From 744b8bed5564af97d37610cc135a8db3910379a9 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:21:04 +0200
Subject: [PATCH 01/19] chore: migrate to .NET SDK `10.0.401`

Update `Microsoft.SourceLink.GitHub` to `10.0.401` together with the SDK it ships with.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Directory.Packages.props | 2 +-
 global.json              | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Directory.Packages.props b/Directory.Packages.props
index 5639be71..02ec46b3 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -25,7 +25,7 @@
     <PackageVersion Include="Fake.IO.FileSystem" Version="6.1.4" />
     <PackageVersion Include="Fake.Tools.Git" Version="6.1.4" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
-    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.300" />
+    <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.401" />
     <PackageVersion Include="MSTest" Version="4.2.3" />
     <PackageVersion Include="NuGet.Common" Version="7.6.0" />
     <PackageVersion Include="NuGet.Protocol" Version="7.6.0" />
diff --git a/global.json b/global.json
index 70c8f035..d3238643 100644
--- a/global.json
+++ b/global.json
@@ -1,6 +1,6 @@
 {
   "sdk": {
-    "version": "10.0.300",
+    "version": "10.0.401",
     "rollForward": "latestMinor"
   },
   "test": {

From d0e89dc8ab84020da8787e7e93d47bdc581a160f Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:21:29 +0200
Subject: [PATCH 02/19] chore: align script line endings between .gitattributes
 and .editorconfig

Batch files are checked out with CRLF and PowerShell scripts with LF on every platform,
and `.editorconfig` states the same instead of asking for CRLF in PowerShell scripts.

The inline comments of `.editorconfig` move onto their own lines:
the specification does not support inline comments, so they were read as part of the value.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .editorconfig  | 22 ++++++++++++++--------
 .gitattributes |  6 ++++++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/.editorconfig b/.editorconfig
index 869005af..656982fe 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -1,5 +1,5 @@
-# EditorConfig is awesome:
-http://EditorConfig.org
+# EditorConfig is awesome: https://EditorConfig.org
+# Comments must be on their own lines: the specification does not support inline comments
 
 # top-most EditorConfig file
 root = true
@@ -8,7 +8,8 @@ root = true
 # Core EditorConfig Options   #
 ###############################
 # All files
-[*]                            # Do not apply to all files not to break something
+# Do not apply to all files not to break something
+[*]
 guidelines = 120 dashed, 130
 # Either crlf | lf, default is system-dependent (when not specified at all)
 # end_of_line=crlf
@@ -22,8 +23,10 @@ indent_style = tab
 [*.{cs,csx,fs,fsi,fsx}]
 trim_trailing_whitespace = true
 insert_final_newline     = true
-indent_style             = space # default=space
-indent_size              = 4     # default=4
+# default=space
+indent_style             = space
+# default=4
+indent_size              = 4
 charset                  = utf-8
 
 # Project files and app specific XML files
@@ -42,7 +45,8 @@ indent_size              = 2
 
 # XML files
 [*.xml]
-trim_trailing_whitespace = false # do not trim as it affects CData
+# do not trim as it affects CData
+trim_trailing_whitespace = false
 insert_final_newline     = true
 indent_style             = space
 indent_size              = 2
@@ -70,12 +74,14 @@ trim_trailing_whitespace = false
 end_of_line              = lf
 
 # Batch Files
+# keep in sync with .gitattributes
 [*.{cmd,bat}]
 end_of_line              = crlf
 
 # Powershell Files
-[*.{ps1, psm1}]
-end_of_line              = crlf
+# keep in sync with .gitattributes
+[*.{ps1,psm1}]
+end_of_line              = lf
 
 # Paket files
 [paket.*]
diff --git a/.gitattributes b/.gitattributes
index cb6f883d..df5e1a85 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -13,6 +13,12 @@
 *.fsproj merge=union
 *.dbproj merge=union
 *.sh text eol=lf
+# cmd.exe misreads labels and goto in LF batch files
+*.cmd text eol=crlf
+*.bat text eol=crlf
+# LF keeps the `#!/usr/bin/env pwsh` shebang working on Linux; PowerShell on Windows reads LF too
+*.ps1 text eol=lf
+*.psm1 text eol=lf
 
 # Standard to msysgit
 *.doc diff=astextplain

From b6a4273e26dd6b6451ae8cb824c6e936f0b304d7 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:21:38 +0200
Subject: [PATCH 03/19] chore(deps): update Fantomas to `8.0.5`

`.editorconfig` follows the settings of Fantomas 8:

- `fsharp_keep_indent_in_branch` became `fsharp_experimental_keep_indent_in_branch`;
  under its old name the setting was ignored.
- `fsharp_semicolon_at_end_of_line` and `fsharp_max_dot_get_expression_width` no longer exist.
- `end_of_line=lf` matches the line endings `.gitattributes` stores F# files with,
  so formatting on Windows no longer rewrites them as CRLF.

The comments state the current defaults and link to the current documentation.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .config/dotnet-tools.json |  2 +-
 .editorconfig             | 43 +++++++++++++++++----------------------
 2 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/.config/dotnet-tools.json b/.config/dotnet-tools.json
index 3c0225ff..9d1a9673 100644
--- a/.config/dotnet-tools.json
+++ b/.config/dotnet-tools.json
@@ -17,7 +17,7 @@
       "rollForward": false
     },
     "fantomas": {
-      "version": "7.0.2",
+      "version": "8.0.5",
       "commands": [
         "fantomas"
       ],
diff --git a/.editorconfig b/.editorconfig
index 656982fe..c4537e1f 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -111,16 +111,12 @@ indent_size=4
 max_line_length=130
 
 # Either crlf | lf, default is system-dependent (when not specified at all)
-# end_of_line=crlf
+# lf matches the eol .gitattributes stores F# files with, so formatting does not touch line endings
+end_of_line=lf
 
 # Whether end-of-file has a newline, default=true
 insert_final_newline=true
 
-# false: someLineOfCode
-# true: someLineOfCode;
-# default false
-fsharp_semicolon_at_end_of_line=false
-
 # false: f(1,2)
 # true: f(1, 2)
 # default true
@@ -141,8 +137,8 @@ fsharp_space_before_uppercase_invocation=true
 # default false
 fsharp_space_before_class_constructor=true
 
-# false: __.member Foo(x) = x
-# true: __.member Foo (x) = x
+# false: member this.Foo(x) = x
+# true: member this.Foo (x) = x
 # default false
 fsharp_space_before_member=true
 
@@ -166,18 +162,18 @@ fsharp_space_before_semicolon=false
 # default true
 fsharp_space_after_semicolon=true
 
-# false: let a = [1;2;3]
-# true: let a = [ 1;2;3 ]
+# false: let a = [1; 2; 3]
+# true: let a = [ 1; 2; 3 ]
 # default true
 fsharp_space_around_delimiter=true
 
 # breaks an if-then-else in smaller parts if it is on one line
-# default 40
+# default 60
 fsharp_max_if_then_else_short_width=60
 
 # breaks an infix operator expression if it is on one line
 # infix: a + b + c
-# default 50
+# default 80
 fsharp_max_infix_operator_expression=60
 
 # breaks a single-line record declaration
@@ -198,7 +194,7 @@ fsharp_max_record_number_of_items=1
 fsharp_record_multiline_formatter=character_width
 
 # breaks a single line array or list if it exceeds this size
-# default 40
+# default 80
 fsharp_max_array_or_list_width=100
 
 # breaks an array or list into one item per line if items exceeds this number
@@ -213,7 +209,7 @@ fsharp_max_array_or_list_number_of_items=1
 # default character_width
 fsharp_array_or_list_multiline_formatter=character_width
 
-# maximum with of a value binding, does not include keyword "let"
+# maximum width of a value binding, does not include keyword "let"
 # default 80
 fsharp_max_value_binding_width=100
 
@@ -221,10 +217,6 @@ fsharp_max_value_binding_width=100
 # default 40
 fsharp_max_function_binding_width=80
 
-# maximum width for expressions like X.DoY().GetZ(10).Help()
-# default 50
-fsharp_max_dot_get_expression_width=80
-
 # whether open/close brackets go on the same column
 # cramped:    type Range =
 #               { From: float
@@ -238,10 +230,10 @@ fsharp_max_dot_get_expression_width=80
 #                 From: float
 #                 To: float
 #             }
-# default cramped
+# default aligned
 fsharp_multiline_bracket_style=stroustrup
 
-# whether to move the beginning of compuitation expression to the new line
+# whether to move the beginning of computation expression to the new line
 # true:  let x =
 #            computation {
 #                ...
@@ -249,6 +241,7 @@ fsharp_multiline_bracket_style=stroustrup
 # false: let x = computation {
 #            ..
 #        }
+# default true
 fsharp_newline_before_multiline_computation_expression=false
 
 # whether a newline should be placed before members
@@ -259,7 +252,7 @@ fsharp_newline_before_multiline_computation_expression=false
 #            { From: float }
 #
 #            member this.Length = this.To - this.From
-# default false
+# default true
 fsharp_newline_between_type_definition_and_members=true
 
 # if a function sign exceeds max_line_length, then:
@@ -268,7 +261,7 @@ fsharp_newline_between_type_definition_and_members=true
 # default false
 fsharp_align_function_signature_to_indentation=false
 
-# see docs: https://github.com/fsprojects/fantomas/blob/master/docs/Documentation.md#fsharp_alternative_long_member_definitions
+# see docs: https://fsprojects.github.io/fantomas/docs/end-users/Configuration.html#fsharp_alternative_long_member_definitions
 # default false
 fsharp_alternative_long_member_definitions=true
 
@@ -276,7 +269,8 @@ fsharp_alternative_long_member_definitions=true
 # default false
 fsharp_multi_line_lambda_closing_newline=true
 
-# allows the 'else'-branch to be aligned at same level as 'else' if the ret type allows it
+# keeps the last branch of if/then/else or match at the same indentation as the expression (early-return style)
+# see docs: https://fsprojects.github.io/fantomas/docs/end-users/Configuration.html#fsharp_experimental_keep_indent_in_branch
 # false: match x with
 #        | null -> ()
 #        | _ -> ()
@@ -285,7 +279,7 @@ fsharp_multi_line_lambda_closing_newline=true
 #        | _ ->
 #        ()
 # default false
-fsharp_keep_indent_in_branch=true
+fsharp_experimental_keep_indent_in_branch=true
 
 # whether a bar is placed before DU
 # false: type MyDU = Short of int
@@ -299,4 +293,5 @@ fsharp_blank_lines_around_nested_multiline_expressions=false
 
 # set maximal number of consecutive blank lines to keep from original source
 # it doesn't change number of new blank lines generated by Fantomas
+# default 100
 fsharp_keep_max_number_of_blank_lines=2

From 0f8c45b005dc4b65a676ce59678474e6b951bc5d Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:22:04 +0200
Subject: [PATCH 04/19] style: reformat with Fantomas `8.0.5`

Fantomas 8 no longer puts a space between a type application and its argument list:
`Create<'T> ()` becomes `Create<'T>()`. Whitespace only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 build/Changelog.fs                            |  2 +-
 build/build.fs                                |  2 +-
 src/FSharp.Collections.Immutable/FlatList.fs  | 24 +++++++++----------
 .../ImmutableList.fs                          |  4 ++--
 src/FSharp.Collections.Immutable/Maps.fs      | 12 +++++-----
 src/FSharp.Collections.Immutable/Queue.fs     |  4 ++--
 src/FSharp.Collections.Immutable/Sets.fs      | 12 +++++-----
 src/FSharp.Collections.Immutable/Stack.fs     |  2 +-
 8 files changed, 31 insertions(+), 31 deletions(-)

diff --git a/build/Changelog.fs b/build/Changelog.fs
index 308013c5..7026b3de 100644
--- a/build/Changelog.fs
+++ b/build/Changelog.fs
@@ -64,7 +64,7 @@ let mkReleaseNotes changelog (latestEntry : Changelog.ChangelogEntry) gitHubRepo
             | Some desc when desc.Contains (linkReference) -> desc
             | Some desc -> sprintf "%s\n\n%s" (desc.Trim ()) linkReference
 
-        { latestEntry with Description = Some description }.ToString ()
+        { latestEntry with Description = Some description }.ToString()
 
 let getVersionNumber envVarName ctx =
     let args = ctx.Context.Arguments
diff --git a/build/build.fs b/build/build.fs
index 441de3e0..bad1b6f1 100644
--- a/build/build.fs
+++ b/build/build.fs
@@ -338,7 +338,7 @@ let dotnetBuild ctx =
         sln
 
 let fsharpAnalyzers _ =
-    let argParser = ArgumentParser.Create<FSharpAnalyzers.Arguments> (programName = "fsharp-analyzers")
+    let argParser = ArgumentParser.Create<FSharpAnalyzers.Arguments>(programName = "fsharp-analyzers")
 
     !!srcGlob
     |> Seq.iter (fun proj ->
diff --git a/src/FSharp.Collections.Immutable/FlatList.fs b/src/FSharp.Collections.Immutable/FlatList.fs
index 82bcce74..b6153265 100644
--- a/src/FSharp.Collections.Immutable/FlatList.fs
+++ b/src/FSharp.Collections.Immutable/FlatList.fs
@@ -23,8 +23,8 @@ module FlatList =
 
     ////////// Creating //////////
 
-    let inline empty<'T> : FlatList<_> = FlatListFactory.Create<'T> ()
-    let inline singleton<'T> (item : 'T) : FlatList<'T> = FlatListFactory.Create<'T> (item)
+    let inline empty<'T> : FlatList<_> = FlatListFactory.Create<'T>()
+    let inline singleton<'T> (item : 'T) : FlatList<'T> = FlatListFactory.Create<'T>(item)
 
     let inline ofSeq source = FlatListFactory.CreateRange source
     let inline ofArray (source : _ array) = FlatListFactory.CreateRange source
@@ -234,7 +234,7 @@ module FlatList =
     let iter2 action list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<'T, 'U, unit>.Adapt (action)
+        let f = OptimizedClosures.FSharpFunc<'T, 'U, unit>.Adapt(action)
         let len = length list1
 
         if len <> length list2 then
@@ -245,7 +245,7 @@ module FlatList =
 
     let distinctBy projection (list : FlatList<'T>) =
         let builder : FlatList<'T>.Builder = builderWith <| length list
-        let set = System.Collections.Generic.HashSet<'Key> (HashIdentity.Structural)
+        let set = System.Collections.Generic.HashSet<'Key>(HashIdentity.Structural)
         let mutable outputIndex = 0
 
         for i = 0 to length list - 1 do
@@ -260,7 +260,7 @@ module FlatList =
     let map2 mapping list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt (mapping)
+        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt(mapping)
         let len1 = list1.Length
 
         if len1 <> list2.Length then
@@ -277,7 +277,7 @@ module FlatList =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
         checkNotDefault (nameof list3) list3
-        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt (mapping)
+        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt(mapping)
         let len1 = list1.Length
 
         if not (len1 = list2.Length) then
@@ -296,7 +296,7 @@ module FlatList =
     let mapi2 mapping list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt (mapping)
+        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt(mapping)
         let len1 = list1.Length
 
         if len1 <> list2.Length then
@@ -311,7 +311,7 @@ module FlatList =
 
     let iteri action list =
         check list
-        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt (action)
+        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt(action)
         let len = list.Length
 
         for i = 0 to len - 1 do
@@ -320,7 +320,7 @@ module FlatList =
     let iteri2 action list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt (action)
+        let f = OptimizedClosures.FSharpFunc<_, _, _, _>.Adapt(action)
         let len1 = list1.Length
 
         if len1 <> list2.Length then
@@ -331,7 +331,7 @@ module FlatList =
 
     let mapi mapping list =
         check list
-        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt (mapping)
+        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt(mapping)
         let len = list.Length
         let res = builderWithLengthOf list
 
@@ -360,7 +360,7 @@ module FlatList =
     let exists2 predicate list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt (predicate)
+        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt(predicate)
         let len1 = list1.Length
 
         if len1 <> list2.Length then
@@ -381,7 +381,7 @@ module FlatList =
     let forall2 predicate list1 list2 =
         checkNotDefault (nameof list1) list1
         checkNotDefault (nameof list2) list2
-        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt (predicate)
+        let f = OptimizedClosures.FSharpFunc<_, _, _>.Adapt(predicate)
         let len1 = list1.Length
 
         if len1 <> list2.Length then
diff --git a/src/FSharp.Collections.Immutable/ImmutableList.fs b/src/FSharp.Collections.Immutable/ImmutableList.fs
index 48ced7c7..6683f84a 100644
--- a/src/FSharp.Collections.Immutable/ImmutableList.fs
+++ b/src/FSharp.Collections.Immutable/ImmutableList.fs
@@ -14,8 +14,8 @@ module ImmutableList =
 
     let inline internal check (list : IImmutableList<_>) = checkNotNull (nameof list) list
 
-    let inline empty<'T> = ImmutableList.Create<'T> ()
-    let inline singleton<'T> (item : 'T) : ImmutableList<'T> = ImmutableList.Create<'T> (item)
+    let inline empty<'T> = ImmutableList.Create<'T>()
+    let inline singleton<'T> (item : 'T) : ImmutableList<'T> = ImmutableList.Create<'T>(item)
 
     let inline ofSeq source =
         checkNotNull (nameof source) source
diff --git a/src/FSharp.Collections.Immutable/Maps.fs b/src/FSharp.Collections.Immutable/Maps.fs
index 12f5d638..7a73565a 100644
--- a/src/FSharp.Collections.Immutable/Maps.fs
+++ b/src/FSharp.Collections.Immutable/Maps.fs
@@ -19,7 +19,7 @@ module HashMap =
 
     ////////// Creating //////////
 
-    let inline empty<'Key, 'Value when 'Key : not null> = HashMapFactory.Create<'Key, 'Value> ()
+    let inline empty<'Key, 'Value when 'Key : not null> = HashMapFactory.Create<'Key, 'Value>()
     let inline singleton item = empty.Add (item)
 
     let inline ofSeq source = HashMapFactory.CreateRange (source)
@@ -57,9 +57,9 @@ module HashMap =
         check map
         map.ToBuilder ()
 
-    let inline ofKeyComparer<'Key, 'Value when 'Key : not null> comparer = HashMapFactory.Create<'Key, 'Value> (comparer)
+    let inline ofKeyComparer<'Key, 'Value when 'Key : not null> comparer = HashMapFactory.Create<'Key, 'Value>(comparer)
     let inline ofComparers<'Key, 'Value when 'Key : not null> keyComparer valueComparer =
-        HashMapFactory.Create<'Key, 'Value> (keyComparer, valueComparer)
+        HashMapFactory.Create<'Key, 'Value>(keyComparer, valueComparer)
 
 
     let inline isEmpty map =
@@ -178,7 +178,7 @@ module SortedMap =
 
     ////////// Creating //////////
 
-    let inline empty<'Key, 'Value when 'Key : not null> = SortedMapFactory.Create<'Key, 'Value> ()
+    let inline empty<'Key, 'Value when 'Key : not null> = SortedMapFactory.Create<'Key, 'Value>()
     let inline singleton item = SortedMapFactory.Create (item)
 
     let inline ofSeq source = SortedMapFactory.CreateRange (source)
@@ -215,9 +215,9 @@ module SortedMap =
         check map
         map.ToBuilder ()
 
-    let inline ofKeyComparer<'Key, 'Value when 'Key : not null> comparer = SortedMapFactory.Create<'Key, 'Value> (comparer)
+    let inline ofKeyComparer<'Key, 'Value when 'Key : not null> comparer = SortedMapFactory.Create<'Key, 'Value>(comparer)
     let inline ofComparers<'Key, 'Value when 'Key : not null> keyComparer valueComparer =
-        SortedMapFactory.Create<'Key, 'Value> (keyComparer, valueComparer)
+        SortedMapFactory.Create<'Key, 'Value>(keyComparer, valueComparer)
 
 
     let inline isEmpty map =
diff --git a/src/FSharp.Collections.Immutable/Queue.fs b/src/FSharp.Collections.Immutable/Queue.fs
index dd8d64fe..ba9d1f39 100644
--- a/src/FSharp.Collections.Immutable/Queue.fs
+++ b/src/FSharp.Collections.Immutable/Queue.fs
@@ -13,9 +13,9 @@ module Queue =
 
     let inline private check (queue : IQueue<_>) = checkNotNull (nameof queue) queue
 
-    let inline empty<'T> : Queue<'T> = QueueFactory.Create<'T> ()
+    let inline empty<'T> : Queue<'T> = QueueFactory.Create<'T>()
 
-    let inline singleton<'T> (item : 'T) : Queue<'T> = QueueFactory.Create<'T> (item)
+    let inline singleton<'T> (item : 'T) : Queue<'T> = QueueFactory.Create<'T>(item)
 
     let inline ofSeq (source : 'T seq) : Queue<'T> = QueueFactory.CreateRange source
 
diff --git a/src/FSharp.Collections.Immutable/Sets.fs b/src/FSharp.Collections.Immutable/Sets.fs
index cbdba229..8d94e56e 100644
--- a/src/FSharp.Collections.Immutable/Sets.fs
+++ b/src/FSharp.Collections.Immutable/Sets.fs
@@ -16,8 +16,8 @@ module HashSet =
 
     ////////// Creating //////////
 
-    let inline empty<'T> = HashSetFactory.Create<'T> ()
-    let inline singleton<'T> (item : 'T) = HashSetFactory.Create<'T> (item)
+    let inline empty<'T> = HashSetFactory.Create<'T>()
+    let inline singleton<'T> (item : 'T) = HashSetFactory.Create<'T>(item)
     let inline ofSeq source = HashSetFactory.CreateRange (source)
     let inline ofSeqWithComparer comparer source = HashSetFactory.Create (comparer, items = (source |> Array.ofSeq))
     let inline ofArray (source : _ array) = HashSetFactory.CreateRange (source)
@@ -26,7 +26,7 @@ module HashSet =
         checkNotNull (nameof hashSetBuilder) hashSetBuilder
         hashSetBuilder.ToImmutable ()
 
-    let inline ofComparer<'T> comparer = HashSetFactory.Create<'T> (equalityComparer = comparer)
+    let inline ofComparer<'T> comparer = HashSetFactory.Create<'T>(equalityComparer = comparer)
 
     let inline toSeq (set : HashSet<_>) = set :> seq<_>
 
@@ -149,8 +149,8 @@ module SortedSet =
 
     ////////// Creating //////////
 
-    let inline empty<'T> = SortedSetFactory.Create<'T> ()
-    let inline singleton<'T> (item : 'T) = SortedSetFactory.Create<'T> (item)
+    let inline empty<'T> = SortedSetFactory.Create<'T>()
+    let inline singleton<'T> (item : 'T) = SortedSetFactory.Create<'T>(item)
     let inline ofSeq source = SortedSetFactory.CreateRange (source)
     let inline ofSeqWithComparer comparer source = SortedSetFactory.Create (comparer, items = (source |> Array.ofSeq))
     let inline ofArray (source : _ array) = SortedSetFactory.CreateRange (source)
@@ -159,7 +159,7 @@ module SortedSet =
         checkNotNull (nameof sortedSetBuilder) sortedSetBuilder
         sortedSetBuilder.ToImmutable ()
 
-    let inline ofComparer<'T> comparer = SortedSetFactory.Create<'T> (comparer = comparer)
+    let inline ofComparer<'T> comparer = SortedSetFactory.Create<'T>(comparer = comparer)
 
     let inline toSeq (set : SortedSet<_>) = set :> seq<_>
 
diff --git a/src/FSharp.Collections.Immutable/Stack.fs b/src/FSharp.Collections.Immutable/Stack.fs
index a9502e53..774ad6b5 100644
--- a/src/FSharp.Collections.Immutable/Stack.fs
+++ b/src/FSharp.Collections.Immutable/Stack.fs
@@ -12,7 +12,7 @@ module Stack =
 
     let inline internal check (stack : IStack<_>) = checkNotNull (nameof stack) stack
 
-    let inline empty<'T> = StackFactory.Create<'T> ()
+    let inline empty<'T> = StackFactory.Create<'T>()
 
     let inline ofSeq source = StackFactory.CreateRange source
 

From 0e1b6c07387d75cfeddaf62a3eea860e866509f3 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:23:34 +0200
Subject: [PATCH 05/19] fix(build): restore tools before restore and format
 each project once

`ToolRestore` ran only in design-time builds, so a command-line build relied on the FAKE
`DotnetToolRestore` target, and that target was a dependency of `BuildDocs` alone:
on CI `CheckFormatCode` found no Fantomas and passed without checking anything.
`ToolRestore` now runs before every restore, and the FAKE target is gone.

`ToolUpdate` is removed: its `Outputs` used an undefined property, so MSBuild always skipped it.

Formatting is delegated to one instance of a project without a target framework,
so a project is formatted once per build however many target frameworks it has,
and Fantomas runs twice because one pass is not always idempotent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Directory.Build.targets | 40 ++++++++++++++++------------------------
 build/build.fs          | 15 ---------------
 2 files changed, 16 insertions(+), 39 deletions(-)

diff --git a/Directory.Build.targets b/Directory.Build.targets
index 484ac5a1..cdec8ba6 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -11,36 +11,28 @@ See https://learn.microsoft.com/en-us/visualstudio/msbuild/customize-by-director
     <_DotnetFantomasOutputFile>$(BaseIntermediateOutputPath)dotnet-fantomas-msbuild-$(NETCoreSdkVersion)-$(OS)</_DotnetFantomasOutputFile>
   </PropertyGroup>
 
-  <!-- Make sure that dotnet tools are up to date before restoring any project -->
-  <Target Name="ToolUpdate"
-          BeforeTargets="ResolveNuGetPackageAssets;BeforeCompile"
-          Condition=" '$(BuildingProject)' == 'false' OR '$(DesignTimeBuild)' == 'true' "
-          Inputs="$(_DotnetToolManifestFile)"
-          Outputs="$(_DotnetToolUpdateOutputFile)">
-    <Message Text="Updating dotnet tools..." Importance="High" />
-    <Exec Command="dotnet tool update --all" WorkingDirectory="$(MSBuildThisFileDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" />
-    <MakeDir Directories="$(_BuildProjBaseIntermediateOutputPath)"/>
-    <Touch Files="$(_DotnetToolUpdateOutputFile)" AlwaysCreate="True" ForceTouch="True" />
-    <Message Text="All tools updated successfully. Updates marked as complete." Importance="High" />
-  </Target>
-
   <!-- Make sure that dotnet tools are restored before restoring any project -->
-  <Target Name="ToolRestore"
-          BeforeTargets="ResolveNuGetPackageAssets;BeforeCompile"
-          AfterTargets="ToolUpdate"
-          Condition=" '$(BuildingProject)' == 'false' OR '$(DesignTimeBuild)' == 'true' "
-          Inputs="$(_DotnetToolManifestFile)"
-          Outputs="$(_DotnetToolRestoreOutputFile)">
-    <Message Text="Restoring dotnet tools..." Importance="High" />
+  <Target Name="ToolRestore" BeforeTargets="Restore;CollectPackageReferences" Inputs="$(_DotnetToolManifestFile)" Outputs="$(_DotnetToolRestoreOutputFile)">
     <Exec Command="dotnet tool restore" WorkingDirectory="$(MSBuildThisFileDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" />
     <MakeDir Directories="$(_BuildProjBaseIntermediateOutputPath)"/>
     <Touch Files="$(_DotnetToolRestoreOutputFile)" AlwaysCreate="True" ForceTouch="True" />
-    <Message Text="All .NET tools restored successfully." Importance="High" />
   </Target>
 
-  <!-- Make sure that files are formatted before building -->
-  <Target Name="Format" Condition=" '$(MSBuildProjectExtension)' == '.fsproj' AND '$(DesignTimeBuild)' != 'true' " BeforeTargets="BeforeBuild" Inputs="@(Compile)" Outputs="$(_DotnetFantomasOutputFile)" >
-    <Exec Command="dotnet tool run fantomas $(MSBuildProjectDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" WorkingDirectory="$(MSBuildThisFileDirectory)" ContinueOnError="WarnAndContinue" />
+  <!--
+    Make sure that files are formatted before building.
+    A multi-targeted project builds its target frameworks in parallel, so formatting in each of them ran Fantomas
+    concurrently on the same files ("being used by another process") and raced on the marker file (MSB3371).
+    Every build of a project therefore delegates to one dedicated instance of it without a target framework.
+    MSBuild runs a target once per project instance, so a project is formatted once per build,
+    whether it is built from the solution, as a project reference or on its own.
+  -->
+  <Target Name="FormatBeforeBuild" Condition=" '$(MSBuildProjectExtension)' == '.fsproj' AND '$(DesignTimeBuild)' != 'true' " BeforeTargets="BeforeBuild">
+    <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="Format" Properties="_FantomasFormatInstance=true" RemoveProperties="TargetFramework;RuntimeIdentifier" />
+  </Target>
+
+  <Target Name="Format" Inputs="@(Compile)" Outputs="$(_DotnetFantomasOutputFile)">
+    <Exec Command="dotnet fantomas $(MSBuildProjectDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" WorkingDirectory="$(MSBuildThisFileDirectory)" ContinueOnError="WarnAndContinue" />
+    <Exec Command="dotnet fantomas $(MSBuildProjectDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" WorkingDirectory="$(MSBuildThisFileDirectory)" ContinueOnError="WarnAndContinue" />
     <Touch Files="$(_DotnetFantomasOutputFile)" AlwaysCreate="True" ForceTouch="True" />
   </Target>
 
diff --git a/build/build.fs b/build/build.fs
index bad1b6f1..fa184286 100644
--- a/build/build.fs
+++ b/build/build.fs
@@ -269,15 +269,6 @@ let dotnetRestore _ =
     )
     |> Seq.iter (retryIfInCI 10)
 
-let dotnetToolRestore _ =
-    let result =
-        fun () -> DotNet.exec id "tool" "restore"
-        |> (retryIfInCI 10)
-
-
-    if not result.OK then
-        failwithf "Failed to restore .NET tools: %A" result.Errors
-
 let updateChangelog ctx =
     latestEntry <-
         if not <| isPublishToGitHub ctx then
@@ -631,7 +622,6 @@ let initTargets (ctx : Context.FakeExecutionContext) =
 
     Target.create "Clean" clean
     Target.create "DotnetRestore" dotnetRestore
-    Target.create "DotnetToolRestore" dotnetToolRestore
     Target.create "UpdateChangelog" updateChangelog
     Target.createBuildFailure "RevertChangelog" revertChangelog // Do NOT put this in the dependency chain
     Target.createFinal "DeleteChangelogBackupFile" deleteChangelogBackupFile // Do NOT put this in the dependency chain
@@ -714,11 +704,6 @@ let initTargets (ctx : Context.FakeExecutionContext) =
 
     "DotnetRestore" ==>! "WatchTests"
 
-    //"DotnetToolRestore" ?=>! "DotnetRestore"
-    "DotnetToolRestore" ==>! "BuildDocs"
-    "DotnetToolRestore" ?=>! "CheckFormatCode"
-    "DotnetToolRestore" ?=>! "FormatCode"
-
 //-----------------------------------------------------------------------------
 // Target Start
 //-----------------------------------------------------------------------------

From e719a9bdc6671603f779189e614c9641e108c9b9 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:24:48 +0200
Subject: [PATCH 06/19] fix(build): collect coverage with the MSTest runner
 instead of the AltCover leftovers

`DotnetTest` passed `/p:AltCover*` properties although no project references AltCover,
and `GenerateCoverageReport` looked for `tests/**/coverage*.xml`, which nothing produced,
so `ENABLE_COVERAGE` collected no coverage.

`DotnetTest` now runs `dotnet test --project` for each test project and lets the MSTest runner
collect coverage with `--coverage --coverage-output-format cobertura` into `TestResults`,
where `GenerateCoverageReport` reads it and writes HTML and Cobertura reports.
Coverage is collected when `ENABLE_COVERAGE` is set or `GenerateCoverageReport` is among the targets.

Also:

- the release commit is named `release: bump version to ...`;
- `quoted` is shared by the test and the documentation targets;
- the workflows no longer explain `ENABLE_COVERAGE: false` with AltCover.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/workflows/publish_ci.yml      |  2 +-
 .github/workflows/publish_release.yml |  2 +-
 build/build.fs                        | 86 ++++++++++++++-------------
 3 files changed, 48 insertions(+), 42 deletions(-)

diff --git a/.github/workflows/publish_ci.yml b/.github/workflows/publish_ci.yml
index 34fd6ed3..e464e278 100644
--- a/.github/workflows/publish_ci.yml
+++ b/.github/workflows/publish_ci.yml
@@ -59,7 +59,7 @@ jobs:
           NUGET_TOKEN: ${{ secrets.NUGET_TOKEN }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           FAKE_DETAILED_ERRORS: true
-          ENABLE_COVERAGE: false # AltCover doesn't work with Release builds, reports lower coverage than actual
+          ENABLE_COVERAGE: false
         run: |
           chmod +x ./build.sh
           ./build.sh "PublishToGitHub"
diff --git a/.github/workflows/publish_release.yml b/.github/workflows/publish_release.yml
index 5598491d..6c399004 100644
--- a/.github/workflows/publish_release.yml
+++ b/.github/workflows/publish_release.yml
@@ -30,7 +30,7 @@ jobs:
           NUGET_TOKEN: ${{ secrets.NUGET_TOKEN }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           FAKE_DETAILED_ERRORS: true
-          ENABLE_COVERAGE: false # AltCover doesn't work with Release builds, reports lower coverage than actual
+          ENABLE_COVERAGE: false
         run: |
           chmod +x ./build.sh
           ./build.sh Publish
diff --git a/build/build.fs b/build/build.fs
index fa184286..50879292 100644
--- a/build/build.fs
+++ b/build/build.fs
@@ -145,12 +145,12 @@ let failOnWrongBranch () =
 
 
 module dotnet =
-    let watch cmdParam program args = DotNet.exec cmdParam (sprintf "watch %s" program) args
+    let watch cmdParam program args = DotNet.exec cmdParam $"watch %s{program}" args
 
     let run cmdParam args = DotNet.exec cmdParam "run" args
 
-    let tool optionConfig command args =
-        DotNet.exec optionConfig (sprintf "%s" command) args
+    let tool optionConfig (command : string) args =
+        DotNet.exec optionConfig command args
         |> failOnBadExitAndPrint
 
     let reportgenerator optionConfig args = tool optionConfig "reportgenerator" args
@@ -175,9 +175,9 @@ module FSharpAnalyzers =
             member s.Usage = ""
 
 
-module DocsTool =
-    let quoted s = $"\"%s{s}\""
+let quoted s = $"\"%s{s}\""
 
+module DocsTool =
     let fsDocsDotnetOptions (o : DotNet.Options) = { o with WorkingDirectory = rootDirectory }
 
     let fsDocsBuildParams configuration (p : Fsdocs.BuildCommandParams) = {
@@ -347,37 +347,37 @@ let fsharpAnalyzers _ =
     )
 
 let dotnetTest ctx =
-    let excludeCoverage =
-        !!testsGlob
-        |> Seq.map (IO.Path.GetFileNameWithoutExtension >> Unchecked.nonNull)
-        |> String.concat "|"
-
-    let isGenerateCoverageReportTarget =
-        String.Equals (ctx.Context.FinalTarget, "GenerateCoverageReport", StringComparison.OrdinalIgnoreCase)
-        || String.Equals (ctx.Context.FinalTarget, "ShowCoverageReport", StringComparison.OrdinalIgnoreCase)
-
-    let shouldCollectCoverage = enableCodeCoverage || isGenerateCoverageReportTarget
-
-    if shouldCollectCoverage then
-        Directory.create testResultsDir
-
-    let args =
-        [
-            "--no-build"
-            $"--configuration {configuration (ctx.Context.AllExecutingTargets)}"
-            if shouldCollectCoverage then
-                "/p:AltCover=true"
-                $"/p:AltCoverAssemblyExcludeFilter={excludeCoverage}"
-                "/p:AltCoverLocalSource=true"
-            $"--solution \"{sln}\""
-        ]
-        |> String.concat " "
+    // Create test results directory if it doesn't exist
+    Directory.create testResultsDir
+
+    let dotnetConfiguration = configuration (ctx.Context.AllExecutingTargets) |> string
+
+    let isGenerateCoverageReport = ctx.Context.TryFindTarget("GenerateCoverageReport").IsSome
+
+    let args = [
+        "--no-build"
+        "--configuration"
+        dotnetConfiguration
+        if enableCodeCoverage || isGenerateCoverageReport then
+            "--coverage"
+            "--coverage-output-format"
+            "cobertura"
+            "--results-directory"
+            quoted testResultsDir
+    ]
 
-    DotNet.exec (DotNet.Options.withWorkingDirectory rootDirectory) "test" args
-    |> failOnBadExitAndPrint
+    !!testsGlob
+    |> Seq.iter (fun testProject ->
+        [ "--project"; quoted testProject; yield! args ]
+        |> String.concat " "
+        |> DotNet.exec id "test"
+        |> failOnBadExitAndPrint
+    )
 
 let generateCoverageReport _ =
-    let coverageFiles = !!(rootDirectory </> "tests/**/coverage*.xml")
+    let coverageFiles =
+        !!(testResultsDir </> "*.cobertura.xml")
+        ++ (testResultsDir </> "*/coverage.cobertura.xml")
 
     let sourceDirs = !!srcGlob |> Seq.map Path.getDirectory |> String.concat ";"
 
@@ -386,9 +386,10 @@ let generateCoverageReport _ =
         sprintf "-targetdir:\"%s\"" coverageReportDir
         // Add source dir
         sprintf "-sourcedirs:\"%s\"" sourceDirs
-        // Ignore test assemblies and AltCover recorder helpers
-        sprintf "-assemblyfilters:\"%s\"" "-*.Tests;-AltCover.Recorder.g"
-        sprintf "-reporttypes:%s" "Html"
+        // Ignore test assemblies
+        sprintf "-assemblyfilters:\"%s\"" "-*.Tests"
+        // Generate HTML and Cobertura reports
+        sprintf "-reporttypes:%s" "Html;Cobertura"
     ]
 
     let args = independentArgs |> String.concat " "
@@ -436,7 +437,7 @@ let generateAssemblyInfo _ =
         | f when f.EndsWith ("fsproj") -> Fsproj
         | f when f.EndsWith ("csproj") -> Csproj
         | f when f.EndsWith ("vbproj") -> Vbproj
-        | _ -> failwith (sprintf "Project file %s not supported. Unknown project type." projFileName)
+        | _ -> failwithf "Project file %s not supported. Unknown project type." projFileName
 
     let releaseChannel =
         match latestEntry.SemVer.PreRelease with
@@ -530,7 +531,7 @@ let gitRelease _ =
     ++ (rootDirectory </> "tests/**/AssemblyInfo.fs")
     |> Seq.iter (Git.Staging.stageFile "" >> ignore)
 
-    let msg = $"Bump version to `%s{latestEntry.NuGetVersion}`\n\n%s{releaseNotesGitCommitFormat}"
+    let msg = $"release: bump version to `%s{latestEntry.NuGetVersion}`\n\n%s{releaseNotesGitCommitFormat}"
 
     Git.Commit.exec "" msg
 
@@ -606,10 +607,15 @@ let initTargets (ctx : Context.FakeExecutionContext) =
             && String.Equals (value, "PublishToGitHub", StringComparison.OrdinalIgnoreCase)
         )
 
-    /// Defines a dependency - y is dependent on x. Finishes the chain.
+    /// <summary>
+    /// Defines a dependency - <paramref name="y"/> is dependent on <paramref name="x"/>. Finishes the chain.
+    /// </summary>
     let (==>!) x y = x ==> y |> ignore
 
-    /// Defines a soft dependency. x must run before y, if it is present, but y does not require x to be run. Finishes the chain.
+    /// <summary>
+    /// Defines a soft dependency. <paramref name="x"/> must run before <paramref name="y"/>, if it is present, but
+    /// <paramref name="y"/> does not require <paramref name="x"/> to be run. Finishes the chain.
+    /// </summary>
     let (?=>!) x y = x ?=> y |> ignore
     //-----------------------------------------------------------------------------
     // Hide Secrets in Logger

From 68ef0c6f4dd8bba13482d36e9d5d20c271c5f294 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:25:13 +0200
Subject: [PATCH 07/19] chore: add src/Directory.Build.props and group the
 solution into folders

`src/Directory.Build.props` holds what every library project shares, next to the
`tests/Directory.Build.props` the test projects already have: it marks the project as packable,
generates the documentation file, publishes the repository URL, embeds untracked sources
and puts the PDB into the package next to the assembly.

The solution groups the projects into `src` and `tests` folders.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 FSharp.Collections.Immutable.slnx | 10 +++++++---
 src/Directory.Build.props         | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 src/Directory.Build.props

diff --git a/FSharp.Collections.Immutable.slnx b/FSharp.Collections.Immutable.slnx
index 4e8a5d03..b2ce8282 100644
--- a/FSharp.Collections.Immutable.slnx
+++ b/FSharp.Collections.Immutable.slnx
@@ -9,7 +9,11 @@
     <File Path="global.json" />
     <File Path="README.md" />
   </Folder>
-  <Project Path="build/build.fsproj" />
-  <Project Path="src/FSharp.Collections.Immutable/FSharp.Collections.Immutable.fsproj" />
-  <Project Path="tests/FSharp.Collections.Immutable.Tests/FSharp.Collections.Immutable.Tests.fsproj" />
+  <Folder Name="/src/">
+    <Project Path="src\FSharp.Collections.Immutable\FSharp.Collections.Immutable.fsproj" />
+  </Folder>
+  <Folder Name="/tests/">
+    <Project Path="tests\FSharp.Collections.Immutable.Tests\FSharp.Collections.Immutable.Tests.fsproj" />
+  </Folder>
+  <Project Path="build\build.fsproj" />
 </Solution>
diff --git a/src/Directory.Build.props b/src/Directory.Build.props
new file mode 100644
index 00000000..5ea09a4f
--- /dev/null
+++ b/src/Directory.Build.props
@@ -0,0 +1,14 @@
+<Project>
+    <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+    <PropertyGroup>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <IsPackable>true</IsPackable>
+        <IsTestProject>false</IsTestProject>
+
+        <!-- Sourcelink -->
+        <PublishRepositoryUrl>true</PublishRepositoryUrl>
+        <EmbedUntrackedSources>true</EmbedUntrackedSources>
+        <AllowedOutputExtensionsInPackageBuildOutputFolder>$(AllowedOutputExtensionsInPackageBuildOutputFolder);.pdb</AllowedOutputExtensionsInPackageBuildOutputFolder>
+    </PropertyGroup>
+
+</Project>

From 070238e8d6429fc8bfa28751e7d32b04793c5518 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:32:06 +0200
Subject: [PATCH 08/19] fix(build): generate the assembly info when the latest
 changelog entry has no date

`GenerateAssemblyInfo` read `latestEntry.Date.Value` and failed with a `NullReferenceException`
for an entry without a date. The `ReleaseDate` metadata is now written only when the entry has one.

This is the case in this repository today: FAKE `6.1.4` moves the link references out of the last
entry of the changelog and rebuilds that entry from its versions and changes alone, dropping its
date and description (fixed in FAKE after `6.1.4`, not released yet). `1.0.0` is the only entry,
so it is both the latest and the last one, and `PublishToGitHub`, which generates the assembly info,
could not get past this target.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 build/build.fs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/build/build.fs b/build/build.fs
index 50879292..3bf22d8e 100644
--- a/build/build.fs
+++ b/build/build.fs
@@ -448,7 +448,12 @@ let generateAssemblyInfo _ =
         AssemblyInfo.Title (projectName)
         AssemblyInfo.Product productName
         AssemblyInfo.Version latestEntry.AssemblyVersion
-        AssemblyInfo.Metadata ("ReleaseDate", latestEntry.Date.Value.ToString ("o"))
+        // The date is optional in a changelog entry, and FAKE 6.1.4 also drops it from the last entry of the file
+        // (https://github.com/fsprojects/FAKE/blob/6.1.4/src/app/Fake.Core.ReleaseNotes/Changelog.fs#L618),
+        // which is the latest one while the changelog has a single entry
+        match latestEntry.Date with
+        | Some releaseDate -> AssemblyInfo.Metadata ("ReleaseDate", releaseDate.ToString ("o"))
+        | None -> ()
         AssemblyInfo.FileVersion latestEntry.AssemblyVersion
         AssemblyInfo.InformationalVersion latestEntry.AssemblyVersion
         AssemblyInfo.Metadata ("ReleaseChannel", releaseChannel)

From 6c5c7fd223ea0698a2c53284d163b113a2ce6948 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:32:46 +0200
Subject: [PATCH 09/19] fix(package): describe the package correctly and stamp
 the assembly version

The package described itself as an F# API for Azure Cosmos DB and carried the
`AzureCosmosDisableNewtonsoftJsonCheck` property, both left over from the project file
this one was copied from. The description is `F# bindings for System.Collections.Immutable` again.

`GenerateAssemblyInfo` is switched off for the SDK because the FAKE target of the same name
writes `AssemblyInfo.fs`, but the project did not compile that file,
so the assembly had version `0.0.0.0`. The generated file is now the first compiled file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../AssemblyInfo.fs                           | 21 +++++++++++++++++++
 .../FSharp.Collections.Immutable.fsproj       |  5 ++---
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 src/FSharp.Collections.Immutable/AssemblyInfo.fs

diff --git a/src/FSharp.Collections.Immutable/AssemblyInfo.fs b/src/FSharp.Collections.Immutable/AssemblyInfo.fs
new file mode 100644
index 00000000..e0e99ef0
--- /dev/null
+++ b/src/FSharp.Collections.Immutable/AssemblyInfo.fs
@@ -0,0 +1,21 @@
+// Auto-Generated by FAKE; do not edit
+namespace System
+open System.Reflection
+
+[<assembly: AssemblyTitleAttribute("FSharp.Collections.Immutable")>]
+[<assembly: AssemblyProductAttribute("FSharp.Collections.Immutable")>]
+[<assembly: AssemblyVersionAttribute("1.0.0")>]
+[<assembly: AssemblyFileVersionAttribute("1.0.0")>]
+[<assembly: AssemblyInformationalVersionAttribute("1.0.0")>]
+[<assembly: AssemblyMetadataAttribute("ReleaseChannel","release")>]
+[<assembly: AssemblyMetadataAttribute("GitHash","68ef0c6f4dd8bba13482d36e9d5d20c271c5f294")>]
+do ()
+
+module internal AssemblyVersionInformation =
+    let [<Literal>] AssemblyTitle = "FSharp.Collections.Immutable"
+    let [<Literal>] AssemblyProduct = "FSharp.Collections.Immutable"
+    let [<Literal>] AssemblyVersion = "1.0.0"
+    let [<Literal>] AssemblyFileVersion = "1.0.0"
+    let [<Literal>] AssemblyInformationalVersion = "1.0.0"
+    let [<Literal>] AssemblyMetadata_ReleaseChannel = "release"
+    let [<Literal>] AssemblyMetadata_GitHash = "68ef0c6f4dd8bba13482d36e9d5d20c271c5f294"
diff --git a/src/FSharp.Collections.Immutable/FSharp.Collections.Immutable.fsproj b/src/FSharp.Collections.Immutable/FSharp.Collections.Immutable.fsproj
index 9f5941f0..6a4bc983 100644
--- a/src/FSharp.Collections.Immutable/FSharp.Collections.Immutable.fsproj
+++ b/src/FSharp.Collections.Immutable/FSharp.Collections.Immutable.fsproj
@@ -5,14 +5,12 @@
     <AssemblyName>$(AssemblyBaseName)</AssemblyName>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <Deterministic>true</Deterministic>
-    <AzureCosmosDisableNewtonsoftJsonCheck>True</AzureCosmosDisableNewtonsoftJsonCheck>
   </PropertyGroup>
 
   <PropertyGroup Label="NuGet">
     <PackageId>FSharp.Collections.Immutable</PackageId>
     <Title>FSharp.Collections.Immutable</Title>
-    <Summary>F# API for using Microsoft Azure Cosmos DB service via NoSQL API</Summary>
-    <Description>Provides extension methods for the FeedIterator and computation expressions to build operations</Description>
+    <Description>F# bindings for System.Collections.Immutable</Description>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)'=='Release'">
@@ -21,6 +19,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <Compile Include="AssemblyInfo.fs" />
     <Compile Include="ImmutableCollectionUtil.fs" />
     <Compile Include="FlatList.fs" />
     <Compile Include="Stack.fs" />

From b3c15a43666244a1d8a1f4ffb9564a56e069473b Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:32:58 +0200
Subject: [PATCH 10/19] chore(ai): add the F# MCP server

FsLangMCP gives agents semantic F# tools: symbol lookup, diagnostics, usages and refactoring previews.
It is a local tool pinned in the tool manifest, so `dotnet tool restore` installs it,
and `.mcp.json` starts it with `dotnet tool run fslangmcp`.

The servers in `.mcp.json` are sorted by name.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .config/dotnet-tools.json |  7 +++++++
 .mcp.json                 | 15 ++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/.config/dotnet-tools.json b/.config/dotnet-tools.json
index 9d1a9673..1ed8fff1 100644
--- a/.config/dotnet-tools.json
+++ b/.config/dotnet-tools.json
@@ -16,6 +16,13 @@
       ],
       "rollForward": false
     },
+    "fslangmcp": {
+      "version": "0.18.0",
+      "commands": [
+        "fslangmcp"
+      ],
+      "rollForward": true
+    },
     "fantomas": {
       "version": "8.0.5",
       "commands": [
diff --git a/.mcp.json b/.mcp.json
index c6181506..1d9b5d3d 100644
--- a/.mcp.json
+++ b/.mcp.json
@@ -1,12 +1,21 @@
 {
   "servers": {
-    "Microsoft Docs": {
-      "type": "http",
-      "url": "https://learn.microsoft.com/api/mcp"
+    "F#": {
+      "type": "stdio",
+      "command": "dotnet",
+      "args": [
+        "tool",
+        "run",
+        "fslangmcp"
+      ]
     },
     "GitHub": {
       "type": "http",
       "url": "https://api.githubcopilot.com/mcp/"
+    },
+    "Microsoft Docs": {
+      "type": "http",
+      "url": "https://learn.microsoft.com/api/mcp"
     }
   }
 }

From b03c497b4ec0aa7e857dcc1bb9b3c0445efa96c6 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:33:30 +0200
Subject: [PATCH 11/19] chore(claude): configure the repository for Claude Code

- `CLAUDE.md` imports `.github/copilot-instructions.md`, so GitHub Copilot and Claude Code share one
  set of instructions; `AGENTS.md` points other agents at the same file.
- `.mcp.json` lists the servers for Claude Code under `mcpServers` next to `servers`.
- The GitHub MCP server does not support the OAuth dynamic client registration Claude Code needs,
  so `.claude/scripts/github-mcp-headers.ps1` passes it the token Git Credential Manager already stores.
- `ClaudeSkillsLink` links `.claude/skills` to `.github/skills` when that folder exists;
  the link is local and git-ignored.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .claude/scripts/github-mcp-headers.ps1 | 22 ++++++++++++++++++++++
 .gitignore                             |  3 +++
 .mcp.json                              | 20 ++++++++++++++++++++
 AGENTS.md                              |  3 +++
 CLAUDE.md                              |  5 +++++
 Directory.Build.targets                | 21 +++++++++++++++++++++
 6 files changed, 74 insertions(+)
 create mode 100644 .claude/scripts/github-mcp-headers.ps1
 create mode 100644 AGENTS.md
 create mode 100644 CLAUDE.md

diff --git a/.claude/scripts/github-mcp-headers.ps1 b/.claude/scripts/github-mcp-headers.ps1
new file mode 100644
index 00000000..98534f2f
--- /dev/null
+++ b/.claude/scripts/github-mcp-headers.ps1
@@ -0,0 +1,22 @@
+# Emits GitHub MCP request headers for Claude Code's `headersHelper`.
+# Reuses the GitHub OAuth token stored by Git Credential Manager, so no PAT is needed.
+# Prints `{}` when no credential is available, so the server stays unauthenticated instead of failing.
+
+$ErrorActionPreference = 'Stop'
+$env:GCM_INTERACTIVE = 'never'
+$env:GIT_TERMINAL_PROMPT = '0'
+
+$token = $null
+try {
+    $credential = "protocol=https`nhost=github.com`n`n" | git credential fill 2>$null
+    $token = ($credential | Where-Object { $_ -like 'password=*' }) -replace '^password=', ''
+}
+catch {
+}
+
+if ($token) {
+    @{ Authorization = "Bearer $token" } | ConvertTo-Json -Compress
+}
+else {
+    '{}'
+}
diff --git a/.gitignore b/.gitignore
index 99fd3b7f..7fe30ed6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -405,3 +405,6 @@ tmp/
 temp/
 .fsdocs
 docs/
+
+# Local junction to .github/skills, created by Directory.Build.targets
+/.claude/skills
diff --git a/.mcp.json b/.mcp.json
index 1d9b5d3d..2379d355 100644
--- a/.mcp.json
+++ b/.mcp.json
@@ -17,5 +17,25 @@
       "type": "http",
       "url": "https://learn.microsoft.com/api/mcp"
     }
+  },
+  "mcpServers": {
+    "F#": {
+      "type": "stdio",
+      "command": "dotnet",
+      "args": [
+        "tool",
+        "run",
+        "fslangmcp"
+      ]
+    },
+    "GitHub": {
+      "type": "http",
+      "url": "https://api.githubcopilot.com/mcp/",
+      "headersHelper": "pwsh -NoProfile -File .claude/scripts/github-mcp-headers.ps1"
+    },
+    "Microsoft Docs": {
+      "type": "http",
+      "url": "https://learn.microsoft.com/api/mcp"
+    }
   }
 }
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 00000000..ae0cbfca
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,3 @@
+# Agent Instructions
+
+Before starting any task, read and follow [.github/copilot-instructions.md](.github/copilot-instructions.md). It holds the full project context and coding standards.
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 00000000..5dab9eb5
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,5 @@
+# Claude Code Instructions
+
+The project instructions are shared with GitHub Copilot and maintained in a single place:
+
+@.github/copilot-instructions.md
diff --git a/Directory.Build.targets b/Directory.Build.targets
index cdec8ba6..e69ea9ed 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -18,6 +18,27 @@ See https://learn.microsoft.com/en-us/visualstudio/msbuild/customize-by-director
     <Touch Files="$(_DotnetToolRestoreOutputFile)" AlwaysCreate="True" ForceTouch="True" />
   </Target>
 
+  <!--
+    Links .claude/skills to .github/skills so Claude Code discovers the repository skills.
+    Git cannot store a Windows junction, and a committed symlink only checks out as a real link
+    with core.symlinks=true plus Developer Mode, so the link is created locally and git-ignored.
+    A junction needs no elevation on Windows; elsewhere a relative symlink is used.
+    When several projects race to create it, the losers only get a warning.
+  -->
+  <PropertyGroup>
+    <_ClaudeSkillsLink>$(MSBuildThisFileDirectory).claude/skills</_ClaudeSkillsLink>
+    <_ClaudeSkillsTarget>$(MSBuildThisFileDirectory).github/skills</_ClaudeSkillsTarget>
+  </PropertyGroup>
+
+  <Target Name="ClaudeSkillsLink"
+          BeforeTargets="ResolveNuGetPackageAssets;BeforeCompile"
+          Condition="( '$(BuildingProject)' == 'false' OR '$(DesignTimeBuild)' == 'true' ) AND !Exists('$(_ClaudeSkillsLink)') AND Exists('$(_ClaudeSkillsTarget)')">
+    <Message Text="Linking .claude/skills to .github/skills..." Importance="High" />
+    <MakeDir Directories="$(MSBuildThisFileDirectory).claude" />
+    <Exec Condition="'$(OS)' == 'Windows_NT'" Command="mklink /J &quot;$([System.IO.Path]::GetFullPath('$(_ClaudeSkillsLink)'))&quot; &quot;$([System.IO.Path]::GetFullPath('$(_ClaudeSkillsTarget)'))&quot;" ContinueOnError="WarnAndContinue" />
+    <Exec Condition="'$(OS)' != 'Windows_NT'" Command="ln -s ../.github/skills &quot;$(_ClaudeSkillsLink)&quot;" ContinueOnError="WarnAndContinue" />
+  </Target>
+
   <!--
     Make sure that files are formatted before building.
     A multi-targeted project builds its target frameworks in parallel, so formatting in each of them ran Fantomas

From f8e65c2ff2f4419cac3f9b6ce06e55455542b903 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:35:46 +0200
Subject: [PATCH 12/19] chore(ai): adopt the latest shared Copilot instructions
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The generic sections are replaced with the current shared ones:

- `MCP Servers` – when to prefer the F#, GitHub and Microsoft Docs servers;
- `F# Coding Guidelines` – tooling, asynchrony and cancellation, values and collections
  (`voption`, struct tuples, `ToLookup`, pipelines kept in one module, comparing `System.Type` values),
  functions, lambdas and strings (explicit `StringComparison`, spans), nullable reference types,
  XML documentation comments and the order of `open` statements;
- `Naming Conventions` – test names with spaces;
- `Testing` – `StringAssert`, `Assert.Contains`, `Assert.HasCount` and running tests with `--no-build`.

The project details, the solution structure, the libraries in use and the test category rules
are specific to this repository and stay as they are.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/copilot-instructions.md | 94 ++++++++++++++++++++++++++++++---
 1 file changed, 86 insertions(+), 8 deletions(-)

diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 29e17260..9bdccfbf 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -74,24 +74,62 @@
 * [`FAKE`](https://fake.build/) – build and release scripting
 * [`Argu`](https://github.com/fsprojects/Argu) – command-line parsing for build tooling
 
+Use GitHub MCP tools for code search in these repositories when needed.
+
+## MCP Servers
+
+Agents discover servers from #file:'.mcp.json'; these are only hints on when to prefer one.
+
+* For F# work, prefer the `F#` server ([FsLangMCP](https://github.com/Neftedollar/FsLangMCP)) over `rg`/plain text search whenever the task depends on symbol meaning, compile context, cross-project usage, diagnostics, or safe refactoring preview. Its tool package is pinned in #file:'.config/dotnet-tools.json' – run `dotnet tool restore` before first use.
+* Use the `GitHub` server for code search in dependency repositories. In Claude Code it authenticates through `.claude/scripts/github-mcp-headers.ps1`, which reuses the GitHub token stored by Git Credential Manager, because the server does not support the OAuth dynamic client registration Claude Code needs.
+* Use the `Microsoft Docs` server for official Microsoft and Azure documentation.
+* When adding or changing a server, keep `servers` (VS Code / GitHub Copilot) and `mcpServers` (Claude Code) in sync and sorted alphabetically by key.
+
 ## F# Coding Guidelines
 
-### Language Preferences
+### Language and Tooling
 
 * Always use the latest F# 10 features over old syntax.
-* Prefer `voption` over `option`.
+* If you are running outside of an IDE, or the IDE does not provide F# semantic tools, use FsLangMCP as the primary tool for F# code navigation, symbol discovery, diagnostics, usage search and refactoring preview. Prefer its semantic tools over plain text search.
+* The compiler generates `IsCaseName` instance properties (for example `IsOk`, `IsNotFound`) for each DU case – use them when a single-case check is needed.
+
+### Asynchrony and Cancellation
+
 * Prefer `task` CE over `async` CE.
-* Prefer underscore lambda syntax like `Seq.map _.Name` over `Seq.map (fun x -> x.Name)`, but only when the expression is a simple member access. Complex expressions like `Seq.where (fun x -> x.Name = name)` or `Seq.map (fun x -> x.Field1, x.Field2)` cannot be simplified.
-* Simplify `Seq.map (fun x -> someFunction x)` to `Seq.map someFunction`.
+* When a method must return non-generic `Task`, annotate the return type explicitly: `member _.MyMethod (...) : Task = task { ... }`. Never cast through pipelines.
+* `task` CE can await `ValueTask` APIs directly.
+* Curried functions take the `CancellationToken` as their **first** parameter, so that it can be partially applied.
+* Never hand-roll wrappers such as `ValueTask (task { ... })`, `.AsTask ()` round-trips or manual `unit -> Task` thunks. Use the matching [`IcedTasks`](https://github.com/TheAngryByrd/IcedTasks) CE instead (`valueTask`, `valueTaskUnit`, `taskUnit`, `coldTask`, `cancellableTask`, `cancellableValueTask`, `backgroundTask`, …) and always use the full CE names, not the short aliases (`vTask`, `pvTask`, …).
+
+### Values and Collections
+
+* Prefer `voption` (`ValueSome`/`ValueNone`) over `option`. Fields, members, parameters and values shared between threads included: none of them is a reason to pick `option`. Exception: when an API hands you `'T option` and has no `voption` counterpart, unwrap it with `Option.defaultValue`/`Option.defaultWith` directly – do not insert `ValueOption.ofOption` just to switch modules.
+* The mirror case, an API that *takes* `'T option` (an optional argument `?name = …`, a field typed `'T option`): stay in `ValueOption` through the whole chain and convert once, last – `x |> ValueOption.bind _.Value |> ValueOption.toOption`, never `x |> ValueOption.toOption |> Option.bind _.Value`.
+* Prefer `struct ('T1 * 'T2)` over reference tuples, and anonymous struct records (`struct {| ... |}`) over tuples for return types of public functions and methods.
+* Never group with `Seq.groupBy` – use `ToLookup` from `System.Linq`. It groups once into an `ILookup<'Key, 'T>` instead of re-grouping on every enumeration and does not allocate a tuple per group. Pass a lambda (`xs.ToLookup (fun x -> keyOf x)`), not a bare function value.
+* When casting sequence items use `Seq.cast<TargetType>` instead of `Seq.map (fun item -> item :> TargetType)`.
+* When concatenating two sequences or lists, prefer `seq { yield! xs; yield! ys }` (or `[ yield! xs; yield! ys ]` for lists) over the `@` operator or `Seq.append`.
 * When pipe operators are used on a materializable collection multiple times in a row, prefer `Seq` module for the chain and materialize at the end.
-* Prefer interpolated strings over `printf` functions for string formatting.
-* Use `withNull` for null checks instead of boxing delegates/functions (avoid `isNull (box value)`).
+* Keep a pipeline in harmony: when consecutive steps can come from one module, take them from that module, the conversion at the end included – `xs |> Seq.filter isValid |> Seq.sort |> Seq.toArray`, not `… |> Seq.sort |> Array.ofSeq`, and `items |> List.map _.Id |> List.toArray`, not `… |> Array.ofList`. Change the module only where the steps that follow need the other collection.
+* Compare `System.Type` values with `Type.(=) (a, b)`, the `Type.op_Equality` operator. The F# `=` goes through generic equality and is several times slower, and comparing names is both slow and wrong: `FullName.StartsWith` is culture-sensitive without a `StringComparison`, and the full name of an array of a generic type, such as ``FSharpOption`1[[System.Int32, ...]][]``, starts with the name of the generic type. To recognize a generic type, check `t.IsGenericType` and compare `t.GetGenericTypeDefinition ()` with its definition, such as `typedefof<_ option>`, through `Type.(=)`.
+
+### Functions, Lambdas and Strings
+
+* Prefer underscore lambda syntax like `Seq.map _.Name` over `Seq.map (fun x -> x.Name)`, but only when the expression is a simple member access. Complex expressions like `Seq.where (fun x -> x.Name = name)` or `Seq.map (fun x -> x.Field1, x.Field2)` cannot be simplified. A member chain ending in a method call is not complex: `_.Changed.Subscribe(handler)`. The shorthand needs its input type known, so pipe the value in first – `value |> ValueOption.map _.Id`, not `ValueOption.map _.Id value` (FS0072). Never write a space in `_.MethodCall()` – it breaks parsing.
+* Simplify `Seq.map (fun x -> someFunction x)` to `Seq.map someFunction`.
+* Prefer interpolated strings over `printf` functions for string formatting. Format specifiers like `$"%s{value}"` are valid in interpolated strings and help type inference.
+* Pass an explicit `StringComparison` to every `Equals`, `StartsWith`, `EndsWith`, `IndexOf`, `Contains` and `Compare`, and an explicit comparer to every `HashSet<string>` and `Dictionary<string, _>`. `Ordinal` by default; culture-sensitive comparison is a decision, never a default. Use `OrdinalIgnoreCase` only where the thing compared really is case-insensitive.
+* A slice of a string that is only inspected – compared, trimmed, scanned, matched against a prefix – is a `ReadOnlySpan<char>` (`text.AsSpan (start, length)`), not a `Substring`: the substring allocates a copy per call, the span does not. Materialize with `Substring`/`ToString ()` only for the value that leaves the function or is stored.
+* The `StringComparison` rule applies to spans unchanged: `MemoryExtensions` has `StringComparison` overloads of `StartsWith`, `EndsWith`, `Equals`, `CompareTo`, `IndexOf` and `Contains` for `ReadOnlySpan<char>` – `s.AsSpan().TrimStart(' ').StartsWith("//", StringComparison.Ordinal)`. The overloads without one are the generic element-wise `ReadOnlySpan<'T>` ones – ordinal for `char` by accident, not by statement.
+* A slice that must be stored – kept in a record or class field, captured by a closure or used across a `let!`/`do!` in a `task` CE, put into a tuple, option or collection – is `ReadOnlyMemory<char>` (`text.AsMemory (...)`), never a `ReadOnlySpan<char>`: a byref-like value cannot be stored. Returning a `ReadOnlySpan<char>` sliced from a string or from a span parameter is fine.
+* To compare two slices without building either, use `String.CompareOrdinal (a, aIndex, b, bIndex, length)` or `spanA.Equals (spanB, StringComparison.Ordinal)`.
 
 ### Nullable Reference Types
 
 * Declare variables non-nullable; check for `null` at entry points only.
 * Trust the SDK null annotations – do not add null checks when the type system says a value cannot be null.
-* Prefer `match` on `null` over `if isNull`:
+* Use `withNull` for null checks instead of boxing delegates/functions (avoid `isNull (box value)`).
+* Prefer `match` on `null` over `if isNull` – it narrows the type and suppresses nullness warnings:
 
   ```fsharp
   // Preferred
@@ -100,6 +138,41 @@
   | someObject -> someObject.SomeProperty
   ```
 
+* Before suppressing a nullness warning (3261, 3262, …), exhaust these alternatives in order:
+  1. `nonNull value` – asserts non-null at runtime and fails fast.
+  2. `Unchecked.nonNull value` – skips the runtime check; only when non-null was already verified upstream.
+  3. An inline `#nowarn` / `#warnon` pair around the smallest possible scope – last resort for interop boundaries, centralised in a single helper rather than scattered across call sites.
+* Never suppress warnings file-wide; `#nowarn` and `#warnon` are valid anywhere in a file.
+
+### XML Documentation Comments
+
+* A doc comment is either plain text with no tags at all, or fully explicit XML starting with `<summary>` – never a mixture. The compiler adds `<summary>` by itself only when the comment has no tags, and silently escapes tags otherwise:
+  * No tags anywhere → bare `///` lines, no `<summary>`.
+  * Any tag at all (`<see/>`, `<c/>`, `<para>`, `<param>`, `<returns>`, …) → the comment must start with an explicit `<summary>`, and every `<para>` must be inside it.
+
+  ```fsharp
+  // ✅ plain text — the compiler supplies <summary>
+  /// Represents the result of a read operation.
+
+  // ❌ a sibling tag without <summary> — the <param> is escaped into the summary and lost
+  /// Reads an item.
+  /// <param name="id">Item Id</param>
+
+  // ✅ any tag present, so the comment is explicit XML throughout
+  /// <summary>Reads an item.</summary>
+  /// <param name="id">Item Id</param>
+  ```
+
+* Every public API must have XML documentation.
+* On an explicit interface implementation (`interface X with member _.M (...) = ...`), write `/// <inheritdoc />` alone instead of restating the interface member's documentation, unless this implementation has behavior worth calling out beyond what the interface already documents – write a normal `<summary>`/`<remarks>` there instead.
+* Refer to types and members through `<see cref="Type.Member"/>`, never through `<c>` or plain text. `<c>` is for literal values only (JSON, SQL, setting names). Refer to language keywords through `<see langword="null"/>`.
+* Split multi-paragraph documentation into `<para>` elements inside `<summary>` – bare line breaks are collapsed by documentation renderers.
+* Write enumerations as `<list type="bullet">` (or `type="number"`) with `<item><description>…</description></item>`, never as Markdown-style bullets.
+
+### Opens Sorting
+
+Sort `open` statements alphabetically within groups: `System` first, `Microsoft` second, `FSharp` third; then other external namespaces; then this solution's namespaces. `open type` goes last in each group. Type and module aliases form a separate final group.
+
 ### Class Constructors
 
 This is how to define a non-default F# class constructor:
@@ -183,16 +256,21 @@ module MyTypeExtensions =
 * Use camelCase for `let` bindings, functions, private fields, and local variables.
 * Prefix interface names with `I`.
 * Do not prefix type parameters with `T` (e.g., use `'Result` instead of `'TResult`).
+* Name tests using spaces (e.g., `member this.``Test name with spaces``() : Task = ...`).
 
 ## Testing
 
-* Tests use MSTest 4.x.
+* Tests use MSTest 4.
 * Each test must have category applied:
   * Add a collection-level category on each test class (for example: `[<TestClass; QueueTestCategory>]`, `[<TestClass; IndexedListTestCategory>]`).
   * Add operation-level categories on each test method using `nameof` (for example: `[<TestMethod; TestCategory(nameof Queue.enqueue)>]`).
   * For specialized areas, add dedicated category attributes together with operation categories (for example: `[<TestMethod; BuilderTestCategory; TestCategory(nameof IndexedList.ofBuilder)>]`).
 * Keep category names centralized in `TestCategories.fs` via custom `TestCategoryBaseAttribute` types; prefer attributes over repeating string literals.
 * `CollectionAssert` cannot work with F# lists – use F# array syntax (`[| ... |]`) instead.
+* `StringAssert` has overloads with `StringComparison`.
+* Use `Assert.Contains` instead of `Assert.IsTrue (str.Contains ..., "message")`, and do not put the actual value into the message.
+* Check collection size with `Assert.HasCount (expected, collection, "message")` instead of `Assert.AreEqual (expected, collection.Length, "message")` (or `.Count` / `Seq.length`); use `Assert.IsEmpty`, `Assert.IsNotEmpty` and `Assert.ContainsSingle` for the zero, non-zero and single-item cases. On failure they report the actual count and items.
+* Try running tests with `--no-build` first, run them individually where possible, and use the trx format for results so failures can be consumed and fixed.
 * Use Unquote only for complex object/hierarchy assertions; for simple scalar checks prefer standard `Assert.*` APIs.
 * Every `Assert.*` call **must include a failure message** so output is self-explanatory.
 * Async tests must return `Task`, not `Async` or `Task<unit>` – always declare `) : Task = task {`.

From 92185631e1c941fb106e742bc4fe2b6ed1a5ead0 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:35:51 +0200
Subject: [PATCH 13/19] chore(ai): add path-scoped instructions for test
 categories

`TestCategories.fs` keeps its `TestCategoryBaseAttribute` descendants sorted by type name.
The rule lives in `.github/instructions/test-categories.instructions.md`, which GitHub Copilot applies
to that file, and `.claude/rules/test-categories.md` imports it for Claude Code under the same path.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .claude/rules/test-categories.md                     | 6 ++++++
 .github/instructions/test-categories.instructions.md | 7 +++++++
 2 files changed, 13 insertions(+)
 create mode 100644 .claude/rules/test-categories.md
 create mode 100644 .github/instructions/test-categories.instructions.md

diff --git a/.claude/rules/test-categories.md b/.claude/rules/test-categories.md
new file mode 100644
index 00000000..44b98c99
--- /dev/null
+++ b/.claude/rules/test-categories.md
@@ -0,0 +1,6 @@
+---
+paths:
+  - "**/TestCategories.fs"
+---
+
+@../../.github/instructions/test-categories.instructions.md
diff --git a/.github/instructions/test-categories.instructions.md b/.github/instructions/test-categories.instructions.md
new file mode 100644
index 00000000..8516ae64
--- /dev/null
+++ b/.github/instructions/test-categories.instructions.md
@@ -0,0 +1,7 @@
+---
+applyTo: "**/TestCategories.fs"
+---
+
+# Test category attributes
+
+Keep the `TestCategoryBaseAttribute` descendants of this file sorted by type name. Add a new attribute at its place in that order, never at the end of the file.

From 42a8ef3245af3f203e3b5bbae006d6b63868b281 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:36:02 +0200
Subject: [PATCH 14/19] ci: update the GitHub Pages actions

- `actions/configure-pages` `v5` -> `v6`
- `actions/upload-pages-artifact` `v4` -> `v5`
- `actions/deploy-pages` `v4` -> `v5`

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/workflows/fsdocs-gh-pages.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/fsdocs-gh-pages.yml b/.github/workflows/fsdocs-gh-pages.yml
index 1f2ff013..993a1b48 100644
--- a/.github/workflows/fsdocs-gh-pages.yml
+++ b/.github/workflows/fsdocs-gh-pages.yml
@@ -29,7 +29,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Setup Pages
-        uses: actions/configure-pages@v5
+        uses: actions/configure-pages@v6
 
       - name: Setup necessary dotnet SDKs
         uses: actions/setup-dotnet@v5
@@ -44,7 +44,7 @@ jobs:
           ./build.sh builddocs
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v4
+        uses: actions/upload-pages-artifact@v5
         with:
           path: docs/
 
@@ -58,4 +58,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v5

From 56bb1697894b845a61443fe9dde6fb5c19f85232 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:36:02 +0200
Subject: [PATCH 15/19] chore(devcontainer): add the starship prompt

The dev container installs the starship feature and enables it in zsh when the container is created.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .devcontainer/devcontainer.json | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index d1253252..09ddbe3f 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -19,6 +19,8 @@
         },
         // https://github.com/devcontainers/features/blob/main/src/github-cli/README.md
         "ghcr.io/devcontainers/features/github-cli:1": {},
+        // https://github.com/devcontainers-extra/features/blob/main/src/starship/README.md
+        "ghcr.io/devcontainers-extra/features/starship:1": {},
         // https://github.com/devcontainers/features/blob/main/src/dotnet/README.md
         "ghcr.io/devcontainers/features/dotnet:2": {
             "version": "10.0",
@@ -28,6 +30,7 @@
     "overrideFeatureInstallOrder": [
         "ghcr.io/devcontainers/features/common-utils",
         "ghcr.io/devcontainers/features/github-cli",
+        "ghcr.io/devcontainers-extra/features/starship",
         "ghcr.io/devcontainers/features/dotnet"
     ],
     "customizations": {
@@ -60,6 +63,9 @@
         // They are used for releasing and publishing from the container
         "GITHUB_TOKEN": "${localEnv:GITHUB_TOKEN}"
     },
+    "onCreateCommand": {
+        "enable-starship": "echo 'eval \"$(starship init zsh)\"' >> ~/.zshrc"
+    },
     "postAttachCommand": {
         "restore": "dotnet tool restore && dotnet restore"
     },

From a308fdeba9d1fb89b7baeb8fa9464cd26c6186c2 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:36:11 +0200
Subject: [PATCH 16/19] fix(ai): indent `update_issue.target` of the repository
 assistant like its sibling keys

`target` was indented by five spaces while the other safe outputs indent their keys by four.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/workflows/repo-assist.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/repo-assist.md b/.github/workflows/repo-assist.md
index 03ca2875..11f07ec8 100644
--- a/.github/workflows/repo-assist.md
+++ b/.github/workflows/repo-assist.md
@@ -39,7 +39,7 @@ safe-outputs:
     labels: [automation, repo-assist]
     max: 3
   update_issue:
-     target: "*"
+    target: "*"
      #title-prefix: "[Repo Assist] "
   add_labels:
     allowed: [bug, enhancement, "help wanted", "good first issue", "spam", "off topic"]

From 59d59515d1f3a3ecee1bb208b9bc1378035e4694 Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sat, 10 Oct 2026 23:36:53 +0200
Subject: [PATCH 17/19] docs: correct the stale statements in the README and
 the PR template

README:

- the required SDK is the `10.0.401` pinned in `global.json`, not `8.0 or higher`;
- `CONFIGURATION` defaults to `Debug`, and to `Release` only when `PublishToNuGet` runs;
- `ENABLE_COVERAGE` and `DotnetTest` describe the MSTest runner instead of AltCover and the solution file;
- `PublishToNuGet` pushes with `dotnet nuget push`, not `paket push`;
- the release commit is named ``release: bump version to `x.y.z` ``;
- the badge of the `.NET Core` workflow, which does not exist, is removed,
  and the NuGet badge is loaded over HTTPS.

The pull request template names this project instead of the one it was copied from.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/PULL_REQUEST_TEMPLATE.md |  2 +-
 README.md                        | 16 +++++++---------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index ab249a8b..1e00d8b1 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -4,7 +4,7 @@ Describe the big picture of your changes here to communicate to the maintainers
 
 ## Types of changes
 
-What types of changes does your code introduce to FSharp.Azure.Cosmos?
+What types of changes does your code introduce to FSharp.Collections.Immutable?
 _Put an `x` in the boxes that apply_
 
 - [ ] Bugfix (non-breaking change which fixes an issue)
diff --git a/README.md b/README.md
index 7819e3fe..33287ccc 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,7 @@
-# FSharp.Collections.Immutable [![NuGet Status](http://img.shields.io/nuget/v/FSharp.Collections.Immutable.svg?style=flat)](https://www.nuget.org/packages/FSharp.Collections.Immutable/) [![GitHub Actions](https://github.com/fsprojects/FSharp.Collections.Immutable/workflows/Build%20main/badge.svg)](https://github.com/fsprojects/FSharp.Collections.Immutable/actions?query=branch%3Amain)
+# FSharp.Collections.Immutable [![NuGet Status](https://img.shields.io/nuget/v/FSharp.Collections.Immutable.svg?style=flat)](https://www.nuget.org/packages/FSharp.Collections.Immutable/) [![GitHub Actions](https://github.com/fsprojects/FSharp.Collections.Immutable/workflows/Build%20main/badge.svg)](https://github.com/fsprojects/FSharp.Collections.Immutable/actions?query=branch%3Amain)
 
 F# bindings for System.Collections.Immutable
 
-![Build status](https://github.com/fsprojects/FSharp.Collections.Immutable/workflows/.NET%20Core/badge.svg)
-
 **FSharp.Collections.Immutable** is a collection of F# bindings for [System.Collections.Immutable](https://learn.microsoft.com/en-us/dotnet/api/system.collections.immutable).
 
 Please contribute to this project. Don't ask for permission, just fork the repository and send pull requests.
@@ -44,7 +42,7 @@ FSharp.Collections.Immutable | [![NuGet Badge](https://img.shields.io/nuget/v/FS
 
 Make sure the following **requirements** are installed on your system:
 
-- [dotnet SDK](https://www.microsoft.com/net/download/core) 8.0 or higher
+- [dotnet SDK](https://www.microsoft.com/net/download/core) 10.0.401 or a later 10.0 SDK (pinned in `global.json`, uses F# 10)
 
 or
 
@@ -55,9 +53,9 @@ or
 
 ### Environment Variables
 
-- `CONFIGURATION` will set the [configuration](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-build?tabs=netcore2x#options) of the dotnet commands.  If not set, it will default to Release.
+- `CONFIGURATION` will set the [configuration](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-build?tabs=netcore2x#options) of the dotnet commands.  If not set, it will default to Debug, and to Release when the `PublishToNuGet` target runs.
   - `CONFIGURATION=Debug ./build.sh` will result in `-c` additions to commands such as in `dotnet build -c Debug`
-- `ENABLE_COVERAGE` Will enable running code coverage metrics.  AltCover can have [severe performance degradation](https://github.com/SteveGilham/altcover/issues/57) so code coverage evaluation are disabled by default to speed up the feedback loop.
+- `ENABLE_COVERAGE` Will enable running code coverage metrics with the MSTest runner (`dotnet test --coverage`). Code coverage evaluation is disabled by default to speed up the feedback loop.
   - `ENABLE_COVERAGE=1 ./build.sh` will enable code coverage evaluation
 
 
@@ -75,14 +73,14 @@ or
 - `DotnetRestore` - Runs [dotnet restore](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-restore?tabs=netcore2x) on the [solution file](https://docs.microsoft.com/en-us/visualstudio/extensibility/internals/solution-dot-sln-file?view=vs-2019).
 - [`DotnetBuild`](#Building) - Runs [dotnet build](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-build?tabs=netcore2x) on the [solution file](https://docs.microsoft.com/en-us/visualstudio/extensibility/internals/solution-dot-sln-file?view=vs-2019).
 - `FSharpAnalyzers` - Runs [BinaryDefense.FSharp.Analyzers](https://github.com/BinaryDefense/BinaryDefense.FSharp.Analyzers).
-- `DotnetTest` - Runs [dotnet test](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-test?tabs=netcore21) on the [solution file](https://docs.microsoft.com/en-us/visualstudio/extensibility/internals/solution-dot-sln-file?view=vs-2019).
+- `DotnetTest` - Runs [dotnet test](https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-test) on each test project with the MSTest runner.
 - `GenerateCoverageReport` - Code coverage is run during `DotnetTest` and this generates a report via [ReportGenerator](https://github.com/danielpalme/ReportGenerator).
 - `ShowCoverageReport` - Shows the report generated in `GenerateCoverageReport`.
 - `WatchTests` - Runs [dotnet watch](https://docs.microsoft.com/en-us/aspnet/core/tutorials/dotnet-watch?view=aspnetcore-3.0) with the test projects. Useful for rapid feedback loops.
 - `GenerateAssemblyInfo` - Generates [AssemblyInfo](https://docs.microsoft.com/en-us/dotnet/api/microsoft.visualbasic.applicationservices.assemblyinfo?view=netframework-4.8) for libraries.
 - `DotnetPack` - Runs [dotnet pack](https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-pack). This includes running [Source Link](https://github.com/dotnet/sourcelink).
 - `SourceLinkTest` - Runs a Source Link test tool to verify Source Links were properly generated.
-- `PublishToNuGet` - Publishes the NuGet packages generated in `DotnetPack` to NuGet via [paket push](https://fsprojects.github.io/Paket/paket-push.html). Runs only from `Github Actions`.
+- `PublishToNuGet` - Publishes the NuGet packages generated in `DotnetPack` to NuGet via [dotnet nuget push](https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-nuget-push). Runs only from `Github Actions`.
 - `GitRelease` - Creates a commit message with the [Release Notes](https://fake.build/apidocs/v5/fake-core-releasenotes.html) and a git tag via the version in the `Release Notes`.
 - `GitHubRelease` - Publishes a [GitHub Release](https://help.github.com/en/articles/creating-releases) with the Release Notes and any NuGet packages. Runs only from `Github Actions`.
 - `FormatCode` - Runs [Fantomas](https://github.com/fsprojects/fantomas) on the solution file.
@@ -107,7 +105,7 @@ git push -u origin main
 - Add your `NUGET_TOKEN` to the [Environment Secrets](https://docs.github.com/en/actions/deployment/targeting-different-environments/using-environments-for-deployment#environment-secrets) of your newly created environment.
 - Then update the `CHANGELOG.md` with an "Unreleased" section containing release notes for this version, in [KeepAChangelog](https://keepachangelog.com/en/1.1.0/) format.
 
-NOTE: Its highly recommend to add a link to the Pull Request next to the release note that it affects. The reason for this is when the `RELEASE` target is run, it will add these new notes into the body of git commit. GitHub will notice the links and will update the Pull Request with what commit referenced it saying ["added a commit that referenced this pull request"](https://github.com/TheAngryByrd/MiniScaffold/pull/179#ref-commit-837ad59). Since the build script automates the commit message, it will say "Bump Version to x.y.z". The benefit of this is when users goto a Pull Request, it will be clear when and which version those code changes released. Also when reading the `CHANGELOG`, if someone is curious about how or why those changes were made, they can easily discover the work and discussions.
+NOTE: Its highly recommend to add a link to the Pull Request next to the release note that it affects. The reason for this is when the `RELEASE` target is run, it will add these new notes into the body of git commit. GitHub will notice the links and will update the Pull Request with what commit referenced it saying ["added a commit that referenced this pull request"](https://github.com/TheAngryByrd/MiniScaffold/pull/179#ref-commit-837ad59). Since the build script automates the commit message, it will say ``release: bump version to `x.y.z` ``. The benefit of this is when users goto a Pull Request, it will be clear when and which version those code changes released. Also when reading the `CHANGELOG`, if someone is curious about how or why those changes were made, they can easily discover the work and discussions.
 
 ### Releasing Documentation
 

From 4a1cfdddc212196b3babc34c9abf9df543efca0e Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sun, 11 Oct 2026 00:49:38 +0200
Subject: [PATCH 18/19] chore(deps): update FAKE to `6.1.5`

FAKE `6.1.5` keeps the date and the description of the last entry of the changelog, which `6.1.4` dropped.
`1.0.0` is the only entry here, so:

- the regenerated `AssemblyInfo.fs` now carries the `ReleaseDate` metadata;
- the release notes of the package start with `## [1.0.0] - 2020-02-23` and `First release`
  instead of a bare `## [1.0.0]`.

`GenerateAssemblyInfo` still writes `ReleaseDate` only for an entry that has a date, because the date
is optional in a changelog entry; its comment no longer refers to the FAKE defect.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Directory.Packages.props                      | 22 +++++++++----------
 build/build.fs                                |  4 +---
 .../AssemblyInfo.fs                           |  6 +++--
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/Directory.Packages.props b/Directory.Packages.props
index 02ec46b3..7c9ec00d 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -13,17 +13,17 @@
   </ItemGroup>
   <ItemGroup Label="Build and Test">
     <PackageVersion Include="Argu" Version="6.2.5" />
-    <PackageVersion Include="Fake.Api.GitHub" Version="6.1.4" />
-    <PackageVersion Include="Fake.BuildServer.GitHubActions" Version="6.1.4" />
-    <PackageVersion Include="Fake.Core.Environment" Version="6.1.4" />
-    <PackageVersion Include="Fake.Core.Process" Version="6.1.4" />
-    <PackageVersion Include="Fake.Core.ReleaseNotes" Version="6.1.4" />
-    <PackageVersion Include="Fake.Core.Target" Version="6.1.4" />
-    <PackageVersion Include="Fake.DotNet.AssemblyInfoFile" Version="6.1.4" />
-    <PackageVersion Include="Fake.DotNet.Cli" Version="6.1.4" />
-    <PackageVersion Include="Fake.DotNet.Paket" Version="6.1.4" />
-    <PackageVersion Include="Fake.IO.FileSystem" Version="6.1.4" />
-    <PackageVersion Include="Fake.Tools.Git" Version="6.1.4" />
+    <PackageVersion Include="Fake.Api.GitHub" Version="6.1.5" />
+    <PackageVersion Include="Fake.BuildServer.GitHubActions" Version="6.1.5" />
+    <PackageVersion Include="Fake.Core.Environment" Version="6.1.5" />
+    <PackageVersion Include="Fake.Core.Process" Version="6.1.5" />
+    <PackageVersion Include="Fake.Core.ReleaseNotes" Version="6.1.5" />
+    <PackageVersion Include="Fake.Core.Target" Version="6.1.5" />
+    <PackageVersion Include="Fake.DotNet.AssemblyInfoFile" Version="6.1.5" />
+    <PackageVersion Include="Fake.DotNet.Cli" Version="6.1.5" />
+    <PackageVersion Include="Fake.DotNet.Paket" Version="6.1.5" />
+    <PackageVersion Include="Fake.IO.FileSystem" Version="6.1.5" />
+    <PackageVersion Include="Fake.Tools.Git" Version="6.1.5" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="10.0.401" />
     <PackageVersion Include="MSTest" Version="4.2.3" />
diff --git a/build/build.fs b/build/build.fs
index 3bf22d8e..2775bf65 100644
--- a/build/build.fs
+++ b/build/build.fs
@@ -448,9 +448,7 @@ let generateAssemblyInfo _ =
         AssemblyInfo.Title (projectName)
         AssemblyInfo.Product productName
         AssemblyInfo.Version latestEntry.AssemblyVersion
-        // The date is optional in a changelog entry, and FAKE 6.1.4 also drops it from the last entry of the file
-        // (https://github.com/fsprojects/FAKE/blob/6.1.4/src/app/Fake.Core.ReleaseNotes/Changelog.fs#L618),
-        // which is the latest one while the changelog has a single entry
+        // The date is optional in a changelog entry
         match latestEntry.Date with
         | Some releaseDate -> AssemblyInfo.Metadata ("ReleaseDate", releaseDate.ToString ("o"))
         | None -> ()
diff --git a/src/FSharp.Collections.Immutable/AssemblyInfo.fs b/src/FSharp.Collections.Immutable/AssemblyInfo.fs
index e0e99ef0..db10dac4 100644
--- a/src/FSharp.Collections.Immutable/AssemblyInfo.fs
+++ b/src/FSharp.Collections.Immutable/AssemblyInfo.fs
@@ -5,17 +5,19 @@ open System.Reflection
 [<assembly: AssemblyTitleAttribute("FSharp.Collections.Immutable")>]
 [<assembly: AssemblyProductAttribute("FSharp.Collections.Immutable")>]
 [<assembly: AssemblyVersionAttribute("1.0.0")>]
+[<assembly: AssemblyMetadataAttribute("ReleaseDate","2020-02-23T00:00:00.0000000")>]
 [<assembly: AssemblyFileVersionAttribute("1.0.0")>]
 [<assembly: AssemblyInformationalVersionAttribute("1.0.0")>]
 [<assembly: AssemblyMetadataAttribute("ReleaseChannel","release")>]
-[<assembly: AssemblyMetadataAttribute("GitHash","68ef0c6f4dd8bba13482d36e9d5d20c271c5f294")>]
+[<assembly: AssemblyMetadataAttribute("GitHash","59d59515d1f3a3ecee1bb208b9bc1378035e4694")>]
 do ()
 
 module internal AssemblyVersionInformation =
     let [<Literal>] AssemblyTitle = "FSharp.Collections.Immutable"
     let [<Literal>] AssemblyProduct = "FSharp.Collections.Immutable"
     let [<Literal>] AssemblyVersion = "1.0.0"
+    let [<Literal>] AssemblyMetadata_ReleaseDate = "2020-02-23T00:00:00.0000000"
     let [<Literal>] AssemblyFileVersion = "1.0.0"
     let [<Literal>] AssemblyInformationalVersion = "1.0.0"
     let [<Literal>] AssemblyMetadata_ReleaseChannel = "release"
-    let [<Literal>] AssemblyMetadata_GitHash = "68ef0c6f4dd8bba13482d36e9d5d20c271c5f294"
+    let [<Literal>] AssemblyMetadata_GitHash = "59d59515d1f3a3ecee1bb208b9bc1378035e4694"

From 40f35f7aebc1f51f304c368261ed496e85eee4da Mon Sep 17 00:00:00 2001
From: XperiAndri <xperiandri@outlook.com>
Date: Sun, 11 Oct 2026 01:11:47 +0200
Subject: [PATCH 19/19] fix(build): restore the tools once per build instead of
 once per project

A solution restores its projects in parallel, so `ToolRestore` ran `dotnet tool restore` in every project
at the same time and all of them touched the same marker file. The `Restore dependencies` step of
the Copilot setup, which restores the solution, failed on Linux after `ToolRestore` started to run
on every restore.

Every project now delegates to one instance of `Directory.Build.targets`, which MSBuild builds once per build,
so the tools are restored once and the other projects wait for that run.
The Copilot setup no longer restores the tools on its own before restoring the solution.

`Format` says why it runs Fantomas twice.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .github/workflows/copilot-setup-steps.yml |  5 ++---
 Directory.Build.targets                   | 15 +++++++++++++--
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/copilot-setup-steps.yml b/.github/workflows/copilot-setup-steps.yml
index 05370ebc..2f332082 100644
--- a/.github/workflows/copilot-setup-steps.yml
+++ b/.github/workflows/copilot-setup-steps.yml
@@ -37,6 +37,5 @@ jobs:
             10.x
 
       - name: Restore dependencies
-        run: |
-          dotnet tool restore
-          dotnet restore FSharp.Collections.Immutable.slnx
+        # Restoring the solution restores the local tools first (see Directory.Build.targets)
+        run: dotnet restore FSharp.Collections.Immutable.slnx
diff --git a/Directory.Build.targets b/Directory.Build.targets
index e69ea9ed..8b9a0783 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -11,8 +11,18 @@ See https://learn.microsoft.com/en-us/visualstudio/msbuild/customize-by-director
     <_DotnetFantomasOutputFile>$(BaseIntermediateOutputPath)dotnet-fantomas-msbuild-$(NETCoreSdkVersion)-$(OS)</_DotnetFantomasOutputFile>
   </PropertyGroup>
 
-  <!-- Make sure that dotnet tools are restored before restoring any project -->
-  <Target Name="ToolRestore" BeforeTargets="Restore;CollectPackageReferences" Inputs="$(_DotnetToolManifestFile)" Outputs="$(_DotnetToolRestoreOutputFile)">
+  <!--
+    Make sure that dotnet tools are restored before restoring any project.
+    A solution restores its projects in parallel, so restoring the tools in each of them ran `dotnet tool restore`
+    concurrently and raced on the marker file.
+    Every project therefore delegates to one instance of this file: MSBuild runs a target once per project instance,
+    so the tools are restored once per build, and the projects that ask at the same time wait for that one run.
+  -->
+  <Target Name="ToolRestore" BeforeTargets="Restore;CollectPackageReferences">
+    <MSBuild Projects="$(MSBuildThisFileFullPath)" Targets="ToolRestoreOnce" Properties="_DotnetToolRestoreOutputFile=$(_DotnetToolRestoreOutputFile)" RemoveProperties="TargetFramework;RuntimeIdentifier" />
+  </Target>
+
+  <Target Name="ToolRestoreOnce" Inputs="$(_DotnetToolManifestFile)" Outputs="$(_DotnetToolRestoreOutputFile)">
     <Exec Command="dotnet tool restore" WorkingDirectory="$(MSBuildThisFileDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" />
     <MakeDir Directories="$(_BuildProjBaseIntermediateOutputPath)"/>
     <Touch Files="$(_DotnetToolRestoreOutputFile)" AlwaysCreate="True" ForceTouch="True" />
@@ -51,6 +61,7 @@ See https://learn.microsoft.com/en-us/visualstudio/msbuild/customize-by-director
     <MSBuild Projects="$(MSBuildProjectFullPath)" Targets="Format" Properties="_FantomasFormatInstance=true" RemoveProperties="TargetFramework;RuntimeIdentifier" />
   </Target>
 
+  <!-- Fantomas runs twice on purpose: one pass is not always idempotent, and the second one settles what the first moved -->
   <Target Name="Format" Inputs="@(Compile)" Outputs="$(_DotnetFantomasOutputFile)">
     <Exec Command="dotnet fantomas $(MSBuildProjectDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" WorkingDirectory="$(MSBuildThisFileDirectory)" ContinueOnError="WarnAndContinue" />
     <Exec Command="dotnet fantomas $(MSBuildProjectDirectory)" StandardOutputImportance="High" StandardErrorImportance="High" WorkingDirectory="$(MSBuildThisFileDirectory)" ContinueOnError="WarnAndContinue" />