Fix generation of unused opaque types referencing private types

CHANGELOG.md

@@ -265,3 +265,7 @@
 - Typos in the error message shown when trying to install a non-existent package
   have been fixed.
   ([Ioan Clarke](https://github.com/ioanclarke))
+
+- Fixed a bug where the compiler would generate invalid Erlang and TypeScript
+  code for unused opaque types referencing private types.
+  ([Surya Rose](https://github.com/GearsDatapacks))

compiler-core/src/erlang.rs

@@ -181,7 +181,6 @@ fn module_document<'a>(
             &mut type_defs,
             &module.name,
             &overridden_publicity,
-            &module.unused_definition_positions,
         );
     }
 
@@ -303,13 +302,7 @@ fn register_imports_and_exports(
     type_defs: &mut Vec<Document<'_>>,
     module_name: &str,
     overridden_publicity: &im::HashSet<EcoString>,
-    unused_definition_positions: &HashSet<u32>,
 ) {
-    // Do not generate any code for unused items
-    if unused_definition_positions.contains(&definition.location().start) {
-        return;
-    }
-
     match definition {
         Definition::Function(Function {
             publicity,

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

@@ -27,3 +27,19 @@ pub fn get(dict: Dict(key, value), key: key) -> Result(value, Nil)
 "#
     );
 }
+
+// https://github.com/gleam-lang/gleam/issues/5127
+#[test]
+fn unused_opaque_constructor_is_generated_correctly() {
+    assert_erl!(
+        "
+type Wibble {
+  Wibble
+}
+
+pub opaque type Wobble {
+  Wobble(Wibble)
+}
+"
+    );
+}

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

@@ -0,0 +1,24 @@
+---
+source: compiler-core/src/erlang/tests/custom_types.rs
+expression: "\ntype Wibble {\n  Wibble\n}\n\npub opaque type Wobble {\n  Wobble(Wibble)\n}\n"
+---
+----- SOURCE CODE
+
+type Wibble {
+  Wibble
+}
+
+pub opaque type Wobble {
+  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_type([wibble/0, wobble/0]).
+
+-type wibble() :: wibble.
+
+-opaque wobble() :: {wobble, wibble()}.

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

@@ -18,10 +18,14 @@ pub fn main(x: Int) -> Int {
 -compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
 -define(FILEPATH, "project/test/my/mod.gleam").
 -export([main/1]).
--export_type([a/0]).
+-export_type([a/0, b/0, c/0]).
 
 -type a() :: {a, integer()}.
 
+-type b() :: {b, binary()}.
+
+-type c() :: {c, integer()}.
+
 -file("project/test/my/mod.gleam", 5).
 -spec main(integer()) -> integer().
 main(X) ->

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

@@ -960,3 +960,19 @@ pub fn get(dict: Dict(key, value), key: key) -> Result(value, Nil)
 "#
     );
 }
+
+// https://github.com/gleam-lang/gleam/issues/5127
+#[test]
+fn unused_opaque_constructor_is_generated_correctly() {
+    assert_ts_def!(
+        "
+type Wibble {
+  Wibble
+}
+
+pub opaque type Wobble {
+  Wobble(Wibble)
+}
+"
+    );
+}

compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__custom_types__unused_opaque_constructor_is_generated_correctly.snap

@@ -0,0 +1,30 @@
+---
+source: compiler-core/src/javascript/tests/custom_types.rs
+expression: "\ntype Wibble {\n  Wibble\n}\n\npub opaque type Wobble {\n  Wobble(Wibble)\n}\n"
+---
+----- SOURCE CODE
+
+type Wibble {
+  Wibble
+}
+
+pub opaque type Wobble {
+  Wobble(Wibble)
+}
+
+
+----- TYPESCRIPT DEFINITIONS
+import type * as _ from "../gleam.d.mts";
+
+declare class Wibble extends _.CustomType {}
+
+type Wibble$ = Wibble;
+
+declare class Wobble extends _.CustomType {
+  /** @deprecated */
+  constructor(argument$0: Wibble$);
+  /** @deprecated */
+  0: Wibble$;
+}
+
+export type Wobble$ = Wobble;

compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__type_alias__private_type_in_opaque_type.snap

@@ -16,6 +16,10 @@ pub opaque type OpaqueType {
 ----- TYPESCRIPT DEFINITIONS
 import type * as _ from "../gleam.d.mts";
 
+declare class PrivateType extends _.CustomType {}
+
+type PrivateType$ = PrivateType;
+
 declare class OpaqueType extends _.CustomType {
   /** @deprecated */
   constructor(argument$0: PrivateType$);

compiler-core/src/javascript/typescript.rs

@@ -11,7 +11,7 @@
 //! <https://www.typescriptlang.org/>
 //! <https://www.typescriptlang.org/docs/handbook/declaration-files/introduction.html>
 
-use crate::ast::{AssignName, Publicity, SrcSpan};
+use crate::ast::{AssignName, Publicity, TypedCustomType};
 use crate::javascript::import::Member;
 use crate::type_::{PRELUDE_MODULE_NAME, RecordAccessor, is_prelude_module};
 use crate::{
@@ -380,23 +380,7 @@ impl<'a> TypeScriptGenerator<'a> {
 
             Definition::Import(Import { .. }) => vec![],
 
-            Definition::CustomType(CustomType {
-                publicity,
-                constructors,
-                opaque,
-                name,
-                typed_parameters,
-                external_javascript,
-                ..
-            }) if publicity.is_importable() => self.custom_type_definition(
-                name,
-                typed_parameters,
-                constructors,
-                *opaque,
-                external_javascript,
-                imports,
-            ),
-            Definition::CustomType(CustomType { .. }) => vec![],
+            Definition::CustomType(type_) => self.custom_type_definition(type_, imports),
 
             Definition::ModuleConstant(ModuleConstant {
                 publicity,
@@ -439,15 +423,21 @@ impl<'a> TypeScriptGenerator<'a> {
     ///
     fn custom_type_definition(
         &mut self,
-        name: &'a str,
-        typed_parameters: &'a [Arc<Type>],
-        constructors: &'a [TypedRecordConstructor],
-        opaque: bool,
-        external: &'a Option<(EcoString, EcoString, SrcSpan)>,
+        type_: &'a TypedCustomType,
         imports: &mut Imports<'_>,
     ) -> Vec<Document<'a>> {
+        let CustomType {
+            publicity,
+            constructors,
+            opaque,
+            name,
+            typed_parameters,
+            external_javascript,
+            ..
+        } = type_;
+
         // Constructors for opaque and private types are not exported
-        let constructor_publicity = if opaque {
+        let constructor_publicity = if publicity.is_private() || *opaque {
             Publicity::Private
         } else {
             Publicity::Public
@@ -469,7 +459,7 @@ impl<'a> TypeScriptGenerator<'a> {
             .collect_vec();
 
         let definition = if constructors.is_empty() {
-            if let Some((module, external_name, _location)) = external {
+            if let Some((module, external_name, _location)) = external_javascript {
                 let member = Member {
                     name: external_name.to_doc(),
                     alias: Some(eco_format!("{name}$").to_doc()),
@@ -491,13 +481,13 @@ impl<'a> TypeScriptGenerator<'a> {
             join(constructors, break_("| ", " | "))
         };
 
-        definitions.push(docvec![
-            "export type ",
-            type_name.clone(),
-            " = ",
-            definition,
-            ";",
-        ]);
+        let head = if publicity.is_private() {
+            "type "
+        } else {
+            "export type "
+        };
+
+        definitions.push(docvec![head, type_name.clone(), " = ", definition, ";",]);
 
         // Generate getters for fields shared between variants
         if let Some(accessors_map) = self.module.type_info.accessors.get(name)

test-package-compiler/src/snapshots/test_package_compiler__generated_tests__import_shadowed_name_warning.snap

@@ -36,6 +36,7 @@ expression: "./cases/import_shadowed_name_warning"
 -compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
 -define(FILEPATH, "src/two.gleam").
 -export([use_type/1]).
+-export_type([shadowing/0]).
 
 -if(?OTP_RELEASE >= 27).
 -define(MODULEDOC(Str), -moduledoc(Str)).
@@ -47,6 +48,8 @@ expression: "./cases/import_shadowed_name_warning"
 
 ?MODULEDOC(" https://github.com/gleam-lang/otp/pull/22\n").
 
+-type shadowing() :: port.
+
 -file("src/two.gleam", 14).
 -spec use_type(one:port_()) -> nil.
 use_type(Port) ->