Include column information in unused variable warning, closes #12591

Author: josevalim

lib/elixir/src/elixir_env.erl

@@ -85,8 +85,8 @@ reset_unused_vars(#elixir_ex{unused={_Unused, Version}} = S) ->
   S#elixir_ex{unused={#{}, Version}}.
 
 check_unused_vars(#elixir_ex{unused={Unused, _Version}}, E) ->
-  [elixir_errors:file_warn([{line, Line}], E, ?MODULE, {unused_var, Name, Overridden}) ||
-    {{{Name, nil}, _}, {Line, Overridden}} <- maps:to_list(Unused), is_unused_var(Name)],
+  [elixir_errors:file_warn(Meta, E, ?MODULE, {unused_var, Name, Overridden}) ||
+    {{{Name, nil}, _}, {Meta, Overridden}} <- maps:to_list(Unused), is_unused_var(Name)],
   E.
 
 merge_and_check_unused_vars(S, #elixir_ex{vars={Read, Write}, unused={Unused, _Version}}, E) ->
@@ -106,11 +106,11 @@ merge_and_check_unused_vars(Current, Unused, ClauseUnused, E) ->
           Acc
       end;
 
-    ({{Name, Kind}, _Count}, {Line, Overridden}, Acc) ->
+    ({{Name, Kind}, _Count}, {Meta, Overridden}, Acc) ->
       case (Kind == nil) andalso is_unused_var(Name) of
         true ->
           Warn = {unused_var, Name, Overridden},
-          elixir_errors:file_warn([{line, Line}], E, ?MODULE, Warn);
+          elixir_errors:file_warn(Meta, E, ?MODULE, Warn);
 
         false ->
           ok

lib/elixir/src/elixir_errors.erl

@@ -74,9 +74,9 @@ file_warn(Meta, E, Module, Desc) when is_list(Meta) ->
   case elixir_config:is_bootstrap() of
     true -> ok;
     false ->
-      {EnvLine, EnvFile, EnvStacktrace} = env_format(Meta, E),
+      {EnvPosition, EnvFile, EnvStacktrace} = env_format(Meta, E),
       Message = Module:format_error(Desc),
-      emit_diagnostic(warning, EnvLine, EnvFile, Message, EnvStacktrace)
+      emit_diagnostic(warning, EnvPosition, EnvFile, Message, EnvStacktrace)
   end.
 
 -spec file_error(list(), binary() | #{file := binary(), _ => _}, module(), any()) -> no_return().
@@ -107,9 +107,9 @@ function_error(Meta, Env, Module, Desc) ->
   file_error(Meta, Env, Module, Desc).
 
 print_error(Meta, Env, Module, Desc) ->
-  {EnvLine, EnvFile, EnvStacktrace} = env_format(Meta, Env),
+  {EnvPosition, EnvFile, EnvStacktrace} = env_format(Meta, Env),
   Message = Module:format_error(Desc),
-  emit_diagnostic(error, EnvLine, EnvFile, Message, EnvStacktrace),
+  emit_diagnostic(error, EnvPosition, EnvFile, Message, EnvStacktrace),
   ok.
 
 %% Compilation error.
@@ -264,7 +264,10 @@ env_format(Meta, #{file := EnvFile} = E) ->
         []
     end,
 
-  {Line, File, Stacktrace}.
+  case lists:keyfind(column, 1, Meta) of
+    {column, Column} -> {{Line, Column}, File, Stacktrace};
+    _ -> {Line, File, Stacktrace}
+  end.
 
 file_format(_, nil) ->
   "";

lib/elixir/src/elixir_expand.erl

@@ -611,7 +611,7 @@ mapfold(_Fun, S, E, [], Acc) ->
 
 var_unused({_, Kind} = Pair, Meta, Version, Unused, Override) ->
   case (Kind == nil) andalso should_warn(Meta) of
-    true -> Unused#{{Pair, Version} => {?line(Meta), Override}};
+    true -> Unused#{{Pair, Version} => {Meta, Override}};
     false -> Unused
   end.
 

lib/elixir/test/elixir/code_test.exs

@@ -54,6 +54,14 @@ defmodule CodeTest do
                  :warn
                end)
     end
+
+    test "includes column information when possible" do
+      assert {_, [%{position: {1, 12}}]} =
+               Code.with_diagnostics(fn ->
+                 quoted = Code.string_to_quoted!("if true do var = :foo end", columns: true)
+                 Code.eval_quoted(quoted, [])
+               end)
+    end
   end
 
   describe "eval_string/1,2,3" do