dialyzer: Fix erlang:abs/1

Fix the range type of erlang:abs/1.

2 files changed, 80 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/abs b/lib/dialyzer/test/small_SUITE_data/results/abs
new file mode 100644
index 0000000000..f229a6d036
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/abs
@@ -0,0 +1,9 @@
+
+abs.erl:12: Function i1/0 has no local return
+abs.erl:16: The pattern 'true' can never match the type 'false'
+abs.erl:23: Function i2/0 has no local return
+abs.erl:27: The pattern 'true' can never match the type 'false'
+abs.erl:34: Function i3/0 has no local return
+abs.erl:37: The pattern 'true' can never match the type 'false'
+abs.erl:45: Function i4/0 has no local return
+abs.erl:49: The pattern 'true' can never match the type 'false'
diff --git a/lib/dialyzer/test/small_SUITE_data/src/abs.erl b/lib/dialyzer/test/small_SUITE_data/src/abs.erl
new file mode 100644
index 0000000000..251e24cdfc
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/abs.erl
@@ -0,0 +1,71 @@
+-module(abs).
+
+%% OTP-12948. erlang:abs/1 bug fix.
+
+-export([t/0]).
+
+t() ->
+    Fs = [fun i1/0, fun i2/0, fun i3/0, fun i4/0, fun f1/0],
+    _ = [catch F() || F <- Fs],
+    ok.
+
+i1() ->
+    A = int(),
+    I1 = i1(A),
+    true = I1 < 2,
+    true = I1 < 1. % can never match
+
+-spec i1(neg_integer()) -> non_neg_integer().
+
+i1(A) when is_integer(A), A < 0 ->
+    abs(A).
+
+i2() ->
+    A = int(),
+    I2 = i2(A),
+    true = I2 < 1,
+    true = I2 < 0. % can never match
+
+-spec i2(non_neg_integer()) -> non_neg_integer().
+
+i2(A) when is_integer(A), A >= 0 ->
+    abs(A).
+
+i3() ->
+    A = int(),
+    I3 = i3(A),
+    true = I3 < -1,
+    true = I3 < 0. % can never match
+
+-spec i3(integer()) -> non_neg_integer().
+
+i3(A) when is_integer(A) ->
+    abs(A).
+
+i4() ->
+    A = int(),
+    I4 = i4(A),
+    true = I4 =:= 0 orelse I4 =:= 1,
+    true = I4 < 0 orelse I4 > 1. % can never match
+
+-spec i4(integer()) -> number().
+
+i4(A) when A =:= -1; A =:= 0; A =:= 1 ->
+    abs(A).
+
+f1() ->
+    F1 = f1(float()),
+    math:sqrt(F1).
+
+f1(A) ->
+    abs(A).
+
+-spec int() -> integer().
+
+int() ->
+    foo:bar().
+
+-spec float() -> float().
+
+float() ->
+    math:sqrt(1.0).