Ensure we also normalize badmap and badkey in rescue

Author: José Valim

lib/elixir/lib/exception.ex

@@ -565,10 +565,10 @@ defmodule BadStructError do
 end
 
 defmodule BadMapError do
-  defexception [map: nil]
-  
+  defexception [term: nil]
+
   def message(exception) do
-    "expected a map, got: #{inspect(exception.map)}"
+    "expected a map, got: #{inspect(exception.term)}"
   end
 end
 
@@ -780,19 +780,19 @@ defmodule ErlangError do
   def normalize({:badmatch, term}, _stacktrace) do
     %MatchError{term: term}
   end
-  
-  # Erlang R18.0 changed this for various functions in the maps module
-  def normalize({:badmap, map}, _stacktrace) do
-    %BadMapError{map: map}
+
+  def normalize({:badmap, term}, _stacktrace) do
+    %BadMapError{term: term}
   end
-  
-  # Erlang R18.0 changed this for various functions in the maps module
+
   def normalize({:badkey, key}, stacktrace) do
-    term = case stacktrace do
-      [{:maps, :update, [_, _, map], []}|_] -> map
-      _                                     -> nil
-    end
-    %KeyError{key: key, term: term }
+    term =
+      case stacktrace || :erlang.get_stacktrace do
+        [{:maps, :update, [_, _, map], _}|_] -> map
+        [{:maps, :get, [_, map], _}|_] -> map
+        _ -> nil
+      end
+    %KeyError{key: key, term: term}
   end
 
   def normalize({:case_clause, term}, _stacktrace) do

lib/elixir/src/elixir_translator.erl

@@ -257,6 +257,9 @@ translate({{'.', _, [Left, Right]}, Meta, Args}, S)
           %% the is_map/1 guard instead of matching on map. Hopefully
           %% we can use a match on 17.1.
           %%
+          %% In the future, we could also use maps:get/2 instead
+          %% of pattern match, reducing the AST footprint.
+          %%
           %% http://erlang.org/pipermail/erlang-bugs/2014-April/004338.html
           {{'case', -1, TLeft, [
             {clause, -1,

lib/elixir/src/elixir_try.erl

@@ -156,6 +156,16 @@ erl_rescue_guard_for(Meta, Var, 'Elixir.BadStructError') ->
           erl_tuple_size(Meta, Var, 3),
           erl_record_compare(Meta, Var, badstruct));
 
+erl_rescue_guard_for(Meta, Var, 'Elixir.BadMapError') ->
+  erl_and(Meta,
+          erl_tuple_size(Meta, Var, 2),
+          erl_record_compare(Meta, Var, badmap));
+
+erl_rescue_guard_for(Meta, Var, 'Elixir.KeyError') ->
+  erl_and(Meta,
+          erl_tuple_size(Meta, Var, 2),
+          erl_record_compare(Meta, Var, badkey));
+
 erl_rescue_guard_for(Meta, Var, 'Elixir.ArgumentError') ->
   erl_or(Meta,
          {erl(Meta, '=='), Meta, [Var, badarg]},

lib/elixir/test/elixir/kernel/raise_test.exs

@@ -304,6 +304,34 @@ defmodule Kernel.RaiseTest do
     assert result == "no match of right hand side value: 0"
   end
 
+  test :bad_key_error do
+    result = try do
+      %{%{} | foo: :bar}
+    rescue
+      x in [KeyError] -> Exception.message(x)
+    end
+
+    assert result == "key :foo not found"
+
+    result = try do
+      %{}.foo
+    rescue
+      x in [KeyError] -> Exception.message(x)
+    end
+
+    assert result == "key :foo not found in: %{}"
+  end
+
+  test :bad_map_error do
+    result = try do
+      %{zero(0) | foo: :bar}
+    rescue
+      x in [BadMapError] -> Exception.message(x)
+    end
+
+    assert result == "expected a map, got: 0"
+  end
+
   test :case_clause_error do
     x = :example
     result = try do

lib/elixir/test/elixir/map_test.exs

@@ -84,7 +84,7 @@ defmodule MapTest do
 
   test "update maps" do
     assert %{two_items_map | a: 3} == %{a: 3, b: 2}
-    
+
     # TODO: proper handling of API changes in different Erlang/OTP releases
     case :erlang.system_info(:otp_release) do
       '17' ->