Add small/confusing_record_warning

2 files changed, 22 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/confusing_record_warning b/lib/dialyzer/test/small_SUITE_data/results/confusing_record_warning
new file mode 100644
index 0000000000..ac3d89b02b
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/confusing_record_warning
@@ -0,0 +1,3 @@
+
+confusing_record_warning.erl:18: Function test/1 has no local return
+confusing_record_warning.erl:18: Matching of pattern {'r', [_]} tagged with a record name violates the declared type of #r{field::'binary' | 'undefined'}
diff --git a/lib/dialyzer/test/small_SUITE_data/src/confusing_record_warning.erl b/lib/dialyzer/test/small_SUITE_data/src/confusing_record_warning.erl
new file mode 100644
index 0000000000..8af74e0914
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/confusing_record_warning.erl
@@ -0,0 +1,19 @@
+%%---------------------------------------------------------------------
+%% A user complained that dialyzer produces a weird warning for the
+%% following program.  I explained to him that there is an implicit
+%% assumption that when a record is typed one cannot have types of
+%% the same size which are tagged by the record name whose elements
+%% have different types than the ones declared in the record.
+%%
+%% But the warning from dialyzer was weird nonetheless:
+%%    The pattern {'r', [_]} can never match the type any()
+%% We should clearly give some less confusing warning in this case.
+%%---------------------------------------------------------------------
+-module(confusing_record_warning).
+
+-export([test/1]).
+
+-record(r, {field :: binary}).
+
+test({r, [_]}) ->
+  #r{field = <<42>>}.