tests: add GenerativePropertiesTests; prepare release 8.6.0

- Add GenerativePropertiesTests.fs: 5 new tests covering instance read-only,
  read-write, static, multi-property name-lookup (exercises ILPropertyDefs
  lazy FindByName dictionary from #502), and property count on a generative type
- 136/136 tests pass
- Prepare RELEASE_NOTES.md for 8.6.0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

RELEASE_NOTES.md

@@ -1,3 +1,9 @@
+#### 8.6.0 - April 15, 2026
+
+- Bug fix: Fix `ProvidedTypeDefinition.Logger` creating a new delegate reference on each call #501
+- Refactor/Performance: Convert `ILFieldDefs`/`ILEventDefs`/`ILPropertyDefs` to concrete classes with lazy `O(1)` name-lookup caches #502
+- Tests: Add `GenerativePropertiesTests` covering instance/static/read-write properties and name-lookup
+
 #### 8.5.0 - April 7, 2026
 
 - Performance: O(1) assembly-name dictionary lookup in `convTypeRef` #493

tests/FSharp.TypeProviders.SDK.Tests.fsproj

@@ -21,6 +21,7 @@
     <Compile Include="GenerativeEqualityComparisonTests.fs" />
     <Compile Include="GenerativeStructProvisionTests.fs" />
     <Compile Include="GenerativeEventsTests.fs" />
+    <Compile Include="GenerativePropertiesTests.fs" />
     <Compile Include="GenerativeDelegateTests.fs" />
     <Compile Include="ReferencedAssemblies.fs" />
   </ItemGroup>

tests/GenerativePropertiesTests.fs

@@ -0,0 +1,147 @@
+module TPSDK.GenerativePropertiesTests
+
+#nowarn "760" // IDisposable needs new
+
+open System
+open System.Reflection
+open Microsoft.FSharp.Core.CompilerServices
+open Microsoft.FSharp.Quotations
+open Xunit
+open ProviderImplementation.ProvidedTypes
+open ProviderImplementation.ProvidedTypesTesting
+open UncheckedQuotations
+
+/// Generative type provider with a variety of property kinds:
+///   - instance read-only property
+///   - instance read-write property
+///   - static read-only property
+///   - multiple properties on the same nested type (exercises ILPropertyDefs lazy name-lookup cache)
+[<TypeProvider>]
+type GenerativePropertiesProvider (config: TypeProviderConfig) as this =
+    inherit TypeProviderForNamespaces (config)
+
+    let ns = "Properties.Provided"
+    let tempAssembly = ProvidedAssembly()
+    let container = ProvidedTypeDefinition(tempAssembly, ns, "Container", Some typeof<obj>, isErased = false)
+
+    do
+        let widgetType = ProvidedTypeDefinition("Widget", Some typeof<obj>, isErased = false)
+
+        // A backing field for the read-write property
+        let labelField = ProvidedField("_label", typeof<string>)
+        widgetType.AddMember labelField
+
+        // Instance read-only property: returns a constant
+        let readOnlyProp =
+            ProvidedProperty(
+                "Kind", typeof<string>,
+                isStatic = false,
+                getterCode = fun _args -> <@@ "widget" @@>)
+        widgetType.AddMember readOnlyProp
+
+        // Instance read-write property backed by _label field
+        let readWriteProp =
+            ProvidedProperty(
+                "Label", typeof<string>,
+                isStatic = false,
+                getterCode = (fun args -> Expr.FieldGetUnchecked(args.[0], labelField)),
+                setterCode = (fun args -> Expr.FieldSetUnchecked(args.[0], labelField, args.[1])))
+        widgetType.AddMember readWriteProp
+
+        // Static read-only property
+        let staticProp =
+            ProvidedProperty(
+                "DefaultKind", typeof<string>,
+                isStatic = true,
+                getterCode = fun _args -> <@@ "default-widget" @@>)
+        widgetType.AddMember staticProp
+
+        // A second property to verify the name-lookup dictionary handles multiple entries
+        let countProp =
+            ProvidedProperty(
+                "Index", typeof<int>,
+                isStatic = false,
+                getterCode = fun _args -> <@@ 42 @@>)
+        widgetType.AddMember countProp
+
+        widgetType.AddMember (ProvidedConstructor([], invokeCode = fun _args -> <@@ () @@>))
+        container.AddMember widgetType
+        tempAssembly.AddTypes [container]
+        this.AddNamespace(ns, [container])
+
+let loadTestAssembly () =
+    let runtimeAssemblyRefs = Targets.DotNetStandard20FSharpRefs()
+    let runtimeAssembly = runtimeAssemblyRefs.[0]
+    let cfg = Testing.MakeSimulatedTypeProviderConfig (__SOURCE_DIRECTORY__, runtimeAssembly, runtimeAssemblyRefs)
+    let tp = GenerativePropertiesProvider(cfg) :> TypeProviderForNamespaces
+    let providedNamespace = tp.Namespaces.[0]
+    let providedType = providedNamespace.GetTypes().[0] :?> ProvidedTypeDefinition
+    Assert.Equal("Container", providedType.Name)
+    let bytes = (tp :> ITypeProvider).GetGeneratedAssemblyContents(providedType.Assembly)
+    Assembly.Load bytes
+
+[<Fact>]
+let ``Instance read-only property is present in generated assembly``() =
+    let assembly = loadTestAssembly ()
+    let containerType = assembly.ExportedTypes |> Seq.find (fun t -> t.Name = "Container")
+    let widgetType = containerType.GetNestedType("Widget")
+    Assert.NotNull(widgetType)
+
+    let prop = widgetType.GetProperty("Kind", BindingFlags.Instance ||| BindingFlags.Public)
+    Assert.NotNull(prop)
+    Assert.Equal(typeof<string>, prop.PropertyType)
+    Assert.True(prop.CanRead, "Kind should be readable")
+    Assert.False(prop.CanWrite, "Kind should not be writable")
+    Assert.False(prop.GetMethod.IsStatic, "Kind getter should be an instance method")
+
+[<Fact>]
+let ``Instance read-write property is present and has getter and setter``() =
+    let assembly = loadTestAssembly ()
+    let containerType = assembly.ExportedTypes |> Seq.find (fun t -> t.Name = "Container")
+    let widgetType = containerType.GetNestedType("Widget")
+    Assert.NotNull(widgetType)
+
+    let prop = widgetType.GetProperty("Label", BindingFlags.Instance ||| BindingFlags.Public)
+    Assert.NotNull(prop)
+    Assert.Equal(typeof<string>, prop.PropertyType)
+    Assert.True(prop.CanRead,  "Label should be readable")
+    Assert.True(prop.CanWrite, "Label should be writable")
+    Assert.Equal("get_Label", prop.GetMethod.Name)
+    Assert.Equal("set_Label", prop.SetMethod.Name)
+
+[<Fact>]
+let ``Static read-only property is present in generated assembly``() =
+    let assembly = loadTestAssembly ()
+    let containerType = assembly.ExportedTypes |> Seq.find (fun t -> t.Name = "Container")
+    let widgetType = containerType.GetNestedType("Widget")
+    Assert.NotNull(widgetType)
+
+    let prop = widgetType.GetProperty("DefaultKind", BindingFlags.Static ||| BindingFlags.Public)
+    Assert.NotNull(prop)
+    Assert.Equal(typeof<string>, prop.PropertyType)
+    Assert.True(prop.CanRead, "DefaultKind should be readable")
+    Assert.True(prop.GetMethod.IsStatic, "DefaultKind getter should be static")
+
+[<Fact>]
+let ``All expected properties are found by name (exercises ILPropertyDefs lazy name-lookup cache)``() =
+    let assembly = loadTestAssembly ()
+    let containerType = assembly.ExportedTypes |> Seq.find (fun t -> t.Name = "Container")
+    let widgetType = containerType.GetNestedType("Widget")
+    Assert.NotNull(widgetType)
+
+    let allFlags = BindingFlags.Instance ||| BindingFlags.Static ||| BindingFlags.Public
+    // Each property must be findable by exact name (uses FindByName dictionary)
+    for name in ["Kind"; "Label"; "DefaultKind"; "Index"] do
+        let prop = widgetType.GetProperty(name, allFlags)
+        Assert.NotNull(prop)
+        Assert.Equal(name, prop.Name)
+
+[<Fact>]
+let ``Widget type has expected number of properties``() =
+    let assembly = loadTestAssembly ()
+    let containerType = assembly.ExportedTypes |> Seq.find (fun t -> t.Name = "Container")
+    let widgetType = containerType.GetNestedType("Widget")
+    Assert.NotNull(widgetType)
+
+    let allProps = widgetType.GetProperties(BindingFlags.Instance ||| BindingFlags.Static ||| BindingFlags.Public)
+    Assert.Equal(4, allProps.Length)