Assume that module names that are not in Env.t are persistent (#2235)

Fix bug introduced by #2041

The environment used to lookup global identifiers coming from loaded
cmi files was incomplete, leading to identifiers that could not be
resolved.

This patch fixes the issue by assuming that module names that are not
found in the environment are always external.

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

Changes

@@ -60,8 +60,8 @@ OCaml 4.08.0
   (Alban Reynaud and Gabriel Scherer,
    review by Jeremy Yallop and Armaël Guéneau)
 
-* MPR#7814, GPR#2041: allow modules from include directories to shadow
-  other ones, even in the toplevel
+* MPR#7814, GPR#2041, GPR#2235: allow modules from include directories
+  to shadow other ones, even in the toplevel
   (Jérémie Dimino, review by Alain Frisch and David Allsopp)
 
 ### Standard library:

testsuite/tests/no-alias-deps/a2235.ml

@@ -0,0 +1 @@
+let x = 42

testsuite/tests/no-alias-deps/gpr2235.ml

@@ -0,0 +1,21 @@
+(* TEST
+flags = "-no-alias-deps -w -49"
+compile_only = "true"
+files = "a2235.ml lib__2235.ml lib2235.ml user_of_lib2235.ml"
+* setup-ocamlc.byte-build-env
+** ocamlc.byte
+module = "lib__2235.ml"
+*** check-ocamlc.byte-output
+**** ocamlc.byte
+flags = "-no-alias-deps -w -49 -open Lib__2235 -o lib__A2235.cmo"
+module = "a2235.ml"
+***** check-ocamlc.byte-output
+****** ocamlc.byte
+flags = "-no-alias-deps -w -49 -open Lib__2235"
+module = "lib2235.ml"
+******* check-ocamlc.byte-output
+******** ocamlc.byte
+flags = "-no-alias-deps -w -49"
+module = "user_of_lib2235.ml"
+********* check-ocamlc.byte-output
+*)

testsuite/tests/no-alias-deps/lib2235.ml

@@ -0,0 +1 @@
+module A2235 = A2235

testsuite/tests/no-alias-deps/lib__2235.ml

@@ -0,0 +1 @@
+module A2235 = Lib__A2235

testsuite/tests/no-alias-deps/ocamltests

@@ -1 +1,2 @@
 aliases.ml
+gpr2235.ml

testsuite/tests/no-alias-deps/user_of_lib2235.ml

@@ -0,0 +1,3 @@
+open Lib2235
+
+let x = A2235.x

typing/env.ml

@@ -675,6 +675,13 @@ let rec print_address ppf = function
 
 let current_unit = ref ""
 
+let find_same_module id tbl =
+  match IdTbl.find_same id tbl with
+  | x -> x
+  | exception Not_found
+    when Ident.persistent id && not (Ident.name id = !current_unit) ->
+      Persistent
+
 (* Persistent structure descriptions *)
 
 type pers_struct =
@@ -771,15 +778,9 @@ let acknowledge_pers_struct check modname
   let id = Ident.create_persistent name in
   let path = Pident id in
   let addr = EnvLazy.create_forced (Aident id) in
-  let env =
-    let add_imported_persistent env (name, _digest) =
-      add_persistent_structure (Ident.create_persistent name) env
-    in
-    List.fold_left add_imported_persistent empty crcs
-  in
   let comps =
       !components_of_module' ~alerts ~loc:Location.none
-        env Subst.identity path addr (Mty_signature sign)
+        empty Subst.identity path addr (Mty_signature sign)
   in
   let ps = { ps_name = name;
              ps_sig = lazy (Subst.signature Subst.identity sign);
@@ -916,7 +917,7 @@ let get_unit_name () =
 let rec find_module_descr path env =
   match path with
     Pident id ->
-      begin match IdTbl.find_same id env.components with
+      begin match find_same_module id env.components with
       | Value x -> fst x
       | Persistent -> (find_pers_struct (Ident.name id)).ps_comps
       end
@@ -1019,7 +1020,7 @@ let find_module ~alias path env =
   match path with
     Pident id ->
       begin
-        match IdTbl.find_same id env.modules with
+        match find_same_module id env.modules with
         | Value (data, _) -> EnvLazy.force subst_modtype_maker data
         | Persistent ->
             let ps = find_pers_struct (Ident.name id) in
@@ -1061,12 +1062,9 @@ let rec find_module_address path env =
   match path with
   | Pident id ->
       begin
-        match IdTbl.find_same id env.modules with
+        match find_same_module id env.modules with
         | Value (_, addr) -> get_address addr
-        | Persistent ->
-            if not (Ident.name id = !current_unit) then
-              Aident id
-            else raise Not_found
+        | Persistent -> Aident id
       end
   | Pdot(p, s) -> begin
       match get_components (find_module_descr p env) with
@@ -1263,11 +1261,16 @@ let mark_module_used name loc =
 let rec lookup_module_descr_aux ?loc ~mark lid env =
   match lid with
     Lident s ->
-      let (p, data) = IdTbl.find_name ~mark s env.components in
-      (p,
-       match data with
-       | Value (comp, _) -> comp
-       | Persistent -> (find_pers_struct s).ps_comps)
+      begin match IdTbl.find_name ~mark s env.components with
+      | exception Not_found when s <> !current_unit ->
+        let p = Path.Pident (Ident.create_persistent s) in
+        (p, (find_pers_struct s).ps_comps)
+      | (p, data) ->
+        (p,
+         match data with
+         | Value (comp, _) -> comp
+         | Persistent -> (find_pers_struct s).ps_comps)
+      end
   | Ldot(l, s) ->
       let (p, descr) = lookup_module_descr ?loc ~mark l env in
       begin match get_components descr with