Tag exceptions as dynamic, closes #14074

Author: josevalim

lib/elixir/lib/module/types/expr.ex

@@ -444,7 +444,8 @@ defmodule Module.Types.Expr do
         # to avoid export dependencies. So we do it here.
         if Code.ensure_loaded?(exception) and function_exported?(exception, :__struct__, 0) do
           {info, context} = Of.struct_info(exception, meta, stack, context)
-          {Of.struct_type(exception, info, args), context}
+          # TODO: For properly defined structs, this should not be dynamic
+          {dynamic(Of.struct_type(exception, info, args)), context}
         else
           # If the exception cannot be found or is invalid, fetch the signature to emit warnings.
           {_, context} = Apply.signature(exception, :__struct__, 0, meta, stack, context)

lib/elixir/test/elixir/module/types/expr_test.exs

@@ -1224,16 +1224,18 @@ defmodule Module.Types.ExprTest do
                    e
                end
              ) ==
-               union(
-                 closed_map(
-                   __struct__: atom([ArgumentError]),
-                   __exception__: atom([true]),
-                   message: term()
-                 ),
-                 closed_map(
-                   __struct__: atom([RuntimeError]),
-                   __exception__: atom([true]),
-                   message: term()
+               dynamic(
+                 union(
+                   closed_map(
+                     __struct__: atom([ArgumentError]),
+                     __exception__: atom([true]),
+                     message: term()
+                   ),
+                   closed_map(
+                     __struct__: atom([RuntimeError]),
+                     __exception__: atom([true]),
+                     message: term()
+                   )
                  )
                )
     end