Fix unbound variable error when matching on const record subjects

CHANGELOG.md

@@ -115,3 +115,7 @@
 - Fixed a bug where renaming would not work properly if there was an error in
   target file.
   ([Surya Rose](https://github.com/GearsDatapacks))
+
+- Fixed a bug where referencing a constant record inside a case branch matching
+  on that constant would generate invalid code on the Erlang target.
+  ([Igor Castejón](https://github.com/IgorCastejon))

compiler-core/src/erlang/tests/case.rs

@@ -131,3 +131,93 @@ pub fn main(x) {
 "#,
     );
 }
+
+#[test]
+fn local_variable_as_case_subject_with_type_refinement_allows_field_access_inside_branch() {
+    assert_erl!(
+        r#"
+pub type User {
+  User(name: String, age: Int)
+  Guest
+}
+
+pub fn main() {
+  let user = User("Gleam", 42)
+
+  case user {
+    User(..) -> user.name
+    Guest -> "Guest"
+  }
+}
+"#
+    );
+}
+
+#[test]
+fn local_variable_as_case_subject_shadows_const() {
+    assert_erl!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  echo wibble
+  // This 'wibble' shadows the const
+  let wibble = Wobble(42)
+  case wibble {
+    // This matches the local variable, not the const
+    Wobble(_) -> wibble
+  }
+}
+"#
+    )
+}
+
+// https://github.com/gleam-lang/gleam/issues/5261
+#[test]
+fn case_with_record_const_as_subject_with_record_constructor_clause_and_referencing_same_const_inside_clause_consequence()
+ {
+    assert_erl!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  case wibble {
+    Wobble(_) -> wibble
+    wobble -> wibble
+  }
+}
+"#
+    );
+}
+
+// https://github.com/gleam-lang/gleam/issues/5261
+#[test]
+fn const_as_case_subject_with_type_refinement_allows_field_access_inside_branch() {
+    assert_erl!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wobble(42)
+
+pub fn main() {
+  case wibble {
+    Wibble -> 24
+    Wobble(_) -> wibble.int
+  }
+}
+"#
+    )
+}

compiler-core/src/erlang/tests/snapshots/gleam_core__erlang__tests__case__case_with_record_const_as_subject_with_record_constructor_clause_and_referencing_same_const_inside_clause_consequence.snap

@@ -0,0 +1,40 @@
+---
+source: compiler-core/src/erlang/tests/case.rs
+expression: "\npub type Wibble {\n  Wibble\n  Wobble(int: Int)\n}\n\nconst wibble = Wibble\n\npub fn main() {\n  case wibble {\n    Wobble(_) -> wibble\n    wobble -> wibble\n  }\n}\n"
+---
+----- SOURCE CODE
+
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  case wibble {
+    Wobble(_) -> wibble
+    wobble -> wibble
+  }
+}
+
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+-export_type([wibble/0]).
+
+-type wibble() :: wibble | {wobble, integer()}.
+
+-file("project/test/my/mod.gleam", 9).
+-spec main() -> wibble().
+main() ->
+    case wibble of
+        {wobble, _} ->
+            wibble;
+
+        Wobble ->
+            wibble
+    end.

compiler-core/src/erlang/tests/snapshots/gleam_core__erlang__tests__case__const_as_case_subject_with_type_refinement_allows_field_access_inside_branch.snap

@@ -0,0 +1,40 @@
+---
+source: compiler-core/src/erlang/tests/case.rs
+expression: "\npub type Wibble {\n  Wibble\n  Wobble(int: Int)\n}\n\nconst wibble = Wobble(42)\n\npub fn main() {\n  case wibble {\n    Wibble -> 24\n    Wobble(_) -> wibble.int\n  }\n}\n"
+---
+----- SOURCE CODE
+
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wobble(42)
+
+pub fn main() {
+  case wibble {
+    Wibble -> 24
+    Wobble(_) -> wibble.int
+  }
+}
+
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+-export_type([wibble/0]).
+
+-type wibble() :: wibble | {wobble, integer()}.
+
+-file("project/test/my/mod.gleam", 9).
+-spec main() -> integer().
+main() ->
+    case {wobble, 42} of
+        wibble ->
+            24;
+
+        {wobble, _} ->
+            erlang:element(2, {wobble, 42})
+    end.

compiler-core/src/erlang/tests/snapshots/gleam_core__erlang__tests__case__local_variable_as_case_subject_shadows_const.snap

@@ -0,0 +1,44 @@
+---
+source: compiler-core/src/erlang/tests/case.rs
+expression: "\npub type Wibble {\n  Wibble\n  Wobble(int: Int)\n}\n\nconst wibble = Wibble\n\npub fn main() {\n  echo wibble\n  // This 'wibble' shadows the const\n  let wibble = Wobble(42)\n  case wibble {\n    // This matches the local variable, not the const\n    Wobble(_) -> wibble\n  }\n}\n"
+---
+----- SOURCE CODE
+
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  echo wibble
+  // This 'wibble' shadows the const
+  let wibble = Wobble(42)
+  case wibble {
+    // This matches the local variable, not the const
+    Wobble(_) -> wibble
+  }
+}
+
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+-export_type([wibble/0]).
+
+-type wibble() :: wibble | {wobble, integer()}.
+
+-file("project/test/my/mod.gleam", 9).
+-spec main() -> wibble().
+main() ->
+    echo(wibble, nil, 10),
+    Wibble = {wobble, 42},
+    case Wibble of
+        {wobble, _} ->
+            Wibble
+    end.
+
+% ...omitted code from `templates/echo.erl`...

compiler-core/src/erlang/tests/snapshots/gleam_core__erlang__tests__case__local_variable_as_case_subject_with_type_refinement_allows_field_access_inside_branch.snap

@@ -0,0 +1,41 @@
+---
+source: compiler-core/src/erlang/tests/case.rs
+expression: "\npub type User {\n  User(name: String, age: Int)\n  Guest\n}\n\npub fn main() {\n  let user = User(\"Gleam\", 42)\n  \n  case user {\n    User(..) -> user.name\n    Guest -> \"Guest\"\n  }\n}\n"
+---
+----- SOURCE CODE
+
+pub type User {
+  User(name: String, age: Int)
+  Guest
+}
+
+pub fn main() {
+  let user = User("Gleam", 42)
+
+  case user {
+    User(..) -> user.name
+    Guest -> "Guest"
+  }
+}
+
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+-export_type([user/0]).
+
+-type user() :: {user, binary(), integer()} | guest.
+
+-file("project/test/my/mod.gleam", 7).
+-spec main() -> binary().
+main() ->
+    User = {user, <<"Gleam"/utf8>>, 42},
+    case User of
+        {user, _, _} ->
+            erlang:element(2, User);
+
+        guest ->
+            <<"Guest"/utf8>>
+    end.

compiler-core/src/javascript/tests/case.rs

@@ -887,3 +887,93 @@ pub fn main() {
 "#
     )
 }
+
+#[test]
+fn local_variable_as_case_subject_with_type_refinement_allows_field_access_inside_branch() {
+    assert_js!(
+        r#"
+pub type User {
+  User(name: String, age: Int)
+  Guest
+}
+
+pub fn main() {
+  let user = User("Gleam", 42)
+
+  case user {
+    User(..) -> user.name
+    Guest -> "Guest"
+  }
+}
+"#
+    );
+}
+
+#[test]
+fn local_variable_as_case_subject_shadows_const() {
+    assert_js!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  echo wibble
+  // This 'wibble' shadows the const
+  let wibble = Wobble(42)
+  case wibble {
+    // This matches the local variable, not the const
+    Wobble(_) -> wibble
+  }
+}
+"#
+    )
+}
+
+// https://github.com/gleam-lang/gleam/issues/5261
+#[test]
+fn case_with_record_const_as_subject_with_record_constructor_clause_and_referencing_same_const_inside_clause_consequence()
+ {
+    assert_js!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wibble
+
+pub fn main() {
+  case wibble {
+    Wobble(_) -> wibble
+    wobble -> wibble
+  }
+}
+"#
+    );
+}
+
+// https://github.com/gleam-lang/gleam/issues/5261
+#[test]
+fn const_as_case_subject_with_type_refinement_allows_field_access_inside_branch() {
+    assert_js!(
+        r#"
+pub type Wibble {
+  Wibble
+  Wobble(int: Int)
+}
+
+const wibble = Wobble(42)
+
+pub fn main() {
+  case wibble {
+    Wibble -> 24
+    Wobble(_) -> wibble.int
+  }
+}
+"#
+    )
+}