stdlib: Allow characters in types and constant patterns

Characters ($char) can be used in constant pattern expressions. They
can also be used in types and contracts.

2 files changed, 36 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/results/chars b/lib/dialyzer/test/small_SUITE_data/results/chars
new file mode 100644
index 0000000000..2c1f8f8d17
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/results/chars
@@ -0,0 +1,4 @@
+
+chars.erl:29: Invalid type specification for function chars:f/1. The success typing is (#{'b':=50}) -> 'ok'
+chars.erl:32: Function t1/0 has no local return
+chars.erl:32: The call chars:f(#{'b':=50}) breaks the contract (#{'a':=49,'b'=>50,'c'=>51}) -> 'ok'
diff --git a/lib/dialyzer/test/small_SUITE_data/src/chars.erl b/lib/dialyzer/test/small_SUITE_data/src/chars.erl
new file mode 100644
index 0000000000..1e9c8ab6b9
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/chars.erl
@@ -0,0 +1,32 @@
+-module(chars).
+
+%% ERL-313
+
+-export([t/0]).
+-export([t1/0]).
+
+-record(r, {f :: $A .. $Z}).
+
+-type cs() :: $A..$Z | $a .. $z | $/.
+
+-spec t() -> $0-$0..$9-$0| $?.
+
+t() ->
+    c(#r{f = $z - 3}),
+    c($z - 3),
+    c($B).
+
+-spec c(cs()) -> $3-$0..$9-$0.
+
+c($A + 1) -> 2;
+c(C) ->
+    case C of
+        $z - 3 -> 3;
+        #r{f = $z - 3} -> 7
+    end.
+
+%% Display contract with character in warning:
+-spec f(#{a := $1, b => $2, c => $3}) -> ok. % invalid type spec
+f(_) -> ok.
+
+t1() -> f(#{b => $2}). % breaks the  contract