From 637bf968d1c2e60c6d51b10550233971424a0c6d Mon Sep 17 00:00:00 2001
From: ncave <777696+ncave@users.noreply.github.com>
Date: Thu, 26 Sep 2024 16:32:38 -0700
Subject: [PATCH] [Rust] Uncurry field types for object expressions

---
 src/Fable.Cli/CHANGELOG.md                    |  1 +
 src/Fable.Transforms/Rust/Fable2Rust.fs       |  5 ++++-
 .../src/FSharp.Collections.fs                 | 21 +++++++++++++++++++
 .../src/Fable.Library.Rust.fsproj             |  1 +
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 src/fable-library-rust/src/FSharp.Collections.fs

diff --git a/src/Fable.Cli/CHANGELOG.md b/src/Fable.Cli/CHANGELOG.md
index ac3912d10..9f8d4e6ed 100644
--- a/src/Fable.Cli/CHANGELOG.md
+++ b/src/Fable.Cli/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 * [GH-3900](https://github.com/fable-compiler/Fable/pull/3900) [Python] Fix nuget packages with hypens in their names  (by @MangelMaxime)
+* [Rust] Uncurry field types for object expressions (by @ncave)
 
 ## 4.21.0 - 2024-09-19
 
diff --git a/src/Fable.Transforms/Rust/Fable2Rust.fs b/src/Fable.Transforms/Rust/Fable2Rust.fs
index 4cc629912..6d936c8b8 100644
--- a/src/Fable.Transforms/Rust/Fable2Rust.fs
+++ b/src/Fable.Transforms/Rust/Fable2Rust.fs
@@ -2116,7 +2116,10 @@ module Util =
                     memberDecl
                 )
 
-            let fieldIdents = fieldsMap.Values |> Seq.toList
+            let fieldIdents =
+                fieldsMap.Values
+                |> Seq.map (fun ident -> { ident with Type = FableTransforms.uncurryType ident.Type })
+                |> Seq.toList
 
             let fields =
                 fieldIdents
diff --git a/src/fable-library-rust/src/FSharp.Collections.fs b/src/fable-library-rust/src/FSharp.Collections.fs
new file mode 100644
index 000000000..1a5573fd5
--- /dev/null
+++ b/src/fable-library-rust/src/FSharp.Collections.fs
@@ -0,0 +1,21 @@
+namespace FSharp.Collections
+
+open System.Collections.Generic
+
+module HashIdentity =
+    let FromFunctions<'T> hasher equals : IEqualityComparer<'T> =
+        EqualityComparer<'T>.Create(equals, hasher)
+
+    let Structural<'T when 'T: equality> : IEqualityComparer<'T> =
+        EqualityComparer<'T>
+            .Create(LanguagePrimitives.GenericEquality, LanguagePrimitives.GenericHash)
+
+    let Reference<'T when 'T: not struct> : IEqualityComparer<'T> =
+        EqualityComparer<'T>
+            .Create(LanguagePrimitives.PhysicalEquality, LanguagePrimitives.PhysicalHash)
+
+module ComparisonIdentity =
+    let FromFunction<'T> comparer : IComparer<'T> = Comparer<'T>.Create(comparer)
+
+    let Structural<'T when 'T: comparison> : IComparer<'T> =
+        Comparer<'T>.Create(LanguagePrimitives.GenericComparison)
diff --git a/src/fable-library-rust/src/Fable.Library.Rust.fsproj b/src/fable-library-rust/src/Fable.Library.Rust.fsproj
index 1365dbd30..2e7c8e0b5 100644
--- a/src/fable-library-rust/src/Fable.Library.Rust.fsproj
+++ b/src/fable-library-rust/src/Fable.Library.Rust.fsproj
@@ -18,6 +18,7 @@
     <Compile Include="Choice.fs" />
     <Compile Include="Util.fs" />
     <Compile Include="FSharp.Control.fs" />
+    <Compile Include="FSharp.Collections.fs" />
     <Compile Include="System.fs" />
     <Compile Include="System.Collections.Generic.fs" />
     <Compile Include="System.Text.fs" />