0005037: 3.12.0+dev18: "module type of" produces unusable signatures for repeated definitions

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Date Submitted

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0005037

OCaml

OCaml general

public

2010-04-24 06:47

2010-04-30 17:23

Reporter

kaustuv

Assigned To

Priority

normal

Severity

major

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

Target Version

Fixed in Version

3.12.0+dev

Summary

0005037: 3.12.0+dev18: "module type of" produces unusable signatures for repeated definitions

Description

   # module type S = module type of (struct
                                       let x = 42
                                       let x = "abc"
                                     end) ;;
   module type S = sig val x : int val x : string end
   # module T : S = struct let x = "abc" end ;;
   Characters 15-39:
     module T : S = struct let x = "abc" end ;;
                    ^^^^^^^^^^^^^^^^^^^^^^^^
   Error: Signature mismatch:
          Modules do not match: sig val x : string end is not included in S
          Values do not match: val x : string is not included in val x : int

These don't work either:

   # module T : S = struct let x = 42 end ;;
   # module T : S = struct let x = 42 let x = "abc" end ;;

Since repeated module level definitions with the same name are very common, "module type of" should use the same heuristic as "sig ... end" and retain only the last one of repeated definitions.

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Attached Files

signature-duplicate-filtering.patch [^] (1,307 bytes) 2010-04-26 17:48 [Show Content] [Hide Content]

Index: typing/typemod.ml
===================================================================
--- typing/typemod.ml	(revision 10311)
+++ typing/typemod.ml	(working copy)
@@ -894,8 +894,31 @@
   in
   if !Clflags.annotations
   then List.iter (function {pstr_loc = l} -> Stypes.record_phrase l) sstr;
-  type_struct env sstr
+  let (str_rem, sig_rem, final_env) = type_struct env sstr in
+  (str_rem, filter_sig_dups sig_rem, final_env)
 
+(* remove duplicates of the same kind from signature *)
+
+and filter_sig_dups =
+    let duplicate si1 si2 = match si1, si2 with
+        Tsig_value (i, _), Tsig_value (j, _)
+      | Tsig_type (i, _, _), Tsig_type (j, _, _)
+      | Tsig_exception (i, _), Tsig_exception (j, _)
+      | Tsig_module (i, _, _), Tsig_module (j, _, _)
+      | Tsig_modtype (i, _), Tsig_modtype (j, _)
+      | Tsig_class (i, _, _), Tsig_class (j, _, _)
+      | Tsig_cltype (i, _, _), Tsig_cltype (j, _, _)
+          -> Ident.equal i j
+      | _ -> false
+    in
+    let rec spin sgn = function
+        [] -> sgn
+      | si :: sis ->
+          let sgn = if List.exists (duplicate si) sgn then sgn else si :: sgn
+          in spin sgn sis
+    in
+    fun sgn -> spin [] (List.rev sgn)
+
 let type_module = type_module false None
 let type_structure = type_structure false None

Relationships

related to	0001441	closed		Inclusion d'une structure dans une signature
related to	0004487	closed	garrigue	Unable to override a value in a module type with ocamlc.
related to	0004974	closed		manque de verifications dans les .mli
related to	0005061	acknowledged		mutiple value components in signatures should produce a warning or an error

Notes
(0005373) Julien Signoles (reporter) 2010-04-26 13:39	This issue is not specific to "module type of". See BTS entries 0001441, 0004487 and 0004974.

(0005376) kaustuv (reporter) 2010-04-26 13:50	0001441 and 0004487 are not relevant because their error conditions are no longer reproducible: # module type S = sig val x : int val x : string end ;; module type S = sig val x : string end That is, it appears that sig ... end now drops all but the last of duplicate definitions. 0004974 is possibly not relevant either, but there isn't enough code there for me to judge.

(0005379) kaustuv (reporter) 2010-04-26 17:49	Attached patch against r10311 that suggests a possible fix. There is probably a better way to do it, though.

(0005397) garrigue (manager) 2010-04-28 07:04	Just needed to call simplify_modtype on the generated signature. Fixed for 3.12.

Issue History
Date Modified	Username	Field	Change
2010-04-24 06:47	kaustuv	New Issue
2010-04-26 13:39	Julien Signoles	Note Added: 0005373
2010-04-26 13:50	kaustuv	Note Added: 0005376
2010-04-26 17:48	kaustuv	File Added: signature-duplicate-filtering.patch
2010-04-26 17:49	kaustuv	Note Added: 0005379
2010-04-28 07:04	garrigue	Note Added: 0005397
2010-04-28 07:04	garrigue	Status	new => closed
2010-04-28 07:04	garrigue	Resolution	open => fixed
2010-04-28 07:04	garrigue	Fixed in Version	=> 3.12.0+dev
2010-04-30 17:22	doligez	Relationship added	related to 0001441
2010-04-30 17:23	doligez	Relationship added	related to 0004487
2010-04-30 17:23	doligez	Relationship added	related to 0004974
2011-06-01 22:54	doligez	Relationship added	related to 0005061