dialyzer: Introduce module local suppression of warnings

The -dialyzer() attribute can be used for suppressing warnings in a
module by specifying functions or warning options. It can also be used
for requesting warnings in a module.

5 files changed, 142 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/src/blame_contract_range_suppressed.erl b/lib/dialyzer/test/small_SUITE_data/src/blame_contract_range_suppressed.erl
new file mode 100644
index 0000000000..8b66d35083
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/blame_contract_range_suppressed.erl
@@ -0,0 +1,15 @@
+%%-----------------------------------------------------------------------
+%% Like ./blame_contract_range.erl, but warning is suppressed.
+%%-----------------------------------------------------------------------
+-module(blame_contract_range_suppressed).
+
+-export([foo/0]).
+
+foo() ->
+  bar(b).
+
+-dialyzer({nowarn_function, bar/1}).
+
+-spec bar(atom()) -> a.
+bar(a) -> a;
+bar(b) -> b.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/request1.erl b/lib/dialyzer/test/small_SUITE_data/src/request1.erl
new file mode 100644
index 0000000000..a6c4ab8dbd
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/request1.erl
@@ -0,0 +1,12 @@
+-module(request1).
+
+-export([a/0]).
+
+-dialyzer(unmatched_returns).
+
+a() ->
+    b(),
+    1.
+
+b() ->
+    {a, b}.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/suppress_request.erl b/lib/dialyzer/test/small_SUITE_data/src/suppress_request.erl
new file mode 100644
index 0000000000..c4275fa110
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/suppress_request.erl
@@ -0,0 +1,50 @@
+-module(suppress_request).
+
+-export([test1/1, test1_b/1, test2/0, test2_b/0,
+         test3/0, test3_b/0, test4/0, test4_b/0]).
+
+-dialyzer({[specdiffs], test1/1}).
+-spec test1(a | b) -> ok. % spec is subtype
+test1(A) ->
+    ok = test1_1(A).
+
+-spec test1_b(a | b) -> ok. % spec is subtype (suppressed by default)
+test1_b(A) ->
+    ok = test1_1(A).
+
+-spec test1_1(a | b | c) -> ok.
+test1_1(_) ->
+    ok.
+
+-dialyzer(unmatched_returns).
+test2() ->
+    tuple(), % unmatched
+    ok.
+
+test2_b() ->
+    tuple(), % unmatched
+    ok.
+
+-dialyzer({[no_return, no_match], [test3/0]}).
+test3() -> % no local return (suppressed)
+    A = fun(_) ->
+                1
+        end,
+    A = 2. % can never succeed (suppressed)
+
+test3_b() -> % no local return (requested by default)
+    A = fun(_) ->
+                1
+        end,
+    A = 2. % can never succeed (requested by default)
+
+-dialyzer(no_improper_lists).
+test4() ->
+    [1 | 2]. % improper list (suppressed)
+
+-dialyzer({no_improper_lists, test4_b/0}).
+test4_b() ->
+    [1 | 2]. % improper list (suppressed)
+
+tuple() ->
+    {a, b}.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/suppression1.erl b/lib/dialyzer/test/small_SUITE_data/src/suppression1.erl
new file mode 100644
index 0000000000..00534704c3
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/suppression1.erl
@@ -0,0 +1,33 @@
+-module(suppression1).
+
+-export([a/1, b/1, c/0]).
+
+-dialyzer({nowarn_function, a/1}).
+
+-spec a(_) -> integer().
+
+a(_) ->
+    A = fun(_) ->
+                B = fun(_) ->
+                            x = 7
+                    end,
+                B = 1
+        end,
+    A.
+
+-spec b(_) -> integer().
+
+-dialyzer({nowarn_function, b/1}).
+
+b(_) ->
+    A = fun(_) ->
+                1
+        end,
+    A = 2.
+
+-record(r, {a = a :: integer()}).
+
+-dialyzer({nowarn_function, c/0}).
+
+c() ->
+    #r{}.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/suppression2.erl b/lib/dialyzer/test/small_SUITE_data/src/suppression2.erl
new file mode 100644
index 0000000000..4cba53fdce
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/suppression2.erl
@@ -0,0 +1,32 @@
+-module(suppression2).
+
+-export([a/1, b/1, c/0]).
+
+-dialyzer({nowarn_function, [a/1, b/1, c/0]}).
+-dialyzer([no_undefined_callbacks]).
+
+-behaviour(not_a_behaviour).
+
+-spec a(_) -> integer().
+
+a(_) ->
+    A = fun(_) ->
+                B = fun(_) ->
+                            x = 7
+                    end,
+                B = 1
+        end,
+    A.
+
+-spec b(_) -> integer().
+
+b(_) ->
+    A = fun(_) ->
+                1
+        end,
+    A = 2.
+
+-record(r, {a = a :: integer()}).
+
+c() ->
+    #r{}.