1 files changed, 32 insertions, 0 deletions
diff --git a/lib/hipe/test/maps_SUITE_data/maps_update_map_expressions.erl b/lib/hipe/test/maps_SUITE_data/maps_update_map_expressions.erl
new file mode 100644
index 0000000000..181e3f18f7
--- /dev/null
+++ b/lib/hipe/test/maps_SUITE_data/maps_update_map_expressions.erl
@@ -0,0 +1,32 @@
+-module(maps_update_map_expressions).
+-export([test/0]).
+
+test() ->
+    M = maps:new(),
+    X = id(fondue),
+    M1 = #{ a := 1 } = M#{a => 1},
+    #{ b := {X} } = M1#{ a := 1, b => {X} },
+
+    #{ b := 2 } = (maps:new())#{ b => 2 },
+
+    #{ a :=42, b:=42, c:=42 } = (maps:from_list([{a,1},{b,2},{c,3}]))#{ a := 42, b := 42, c := 42 },
+    #{ "a" :=1, "b":=42, "c":=42 } = (maps:from_list([{"a",1},{"b",2}]))#{ "b" := 42, "c" => 42 },
+
+    %% Test need to be in a fun.
+    %% This tests that let expr optimisation in sys_core_fold
+    %% covers maps correctly.
+    F = fun() ->
+	    M0 = id(#{ "a" => [1,2,3] }),
+	    #{ "a" := _ } = M0,
+	    M0#{ "a" := b }
+    end,
+
+    #{ "a" := b } = F(),
+
+    %% Error cases, FIXME: should be 'badmap'?
+    {'EXIT',{badarg,_}} = (catch (id(<<>>))#{ a := 42, b => 2 }),
+    {'EXIT',{badarg,_}} = (catch (id([]))#{ a := 42, b => 2 }),
+    ok.
+
+%% Use this function to avoid compile-time evaluation of an expression.
+id(I) -> I.