Merge branch 'hasse/dialyzer/funs_in_dead_code/OTP-15079/ERL-593'

* hasse/dialyzer/funs_in_dead_code/OTP-15079/ERL-593:
  dialyzer: Do not emit warnings for unreachable funs

2 files changed, 26 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/unused_funs b/lib/dialyzer/test/small_SUITE_data/results/unused_funs
new file mode 100644
index 0000000000..c468457ead
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/unused_funs
@@ -0,0 +1,5 @@
+
+unused_funs.erl:10: The pattern 'error' can never match the type 'other_error'
+unused_funs.erl:15: Function not_used/0 will never be called
+unused_funs.erl:19: Function foo/1 will never be called
+unused_funs.erl:7: Function test/0 has no local return
diff --git a/lib/dialyzer/test/small_SUITE_data/src/unused_funs.erl b/lib/dialyzer/test/small_SUITE_data/src/unused_funs.erl
new file mode 100644
index 0000000000..c24cf3ea81
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/unused_funs.erl
@@ -0,0 +1,21 @@
+%% See also ERL-593.
+
+-module(unused_funs).
+
+-export([test/0]).
+
+test() -> % "has no local return"
+    Var = outer_scope,
+    case other_error of
+        error -> % "can never match"
+            %% No warnings "no local return" and "_ = 1 can never match 0" (!)
+            foo(fun() -> {Var, 1 = 0} end)
+    end.
+
+not_used() -> % "will never be called"
+    %% No warnings "no local return" and "1 can never match 0".
+    foo(fun() -> 1 = 0 end).
+
+foo(Fun) -> % "will never be called"
+    1 = 0, % No pattern match warning (foo/1 is not traversed at all).
+    Fun().