Give an error when nesting a big_map inside another big_map

gitlab-pages/docs/reference/big_map.md

@@ -9,8 +9,12 @@ import Syntax from '@theme/Syntax';
 import SyntaxTitle from '@theme/SyntaxTitle';
 
 A lazily deserialized map that's intended to store large amounts of data. 
+Lazily means that storage is read or written per key on demand. Therefore 
+there are no `map`, `fold`, and `iter` operations as in 
+[Map](./map-reference).
 
-The gast costs of deserialized maps are higher than standard maps as data is lazily deserialized.
+The gast costs of big maps are higher than standard maps as data is lazily 
+deserialized.
 
 <SyntaxTitle syntax="pascaligo">
 type big_map ('key, 'value)

src/bin/expect_tests/contract_tests.ml

@@ -1338,6 +1338,58 @@ let%expect_test _ =
     ligo: in file "self_bad_entrypoint_format.ligo", line 8, characters 52-58. bad entrypoint format: entrypoint "Toto" is badly formatted. We expect "%bar" for entrypoint Bar and "%default" when no entrypoint used {"location":"in file \"self_bad_entrypoint_format.ligo\", line 8, characters 52-58"}
 
 
+     If you're not sure how to fix this error, you can
+     do one of the following:
+
+    * Visit our documentation: https://ligolang.org/docs/intro/what-and-why/
+    * Ask a question on our Discord: https://discord.gg/9rhYaEt
+    * Open a gitlab issue: https://gitlab.com/ligolang/ligo/issues/new
+    * Check the changelog by running 'ligo changelog' |}];
+
+  run_ligo_bad ["compile-contract"; bad_contract "nested_bigmap_1.religo"; "main"];
+  [%expect {|
+    ligo: It looks like you have nested a big map inside another big map. This is not supported. :  {}
+
+
+     If you're not sure how to fix this error, you can
+     do one of the following:
+
+    * Visit our documentation: https://ligolang.org/docs/intro/what-and-why/
+    * Ask a question on our Discord: https://discord.gg/9rhYaEt
+    * Open a gitlab issue: https://gitlab.com/ligolang/ligo/issues/new
+    * Check the changelog by running 'ligo changelog' |}];
+
+  run_ligo_bad ["compile-contract"; bad_contract "nested_bigmap_2.religo"; "main"];
+  [%expect {|
+    ligo: It looks like you have nested a big map inside another big map. This is not supported. :  {}
+
+
+     If you're not sure how to fix this error, you can
+     do one of the following:
+
+    * Visit our documentation: https://ligolang.org/docs/intro/what-and-why/
+    * Ask a question on our Discord: https://discord.gg/9rhYaEt
+    * Open a gitlab issue: https://gitlab.com/ligolang/ligo/issues/new
+    * Check the changelog by running 'ligo changelog' |}];
+  
+  run_ligo_bad ["compile-contract"; bad_contract "nested_bigmap_3.religo"; "main"];
+  [%expect {|
+    ligo: It looks like you have nested a big map inside another big map. This is not supported. :  {}
+
+
+     If you're not sure how to fix this error, you can
+     do one of the following:
+
+    * Visit our documentation: https://ligolang.org/docs/intro/what-and-why/
+    * Ask a question on our Discord: https://discord.gg/9rhYaEt
+    * Open a gitlab issue: https://gitlab.com/ligolang/ligo/issues/new
+    * Check the changelog by running 'ligo changelog' |}];
+
+  run_ligo_bad ["compile-contract"; bad_contract "nested_bigmap_4.religo"; "main"];
+  [%expect {|
+    ligo: It looks like you have nested a big map inside another big map. This is not supported. :  {}
+
+
      If you're not sure how to fix this error, you can
      do one of the following:
 

src/passes/3-self_ast_imperative/self_ast_imperative.ml

@@ -6,7 +6,7 @@ let all_expression_mapper = [
   Literals.peephole_expression ;
 ]
 let all_type_expression_mapper = [
-  Entrypoints_lenght_limit.peephole_type_expression ;
+  Entrypoints_length_limit.peephole_type_expression ;
 ]
 
 let all_exp = List.map (fun el -> Helpers.Expression el) all_expression_mapper

src/passes/9-self_ast_typed/no_nested_big_map.ml

@@ -0,0 +1,53 @@
+open Ast_typed
+open Trace
+
+type contract_pass_data = Contract_passes.contract_pass_data
+
+module Errors = struct
+  let no_nested_bigmap () =
+    let title = (thunk ("It looks like you have nested a big map inside another big map. This is not supported. ")) in
+    let message () = "" in
+    let data = [
+      (* ("location" , fun () -> Format.asprintf "%a" Location.pp loc) TODO once types have an actual location *)
+    ] in
+    error ~data title message ()
+end
+
+let rec check_no_nested_bigmap is_in_bigmap e = 
+  match e.type_content with
+  | T_operator (TC_big_map (_, _)) when is_in_bigmap  -> 
+    fail @@ Errors.no_nested_bigmap
+  | T_operator (TC_big_map (key, value)) -> 
+    let%bind _ = check_no_nested_bigmap true key in
+    let%bind _ = check_no_nested_bigmap true value in
+    ok ()
+  | T_operator (TC_contract t)
+  | T_operator (TC_option t)
+  | T_operator (TC_list t)
+  | T_operator (TC_set t) ->
+    let%bind _ = check_no_nested_bigmap is_in_bigmap t in
+    ok ()
+  | T_operator (TC_map (a, b))
+  | T_operator (TC_arrow (a, b)) -> 
+    let%bind _ = check_no_nested_bigmap is_in_bigmap a in
+    let%bind _ = check_no_nested_bigmap is_in_bigmap b in
+    ok ()
+  | T_sum s -> 
+    let es = CMap.to_list s in
+    let%bind _ = bind_map_list (fun l -> check_no_nested_bigmap is_in_bigmap l) es in
+    ok ()
+  | T_record elm -> 
+    let es = LMap.to_list elm in
+    let%bind _ = bind_map_list (fun l -> check_no_nested_bigmap is_in_bigmap l) es in
+    ok ()
+  | T_arrow { type1; type2 } -> 
+    let%bind _ = check_no_nested_bigmap is_in_bigmap type1 in
+    let%bind _ = check_no_nested_bigmap is_in_bigmap type2 in
+    ok ()
+  | T_variable _
+  | T_constant _ -> 
+    ok ()
+
+let self_typing : contract_pass_data -> expression -> (bool * contract_pass_data * expression) result = fun dat el ->
+  let%bind _ = check_no_nested_bigmap false el.type_expression in 
+  ok (true, dat, el)

src/passes/9-self_ast_typed/self_ast_typed.ml

@@ -6,6 +6,7 @@ let all_passes = [
 
 let contract_passes = [
   Contract_passes.self_typing ;
+  No_nested_big_map.self_typing ;
 ]
 
 let all_program =

src/test/contracts/negative/nested_bigmap_1.religo

@@ -0,0 +1,10 @@
+type bar = big_map (nat, int);
+
+/* this should result in an error as nested big_maps are not supported: */
+type storage = big_map (int, bar); 
+
+type return = (list (operation), storage);
+
+let main = ((ignore, store): (unit, storage)): return  => {
+    ([]: list(operation), store)
+};

src/test/contracts/negative/nested_bigmap_2.religo

@@ -0,0 +1,9 @@
+/* this should result in an error as nested big_maps are not supported: */
+type storage = big_map (nat, big_map (int, string)); 
+
+type return = (list (operation), storage);
+
+let main = ((ignore, store): (unit, storage)): return  => {
+    ([]: list(operation), store)
+};
+  

src/test/contracts/negative/nested_bigmap_3.religo

@@ -0,0 +1,15 @@
+type bar = big_map (nat, int); 
+
+type foo = {
+    a: int,
+    b: bar
+};
+
+/* this should result in an error as nested big_maps are not supported: */
+type storage = big_map(nat, foo);
+
+type return = (list (operation), storage);
+
+let main = ((ignore, store): (unit, storage)): return  => {
+    ([]: list(operation), store)
+};

src/test/contracts/negative/nested_bigmap_4.religo

@@ -0,0 +1,9 @@
+/* this should result in an error as nested big_maps are not supported: */
+type storage = map (int, big_map (nat, big_map (int, string))); 
+
+type return = (list (operation), storage);
+
+let main = ((ignore, store): (unit, storage)): return  => {
+    ([]: list(operation), store)
+};
+