Improve invalid match and guard errors, closes #1673

Author: José Valim

lib/elixir/src/elixir_errors.erl

@@ -178,18 +178,6 @@ assert_no_function_scope(_Meta, _Kind, #elixir_scope{function=nil}) -> [];
 assert_no_function_scope(Meta, Kind, S) ->
   syntax_error(Meta, S#elixir_scope.file, "cannot invoke ~ts inside a function", [Kind]).
 
-assert_no_match_or_guard_scope(Meta, Kind, S) ->
-  assert_no_match_scope(Meta, Kind, S),
-  assert_no_guard_scope(Meta, Kind, S).
-
-assert_no_match_scope(Meta, Kind, #elixir_scope{context=match} = S) ->
-  syntax_error(Meta, S#elixir_scope.file, "cannot invoke ~ts inside match clause", [Kind]);
-assert_no_match_scope(_Meta, _Kind, _S) -> [].
-
-assert_no_guard_scope(Meta, Kind, #elixir_scope{context=guard} = S) ->
-  syntax_error(Meta, S#elixir_scope.file, "cannot invoke ~ts inside guard", [Kind]);
-assert_no_guard_scope(_Meta, _Kind, _S) -> [].
-
 assert_module_scope(Meta, Kind, #elixir_scope{module=nil,file=File}) ->
   syntax_error(Meta, File, "cannot invoke ~ts outside module", [Kind]);
 assert_module_scope(_Meta, _Kind, #elixir_scope{module=Module}) -> Module.
@@ -198,6 +186,18 @@ assert_function_scope(Meta, Kind, #elixir_scope{function=nil,file=File}) ->
   syntax_error(Meta, File, "cannot invoke ~ts outside function", [Kind]);
 assert_function_scope(_Meta, _Kind, #elixir_scope{function=Function}) -> Function.
 
+assert_no_match_or_guard_scope(Meta, Kind, S) ->
+  assert_no_match_scope(Meta, Kind, S),
+  assert_no_guard_scope(Meta, Kind, S).
+
+assert_no_match_scope(Meta, _Kind, #elixir_scope{context=match} = S) ->
+  compile_error(Meta, S#elixir_scope.file, "invalid pattern in match clause", []);
+assert_no_match_scope(_Meta, _Kind, _S) -> [].
+
+assert_no_guard_scope(Meta, _Kind, #elixir_scope{context=guard} = S) ->
+  compile_error(Meta, S#elixir_scope.file, "invalid pattern in guard", []);
+assert_no_guard_scope(_Meta, _Kind, _S) -> [].
+
 %% Helpers
 
 raise(Meta, File, Kind, Message) when is_list(Meta) ->

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

@@ -113,6 +113,16 @@ defmodule Kernel.ErrorsTest do
       '''
   end
 
+  test :invalid_match_pattern do
+    assert_compile_fail CompileError,
+    "nofile:2: invalid pattern in match clause",
+    '''
+    case true do
+      true && true -> true
+    end
+    '''
+  end
+
   test :different_defs_with_defaults do
     assert_compile_fail CompileError,
       "nofile:3: def hello/3 defaults conflicts with def hello/2",