Small cleanup and doc on the module handling refactor

compiler/driver.ml

@@ -62,8 +62,10 @@ let load_module_interfaces options includes program =
         (Format.pp_print_list ~pp_sep:Format.pp_print_space File.format)
         ms
   in
-  (* modulename * program * (id -> modulename) *)
-  let rec aux req_chain seen uses =
+  let rec aux req_chain seen uses :
+      (ModuleName.t * Surface.Ast.interface * ModuleName.t Ident.Map.t) option
+      File.Map.t
+      * ModuleName.t Ident.Map.t =
     List.fold_left
       (fun (seen, use_map) use ->
         let f = find_module req_chain use.Surface.Ast.mod_use_name in
@@ -297,11 +299,14 @@ module Commands = struct
 
   let get_scope_uid (ctx : decl_ctx) (scope : string) : ScopeName.t =
     if String.contains scope '.' then
-      Message.raise_error "Only references to the top-level module are allowed";
+      Message.raise_error
+        "Bad scope argument @{<yellow>%s@}: only references to the top-level \
+         module are allowed"
+        scope;
     try Ident.Map.find scope ctx.ctx_scope_index
     with Ident.Map.Not_found _ ->
       Message.raise_error
-        "There is no scope @{<yellow>\"%s\"@} inside the program." scope
+        "There is no scope \"@{<yellow>%s@}\" inside the program." scope
 
   (* TODO: this is very weird but I'm trying to maintain the current behaviour
      for now *)

compiler/surface/lexer.cppo.ml

@@ -819,6 +819,11 @@ let line_dir_arg_re =
       eol
     ])
 
+(* This is a bit cheap, but we don't want a full-fledged parser to handle these
+   trivial line directives. Here we extract the first uppercase argument of a
+   directive line, which is guaranteed to match the module name we are
+   interested in and nothing else (e.g. in French, the module usage "keywords"
+   are multiple words) *)
 let line_dir_arg_upcase_re =
   Re.(compile @@ seq [
       bos; char '>'; rep space; rep1 alpha;
@@ -840,23 +845,27 @@ let lex_line (lexbuf : lexbuf) : (string * L.line_token) option =
        Some (str, LINE_TEST id)
      with Not_found ->
        Message.emit_spanned_warning (Pos.from_lpos (lexing_positions lexbuf))
-         "Ignored invalid test section, must have an explicit `{ id = \"name\" }` specification";
+         "Ignored invalid test section, must have an explicit \
+          `{ id = \"name\" }` specification";
        Some (str, LINE_ANY))
   | "```", Star hspace, ('\n' | eof) ->
     Some (Utf8.lexeme lexbuf, LINE_BLOCK_END)
-  | '>', Star hspace, MR_LAW_INCLUDE, Star hspace, ':', Plus (Compl '\n'), ('\n' | eof)  ->
+  | '>', Star hspace, MR_LAW_INCLUDE, Star hspace, ':', Plus (Compl '\n'),
+    ('\n' | eof)  ->
     let str = Utf8.lexeme lexbuf in
     (try
        let file = Re.Group.get (Re.exec line_dir_arg_re str) 1 in
        Some (str, LINE_INCLUDE file)
      with Not_found -> Some (str, LINE_ANY))
-  | '>', Star hspace, MR_MODULE_DEF, Plus hspace, uppercase, Star (Compl '\n'), ('\n' | eof)  ->
+  | '>', Star hspace, MR_MODULE_DEF, Plus hspace, uppercase, Star (Compl '\n'),
+    ('\n' | eof)  ->
     let str = Utf8.lexeme lexbuf in
     (try
        let mdl = Re.Group.get (Re.exec line_dir_arg_upcase_re str) 1 in
        Some (str, LINE_MODULE_DEF mdl)
      with Not_found -> Some (str, LINE_ANY))
-  | '>', Star hspace, MR_MODULE_USE, Plus hspace, uppercase, Star (Compl '\n'), ('\n' | eof)  ->
+  | '>', Star hspace, MR_MODULE_USE, Plus hspace, uppercase, Star (Compl '\n'),
+    ('\n' | eof)  ->
     let str = Utf8.lexeme lexbuf in
     (try
        let mdl = Re.Group.get (Re.exec line_dir_arg_upcase_re str) 1 in

compiler/surface/parser_driver.ml

@@ -403,8 +403,13 @@ let check_modname program source_file =
       (Cli.FileName file | Cli.Contents (_, file) | Cli.Stdin file) )
     when not File.(equal mname Filename.(remove_extension (basename file))) ->
     Message.raise_spanned_error pos
-      "Module declared as @{<blue>%s@}, which does not match the file name %a"
+      "@[<hov>Module declared as@ @{<blue>%s@},@ which@ does@ not@ match@ the@ \
+       file@ name@ %a.@ Rename the module to@ @{<blue>%s@}@ or@ the@ file@ to@ \
+       %a.@]"
       mname File.format file
+      (String.capitalize_ascii Filename.(remove_extension (basename file)))
+      File.format
+      File.((dirname file / mname) ^ Filename.extension file)
   | _ -> ()
 
 let load_interface source_file =

tests/test_modules/bad/mod_badname.catala_en

@@ -4,7 +4,10 @@
 ```catala-test-inline
 $ catala typecheck
 [ERROR]
-Module declared as This_is_not_the_file_name, which does not match the file name "tests/test_modules/bad/mod_badname.catala_en"
+Module declared as This_is_not_the_file_name, which does not match the file
+name "tests/test_modules/bad/mod_badname.catala_en". Rename the module to
+Mod_badname or the file to
+"tests/test_modules/bad/This_is_not_the_file_name.catala_en".
 
 ┌─⯈ tests/test_modules/bad/mod_badname.catala_en:1.10-1.35:
 └─┐