Fix false warning about closure application

Whenever a variable that could hold one of two or more possible closures was
used in a particular application, the application was assumed to fail if ONE of
the closures would fail in this application. This has been corrected to infer
failing application if ALL possible closures would fail in the particular
application.

5 files changed, 55 insertions, 7 deletions

diff --git a/lib/dialyzer/src/dialyzer_typesig.erl b/lib/dialyzer/src/dialyzer_typesig.erl
index 30aec59d22..92868b6878 100644
--- a/lib/dialyzer/src/dialyzer_typesig.erl
+++ b/lib/dialyzer/src/dialyzer_typesig.erl
@@ -2161,13 +2161,21 @@ get_apply_constr(FunLabels, Dst, ArgTypes, #state{callgraph = CG} = State) ->
   case lists:member(error, MFAs) of
     true -> error;
     false ->
-      Constrs = [begin
-		   State1 = state__new_constraint_context(State),
-		   State2 = get_plt_constr(MFA, Dst, ArgTypes, State1),
-		   state__cs(State2)
-		 end || {ok, MFA} <- MFAs],
-      ApplyConstr = mk_disj_constraint_list(Constrs),
-      {ok, state__store_conj(ApplyConstr, State)}
+      Constrs0 =
+	[begin
+	   State1 = state__new_constraint_context(State),
+	   try get_plt_constr(MFA, Dst, ArgTypes, State1) of
+	       State2 -> state__cs(State2)
+	   catch
+	     throw:error -> error
+	   end
+	 end || {ok, MFA} <- MFAs],
+      case [C || C <- Constrs0, C =/= error] of
+	[] -> throw(error);
+	Constrs ->
+	  ApplyConstr = mk_disj_constraint_list(Constrs),
+	  {ok, state__store_conj(ApplyConstr, State)}
+      end
   end.
 
 state__scc(#state{scc = SCC}) ->
diff --git a/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy b/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy
new file mode 100644
index 0000000000..7ce440a60d
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy
@@ -0,0 +1,4 @@
+
+higher_order_discrepancy.erl:11: The call higher_order_discrepancy:g('foo') will never return since it differs in the 1st argument from the success typing arguments: ('bar')
+higher_order_discrepancy.erl:14: Function g/1 has no local return
+higher_order_discrepancy.erl:14: The pattern 'bar' can never match the type 'foo'
diff --git a/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy_2 b/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy_2
new file mode 100644
index 0000000000..c1c7dbbfcc
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/higher_order_discrepancy_2
@@ -0,0 +1,8 @@
+
+higher_order_discrepancy_2.erl:11: The call higher_order_discrepancy_2:f('foo') will never return since it differs in the 1st argument from the success typing arguments: ('bar')
+higher_order_discrepancy_2.erl:11: The call higher_order_discrepancy_2:g('foo') will never return since it differs in the 1st argument from the success typing arguments: ('baz')
+higher_order_discrepancy_2.erl:13: Function f/1 has no local return
+higher_order_discrepancy_2.erl:13: The pattern 'bar' can never match the type 'foo'
+higher_order_discrepancy_2.erl:14: Function g/1 has no local return
+higher_order_discrepancy_2.erl:14: The pattern 'baz' can never match the type 'foo'
+higher_order_discrepancy_2.erl:5: Function test/1 has no local return
diff --git a/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy.erl b/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy.erl
new file mode 100644
index 0000000000..ff5ee6bac4
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy.erl
@@ -0,0 +1,14 @@
+-module(higher_order_discrepancy).
+
+-export([test/1]).
+
+test(X) ->
+    F =
+	case X of
+	    1 -> fun f/1;
+	    2 -> fun g/1
+	end,
+    F(foo).
+
+f(foo) -> ok.
+g(bar) -> ok.
diff --git a/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy_2.erl b/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy_2.erl
new file mode 100644
index 0000000000..4b0d4f6b45
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/higher_order_discrepancy_2.erl
@@ -0,0 +1,14 @@
+-module(higher_order_discrepancy_2).
+
+-export([test/1]).
+
+test(X) ->
+    F =
+	case X of
+	    1 -> fun f/1;
+	    2 -> fun g/1
+	end,
+    F(foo).
+
+f(bar) -> ok.
+g(baz) -> ok.