[textual] make type error better localized

Summary: when possible we give a location error that is closer to the problem.

Reviewed By: geralt-encore

Differential Revision: D46845506

fbshipit-source-id: 97d94ade358934534e315c1efc249ffb7475bf0c

infer/src/textual/TextualTypeVerification.ml

@@ -119,7 +119,28 @@ let pp_error sourcefile fmt error =
       F.fprintf fmt "variable %a has not been declared" VarName.pp var
 
 
-let mk_type_mismatch_error expected loc exp typ : error = TypeMismatch {exp; typ; expected; loc}
+let rec loc_of_exp exp =
+  match (exp : Exp.t) with
+  | Var _ ->
+      None
+  | Lvar {loc} ->
+      Some loc
+  | Field {exp} ->
+      loc_of_exp exp
+  | Index (exp, _) ->
+      loc_of_exp exp
+  | Const _ ->
+      None
+  | Call {proc} ->
+      Some proc.name.loc
+  | Typ _ ->
+      None
+
+
+let mk_type_mismatch_error expected loc exp typ : error =
+  let loc = loc_of_exp exp |> Option.value ~default:loc in
+  TypeMismatch {exp; typ; expected; loc}
+
 
 (** state + error monad *)
 type state =
@@ -208,7 +229,7 @@ let typeof_var var : Typ.t monad =
   let optional_typ = VarName.Map.find_opt var state.vars in
   option_value_map optional_typ state
     ~none:
-      (let* loc = get_location in
+      (let loc = var.VarName.loc in
        let* () = add_error (VarTypeNotDeclared {var; loc}) in
        abort )
     ~some:ret

infer/tests/codetoanalyze/sil/verif/issues.exp

@@ -1,14 +1,14 @@
-annotated.sil, line 21, column 4: textual type error: expression &y has type *float, while a subtype of *int was expected
-annotated.sil, line 22, column 4: textual type error: expression &n has type **node, while a pointer of array type was expected
-basic.sil, line 17, column 4: textual type error: expression &y has type *float, while a subtype of *int was expected
-basic.sil, line 18, column 4: textual type error: expression &n has type **node, while a pointer of array type was expected
+annotated.sil, line 21, column 19: textual type error: expression &y has type *float, while a subtype of *int was expected
+annotated.sil, line 22, column 19: textual type error: expression &n has type **node, while a pointer of array type was expected
+basic.sil, line 17, column 19: textual type error: expression &y has type *float, while a subtype of *int was expected
+basic.sil, line 18, column 19: textual type error: expression &n has type **node, while a pointer of array type was expected
 basic.sil, line 20, column 4: textual type error: expression n1 has type int, while a subtype of *node was expected
-basic.sil, line 35, column 4: textual type error: variable u has not been declared
+basic.sil, line 35, column 11: textual type error: variable u has not been declared
 basic.sil, line 36, column 4: textual type error: ident n0 is given the type float, but it has already been given the type int at line 17
 basic.sil, line 24, column 4: textual type error: expression n0 has type int, while a subtype of float was expected
-basic.sil, line 24, column 4: textual type error: expression &x has type *int, while a supertype of *float was expected
+basic.sil, line 24, column 11: textual type error: expression &x has type *int, while a supertype of *float was expected
 basic.sil, line 25, column 4: textual type error: expression n1 has type int, while a subtype of float was expected
-basic.sil, line 25, column 4: textual type error: expression &x has type *int, while a pointer of array type was expected
+basic.sil, line 25, column 11: textual type error: expression &x has type *int, while a pointer of array type was expected
 basic.sil, line 29, column 4: textual type error: expression n3 has type *int[], while a pointer of struct type was expected
 basic.sil, line 49, column 4: textual type error: ident n1 is read before being written
 basic.sil, line 60, column 4: textual type error: builtin __sil_allocate is called with 2 arguments while it expects 1