Generic enums with concrete type aliases

[nightscape]

Changes

Fixes #2252

The idea of this PR is to be able to do something like this:

pub enum Change<T> {
    Created { data: T },
    Updated { id: String, data: T },
    Deleted { id: String },
}

pub type StringChange = Change<String>;
pub type MapChange = Change<HashMap<String, String>>;

Procedure and Checklist

In order to quickly iterate and avoid slowing down development pace by making CI pass, only the following simplified steps are needed, and I (fzyzcjy) will handle the rest of CI / moving the tests currently (will have more automation in the future).

• Implement the feature / fix the bug.
• Add tests in frb_example/dart_minimal.
• Make dart_minimal's CI green.

Utility commands

• Run codegen: cargo run --manifest-path /path/to/flutter_rust_bridge/frb_codegen/Cargo.toml -- generate
• Run tests: ./frb_internal test-dart-native --package frb_example/dart_minimal

[codecov]

Codecov Report

❌ Patch coverage is 0.16026% with 623 lines in your changes missing coverage. Please review.
✅ Project coverage is 1.83%. Comparing base (67bfaec) to head (ee99ac3).

Files with missing lines	Patch %	Lines
.../codegen/parser/mir/parser/ty/type_substitution.rs	0.00%	174 Missing ⚠️
...ibrary/codegen/parser/mir/parser/ty/enumeration.rs	0.00%	125 Missing ⚠️
.../library/codegen/parser/mir/parser/ty/structure.rs	0.00%	122 Missing ⚠️
...gen/src/library/codegen/parser/mir/parser/ty/ty.rs	0.00%	86 Missing ⚠️
...rc/library/utils/dart_repository/dart_toolchain.rs	0.00%	16 Missing ⚠️
...c/library/codegen/parser/mir/parser/ty/generics.rs	0.00%	15 Missing ⚠️
...b_codegen/src/library/codegen/ir/mir/ty/generic.rs	0.00%	13 Missing ⚠️
...ary/codegen/parser/mir/parser/ty/enum_or_struct.rs	0.00%	13 Missing ⚠️
...en/src/library/codegen/parser/mir/parser/ty/mod.rs	0.00%	8 Missing ⚠️
...rc/library/codegen/parser/mir/parser/extra_type.rs	0.00%	7 Missing ⚠️
... and 16 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #2933       +/-   ##
==========================================
- Coverage   98.57%   1.83%   -96.75%     
==========================================
  Files         464     363      -101     
  Lines       19202   14525     -4677     
==========================================
- Hits        18928     266    -18662     
- Misses        274   14259    +13985     

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[fzyzcjy]

Great job! Feel free to ping me if need any suggestions

[nightscape]

@fzyzcjy I've made a few more fixes and it works reliably now for my use case.
Would you mind having a look?

[Copilot]

Pull request overview

This PR implements support for generic enums with concrete type aliases in flutter_rust_bridge, enabling developers to define a generic enum template and instantiate it with specific types through type aliases. The feature allows both visible generic enums (e.g., ChangeTwinNormal<T>) and ignored generic enum templates (e.g., ChangeIgnoredTwinNormal<T> with #[frb(ignore)]) that can be instantiated via #[frb(non_opaque)] type aliases.

Key Changes:

• Added generic enum support with type alias instantiation across multiple test variants (Normal, Sync, SSE, RustAsync, RustAsyncSSE)
• Generated comprehensive Dart code for enum variants with freezed classes
• Added test cases covering identity functions, nested generics in StreamSink, and struct wrappers
• Updated dependency versions in pubspec.lock files

Reviewed changes

Copilot reviewed 83 out of 96 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
frb_example/pure_dart/rust/src/api/enumeration.rs	Implements generic enum ChangeTwinNormal<T> with String and HashMap type aliases, plus ignored template pattern with ChangeIgnoredTwinNormal<T>
frb_example/pure_dart/rust/src/api/pseudo_manual/enumeration_twin_*.rs	Adds ChangeTwin*<T> generic enums with String type aliases across all test variants (Sync, SSE, RustAsync, RustAsyncSSE)
frb_example/pure_dart/test/api/enumeration_test.dart	Adds comprehensive tests for generic enum functionality including identity functions, nested generics in StreamSink, and batch/struct wrappers
frb_example/pure_dart/lib/src/rust/api/enumeration.dart	Generated Dart API with freezed classes for all concrete enum instantiations (ChangeStringTwinNormal, ChangeMapTwinNormal, etc.)
frb_example/pure_dart/rust/src/frb_generated.rs	Generated bridge code with codec implementations, wire functions, and type conversions for the new generic enum types
tools/frb_internal/pubspec.lock, frb_example/rust_ui_*/pubspec.lock	Updated Dart SDK and package dependencies
frb_example/dart_minimal/rust/src/frb_generated.rs	Removed clippy::uninlined_format_args lint suppression

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[fzyzcjy]

Excellent job!

[fzyzcjy]

BatchTwinNormal?

[fzyzcjy]

maybe AnotherBatchTwiNormal

[fzyzcjy]

Before digging into details, I wonder whether it will generalize to generic structs (seems you add some fields to struct logic, but there are no tests yet)

[rlch]

Thinking of investigating this myself. This would be really useful

[fzyzcjy]

Totally agree!