From b4f5b85d0a7f288db70093d806920d004d8b0e83 Mon Sep 17 00:00:00 2001
From: Ivan Dubrov <wfragg@gmail.com>
Date: Wed, 13 Jul 2011 15:25:01 +0700
Subject: Fix dialyzer warning on default clause for binary comprehension

Fixed dialyzer warning occuring on binary comprehension of form
"<< <<>> || {A, B} <- [{a, b}] >>" caused by default clause
inserted by compiler. Since this clause is different from the
case of list comprehension, dialyzer fails to suppress that warning.
---
 lib/dialyzer/src/dialyzer_dataflow.erl                   | 11 +++++++++++
 lib/dialyzer/test/small_SUITE_data/src/binary_lc_bug.erl |  8 ++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 lib/dialyzer/test/small_SUITE_data/src/binary_lc_bug.erl

(limited to 'lib/dialyzer')

diff --git a/lib/dialyzer/src/dialyzer_dataflow.erl b/lib/dialyzer/src/dialyzer_dataflow.erl
index 121667b5a5..8cb16d8f09 100644
--- a/lib/dialyzer/src/dialyzer_dataflow.erl
+++ b/lib/dialyzer/src/dialyzer_dataflow.erl
@@ -1414,6 +1414,17 @@ do_clause(C, Arg, ArgType0, OrigArgType, Map,
 			    false ->
 			      true
 			  end;
+			[Pat0, Pat1] -> % binary comprehension
+			  case cerl:is_c_cons(Pat0) of
+			    true ->
+			      not (cerl:is_c_var(cerl:cons_hd(Pat0)) andalso
+				   cerl:is_c_var(cerl:cons_tl(Pat0)) andalso
+                                   cerl:is_c_var(Pat1) andalso
+				   cerl:is_literal(Guard) andalso
+				   (cerl:concrete(Guard) =:= true));
+			    false ->
+			      true
+			  end;
 			_ -> true
 		      end;
 		    false ->
diff --git a/lib/dialyzer/test/small_SUITE_data/src/binary_lc_bug.erl b/lib/dialyzer/test/small_SUITE_data/src/binary_lc_bug.erl
new file mode 100644
index 0000000000..c1e82bfa59
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/binary_lc_bug.erl
@@ -0,0 +1,8 @@
+-module(test).
+
+-export([bin_compr/0]).
+
+bin_compr() ->
+%    [ 0 || {N, V} <- [{a, b}] ]. % Works ok
+    << <<>> || {A, B} <- [{a, b}] >>. % Complains
+%    << <<>> || X <- [{a, b}] >>. % Works ok
-- 
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