(************************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(************************************************************************)
(* $Id: himsg.ml,v 1.86.2.4 2004/12/03 18:45:53 herbelin Exp $ *)
open Pp
open Util
open Options
open Names
open Nameops
open Term
open Termops
open Inductive
open Indtypes
open Sign
open Environ
open Pretype_errors
open Type_errors
open Reduction
open Cases
open Logic
open Printer
open Ast
open Rawterm
let quote s = if !Options.v7 then s else h 0 (str "\"" ++ s ++ str "\"")
let prterm c = quote (prterm c)
let prterm_env e c = quote (prterm_env e c)
let prjudge_env e c = let v,t = prjudge_env e c in (quote v,quote t)
let nth i =
let many = match i mod 10 with 1 -> "st" | 2 -> "nd" | _ -> "th" in
int i ++ str many
let pr_db ctx i =
try
match lookup_rel i ctx with
Name id, _, _ -> pr_id id
| Anonymous, _, _ -> str"<>"
with Not_found -> str"UNBOUND_REL_"++int i
let explain_unbound_rel ctx n =
let pe = pr_ne_context_of (str "In environment") ctx in
str"Unbound reference: " ++ pe ++
str"The reference " ++ int n ++ str " is free"
let explain_unbound_var ctx v =
let var = pr_id v in
str"No such section variable or assumption : " ++ var
let explain_not_type ctx j =
let pe = pr_ne_context_of (str"In environment") ctx in
let pc,pt = prjudge_env ctx j in
pe ++ str "the term" ++ brk(1,1) ++ pc ++ spc () ++
str"has type" ++ spc () ++ pt ++ spc () ++
str"which should be Set, Prop or Type."
let explain_bad_assumption ctx j =
let pe = pr_ne_context_of (str"In environment") ctx in
let pc,pt = prjudge_env ctx j in
pe ++ str "cannot declare a variable or hypothesis over the term" ++
brk(1,1) ++ pc ++ spc () ++ str"of type" ++ spc () ++ pt ++ spc () ++
str "because this term is not a type."
let explain_reference_variables c =
let pc = prterm c in
str "the constant" ++ spc () ++ pc ++ spc () ++
str "refers to variables which are not in the context"
let rec pr_disjunction pr = function
| [a] -> pr a
| [a;b] -> pr a ++ str " or" ++ spc () ++ pr b
| a::l -> pr a ++ str "," ++ spc () ++ pr_disjunction pr l
| [] -> assert false
let explain_elim_arity ctx ind aritylst c pj okinds =
let ctx = make_all_name_different ctx in
let pi = pr_inductive ctx ind in
let pc = prterm_env ctx c in
let ppt = prterm_env ctx pj.uj_type in
let msg = match okinds with
| Some(kp,ki,explanation) ->
let pki = prterm_env ctx ki in
let pkp = prterm_env ctx kp in
let explanation = match explanation with
| NonInformativeToInformative ->
"proofs can be eliminated only to build proofs"
| StrongEliminationOnNonSmallType ->
"strong elimination on non-small inductive types leads to paradoxes."
| WrongArity ->
"wrong arity" in
(hov 0
(fnl () ++ str "Elimination of an inductive object of sort " ++
pki ++ brk(1,0) ++
str "is not allowed on a predicate in sort " ++ pkp ++fnl () ++
str "because" ++ spc () ++ str explanation))
| None ->
mt ()
in
hov 0 (
str "Incorrect elimination of" ++ spc() ++ pc ++ spc () ++
str "in the inductive type " ++ spc() ++ quote pi ++
(if !Options.v7 then
let pp = prterm_env ctx pj.uj_val in
let ppar = pr_disjunction (prterm_env ctx) aritylst in
let ppt = prterm_env ctx pj.uj_type in
fnl () ++
str "The elimination predicate" ++ brk(1,1) ++ pp ++ spc () ++
str "has arity" ++ brk(1,1) ++ ppt ++ fnl () ++
str "It should be " ++ brk(1,1) ++ ppar
else
let sorts = List.map (fun x -> mkSort (new_sort_in_family x))
(list_uniquize (List.map (fun ar ->
family_of_sort (destSort (snd (decompose_prod_assum ar)))) aritylst)) in
let ppar = pr_disjunction (prterm_env ctx) sorts in
let ppt = prterm_env ctx (snd (decompose_prod_assum pj.uj_type)) in
str "," ++ spc() ++ str "the return type has sort" ++ spc() ++ ppt ++
spc () ++ str "while it should be " ++ ppar))
++ fnl () ++ msg
let explain_case_not_inductive ctx cj =
let ctx = make_all_name_different ctx in
let pc = prterm_env ctx cj.uj_val in
let pct = prterm_env ctx cj.uj_type in
match kind_of_term cj.uj_type with
| Evar _ ->
str "Cannot infer a type for this expression"
| _ ->
str "The term" ++ brk(1,1) ++ pc ++ spc () ++
str "has type" ++ brk(1,1) ++ pct ++ spc () ++
str "which is not a (co-)inductive type"
let explain_number_branches ctx cj expn =
let ctx = make_all_name_different ctx in
let pc = prterm_env ctx cj.uj_val in
let pct = prterm_env ctx cj.uj_type in
str "Matching on term" ++ brk(1,1) ++ pc ++ spc () ++
str "of type" ++ brk(1,1) ++ pct ++ spc () ++
str "expects " ++ int expn ++ str " branches"
let explain_ill_formed_branch ctx c i actty expty =
let ctx = make_all_name_different ctx in
let pc = prterm_env ctx c in
let pa = prterm_env ctx actty in
let pe = prterm_env ctx expty in
str "In pattern-matching on term" ++ brk(1,1) ++ pc ++
spc () ++ str "the branch " ++ int (i+1) ++
str " has type" ++ brk(1,1) ++ pa ++ spc () ++
str "which should be" ++ brk(1,1) ++ pe
let explain_generalization ctx (name,var) j =
let pe = pr_ne_context_of (str "In environment") ctx in
let pv = prtype_env ctx var in
let (pc,pt) = prjudge_env (push_rel_assum (name,var) ctx) j in
str"Illegal generalization: " ++ pe ++
str"Cannot generalize" ++ brk(1,1) ++ pv ++ spc () ++
str"over" ++ brk(1,1) ++ pc ++ str"," ++ spc () ++
str"it has type" ++ spc () ++ pt ++
spc () ++ str"which should be Set, Prop or Type."
let explain_actual_type ctx j pt =
let pe = pr_ne_context_of (str "In environment") ctx in
let (pc,pct) = prjudge_env ctx j in
let pt = prterm_env ctx pt in
pe ++
str "The term" ++ brk(1,1) ++ pc ++ spc () ++
str "has type" ++ brk(1,1) ++ pct ++ brk(1,1) ++
str "while it is expected to have type" ++ brk(1,1) ++ pt
let explain_cant_apply_bad_type ctx (n,exptyp,actualtyp) rator randl =
let randl = Array.to_list randl in
(* let pe = pr_ne_context_of (str"in environment") ctx in*)
let pr,prt = prjudge_env ctx rator in
let term_string1,term_string2 =
if List.length randl > 1 then
str "terms", (str"The "++nth n++str" term")
else
str "term", str "This term" in
let appl = prlist_with_sep pr_fnl
(fun c ->
let pc,pct = prjudge_env ctx c in
hov 2 (pc ++ spc () ++ str": " ++ pct)) randl
in
str"Illegal application (Type Error): " ++ (* pe ++ *) fnl () ++
str"The term" ++ brk(1,1) ++ pr ++ spc () ++
str"of type" ++ brk(1,1) ++ prt ++ spc () ++
str"cannot be applied to the " ++ term_string1 ++ fnl () ++
str" " ++ v 0 appl ++ fnl () ++ term_string2 ++ str" has type" ++
brk(1,1) ++ prterm_env ctx actualtyp ++ spc () ++
str"which should be coercible to" ++ brk(1,1) ++ prterm_env ctx exptyp
let explain_cant_apply_not_functional ctx rator randl =
let randl = Array.to_list randl in
(* let pe = pr_ne_context_of (str"in environment") ctx in*)
let pr = prterm_env ctx rator.uj_val in
let prt = prterm_env ctx rator.uj_type in
let term_string = if List.length randl > 1 then "terms" else "term" in
let appl = prlist_with_sep pr_fnl
(fun c ->
let pc = prterm_env ctx c.uj_val in
let pct = prterm_env ctx c.uj_type in
hov 2 (pc ++ spc () ++ str": " ++ pct)) randl
in
str"Illegal application (Non-functional construction): " ++
(* pe ++ *) fnl () ++
str"The expression" ++ brk(1,1) ++ pr ++ spc () ++
str"of type" ++ brk(1,1) ++ prt ++ spc () ++
str("cannot be applied to the "^term_string) ++ fnl () ++
str" " ++ v 0 appl
let explain_unexpected_type ctx actual_type expected_type =
let pract = prterm_env ctx actual_type in
let prexp = prterm_env ctx expected_type in
str"This type is" ++ spc () ++ pract ++ spc () ++
str "but is expected to be" ++
spc () ++ prexp
let explain_not_product ctx c =
let pr = prterm_env ctx c in
str"The type of this term is a product," ++ spc () ++
str"but it is casted with type" ++
brk(1,1) ++ pr
(* TODO: use the names *)
(* (co)fixpoints *)
let explain_ill_formed_rec_body ctx err names i =
let prt_name i =
match names.(i) with
Name id -> str "Recursive definition of " ++ pr_id id
| Anonymous -> str"The " ++ nth i ++ str" definition" in
let st = match err with
(* Fixpoint guard errors *)
| NotEnoughAbstractionInFixBody ->
str "Not enough abstractions in the definition"
| RecursionNotOnInductiveType ->
str "Recursive definition on a non inductive type"
| RecursionOnIllegalTerm(j,arg,le,lt) ->
let called =
match names.(j) with
Name id -> pr_id id
| Anonymous -> str"the " ++ nth i ++ str" definition" in
let vars =
match (lt,le) with
([],[]) -> mt()
| ([],[x]) ->
str "a subterm of " ++ pr_db ctx x
| ([],_) ->
str "a subterm of the following variables: " ++
prlist_with_sep pr_spc (pr_db ctx) le
| ([x],_) -> pr_db ctx x
| _ ->
str "one of the following variables: " ++
prlist_with_sep pr_spc (pr_db ctx) lt in
str "Recursive call to " ++ called ++ spc() ++
str "has principal argument equal to" ++ spc() ++
prterm_env ctx arg ++ fnl() ++ str "instead of " ++ vars
| NotEnoughArgumentsForFixCall j ->
let called =
match names.(j) with
Name id -> pr_id id
| Anonymous -> str"the " ++ nth i ++ str" definition" in
str "Recursive call to " ++ called ++ str " had not enough arguments"
(* CoFixpoint guard errors *)
| CodomainNotInductiveType c ->
str "the codomain is" ++ spc () ++ prterm_env ctx c ++ spc () ++
str "which should be a coinductive type"
| NestedRecursiveOccurrences ->
str "nested recursive occurrences"
| UnguardedRecursiveCall c ->
str "unguarded recursive call in" ++ spc() ++ prterm_env ctx c
| RecCallInTypeOfAbstraction c ->
str "recursive call forbidden in the domain of an abstraction:" ++
spc() ++ prterm_env ctx c
| RecCallInNonRecArgOfConstructor c ->
str "recursive call on a non-recursive argument of constructor" ++
spc() ++ prterm_env ctx c
| RecCallInTypeOfDef c ->
str "recursive call forbidden in the type of a recursive definition" ++
spc() ++ prterm_env ctx c
| RecCallInCaseFun c ->
str "recursive call in a branch of" ++ spc() ++ prterm_env ctx c
| RecCallInCaseArg c ->
str "recursive call in the argument of cases in" ++ spc() ++
prterm_env ctx c
| RecCallInCasePred c ->
str "recursive call in the type of cases in" ++ spc() ++
prterm_env ctx c
| NotGuardedForm c ->
str "sub-expression " ++ prterm_env ctx c ++ spc() ++
str "not in guarded form" ++ spc()++
str"(should be a constructor, an abstraction, a match, a cofix or a recursive call)"
in
prt_name i ++ str" is ill-formed." ++ fnl() ++
pr_ne_context_of (str "In environment") ctx ++
st
let explain_ill_typed_rec_body ctx i names vdefj vargs =
let ctx = make_all_name_different ctx in
let pvd,pvdt = prjudge_env ctx (vdefj.(i)) in
let pv = prterm_env ctx vargs.(i) in
str"The " ++
(if Array.length vdefj = 1 then mt () else int (i+1) ++ str "-th") ++
str"recursive definition" ++ spc () ++ pvd ++ spc () ++
str "has type" ++ spc () ++ pvdt ++spc () ++
str "it should be" ++ spc () ++ pv
(*
let explain_not_inductive ctx c =
let ctx = make_all_name_different ctx in
let pc = prterm_env ctx c in
str"The term" ++ brk(1,1) ++ pc ++ spc () ++
str "is not an inductive definition"
*)
let explain_cant_find_case_type ctx c =
let ctx = make_all_name_different ctx in
let pe = prterm_env ctx c in
hov 3 (str "Cannot infer type of pattern-matching on" ++ ws 1 ++ pe)
let explain_occur_check ctx ev rhs =
let ctx = make_all_name_different ctx in
let id = Evd.string_of_existential ev in
let pt = prterm_env ctx rhs in
str"Occur check failed: tried to define " ++ str id ++
str" with term" ++ brk(1,1) ++ pt
let explain_hole_kind env = function
| QuestionMark -> str "a term for this placeholder"
| CasesType ->
str "the type of this pattern-matching problem"
| BinderType (Name id) ->
str "a type for " ++ Nameops.pr_id id
| BinderType Anonymous ->
str "a type for this anonymous binder"
| ImplicitArg (c,(n,ido)) ->
if !Options.v7 then
str "the " ++ pr_ord n ++
str " implicit argument of " ++ Nametab.pr_global_env Idset.empty c
else
let id = out_some ido in
str "an instance for the implicit parameter " ++
pr_id id ++ spc () ++ str "of" ++
spc () ++ Nametab.pr_global_env Idset.empty c
| InternalHole ->
str "a term for an internal placeholder"
| TomatchTypeParameter (tyi,n) ->
str "the " ++ pr_ord n ++
str " argument of the inductive type (" ++ pr_inductive env tyi ++
str ") of this term"
let explain_not_clean ctx ev t k =
let ctx = make_all_name_different ctx in
let c = mkRel (Intset.choose (free_rels t)) in
let id = Evd.string_of_existential ev in
let var = prterm_env ctx c in
str"Tried to define " ++ explain_hole_kind ctx k ++
str" (" ++ str id ++ str ")" ++ spc() ++
str"with a term using variable " ++ var ++ spc () ++
str"which is not in its scope."
let explain_unsolvable_implicit env k =
str "Cannot infer " ++ explain_hole_kind env k
let explain_var_not_found ctx id =
str "The variable" ++ spc () ++ str (string_of_id id) ++
spc () ++ str "was not found" ++
spc () ++ str "in the current" ++ spc () ++ str "environment"
let explain_wrong_case_info ctx ind ci =
let ctx = make_all_name_different ctx in
let pi = prterm (mkInd ind) in
if ci.ci_ind = ind then
str"Pattern-matching expression on an object of inductive" ++ spc () ++ pi ++
spc () ++ str"has invalid information"
else
let pc = prterm (mkInd ci.ci_ind) in
str"A term of inductive type" ++ spc () ++ pi ++ spc () ++
str"was given to a pattern-matching expression on the inductive type" ++
spc () ++ pc
let explain_type_error ctx err =
let ctx = make_all_name_different ctx in
match err with
| UnboundRel n ->
explain_unbound_rel ctx n
| UnboundVar v ->
explain_unbound_var ctx v
| NotAType j ->
explain_not_type ctx j
| BadAssumption c ->
explain_bad_assumption ctx c
| ReferenceVariables id ->
explain_reference_variables id
| ElimArity (ind, aritylst, c, pj, okinds) ->
explain_elim_arity ctx ind aritylst c pj okinds
| CaseNotInductive cj ->
explain_case_not_inductive ctx cj
| NumberBranches (cj, n) ->
explain_number_branches ctx cj n
| IllFormedBranch (c, i, actty, expty) ->
explain_ill_formed_branch ctx c i actty expty
| Generalization (nvar, c) ->
explain_generalization ctx nvar c
| ActualType (j, pt) ->
explain_actual_type ctx j pt
| CantApplyBadType (t, rator, randl) ->
explain_cant_apply_bad_type ctx t rator randl
| CantApplyNonFunctional (rator, randl) ->
explain_cant_apply_not_functional ctx rator randl
| IllFormedRecBody (err, lna, i) ->
explain_ill_formed_rec_body ctx err lna i
| IllTypedRecBody (i, lna, vdefj, vargs) ->
explain_ill_typed_rec_body ctx i lna vdefj vargs
| WrongCaseInfo (ind,ci) ->
explain_wrong_case_info ctx ind ci
(*
| NotInductive c ->
explain_not_inductive ctx c
*)
let explain_pretype_error ctx err =
let ctx = make_all_name_different ctx in
match err with
| CantFindCaseType c ->
explain_cant_find_case_type ctx c
| OccurCheck (n,c) ->
explain_occur_check ctx n c
| NotClean (n,c,k) ->
explain_not_clean ctx n c k
| UnsolvableImplicit k ->
explain_unsolvable_implicit ctx k
| VarNotFound id ->
explain_var_not_found ctx id
| UnexpectedType (actual,expected) ->
explain_unexpected_type ctx actual expected
| NotProduct c ->
explain_not_product ctx c
(* Refiner errors *)
let explain_refiner_bad_type arg ty conclty =
str"refiner was given an argument" ++ brk(1,1) ++
prterm arg ++ spc () ++
str"of type" ++ brk(1,1) ++ prterm ty ++ spc () ++
str"instead of" ++ brk(1,1) ++ prterm conclty
let explain_refiner_occur_meta t =
str"cannot refine with term" ++ brk(1,1) ++ prterm t ++
spc () ++ str"because there are metavariables, and it is" ++
spc () ++ str"neither an application nor a Case"
let explain_refiner_occur_meta_goal t =
str"generated subgoal" ++ brk(1,1) ++ prterm t ++
spc () ++ str"has metavariables in it"
let explain_refiner_cannot_applt t harg =
str"in refiner, a term of type " ++ brk(1,1) ++
prterm t ++ spc () ++ str"could not be applied to" ++ brk(1,1) ++
prterm harg
let explain_cannot_unify m n =
let pm = prterm m in
let pn = prterm n in
str"Impossible to unify" ++ brk(1,1) ++ pm ++ spc () ++
str"with" ++ brk(1,1) ++ pn
let explain_cannot_unify_binding_type m n =
let pm = prterm m in
let pn = prterm n in
str "This binding has type" ++ brk(1,1) ++ pm ++ spc () ++
str "which should be unifiable with" ++ brk(1,1) ++ pn
let explain_refiner_cannot_generalize ty =
str "Cannot find a well-typed generalisation of the goal with type : " ++
prterm ty
let explain_refiner_not_well_typed c =
str"The term " ++ prterm c ++ str" is not well-typed"
let explain_intro_needs_product () =
str "Introduction tactics needs products"
let explain_does_not_occur_in c hyp =
str "The term" ++ spc () ++ prterm c ++ spc () ++ str "does not occur in" ++
spc () ++ pr_id hyp
let explain_non_linear_proof c =
str "cannot refine with term" ++ brk(1,1) ++ prterm c ++
spc () ++ str"because a metavariable has several occurrences"
let explain_no_occurrence_found c =
str "Found no subterm matching " ++ prterm c ++ str " in the current goal"
let explain_refiner_error = function
| BadType (arg,ty,conclty) -> explain_refiner_bad_type arg ty conclty
| OccurMeta t -> explain_refiner_occur_meta t
| OccurMetaGoal t -> explain_refiner_occur_meta_goal t
| CannotApply (t,harg) -> explain_refiner_cannot_applt t harg
| CannotUnify (m,n) -> explain_cannot_unify m n
| CannotUnifyBindingType (m,n) -> explain_cannot_unify_binding_type m n
| CannotGeneralize ty -> explain_refiner_cannot_generalize ty
| NotWellTyped c -> explain_refiner_not_well_typed c
| IntroNeedsProduct -> explain_intro_needs_product ()
| DoesNotOccurIn (c,hyp) -> explain_does_not_occur_in c hyp
| NonLinearProof c -> explain_non_linear_proof c
| NoOccurrenceFound c -> explain_no_occurrence_found c
(* Inductive errors *)
let error_non_strictly_positive env c v =
let pc = prterm_env env c in
let pv = prterm_env env v in
str "Non strictly positive occurrence of " ++ pv ++ str " in" ++
brk(1,1) ++ pc
let error_ill_formed_inductive env c v =
let pc = prterm_env env c in
let pv = prterm_env env v in
str "Not enough arguments applied to the " ++ pv ++
str " in" ++ brk(1,1) ++ pc
let error_ill_formed_constructor env c v =
let pc = prterm_env env c in
let pv = prterm_env env v in
str "The conclusion of" ++ brk(1,1) ++ pc ++ brk(1,1) ++
str "is not valid;" ++ brk(1,1) ++ str "it must be built from " ++ pv
let str_of_nth n =
(string_of_int n)^
(match n mod 10 with
| 1 -> "st"
| 2 -> "nd"
| 3 -> "rd"
| _ -> "th")
let error_bad_ind_parameters env c n v1 v2 =
let pc = prterm_env_at_top env c in
let pv1 = prterm_env env v1 in
let pv2 = prterm_env env v2 in
str ("The "^(str_of_nth n)^" argument of ") ++ pv2 ++ brk(1,1) ++
str "must be " ++ pv1 ++ str " in" ++ brk(1,1) ++ pc
let error_same_names_types id =
str "The name" ++ spc () ++ pr_id id ++ spc () ++
str "is used twice is the inductive types definition."
let error_same_names_constructors id cid =
str "The constructor name" ++ spc () ++ pr_id cid ++ spc () ++
str "is used twice is the definition of type" ++ spc () ++
pr_id id
let error_same_names_overlap idl =
str "The following names" ++ spc () ++
str "are used both as type names and constructor names:" ++ spc () ++
prlist_with_sep pr_coma pr_id idl
let error_not_an_arity id =
str "The type of" ++ spc () ++ pr_id id ++ spc () ++ str "is not an arity."
let error_bad_entry () =
str "Bad inductive definition."
let error_not_allowed_case_analysis dep kind i =
str (if dep then "Dependent" else "Non Dependent") ++
str " case analysis on sort: " ++ print_sort kind ++ fnl () ++
str "is not allowed for inductive definition: " ++
pr_inductive (Global.env()) i
let error_bad_induction dep indid kind =
str (if dep then "Dependent" else "Non dependent") ++
str " induction for type " ++ pr_id indid ++
str " and sort " ++ print_sort kind ++ spc () ++
str "is not allowed"
let error_not_mutual_in_scheme () =
str "Induction schemes is concerned only with mutually inductive types"
let explain_inductive_error = function
(* These are errors related to inductive constructions *)
| NonPos (env,c,v) -> error_non_strictly_positive env c v
| NotEnoughArgs (env,c,v) -> error_ill_formed_inductive env c v
| NotConstructor (env,c,v) -> error_ill_formed_constructor env c v
| NonPar (env,c,n,v1,v2) -> error_bad_ind_parameters env c n v1 v2
| SameNamesTypes id -> error_same_names_types id
| SameNamesConstructors (id,cid) -> error_same_names_constructors id cid
| SameNamesOverlap idl -> error_same_names_overlap idl
| NotAnArity id -> error_not_an_arity id
| BadEntry -> error_bad_entry ()
(* These are errors related to recursors *)
| NotAllowedCaseAnalysis (dep,k,i) ->
error_not_allowed_case_analysis dep k i
| BadInduction (dep,indid,kind) -> error_bad_induction dep indid kind
| NotMutualInScheme -> error_not_mutual_in_scheme ()
(* Pattern-matching errors *)
let explain_bad_pattern ctx cstr ty =
let ctx = make_all_name_different ctx in
let pt = prterm_env ctx ty in
let pc = pr_constructor ctx cstr in
str "Found the constructor " ++ pc ++ brk(1,1) ++
str "while matching a term of type " ++ pt ++ brk(1,1) ++
str "which is not an inductive type"
let explain_bad_constructor ctx cstr ind =
let pi = pr_inductive ctx ind in
(* let pc = pr_constructor ctx cstr in*)
let pt = pr_inductive ctx (inductive_of_constructor cstr) in
str "Found a constructor of inductive type " ++ pt ++ brk(1,1) ++
str "while a constructor of " ++ pi ++ brk(1,1) ++
str "is expected"
let explain_wrong_numarg_of_constructor ctx cstr n =
let pc = pr_constructor ctx cstr in
str "The constructor " ++ pc ++ str " expects " ++
(if n = 0 then str "no argument." else if n = 1 then str "1 argument."
else (int n ++ str " arguments."))
let explain_wrong_predicate_arity ctx pred nondep_arity dep_arity=
let ctx = make_all_name_different ctx in
let pp = prterm_env ctx pred in
str "The elimination predicate " ++ spc () ++ pp ++ fnl () ++
str "should be of arity" ++ spc () ++
prterm_env ctx nondep_arity ++ spc () ++
str "(for non dependent case) or" ++
spc () ++ prterm_env ctx dep_arity ++ spc () ++ str "(for dependent case)."
let explain_needs_inversion ctx x t =
let ctx = make_all_name_different ctx in
let px = prterm_env ctx x in
let pt = prterm_env ctx t in
str "Sorry, I need inversion to compile pattern matching of term " ++
px ++ str " of type: " ++ pt
let explain_unused_clause env pats =
let s = if List.length pats > 1 then "s" else "" in
(* Without localisation
(str ("Unused clause with pattern"^s) ++ spc () ++
hov 0 (prlist_with_sep pr_spc pr_cases_pattern pats) ++ str ")")
*)
str "This clause is redundant"
let explain_non_exhaustive env pats =
let s = if List.length pats > 1 then "s" else "" in
str ("Non exhaustive pattern-matching: no clause found for pattern"^s) ++
spc () ++ hov 0 (prlist_with_sep pr_spc pr_cases_pattern pats)
let explain_cannot_infer_predicate ctx typs =
let ctx = make_all_name_different ctx in
let pr_branch (cstr,typ) =
let cstr,_ = decompose_app cstr in
str "For " ++ prterm_env ctx cstr ++ str " : " ++ prterm_env ctx typ
in
str "Unable to unify the types found in the branches:" ++
spc () ++ hov 0 (prlist_with_sep pr_fnl pr_branch (Array.to_list typs))
let explain_pattern_matching_error env = function
| BadPattern (c,t) ->
explain_bad_pattern env c t
| BadConstructor (c,ind) ->
explain_bad_constructor env c ind
| WrongNumargConstructor (c,n) ->
explain_wrong_numarg_of_constructor env c n
| WrongPredicateArity (pred,n,dep) ->
explain_wrong_predicate_arity env pred n dep
| NeedsInversion (x,t) ->
explain_needs_inversion env x t
| UnusedClause tms ->
explain_unused_clause env tms
| NonExhaustive tms ->
explain_non_exhaustive env tms
| CannotInferPredicate typs ->
explain_cannot_infer_predicate env typs