Improve some Kernel error messages

Author: José Valim

lib/elixir/src/elixir_dispatch.erl

@@ -342,12 +342,13 @@ remote_function(Meta, Receiver, Name, Arity, S) ->
 %% ERROR HANDLING
 
 format_error({ unrequired_module, { Receiver, Name, Arity, Required }}) ->
-  String = 'Elixir.Enum':join([elixir_errors:inspect(R) || R <- Required], <<", ">>),
-  io_lib:format("tried to invoke macro ~ts.~ts/~B but module was not required. Required: ~ts",
-    [elixir_errors:inspect(Receiver), Name, Arity, String]);
+  Module = elixir_errors:inspect(Receiver),
+  io_lib:format("you must require ~ts before invoking the macro ~ts.~ts/~B",
+    [Module, Module, Name, Arity]);
 
 format_error({ macro_conflict, { Receiver, Name, Arity } }) ->
-  io_lib:format("call to local macro ~ts/~B conflicts with imported ~ts.~ts/~B",
+  io_lib:format("call to local macro ~ts/~B conflicts with imported ~ts.~ts/~B, "
+    "please rename the local macro or remove the conflicting import",
     [Name, Arity, elixir_errors:inspect(Receiver), Name, Arity]);
 
 format_error({ ambiguous_call, { Mod1, Mod2, Name, Arity }}) ->

lib/elixir/test/elixir/kernel/errors_test.exs

@@ -249,7 +249,8 @@ defmodule Kernel.ErrorsTest do
 
   test :macro_local_conflict do
     assert_compile_fail CompileError,
-      "nofile:6: call to local macro &&/2 conflicts with imported Kernel.&&/2",
+      "nofile:6: call to local macro &&/2 conflicts with imported Kernel.&&/2, " <>
+      "please rename the local macro or remove the conflicting import",
       '''
       defmodule ErrorsTest do
         def hello, do: 1 || 2
@@ -314,9 +315,9 @@ defmodule Kernel.ErrorsTest do
   end
 
   test :unrequired_macro do
-    assert_compile_fail CompileError,
-      "nofile:2: tried to invoke macro Kernel.ErrorsTest.UnproperMacro.unproper/1 " <>
-      "but module was not required. Required: Integer, Kernel, Kernel.Typespec, Record",
+    assert_compile_fail SyntaxError,
+      "nofile:2: you must require Kernel.ErrorsTest.UnproperMacro before invoking " <>
+      "the macro Kernel.ErrorsTest.UnproperMacro.unproper/1 "
       '''
       defmodule ErrorsTest do
         Kernel.ErrorsTest.UnproperMacro.unproper([])