Fix echo tuple format

CHANGELOG.md

@@ -12,6 +12,9 @@
 
 ### Bug fixes
 
+- Fixed a bug where tuples with atoms in the first position could be
+  incorrectly formatted by `echo`.
+
 ## v1.9.1 - 2025-03-10
 
 ### Formatter

compiler-core/templates/echo.erl

@@ -88,17 +88,24 @@ inspect@list(List) ->
 inspect@map(Map) ->
     Fields = [
         [<<"#(">>, echo@inspect(Key), <<", ">>, echo@inspect(Value), <<")">>]
-     || {Key, Value} <- maps:to_list(Map)
+        || {Key, Value} <- maps:to_list(Map)
     ],
     ["dict.from_list([", lists:join(", ", Fields), "])"].
 
 inspect@record(Record) ->
-    [Atom | ArgsList] = erlang:tuple_to_list(Record),
-    Args = lists:join(", ", lists:map(fun echo@inspect/1, ArgsList)),
-    [echo@inspect(Atom), "(", Args, ")"].
+    [Atom | ArgsList] = Tuple = erlang:tuple_to_list(Record),
+    case inspect@maybe_gleam_atom(Atom, none, <<>>) of
+        {ok, Tag} ->
+            Args = lists:join(", ", lists:map(fun echo@inspect/1, ArgsList)),
+            [Tag, "(", Args, ")"];
+        _ ->
+            inspect@tuple(Tuple)
+    end.
 
+inspect@tuple(Tuple) when erlang:is_tuple(Tuple) ->
+    inspect@tuple(erlang:tuple_to_list(Tuple));
 inspect@tuple(Tuple) ->
-    Elements = lists:map(fun echo@inspect/1, erlang:tuple_to_list(Tuple)),
+    Elements = lists:map(fun echo@inspect/1, Tuple),
     ["#(", lists:join(", ", Elements), ")"].
 
 inspect@function(Function) ->
@@ -147,6 +154,9 @@ inspect@proper_or_improper_list(List) ->
             {improper, [echo@inspect(First), " | ", echo@inspect(ImproperRest)]}
     end.
 
+inspect@maybe_gleam_atom(Atom, PrevChar, Acc) when erlang:is_atom(Atom) ->
+    Binary = erlang:atom_to_binary(Atom),
+    inspect@maybe_gleam_atom(Binary, PrevChar, Acc);
 inspect@maybe_gleam_atom(Atom, PrevChar, Acc) ->
     case {Atom, PrevChar} of
         {<<>>, none} ->

test-output/cases/echo_non_record_atom_tag/gleam.toml

@@ -0,0 +1,2 @@
+name = "echo_non_record_atom_tag"
+version = "1.0.0"

test-output/cases/echo_non_record_atom_tag/src/main.gleam

@@ -0,0 +1,10 @@
+pub fn main() {
+  echo #(to_atom("UP"), 1, 2)
+  echo #(to_atom("down"), 12.34)
+  echo #(to_atom("Both"), "ok")
+}
+
+pub type Atom
+
+@external(erlang, "erlang", "binary_to_atom")
+pub fn to_atom(string: String) -> Atom

test-output/src/tests/echo.rs

@@ -185,3 +185,8 @@ fn echo_string() {
 fn echo_tuple() {
     assert_echo!("echo_tuple");
 }
+
+#[test]
+fn echo_non_record_atom_tag() {
+    assert_echo!(Target::Erlang, "echo_non_record_atom_tag");
+}

test-output/src/tests/snapshots/test_output__tests__echo__erlang-echo_non_record_atom_tag.snap

@@ -0,0 +1,26 @@
+---
+source: test-output/src/tests/echo.rs
+assertion_line: 191
+expression: output
+snapshot_kind: text
+---
+--- main.gleam ----------------------
+pub fn main() {
+  echo #(to_atom("UP"), 1, 2)
+  echo #(to_atom("down"), 12.34)
+  echo #(to_atom("Both"), "ok")
+}
+
+pub type Atom
+
+@external(erlang, "erlang", "binary_to_atom")
+pub fn to_atom(string: String) -> Atom
+
+
+--- gleam run output ----------------
+src/main.gleam:2
+#(atom.create_from_string("UP"), 1, 2)
+src/main.gleam:3
+Down(12.34)
+src/main.gleam:4
+#(atom.create_from_string("Both"), "ok")