From 86fbd6d76d342906e2a77df877013ea68de73cfb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Thu, 12 Feb 2015 09:22:35 +0100
Subject: sys_core_fold: Strengthen type optimization in lets

Make sure that we take extract all possible type information when
optimizing a 'let' construct.

Since the stronger optimization may generate false warnings, we also
need to take special care to suppress false warnings.
---
 lib/compiler/test/warnings_SUITE.erl | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

(limited to 'lib/compiler/test')

diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl
index dcd3910926..d0b7c71be8 100644
--- a/lib/compiler/test/warnings_SUITE.erl
+++ b/lib/compiler/test/warnings_SUITE.erl
@@ -39,7 +39,7 @@
 	 guard/1,bad_arith/1,bool_cases/1,bad_apply/1,
          files/1,effect/1,bin_opt_info/1,bin_construction/1,
 	 comprehensions/1,maps/1,redundant_boolean_clauses/1,
-	 latin1_fallback/1,underscore/1]).
+	 latin1_fallback/1,underscore/1,no_warnings/1]).
 
 % Default timetrap timeout (set in init_per_testcase).
 -define(default_timeout, ?t:minutes(2)).
@@ -65,7 +65,7 @@ groups() ->
        bad_arith,bool_cases,bad_apply,files,effect,
        bin_opt_info,bin_construction,comprehensions,maps,
        redundant_boolean_clauses,latin1_fallback,
-       underscore]}].
+       underscore,no_warnings]}].
 
 init_per_suite(Config) ->
     Config.
@@ -281,7 +281,6 @@ bad_arith(Config) when is_list(Config) ->
 	     {3,sys_core_fold,{eval_failure,badarith}},
 	     {9,sys_core_fold,nomatch_guard},
 	     {9,sys_core_fold,{eval_failure,badarith}},
-	     {9,sys_core_fold,{no_effect,{erlang,is_integer,1}}},
 	     {10,sys_core_fold,nomatch_guard},
 	     {10,sys_core_fold,{eval_failure,badarith}},
 	     {15,sys_core_fold,{eval_failure,badarith}}
@@ -719,6 +718,27 @@ underscore(Config) when is_list(Config) ->
 
     ok.
 
+no_warnings(Config) when is_list(Config) ->
+    Ts = [{no_warnings,
+           <<"-record(r, {s=ordsets:new(),a,b}).
+
+              a() ->
+                R = #r{},			%No warning expected.
+                {R#r.a,R#r.b}.
+
+              b(X) ->
+                T = true,
+                Var = [X],			%No warning expected.
+                case T of
+	          false -> Var;
+                  true -> []
+                end.
+           ">>,
+           [],
+           []}],
+    run(Config, Ts),
+    ok.
+
 %%%
 %%% End of test cases.
 %%%
-- 
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