dialyzer: Modify handling of singleton map key types

The test case loop.erl shows that there is a problem with certain
singleton key types. Here the internal representation toggles between
 #{a | b => ...} and #{a => ..., b => ...}

The choice is to turn #{a | b => ...} into #{a => ..., b => ...} early
(t_from_form()). The aim is to keep as much info as possible (in
pairs). However, including complex singleton keys (tuples, maps) in
this scheme is potentially too costly, and a bit complicated. So one
more choice is made: let atoms and number (and nothing else) be
singleton types, and let complex keys go into the default key.

2 files changed, 5 insertions, 0 deletions

diff --git a/lib/dialyzer/test/map_SUITE_data/results/loop b/lib/dialyzer/test/map_SUITE_data/results/loop
new file mode 100644
index 0000000000..2e956a5709
--- /dev/null
+++ b/lib/dialyzer/test/map_SUITE_data/results/loop
@@ -0,0 +1,4 @@
+
+loop.erl:63: The call loop:start_timer(#loop{state::'idle' | 'waiting',queues::#{'category1'=>#queue{limit::non_neg_integer(),buffer::[any()]}, 'category2'=>#queue{limit::non_neg_integer(),buffer::[any()]}},counters::#{'counter1':=10, 2:=10}}) does not have a term of type #loop{state::'idle' | 'waiting',timer::timer:tref(),queues::#{'category1'=>#queue{limit::non_neg_integer(),buffer::[any()]}, 'category2'=>#queue{limit::non_neg_integer(),buffer::[any()]}},counters::#{'counter1'=>non_neg_integer(), 2=>non_neg_integer()}} (with opaque subterms) as 1st argument
+loop.erl:67: Function wait/1 has no local return
+loop.erl:85: Record construction #loop{state::'idle' | 'waiting',timer::{'error',_} | {'ok',timer:tref()},queues::#{'category1'=>#queue{limit::non_neg_integer(),buffer::[any()]}, 'category2'=>#queue{limit::non_neg_integer(),buffer::[any()]}},counters::#{'counter1'=>non_neg_integer(), 2=>non_neg_integer()}} violates the declared type of field timer::'undefined' | timer:tref()
diff --git a/lib/dialyzer/test/map_SUITE_data/results/opaque_key b/lib/dialyzer/test/map_SUITE_data/results/opaque_key
index 2ae0e0c5c6..8d6379b5e0 100644
--- a/lib/dialyzer/test/map_SUITE_data/results/opaque_key
+++ b/lib/dialyzer/test/map_SUITE_data/results/opaque_key
@@ -1,4 +1,5 @@
 
+opaque_key_adt.erl:35: Invalid type specification for function opaque_key_adt:s2/0. The success typing is () -> #{3:='a'}
 opaque_key_adt.erl:41: Invalid type specification for function opaque_key_adt:s4/0. The success typing is () -> #{1:='a'}
 opaque_key_adt.erl:44: Invalid type specification for function opaque_key_adt:s5/0. The success typing is () -> #{2:=3}
 opaque_key_adt.erl:56: Invalid type specification for function opaque_key_adt:smt1/0. The success typing is () -> #{3:='a'}