diff options
Diffstat (limited to 'lib/dialyzer/test/small_tests_SUITE_data/src/confusing_warning.erl')
-rw-r--r-- | lib/dialyzer/test/small_tests_SUITE_data/src/confusing_warning.erl | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/lib/dialyzer/test/small_tests_SUITE_data/src/confusing_warning.erl b/lib/dialyzer/test/small_tests_SUITE_data/src/confusing_warning.erl new file mode 100644 index 0000000000..c82df0f056 --- /dev/null +++ b/lib/dialyzer/test/small_tests_SUITE_data/src/confusing_warning.erl @@ -0,0 +1,22 @@ +%% Test case that results in a confusing warning -- created from a +%% very stripped down actual application. The second case clause of +%% test/1 cannot possibly match because all a-pairs match with the +%% first clause. Dialyzer complains that the second argument of the +%% second 2-tuple has type 'aaa' | 'bbb'. This is mucho confusing +%% since there is no 'a'-pair whose second element is 'aaa' | 'bbb'. +%% Pattern matching compilation is of course what's to blame here. + +-module(confusing_warning). +-export([test/1]). + +test(N) when is_integer(N) -> + case foo(N) of + {a, I} when is_integer(I) -> + I; + {a, {_, L}} -> % this clause cannot possibly match + L + end. + +foo(1) -> {a, 42}; +foo(2) -> {b, aaa}; % this is really unused +foo(3) -> {b, bbb}. % this is really unused |