Merge branch 'bg/compiler-suppress-result-ignored' into dev

* bg/compiler-suppress-result-ignored:
  compiler tests: Eliminate "result of expression is ignored" warnings
  Silence warnings for expressions that are assigned to "_"

OTP-8602 bg/compiler-suppress-result-ignored

It is now possible to suppress the warning in code such as
"list_to_integer(S), ok" by assigning the ignored value "_" like this: "_ =
list_to_integer(S), ok".

1 files changed, 11 insertions, 6 deletions

diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl
index 6e60ab88cb..5ed8836c70 100644
--- a/lib/compiler/test/warnings_SUITE.erl
+++ b/lib/compiler/test/warnings_SUITE.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 2003-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 2003-2010. All Rights Reserved.
+%%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(warnings_SUITE).
@@ -375,7 +375,12 @@ effect(Config) when is_list(Config) ->
                 comp_op ->
                     X =:= 2;
                 cookie ->
-                    erlang:get_cookie()
+                    erlang:get_cookie();
+		result_ignore ->
+                    _ = list_to_integer(X);
+                warn_lc_4 ->
+                    %% No warning because of assignment to _.
+                    [_ = abs(Z) || Z <- [1,2,3]]
                end,
                ok.