe variable status to change in refresh_universes to avoid this. Fix ind sort inference: Use syntactic universe equality for inductive sort inference instead of check_leq (which now correctly takes constraints into account) and simplify code
* Fixing error localisation bug introduced in fixing #5142 (21e1d501e17c).Gravatar Hugo Herbelin2016-10-29
| | | | (May it fell in the case mentioned in the inner comment of Exninfo.info?)
* Attempt to improve error rendering in pattern-matching compilation (#5142).Gravatar Hugo Herbelin2016-10-19
| | | | | When trying different possible return predicates, returns the error given by the first try, assuming this is the most interesting one.
* Completing reverting generalization and cleaning of the return clause inference.Gravatar Hugo Herbelin2016-10-13
| | | | | Revert "Inference of return clause: giving uniformly priority to "small inversion"." This reverts commit 980b434552d73cb990860f8d659b64686f6dbc87.
* Reverting generalization and cleaning of the return clause inference in v8.6.Gravatar Hugo Herbelin2016-10-11
| | | | | | | | | | | | | | | | The move to systematically trying small inversion first bumps sometimes as feared to the weakness of unification (see #5107). ---- Revert "Posssible abstractions over goal variables when inferring match return clause." This reverts commit 0658ba7b908dad946200f872f44260d0e4893a94. Revert "Trying an abstracting dependencies heuristic for the match return clause even when no type constraint is given." This reverts commit 292f365185b7acdee79f3ff7b158551c2764c548. Revert "Trying a no-inversion no-dependency heuristic for match return clause." This reverts commit 2422aeb2b59229891508f35890653a9737988c00.
* Quick fix to #4595 (making notations containing "ltac:" unused for printing).Gravatar Hugo Herbelin2016-10-04
| | | | Also getting rid of a global side-effect.
* Posssible abstractions over goal variables when inferring match return clause.Gravatar Hugo Herbelin2016-09-26
| | | | | | | | | | | | | | The no-inversion and maximal abstraction over dependencies now supports abstraction over goal variables rather than only on "rel" variables. In particular, it now works consistently using "intro H; refine (match H with ... end)" or "refine (fun H => match H with ... end)". By doing so, we ensure that all three strategies are tried in all situations where a return clause has to be inferred, even in the context of a "refine". See antepenultimate commit for discussion.
* Trying an abstracting dependencies heuristic for the match return clause ↵Gravatar Hugo Herbelin2016-09-26
| | | | | | | | | | | | | | | even when no type constraint is given. This no-inversion and maximal abstraction over dependencies in (rel) variables heuristic was used only when a type constraint was given. By doing so, we ensure that all three strategies "inversion with dependencies as evars", "no-inversion and maximal abstraction over dependencies in (rel) variables", "no-inversion and no abstraction over dependencies" are tried in all situations where a return clause has to be inferred. See penultimate commit for discussion.
* Trying a no-inversion no-dependency heuristic for match return clause.Gravatar Hugo Herbelin2016-09-26
| | | | | | | | The no-inversion no-dependency heuristic was used only in the absence of type constraint. We may now use it also in the presence of a type constraint. See previous commit for discussion.
* Inference of return clause: giving uniformly priority to "small inversion".Gravatar Hugo Herbelin2016-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As noted by Jason Gross on coq-club (Aug 18, 2016), the "small inversion" heuristic is not used consistently depending on whether the variables in the type constraint are Rel or Var. This commit simply gives uniformly preference to the inversion of the predicate along the indices of the type over other heuristics. The next three commits will improve further a uniform use of the different heuristics. ---------------------------------------------------------------------- Here are some extra comments on how to go further with the inference of the return predicate: The "small inversion" heuristic build_inversion_problem (1) is characterized by two features: - small inversion properly speaking (a), i.e. that is for a match on t:I params p1(u11..u1p1) ... pn(un1..unpn) with pi exposing the constructor structure of the indices of the type of t, a return clause of the form "fun x1..xn (y:I params x1..xn) => match x1..xn y with | p1(z11..z1p1) ... pn(zn1..znpn) => ?T@{z11..znpn} | _ => IDProp end" is used, - the dependent subterms in the external type constraint U are replaced by existential variables (b) which can be filled either by projecting (i.e. installing a dependency) or imitating (i.e. no dependency); this is obtained by solving the constraint ?T@{u11..unpn} == U by setting ?T@{z11..znpn} := U'(...?wij@{zij:=uij}...) where U has been written under the form U'(...uij...) highlighting all occurrences of each of the uij occurring in U; otherwise said the problem is reduced to the question of instantiating each wij, deciding whether wij@{zij} := zij (projection) or wij@{zij} := uij (imitation) [There may be different way to expose the uij in U, e.g. in the presence of overlapping, or of evars in U; this is left undetermined]. The two other heuristics used are: - prepare_predicate_from_arsign_tycon (2): takes the external type constraint U and decides that each subterm of the form xi or y for a match on "y:I params x1 ... xn" is dependent; otherwise said, it corresponds to the degenerated form of (1) where - no constructor structure is exposed (i.e. each pi is trivial) - only uij that are Rel are replaced by an evar ?wij and this evar is directly instantiated by projection (hence creating a dependency), - simple use of of an evar in case no type constraint is given (3): this evar is not dependent on the indices nor on the term to match. Heuristic (1) is not strictly more powerful than other heuristics because of (at least) two weaknesses. - The first weakness is due to feature (b), i.e. to letting unification decide whether these evars have to create a dependency (projection) or not (imitation). In particular, the heuristic (2) gives priority to systematic abstraction over the dependencies (i.e. giving priority to projection over imitation) and it can then be better as the following example (from RelationClasses.v) shows: Fixpoint arrows (l : Tlist) (r : Type) : Type := match l with | Tnil => r | A :: l' => A -> arrows l' r end. Fixpoint predicate_all (l : Tlist) : arrows l Prop -> Prop := match l with | Tnil => fun f => f | A :: tl => fun f => forall x : A, predicate_all tl (f x) end. Using (1) fails. It proposes the predicate "fun l' => arrows ?l[l':=l'] Prop" so that typing the first branch leads to unify "arrows ?l[l:=Tnil] Prop == Prop", a problem about which evarconv unification is not able (yet!) to see what are the two possible solutions. Using (2) works. It instead directly suggests that the predicate is "fun l => arrows l Prop" is used, so that unification is not needed. Even if in practice the (2) is good (and hence could be added to (1)), it is not universally better. Consider e.g. y:bool,H1:P y,H2:P y,f:forall y, P y -> Q y |- match y as z return Q y with | true => f y H1 | false => f y H2 end : Q y There is no way to type it with clause "as z return Q z" even if trying to generalize H1 and H2 so that they get type P z. - A second weakness is due to the interaction between small inversion and constructors having a type whose indices havex a less refined constructor structure than in the term to match, as in: Inductive I : nat -> Set := | C1 : forall n : nat, listn n -> I n | C2 : forall n : nat, I n -> I n. Check (fun x : I 0 => match x with | C1 n l => 0 | C2 n c => 0 end). where the inverted predicate is "in I n return match n with 0 => ?T | _ => IDProp end" but neither C1 nor C2 have fine enough types so that n becomes constructed. There is a generic solution to that kind of situation which is to compile the above into Check (fun x : I 0 => match x with | C1 n l => match n with 0 => 0 | _ -> id end | C2 n c => match n with 0 => 0 | _ -> id end end). but this is not implemented yet. In the absence of this refinement, heuristic (3) can here work better. So, the current status of the claim is that for (1) to be strictly more powerful than other current heuristics, work has to be done - (A) at the unification level (by either being able to reduce problems of the form "match ?x[constructor] with ... end = a-rigid-term", or, at worst, by being able to use the heuristic favoring projecting for such a problem), so that it is better than (2), - (B) at the match compilation level, by enforcing that, in each branch, the corresponding constructor is refined so has to match (or discriminate) the constraints given by the type of the term to match, and hence being better than (3). Moreover, (2) and (3) are disjoint. Here is an example which (3) can solve but not (2) (and (1) cannot because of (B)). [To be fixed in next commit.] Inductive I : bool -> bool -> Type := C : I true true | D x : I x x. Check fun z P Q (y:I true z) (H1 H2:P y) (f:forall y, P y -> Q y z) => match y with | C => f y H1 | D _ => f y H2 end : Q y z. Indeed, (2) infers "as y' in I b z return Q y z" which does not work. Here is an example which (2) can solve but not (3) (and (1) cannot because of (B) again). [To be fixed in 2nd next commit]. Check fun z P Q (y:I true z) (H1 H2:P y) (f:forall y z, P y -> Q y z) => match y with | C => f y true H1 | D b => f y b H2 end : Q y z.
* Fixing a bug in the presence of let-in while inferring the return clause.Gravatar Hugo Herbelin2016-08-20
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* Disallow dependent case on prim records w/o etaGravatar Matthieu Sozeau2016-07-06
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* errors.ml renamed into cErrors.ml (avoid clash with an OCaml compiler-lib ↵Gravatar Pierre Letouzey2016-07-03
| | | | | | module) For the moment, there is an Error module in compilers-lib/ocamlbytecomp.cm(x)a
* Separate flags for fix/cofix/match reduction and clean reduction function names.Gravatar Maxime Dénès2016-07-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a reimplementation of Hugo's PR#117. We are trying to address the problem that the name of some reduction functions was not saying what they were doing (e.g. whd_betadeltaiota was doing let-in reduction). Like PR#117, we are careful that no function changed semantics without changing the names. Porting existing ML code should be a matter of renamings a few function calls. Also, we introduce more precise reduction flags fMATCH, fFIX, fCOFIX collectively denominated iota. We renamed the following functions: Closure.betadeltaiota -> Closure.all Closure.betadeltaiotanolet -> Closure.allnolet Reductionops.beta -> Closure.beta Reductionops.zeta -> Closure.zeta Reductionops.betaiota -> Closure.betaiota Reductionops.betaiotazeta -> Closure.betaiotazeta Reductionops.delta -> Closure.delta Reductionops.betalet -> Closure.betazeta Reductionops.betadelta -> Closure.betadeltazeta Reductionops.betadeltaiota -> Closure.all Reductionops.betadeltaiotanolet -> Closure.allnolet Closure.no_red -> Closure.nored Reductionops.nored -> Closure.nored Reductionops.nf_betadeltaiota -> Reductionops.nf_all Reductionops.whd_betadelta -> Reductionops.whd_betadeltazeta Reductionops.whd_betadeltaiota -> Reductionops.whd_all Reductionops.whd_betadeltaiota_nolet -> Reductionops.whd_allnolet Reductionops.whd_betadelta_stack -> Reductionops.whd_betadeltazeta_stack Reductionops.whd_betadeltaiota_stack -> Reductionops.whd_all_stack Reductionops.whd_betadeltaiota_nolet_stack -> Reductionops.whd_allnolet_stack Reductionops.whd_betadelta_state -> Reductionops.whd_betadeltazeta_state Reductionops.whd_betadeltaiota_state -> Reductionops.whd_all_state Reductionops.whd_betadeltaiota_nolet_state -> Reductionops.whd_allnolet_state Reductionops.whd_eta -> Reductionops.shrink_eta Tacmach.pf_whd_betadeltaiota -> Tacmach.pf_whd_all Tacmach.New.pf_whd_betadeltaiota -> Tacmach.New.pf_whd_all And removed the following ones: Reductionops.whd_betaetalet Reductionops.whd_betaetalet_stack Reductionops.whd_betaetalet_state Reductionops.whd_betadeltaeta_stack Reductionops.whd_betadeltaeta_state Reductionops.whd_betadeltaeta Reductionops.whd_betadeltaiotaeta_stack Reductionops.whd_betadeltaiotaeta_state Reductionops.whd_betadeltaiotaeta They were unused and having some reduction functions perform eta is confusing as whd_all and nf_all don't do it.
* Program: cleanup in cases, add optionsGravatar Matthieu Sozeau2016-06-29
| | | | | | | Unset Program Generalized Coercion to avoid coercion of general applications. Unset Program Cases to deactivate generation equalities and disequalities of cases.
* Rework treatment of default transparency of obligationsGravatar Matthieu Sozeau2016-06-27
| | | | | | | | | | | | | | | | By default obligations defined by tactics are defined transparently or opaque according to the Obligations Transparent flag, except proofs of subset obligations which are treated as opaque by default. When the user proves the obligation using Qed or Defined, this information takes precedence, and only when the obligation cannot be Qed'ed because it contains references to a recursive function an error is raised (this prevents the guardness checker error). Shrinked obligations were not doings this correctly. Forcing transparency due to fixpoint prototypes takes precedence over the user preference. Program: do not force opacity of subset proofs, maintaining compatibility.
* Merge branch 'v8.5'Gravatar Pierre-Marie Pédrot2016-05-02
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* | Revert "Add support for generalization also on named variables in ↵Gravatar Hugo Herbelin2016-04-27
| | | | | | | | | | | | pattern-matching" This reverts commit be80899499094fc8a15362931e3cec650f2fb14e.
* | Revert "Add support for deep dependencies in variables within the recursive ↵Gravatar Hugo Herbelin2016-04-27
| | | | | | | | | | | | structure." This reverts commit eaca8dadf7dd8152a86f4fc75631754344268dbf.
* | Revert "Fixing a De Bruijn bug in computing return predicate by inversion."Gravatar Hugo Herbelin2016-04-27
| | | | | | | | This reverts commit 94e9e28ebaa33e11164ca07f225d998ca7f8e52c.
* | Revert "Using existing names as a basis for the inner names of the ↵Gravatar Hugo Herbelin2016-04-27
| | | | | | | | | | | | pattern-matching produced by an implicit "in" clause" This reverts commit ba9f53314ff6132d0013e53879395e0dc9d8038c.
* | Revert "Vers un filtrage profond ..."Gravatar Hugo Herbelin2016-04-27
| | | | | | | | This reverts commit d9f0daefb437955df8102de2b3c4c31749b6946e.
* | Vers un filtrage profond ...Gravatar Hugo Herbelin2016-04-27
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* | Using existing names as a basis for the inner names of the pattern-matching ↵Gravatar Hugo Herbelin2016-04-27
| | | | | | | | produced by an implicit "in" clause
* | Fixing a De Bruijn bug in computing return predicate by inversion.Gravatar Hugo Herbelin2016-04-27
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* | Add support for deep dependencies in variables within the recursive structure.Gravatar Hugo Herbelin2016-04-27
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* | Add support for generalization also on named variables in pattern-matchingGravatar Hugo Herbelin2016-04-27
| | | | | | | | algorithm.
| * Optimization in building a return clause by pattern-matching: do notGravatar Hugo Herbelin2016-04-27
| | | | | | | | | | build a default case if the pattern is irrefutable. It did not matter in practice because we did not check for unused clauses in this case.
* | Splitting Evarutil in two distinct files.Gravatar Pierre-Marie Pédrot2016-03-20
| | | | | | | | | | Some parts of Evarutils were related to the management of evars under constraints. We put them in the Evardefine file.
* | merging conflicts with the original "trunk__CLEANUP__Context__2" branchGravatar Matej Kosik2016-02-15
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* | | Monotonizing the Evarutil module.Gravatar Pierre-Marie Pédrot2016-02-15
| | | | | | | | | | | | | | | Some functions were left in the old paradigm because they are only used by the unification algorithms, so they are not worthwhile to change for now.
| * | CLEANUP: Context.{Rel,Named}.Declaration.tGravatar Matej Kosik2016-02-09
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Originally, rel-context was represented as: Context.rel_context = Names.Name.t * Constr.t option * Constr.t Now it is represented as: Context.Rel.t = LocalAssum of Names.Name.t * Constr.t | LocalDef of Names.Name.t * Constr.t * Constr.t Originally, named-context was represented as: Context.named_context = Names.Id.t * Constr.t option * Constr.t Now it is represented as: Context.Named.t = LocalAssum of Names.Id.t * Constr.t | LocalDef of Names.Id.t * Constr.t * Constr.t Motivation: (1) In "tactics/hipattern.ml4" file we define "test_strict_disjunction" function which looked like this: let test_strict_disjunction n lc = Array.for_all_i (fun i c -> match (prod_assum (snd (decompose_prod_n_assum n c))) with | [_,None,c] -> isRel c && Int.equal (destRel c) (n - i) | _ -> false) 0 lc Suppose that you do not know about rel-context and named-context. (that is the case of people who just started to read the source code) Merlin would tell you that the type of the value you are destructing by "match" is: 'a * 'b option * Constr.t (* worst-case scenario *) or Named.Name.t * Constr.t option * Constr.t (* best-case scenario (?) *) To me, this is akin to wearing an opaque veil. It is hard to figure out the meaning of the values you are looking at. In particular, it is hard to discover the connection between the value we are destructing above and the datatypes and functions defined in the "kernel/context.ml" file. In this case, the connection is there, but it is not visible (between the function above and the "Context" module). ------------------------------------------------------------------------ Now consider, what happens when the reader see the same function presented in the following form: let test_strict_disjunction n lc = Array.for_all_i (fun i c -> match (prod_assum (snd (decompose_prod_n_assum n c))) with | [LocalAssum (_,c)] -> isRel c && Int.equal (destRel c) (n - i) | _ -> false) 0 lc If the reader haven't seen "LocalAssum" before, (s)he can use Merlin to jump to the corresponding definition and learn more. In this case, the connection is there, and it is directly visible (between the function above and the "Context" module). (2) Also, if we already have the concepts such as: - local declaration - local assumption - local definition and we describe these notions meticulously in the Reference Manual, then it is a real pity not to reinforce the connection of the actual code with the abstract description we published.
* | Merge branch 'v8.5'Gravatar Pierre-Marie Pédrot2016-01-21
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| * Update copyright headers.Gravatar Maxime Dénès2016-01-20
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* | CLEANUP: kernel/context.ml{,i}Gravatar Matej Kosik2016-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The structure of the Context module was refined in such a way that: - Types and functions related to rel-context declarations were put into the Context.Rel.Declaration module. - Types and functions related to rel-context were put into the Context.Rel module. - Types and functions related to named-context declarations were put into the Context.Named.Declaration module. - Types and functions related to named-context were put into the Context.Named module. - Types and functions related to named-list-context declarations were put into Context.NamedList.Declaration module. - Types and functions related to named-list-context were put into Context.NamedList module. Some missing comments were added to the *.mli file. The output of ocamldoc was checked whether it looks in a reasonable way. "TODO: cleanup" was removed The order in which are exported functions listed in the *.mli file was changed. (as in a mature modules, this order usually is not random) The order of exported functions in Context.{Rel,Named} modules is now consistent. (as there is no special reason why that order should be different) The order in which are functions defined in the *.ml file is the same as the order in which they are listed in the *.mli file. (as there is no special reason to define them in a different order) The name of the original fold_{rel,named}_context{,_reverse} functions was changed to better indicate what those functions do. (Now they are called Context.{Rel,Named}.fold_{inside,outside}) The original comments originally attached to the fold_{rel,named}_context{,_reverse} did not full make sense so they were updated. Thrown exceptions are now documented. Naming of formal parameters was made more consistent across different functions. Comments of similar functions in different modules are now consistent. Comments from *.mli files were copied to *.ml file. (We need that information in *.mli files because that is were ocamldoc needs it. It is nice to have it also in *.ml files because when we are using Merlin and jump to the definion of the function, we can see the comments also there and do not need to open a different file if we want to see it.) When we invoke ocamldoc, we instruct it to generate UTF-8 HTML instead of (default) ISO-8859-1. (UTF-8 characters are used in our ocamldoc markup) "open Context" was removed from all *.mli and *.ml files. (Originally, it was OK to do that. Now it is not.) An entry to dev/doc/changes.txt file was added that describes how the names of types and functions have changed.
* | About building of substitutions from instances.Gravatar Hugo Herbelin2015-12-05
|/ | | | | | | | | | Redefining adjust_subst_to_rel_context from instantiate_context who was hidden in inductiveops.ml, renamed the latter into subst_of_rel_context_instance and moving them to Vars. The new name highlights that the input is an instance (as for applist) and the output a substitution (as for substl). This is a clearer unified interface, centralizing the difficult de-Bruijn job in one place. It saves a couple of List.rev.
* Using appropriate lambda decomposition function counting let-ins whenGravatar Hugo Herbelin2015-10-18
| | | | | | | | dealing with "match". Contrastingly, "fix" is considered not to count let-ins for finding the recursive argument (which is ok because the last argument is necessarily a lambda).
* Fix inference of return clause raising a type error.Gravatar Matthieu Sozeau2015-10-09
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* Univs: fix bug #4161.Gravatar Matthieu Sozeau2015-10-08
| | | | | Retypecheck abstracted infered predicate to register the right universe constraints.
* Documenting the code when preference is given to expansion of defaultGravatar Hugo Herbelin2015-09-08
| | | | clause in pattern-matching or not.
* Safer typing primitives.Gravatar Pierre-Marie Pédrot2015-05-13
| | | | | | | | | | | | | | | | Some functions from pretyping/typing.ml and their derivatives were potential source of evarmap leaks, as they dropped their resulting evarmap. This commit clarifies the situation by renaming them according to a unsafe_* scheme. Their sound variant is likewise renamed to their old name. The following renamings were made. - Typing.type_of -> unsafe_type_of - Typing.e_type_of -> type_of - A new e_type_of function that matches the e_ prefix policy - Tacmach.pf_type_of -> pf_unsafe_type_of - A new safe pf_type_of function. All uses of unsafe_* functions should be eventually eliminated.
* Fixing first part of bug #3210 (inference of pattern-matching returnGravatar Hugo Herbelin2015-02-27
| | | | clause in the presence of let-ins in the arity of inductive type).
* Fixing #4001 (missing type constraints when building return clause of match).Gravatar Hugo Herbelin2015-02-10
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* Update headers.Gravatar Maxime Dénès2015-01-12
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* Tentatively more informative report of failure when inferringGravatar Hugo Herbelin2014-12-11
| | | | pattern-matching predicate.
* Fixing wrong evar_map in return clause inference, revealed by 48509b611.Gravatar Hugo Herbelin2014-12-08
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* Improved tracking of the origin of evars.Gravatar Hugo Herbelin2014-12-07
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