Merge pull request #1021 from adamhaber/feature/incomplete-probability-calls

Better error messages for incomplete probability calls

Author: WardBrian

src/frontend/Semantic_error.ml

@@ -34,6 +34,8 @@ module TypeError = struct
     | ReturningFnExpectedNonReturningFound of string
     | ReturningFnExpectedNonFnFound of string
     | ReturningFnExpectedUndeclaredIdentFound of string
+    | ReturningFnExpectedUndeclaredDistSuffixFound of string * string
+    | ReturningFnExpectedWrongDistSuffixFound of string * string
     | NonReturningFnExpectedReturningFound of string
     | NonReturningFnExpectedNonFnFound of string
     | NonReturningFnExpectedUndeclaredIdentFound of string
@@ -163,6 +165,22 @@ module TypeError = struct
           "A returning function was expected but an undeclared identifier \
            '%s' was supplied."
           fn_name
+    | ReturningFnExpectedUndeclaredDistSuffixFound (prefix, suffix) ->
+        Fmt.pf ppf "Function '%s_%s' is not implemented for distribution '%s'."
+          prefix suffix prefix
+    | ReturningFnExpectedWrongDistSuffixFound (prefix, suffix) ->
+        let newsuffix =
+          match suffix with
+          | "lpdf" -> "lpmf"
+          | "lupdf" -> "lupmf"
+          | "lpmf" -> "lpdf"
+          | "lupmf" -> "lupdf"
+          | _ -> raise_s [%message "This should never happen."]
+        in
+        Fmt.pf ppf
+          "Function '%s_%s' is not implemented for distribution '%s', use \
+           '%s_%s' instead."
+          prefix suffix prefix prefix newsuffix
     | NonReturningFnExpectedUndeclaredIdentFound fn_name ->
         Fmt.pf ppf
           "A non-returning function was expected but an undeclared identifier \
@@ -487,6 +505,16 @@ let returning_fn_expected_nonfn_found loc name =
 let returning_fn_expected_undeclaredident_found loc name =
   TypeError (loc, TypeError.ReturningFnExpectedUndeclaredIdentFound name)
 
+let returning_fn_expected_undeclared_dist_suffix_found loc (prefix, suffix) =
+  TypeError
+    ( loc
+    , TypeError.ReturningFnExpectedUndeclaredDistSuffixFound (prefix, suffix)
+    )
+
+let returning_fn_expected_wrong_dist_suffix_found loc (prefix, suffix) =
+  TypeError
+    (loc, TypeError.ReturningFnExpectedWrongDistSuffixFound (prefix, suffix))
+
 let nonreturning_fn_expected_returning_found loc name =
   TypeError (loc, TypeError.NonReturningFnExpectedReturningFound name)
 

src/frontend/Semantic_error.mli

@@ -36,6 +36,12 @@ val returning_fn_expected_nonfn_found : Location_span.t -> string -> t
 val returning_fn_expected_undeclaredident_found :
   Location_span.t -> string -> t
 
+val returning_fn_expected_undeclared_dist_suffix_found :
+  Location_span.t -> string * string -> t
+
+val returning_fn_expected_wrong_dist_suffix_found :
+  Location_span.t -> string * string -> t
+
 val illtyped_reduce_sum :
      Location_span.t
   -> string

src/frontend/Typechecker.ml

@@ -394,7 +394,38 @@ let check_fn ~is_cond_dist loc tenv id es =
               (Utils.normalized_name id.name)) ->
       Semantic_error.returning_fn_expected_nonfn_found loc id.name |> error
   | [] ->
-      Semantic_error.returning_fn_expected_undeclaredident_found loc id.name
+      ( match Utils.split_distribution_suffix id.name with
+      | Some (prefix, suffix) -> (
+          let known_families =
+            List.map
+              ~f:(fun (_, y, _, _) -> y)
+              Stan_math_signatures.distributions
+          in
+          let is_known_family s =
+            List.mem known_families s ~equal:String.equal
+          in
+          match suffix with
+          | ("lpmf" | "lumpf") when Env.mem tenv (prefix ^ "_lpdf") ->
+              Semantic_error.returning_fn_expected_wrong_dist_suffix_found loc
+                (prefix, suffix)
+          | ("lpdf" | "lumdf") when Env.mem tenv (prefix ^ "_lpmf") ->
+              Semantic_error.returning_fn_expected_wrong_dist_suffix_found loc
+                (prefix, suffix)
+          | _ ->
+              if
+                is_known_family prefix
+                && List.mem ~equal:String.equal
+                     Utils.cumulative_distribution_suffices_w_rng suffix
+              then
+                Semantic_error
+                .returning_fn_expected_undeclared_dist_suffix_found loc
+                  (prefix, suffix)
+              else
+                Semantic_error.returning_fn_expected_undeclaredident_found loc
+                  id.name )
+      | None ->
+          Semantic_error.returning_fn_expected_undeclaredident_found loc
+            id.name )
       |> error
   | _ (* a function *) -> (
     match SignatureMismatch.returntype tenv id.name (get_arg_types es) with

src/middle/Utils.ml

@@ -14,6 +14,13 @@ let conditioning_suffices =
   ["_lpdf"; "_lupdf"; "_lupmf"; "_lpmf"; "_cdf"; "_lcdf"; "_lccdf"]
 
 let conditioning_suffices_w_log = conditioning_suffices @ ["_log"]
+
+let cumulative_distribution_suffices =
+  ["cdf"; "lcdf"; "lccdf"; "cdf_log"; "ccdf_log"]
+
+let cumulative_distribution_suffices_w_rng =
+  cumulative_distribution_suffices @ ["rng"]
+
 let is_user_ident = Fn.non (String.is_suffix ~suffix:"__")
 
 let unnormalized_suffix = function

test/integration/bad/missing_dist_suffix/completely_undefined1.stan

@@ -0,0 +1,3 @@
+model {
+  target += foo_lpdf(1);
+}

test/integration/bad/missing_dist_suffix/completely_undefined2.stan

@@ -0,0 +1,6 @@
+data {
+   int foo_lpmf;
+}
+model {
+  target += foo_lpdf(1);
+}

test/integration/bad/missing_dist_suffix/deprecated_suffix.stan

@@ -0,0 +1,5 @@
+data {
+}
+model {
+    target += von_mises_ccdf_log(1, 0,1);
+}

test/integration/bad/missing_dist_suffix/dune

@@ -0,0 +1 @@
+(include ../dune)

test/integration/bad/missing_dist_suffix/lpmf_lpdf_replacement1.stan

@@ -0,0 +1,6 @@
+data { 
+}
+model {  
+    // known family, known suffix, not implemented  
+    target += binomial_lpdf(1|0,1);
+}

test/integration/bad/missing_dist_suffix/lpmf_lpdf_replacement2.stan

@@ -0,0 +1,6 @@
+data { 
+}
+model {  
+    // known family, known suffix, not implemented  
+    target += normal_lpmf(1|0,1);
+}