stdlib: Fix map type listing

2 files changed, 23 insertions, 0 deletions

diff --git a/lib/stdlib/src/erl_pp.erl b/lib/stdlib/src/erl_pp.erl
index 9dbe89da91..82bc2c1460 100644
--- a/lib/stdlib/src/erl_pp.erl
+++ b/lib/stdlib/src/erl_pp.erl
@@ -256,6 +256,10 @@ ltype({type,_Line,nonempty_list,[T]}) ->
     {seq,$[,$],[$,],[ltype(T),leaf("...")]};
 ltype({type,Line,nil,[]}) ->
     lexpr({nil,Line}, 0, options(none));
+ltype({type,Line,map,any}) ->
+    simple_type({atom,Line,map}, []);
+ltype({type,_Line,map,Pairs}) ->
+    map_type(Pairs);
 ltype({type,Line,tuple,any}) ->
     simple_type({atom,Line,tuple}, []);
 ltype({type,_Line,tuple,Ts}) ->
@@ -289,6 +293,15 @@ binary_type(I1, I2) ->
     E2 = [[leaf("_:_*"),lexpr(I2, P, options(none))] || U],
     {seq,'<<','>>',[$,],E1++E2}.
 
+map_type(Fs) ->
+    {first,[$#],map_pair_types(Fs)}.
+
+map_pair_types(Fs) ->
+    tuple_type(Fs, fun map_pair_type/1).
+
+map_pair_type({type,_Line,map_field_assoc,Ktype,Vtype}) ->
+    {seq,[],[]," =>",[ltype(Ktype),ltype(Vtype)]}.
+
 record_type(Name, Fields) ->
     {first,[record_name(Name)],field_types(Fields)}.
 
diff --git a/lib/stdlib/test/erl_pp_SUITE.erl b/lib/stdlib/test/erl_pp_SUITE.erl
index 390322a5fa..babf3a49eb 100644
--- a/lib/stdlib/test/erl_pp_SUITE.erl
+++ b/lib/stdlib/test/erl_pp_SUITE.erl
@@ -993,6 +993,16 @@ maps_syntax(Config) when is_list(Config) ->
     ok = pp_expr(<<"#{ a => 1, <<\"hi\">> => \"world\", 33 => 1.0 }">>),
     ok = pp_expr(<<"#{ a := V1, <<\"hi\">> := V2 } = M">>),
     ok = pp_expr(<<"M#{ a => V1, <<\"hi\">> := V2 }">>),
+    F = <<"-module(maps_type_syntax).\n"
+          "-compile(export_all).\n"
+          "-type t1() :: map().\n"
+          "-type t2() :: #{ atom() => integer(), atom() => float() }.\n"
+          "-spec f1(t1()) -> 'true'.\n"
+          "f1(M) when is_map(M) -> true.\n"
+          "-spec f2(t2()) -> integer().\n"
+          "f2(#{a := V1,b := V2}) -> V1 + V2.\n"
+          "\n">>,
+    ok = pp_forms(F),
     ok.