Merge pull request #2752 from paulo-ferraz-oliveira/xref/suppress_behaviour_info_1_not_used

Suppress Xref output for 'exports_not_used' on generated  behaviour_info/1
OTP-16922

4 files changed, 35 insertions, 2 deletions

diff --git a/lib/tools/src/xref_reader.erl b/lib/tools/src/xref_reader.erl
index d28bdb78db..87c02db9eb 100644
--- a/lib/tools/src/xref_reader.erl
+++ b/lib/tools/src/xref_reader.erl
@@ -95,6 +95,8 @@ form({function, _, module_info, 0, _Clauses}, S) ->
     S;
 form({function, _, module_info, 1, _Clauses}, S) ->
     S;
+form({function, 0 = _Line, behaviour_info, 1, _Clauses}, S) ->
+    S;
 form({function, Anno, Name, Arity, Clauses}, S) ->
     MFA0 = {S#xrefr.module, Name, Arity},
     MFA = adjust_arity(S, MFA0),
diff --git a/lib/tools/test/xref_SUITE.erl b/lib/tools/test/xref_SUITE.erl
index c84f47c207..b5b3ff7796 100644
--- a/lib/tools/test/xref_SUITE.erl
+++ b/lib/tools/test/xref_SUITE.erl
@@ -48,7 +48,8 @@
          fun_mfa/1, fun_mfa_r14/1,
          fun_mfa_vars/1, qlc/1]).
 
--export([analyze/1, basic/1, md/1, q/1, variables/1, unused_locals/1]).
+-export([analyze/1, basic/1, md/1, q/1, variables/1, unused_locals/1,
+         behaviour_info_t/1, fake_behaviour_info_t/1]).
 
 -export([format_error/1, otp_7423/1, otp_7831/1, otp_10192/1, otp_13708/1,
          otp_14464/1, otp_14344/1]).
@@ -83,7 +84,7 @@ groups() ->
        fun_mfa_r14, fun_mfa_vars, qlc]},
      {analyses, [],
 
-      [analyze, basic, md, q, variables, unused_locals]},
+      [analyze, basic, md, q, variables, unused_locals, behaviour_info_t, fake_behaviour_info_t]},
      {misc, [], [format_error, otp_7423, otp_7831, otp_10192, otp_13708,
                  otp_14464, otp_14344]}].
 
@@ -2825,3 +2826,24 @@ add_erts_code_path(KernelPath) ->
                     [KernelPath]
             end
     end.
+
+behaviour_info_t(Config) ->
+    bi_t(_Module = bi,
+         _IsExportNotUsed = false,
+         Config).
+
+fake_behaviour_info_t(Config) ->
+    bi_t(_Module = no_bi,
+         _IsExportNotUsed = true,
+         Config).
+
+bi_t(Module, IsExportNotUsed, Conf) ->
+    LibTestDir = fname(?copydir, "lib_test"),
+    XRefServer = s,
+    {ok, Module} = compile:file(fname(LibTestDir, Module),
+                                [debug_info, {outdir, LibTestDir}]),
+    {ok, _} = start(XRefServer),
+    {ok, Module} = xref:add_module(XRefServer, fname(LibTestDir, Module)),
+    {ok, MFAs} = xref:analyze(XRefServer, exports_not_used),
+    true = lists:member({Module, behaviour_info, 1}, MFAs) =:= IsExportNotUsed,
+    _ = xref:stop(XRefServer).
diff --git a/lib/tools/test/xref_SUITE_data/lib_test/bi.erl b/lib/tools/test/xref_SUITE_data/lib_test/bi.erl
new file mode 100644
index 0000000000..e083fa0f3c
--- /dev/null
+++ b/lib/tools/test/xref_SUITE_data/lib_test/bi.erl
@@ -0,0 +1,3 @@
+-module(bi).
+
+-callback a() -> ok.
diff --git a/lib/tools/test/xref_SUITE_data/lib_test/no_bi.erl b/lib/tools/test/xref_SUITE_data/lib_test/no_bi.erl
new file mode 100644
index 0000000000..5aac4a193e
--- /dev/null
+++ b/lib/tools/test/xref_SUITE_data/lib_test/no_bi.erl
@@ -0,0 +1,6 @@
+-module(no_bi).
+
+-export([behaviour_info/1]).
+
+behaviour_info(_) ->
+    ok.