diff options
| -rw-r--r-- | plugins/extraction/mlutil.ml | 2 | ||||
| -rw-r--r-- | test-suite/bugs/closed/4844.v | 47 |
2 files changed, 48 insertions, 1 deletions
diff --git a/plugins/extraction/mlutil.ml b/plugins/extraction/mlutil.ml index f1bcde2f3..a4c2bcd88 100644 --- a/plugins/extraction/mlutil.ml +++ b/plugins/extraction/mlutil.ml @@ -120,7 +120,6 @@ let rec mgu = function mgu (a, a'); mgu (b, b') | Tglob (r,l), Tglob (r',l') when Globnames.eq_gr r r' -> List.iter mgu (List.combine l l') - | (Tdummy _, _ | _, Tdummy _) when lang() == Haskell -> () | Tdummy _, Tdummy _ -> () | Tvar i, Tvar j when Int.equal i j -> () | Tvar' i, Tvar' j when Int.equal i j -> () @@ -1052,6 +1051,7 @@ let rec simpl o = function | MLmagic(MLcase(typ,e,br)) -> let br' = Array.map (fun (ids,p,c) -> (ids,p,MLmagic c)) br in simpl o (MLcase(typ,e,br')) + | MLmagic(MLdummy _ as e) when lang () == Haskell -> e | MLmagic(MLexn _ as e) -> e | a -> ast_map (simpl o) a diff --git a/test-suite/bugs/closed/4844.v b/test-suite/bugs/closed/4844.v new file mode 100644 index 000000000..f140939cc --- /dev/null +++ b/test-suite/bugs/closed/4844.v @@ -0,0 +1,47 @@ + +(* Bug report 4844 (and 4824): + The Haskell extraction was erroneously considering [Any] and + [()] as convertible ([Tunknown] an [Tdummy] internally). *) + +(* A value with inner logical parts. + Its extracted type will be [Sum () ()]. *) + +Definition semilogic : True + True := inl I. + +(* Higher-order record, whose projection [ST] isn't expressible + as an Haskell (or OCaml) type. Hence [ST] is extracted as the + unknown type [Any] in Haskell. *) + +Record SomeType := { ST : Type }. + +Definition SomeTrue := {| ST := True |}. + +(* A first version of the issue: + [abstrSum] is extracted as [Sum Any Any], so an unsafeCoerce + is required to cast [semilogic] into [abstrSum SomeTrue]. *) + +Definition abstrSum (t : SomeType) := ((ST t) + (ST t))%type. + +Definition semilogic' : abstrSum SomeTrue := semilogic. + +(* A deeper version of the issue. + In the previous example, the extraction could have reduced + [abstrSum SomeTrue] into [True+True], solving the issue. + It might do so in future versions. But if we put an inductive + in the way, a reduction isn't helpful. *) + +Inductive box (t : SomeType) := Box : ST t + ST t -> box t. + +Definition boxed_semilogic : box SomeTrue := + Box SomeTrue semilogic. + +Require Extraction. +Extraction Language Haskell. +Recursive Extraction semilogic' boxed_semilogic. +(* Warning! To fully check that this bug is still closed, + you should run ghc on the extracted code: + +Extraction "bug4844.hs" semilogic' boxed_semilogic. +ghc bug4844.hs + +*) |