Enhance Dialyzer's inference on comparisons

This patch makes Dialyzer aware of Erlang's total ordering of terms,
enabling discrepancy detection in cases where e.g. integer() < tuple()
is treated as a comparison that might also return false (when it is
certain to always return true).

1 files changed, 153 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/comparisons b/lib/dialyzer/test/small_SUITE_data/results/comparisons
new file mode 100644
index 0000000000..642585d25e
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/comparisons
@@ -0,0 +1,153 @@
+
+comparisons.erl:100: The pattern 'true' can never match the type 'false'
+comparisons.erl:101: The pattern 'true' can never match the type 'false'
+comparisons.erl:102: The pattern 'false' can never match the type 'true'
+comparisons.erl:103: The pattern 'false' can never match the type 'true'
+comparisons.erl:104: The pattern 'true' can never match the type 'false'
+comparisons.erl:105: The pattern 'true' can never match the type 'false'
+comparisons.erl:107: The pattern 'true' can never match the type 'false'
+comparisons.erl:108: The pattern 'true' can never match the type 'false'
+comparisons.erl:109: The pattern 'false' can never match the type 'true'
+comparisons.erl:110: The pattern 'false' can never match the type 'true'
+comparisons.erl:111: The pattern 'true' can never match the type 'false'
+comparisons.erl:112: The pattern 'true' can never match the type 'false'
+comparisons.erl:113: The pattern 'false' can never match the type 'true'
+comparisons.erl:114: The pattern 'false' can never match the type 'true'
+comparisons.erl:115: The pattern 'true' can never match the type 'false'
+comparisons.erl:116: The pattern 'true' can never match the type 'false'
+comparisons.erl:117: The pattern 'false' can never match the type 'true'
+comparisons.erl:118: The pattern 'false' can never match the type 'true'
+comparisons.erl:123: The pattern 'false' can never match the type 'true'
+comparisons.erl:124: The pattern 'false' can never match the type 'true'
+comparisons.erl:125: The pattern 'true' can never match the type 'false'
+comparisons.erl:126: The pattern 'true' can never match the type 'false'
+comparisons.erl:127: The pattern 'false' can never match the type 'true'
+comparisons.erl:128: The pattern 'false' can never match the type 'true'
+comparisons.erl:129: The pattern 'true' can never match the type 'false'
+comparisons.erl:130: The pattern 'true' can never match the type 'false'
+comparisons.erl:132: The pattern 'true' can never match the type 'false'
+comparisons.erl:133: The pattern 'true' can never match the type 'false'
+comparisons.erl:134: The pattern 'false' can never match the type 'true'
+comparisons.erl:135: The pattern 'false' can never match the type 'true'
+comparisons.erl:136: The pattern 'true' can never match the type 'false'
+comparisons.erl:137: The pattern 'true' can never match the type 'false'
+comparisons.erl:138: The pattern 'false' can never match the type 'true'
+comparisons.erl:139: The pattern 'false' can never match the type 'true'
+comparisons.erl:140: The pattern 'true' can never match the type 'false'
+comparisons.erl:141: The pattern 'true' can never match the type 'false'
+comparisons.erl:142: The pattern 'false' can never match the type 'true'
+comparisons.erl:143: The pattern 'false' can never match the type 'true'
+comparisons.erl:144: The pattern 'true' can never match the type 'false'
+comparisons.erl:145: The pattern 'true' can never match the type 'false'
+comparisons.erl:146: The pattern 'false' can never match the type 'true'
+comparisons.erl:147: The pattern 'false' can never match the type 'true'
+comparisons.erl:152: The pattern 'false' can never match the type 'true'
+comparisons.erl:153: The pattern 'false' can never match the type 'true'
+comparisons.erl:154: The pattern 'true' can never match the type 'false'
+comparisons.erl:155: The pattern 'true' can never match the type 'false'
+comparisons.erl:157: The pattern 'true' can never match the type 'false'
+comparisons.erl:158: The pattern 'true' can never match the type 'false'
+comparisons.erl:159: The pattern 'false' can never match the type 'true'
+comparisons.erl:160: The pattern 'false' can never match the type 'true'
+comparisons.erl:161: The pattern 'true' can never match the type 'false'
+comparisons.erl:162: The pattern 'true' can never match the type 'false'
+comparisons.erl:163: The pattern 'false' can never match the type 'true'
+comparisons.erl:164: The pattern 'false' can never match the type 'true'
+comparisons.erl:165: The pattern 'true' can never match the type 'false'
+comparisons.erl:166: The pattern 'true' can never match the type 'false'
+comparisons.erl:167: The pattern 'false' can never match the type 'true'
+comparisons.erl:168: The pattern 'false' can never match the type 'true'
+comparisons.erl:169: The pattern 'true' can never match the type 'false'
+comparisons.erl:170: The pattern 'true' can never match the type 'false'
+comparisons.erl:171: The pattern 'false' can never match the type 'true'
+comparisons.erl:172: The pattern 'false' can never match the type 'true'
+comparisons.erl:173: The pattern 'true' can never match the type 'false'
+comparisons.erl:174: The pattern 'true' can never match the type 'false'
+comparisons.erl:175: The pattern 'false' can never match the type 'true'
+comparisons.erl:176: The pattern 'false' can never match the type 'true'
+comparisons.erl:186: The pattern 'false' can never match the type 'true'
+comparisons.erl:187: The pattern 'false' can never match the type 'true'
+comparisons.erl:188: The pattern 'true' can never match the type 'false'
+comparisons.erl:189: The pattern 'true' can never match the type 'false'
+comparisons.erl:190: The pattern 'false' can never match the type 'true'
+comparisons.erl:191: The pattern 'false' can never match the type 'true'
+comparisons.erl:192: The pattern 'true' can never match the type 'false'
+comparisons.erl:193: The pattern 'true' can never match the type 'false'
+comparisons.erl:203: The pattern 'false' can never match the type 'true'
+comparisons.erl:204: The pattern 'false' can never match the type 'true'
+comparisons.erl:205: The pattern 'true' can never match the type 'false'
+comparisons.erl:206: The pattern 'true' can never match the type 'false'
+comparisons.erl:208: The pattern 'true' can never match the type 'false'
+comparisons.erl:209: The pattern 'true' can never match the type 'false'
+comparisons.erl:210: The pattern 'false' can never match the type 'true'
+comparisons.erl:211: The pattern 'false' can never match the type 'true'
+comparisons.erl:221: The pattern 'true' can never match the type 'false'
+comparisons.erl:222: The pattern 'true' can never match the type 'false'
+comparisons.erl:223: The pattern 'false' can never match the type 'true'
+comparisons.erl:224: The pattern 'false' can never match the type 'true'
+comparisons.erl:225: The pattern 'true' can never match the type 'false'
+comparisons.erl:226: The pattern 'true' can never match the type 'false'
+comparisons.erl:227: The pattern 'false' can never match the type 'true'
+comparisons.erl:228: The pattern 'false' can never match the type 'true'
+comparisons.erl:242: The pattern 'false' can never match the type 'true'
+comparisons.erl:243: The pattern 'false' can never match the type 'true'
+comparisons.erl:244: The pattern 'true' can never match the type 'false'
+comparisons.erl:245: The pattern 'true' can never match the type 'false'
+comparisons.erl:246: The pattern 'false' can never match the type 'true'
+comparisons.erl:247: The pattern 'false' can never match the type 'true'
+comparisons.erl:248: The pattern 'true' can never match the type 'false'
+comparisons.erl:249: The pattern 'true' can never match the type 'false'
+comparisons.erl:251: The pattern 'true' can never match the type 'false'
+comparisons.erl:252: The pattern 'true' can never match the type 'false'
+comparisons.erl:253: The pattern 'false' can never match the type 'true'
+comparisons.erl:254: The pattern 'false' can never match the type 'true'
+comparisons.erl:263: The pattern 'false' can never match the type 'true'
+comparisons.erl:264: The pattern 'false' can never match the type 'true'
+comparisons.erl:265: The pattern 'true' can never match the type 'false'
+comparisons.erl:266: The pattern 'true' can never match the type 'false'
+comparisons.erl:268: The pattern 'true' can never match the type 'false'
+comparisons.erl:269: The pattern 'true' can never match the type 'false'
+comparisons.erl:270: The pattern 'false' can never match the type 'true'
+comparisons.erl:271: The pattern 'false' can never match the type 'true'
+comparisons.erl:272: The pattern 'true' can never match the type 'false'
+comparisons.erl:273: The pattern 'true' can never match the type 'false'
+comparisons.erl:274: The pattern 'false' can never match the type 'true'
+comparisons.erl:275: The pattern 'false' can never match the type 'true'
+comparisons.erl:293: The pattern 'false' can never match the type 'true'
+comparisons.erl:294: The pattern 'false' can never match the type 'true'
+comparisons.erl:295: The pattern 'true' can never match the type 'false'
+comparisons.erl:296: The pattern 'true' can never match the type 'false'
+comparisons.erl:311: The pattern 'true' can never match the type 'false'
+comparisons.erl:312: The pattern 'true' can never match the type 'false'
+comparisons.erl:313: The pattern 'false' can never match the type 'true'
+comparisons.erl:314: The pattern 'false' can never match the type 'true'
+comparisons.erl:44: The pattern 'false' can never match the type 'true'
+comparisons.erl:45: The pattern 'false' can never match the type 'true'
+comparisons.erl:46: The pattern 'true' can never match the type 'false'
+comparisons.erl:47: The pattern 'true' can never match the type 'false'
+comparisons.erl:48: The pattern 'false' can never match the type 'true'
+comparisons.erl:49: The pattern 'false' can never match the type 'true'
+comparisons.erl:50: The pattern 'true' can never match the type 'false'
+comparisons.erl:51: The pattern 'true' can never match the type 'false'
+comparisons.erl:52: The pattern 'false' can never match the type 'true'
+comparisons.erl:53: The pattern 'false' can never match the type 'true'
+comparisons.erl:54: The pattern 'true' can never match the type 'false'
+comparisons.erl:55: The pattern 'true' can never match the type 'false'
+comparisons.erl:69: The pattern 'false' can never match the type 'true'
+comparisons.erl:70: The pattern 'false' can never match the type 'true'
+comparisons.erl:71: The pattern 'true' can never match the type 'false'
+comparisons.erl:72: The pattern 'true' can never match the type 'false'
+comparisons.erl:73: The pattern 'false' can never match the type 'true'
+comparisons.erl:74: The pattern 'false' can never match the type 'true'
+comparisons.erl:75: The pattern 'true' can never match the type 'false'
+comparisons.erl:76: The pattern 'true' can never match the type 'false'
+comparisons.erl:77: The pattern 'false' can never match the type 'true'
+comparisons.erl:78: The pattern 'false' can never match the type 'true'
+comparisons.erl:79: The pattern 'true' can never match the type 'false'
+comparisons.erl:80: The pattern 'true' can never match the type 'false'
+comparisons.erl:94: The pattern 'false' can never match the type 'true'
+comparisons.erl:95: The pattern 'false' can never match the type 'true'
+comparisons.erl:96: The pattern 'true' can never match the type 'false'
+comparisons.erl:97: The pattern 'true' can never match the type 'false'
+comparisons.erl:98: The pattern 'false' can never match the type 'true'
+comparisons.erl:99: The pattern 'false' can never match the type 'true'