Remove the non-BCL generic params AppendJoin overloads

apiCount.include.md

@@ -1,17 +1,17 @@
-**API count: 1022**
+**API count: 1020**
 
 ### Per Target Framework
 
 | Target | APIs |
 | -- | -- |
-| `net461` | 969 |
-| `net462` | 969 |
-| `net47` | 968 |
-| `net471` | 967 |
-| `net472` | 963 |
+| `net461` | 967 |
+| `net462` | 967 |
+| `net47` | 966 |
+| `net471` | 965 |
+| `net472` | 961 |
 | `net48` | 963 |
-| `net481` | 963 |
-| `netstandard2.0` | 965 |
+| `net481` | 961 |
+| `netstandard2.0` | 963 |
 | `netstandard2.1` | 816 |
 | `netcoreapp2.0` | 886 |
 | `netcoreapp2.1` | 827 |
@@ -25,4 +25,4 @@
 | `net9.0` | 184 |
 | `net10.0` | 131 |
 | `net11.0` | 58 |
-| `uap10.0` | 955 |
+| `uap10.0` | 953 |

api_list.include.md

@@ -1148,8 +1148,6 @@
  * `StringBuilder AppendJoin(string?, object?[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin(system-string-system-object()))
  * `StringBuilder AppendJoin(string?, string?[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin(system-string-system-string()))
  * `StringBuilder AppendJoin<T>(char, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-string-system-collections-generic-ienumerable((-0))))
- * `StringBuilder AppendJoin<T>(char, T[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-char-system-collections-generic-ienumerable((-0))))
- * `StringBuilder AppendJoin<T>(string, T[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-string-system-collections-generic-ienumerable((-0))))
  * `StringBuilder AppendJoin<T>(string?, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-char-system-collections-generic-ienumerable((-0))))
  * `StringBuilder AppendLine(StringBuilder, AppendInterpolatedStringHandler)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendline?view=net-11.0#system-text-stringbuilder-appendline(system-text-stringbuilder-appendinterpolatedstringhandler@))
  * `StringBuilder AppendLine(StringBuilder, IFormatProvider?, AppendInterpolatedStringHandler)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendline?view=net-11.0#system-text-stringbuilder-appendline(system-iformatprovider-system-text-stringbuilder-appendinterpolatedstringhandler@))

readme.md

@@ -13,20 +13,20 @@ The package targets `netstandard2.0` and is designed to support the following ru
  * `uap10`
 
 
-**API count: 1022**<!-- include: apiCount. path: /apiCount.include.md -->
+**API count: 1020**<!-- include: apiCount. path: /apiCount.include.md -->
 
 ### Per Target Framework
 
 | Target | APIs |
 | -- | -- |
-| `net461` | 969 |
-| `net462` | 969 |
-| `net47` | 968 |
-| `net471` | 967 |
-| `net472` | 963 |
+| `net461` | 967 |
+| `net462` | 967 |
+| `net47` | 966 |
+| `net471` | 965 |
+| `net472` | 961 |
 | `net48` | 963 |
-| `net481` | 963 |
-| `netstandard2.0` | 965 |
+| `net481` | 961 |
+| `netstandard2.0` | 963 |
 | `netstandard2.1` | 816 |
 | `netcoreapp2.0` | 886 |
 | `netcoreapp2.1` | 827 |
@@ -40,7 +40,7 @@ The package targets `netstandard2.0` and is designed to support the following ru
 | `net9.0` | 184 |
 | `net10.0` | 131 |
 | `net11.0` | 58 |
-| `uap10.0` | 955 |
+| `uap10.0` | 953 |
 <!-- endInclude -->
 
 
@@ -1679,8 +1679,6 @@ The class `Polyfill` includes the following extension methods:
  * `StringBuilder AppendJoin(string?, object?[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin(system-string-system-object()))
  * `StringBuilder AppendJoin(string?, string?[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin(system-string-system-string()))
  * `StringBuilder AppendJoin<T>(char, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-string-system-collections-generic-ienumerable((-0))))
- * `StringBuilder AppendJoin<T>(char, T[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-char-system-collections-generic-ienumerable((-0))))
- * `StringBuilder AppendJoin<T>(string, T[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-string-system-collections-generic-ienumerable((-0))))
  * `StringBuilder AppendJoin<T>(string?, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-char-system-collections-generic-ienumerable((-0))))
  * `StringBuilder AppendLine(StringBuilder, AppendInterpolatedStringHandler)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendline?view=net-11.0#system-text-stringbuilder-appendline(system-text-stringbuilder-appendinterpolatedstringhandler@))
  * `StringBuilder AppendLine(StringBuilder, IFormatProvider?, AppendInterpolatedStringHandler)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendline?view=net-11.0#system-text-stringbuilder-appendline(system-iformatprovider-system-text-stringbuilder-appendinterpolatedstringhandler@))

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;NETSDK1138;NU1901;NU1902;NU1903;CA1822;CA1847;CA1861;NU1510;NU1608;NU1109</NoWarn>
-    <Version>11.0.1</Version>
+    <Version>11.0.2</Version>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Polyfill</PackageTags>
     <DisableImplicitNamespaceImports>true</DisableImplicitNamespaceImports>

src/Polyfill/Polyfill_StringBuilder_AppendJoin.cs

@@ -59,22 +59,6 @@ public static StringBuilder AppendJoin(
         params object?[] values) =>
         target.AppendJoinCore(separator, values);
 
-    /// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-char-system-collections-generic-ienumerable((-0)))
-    public static StringBuilder AppendJoin<T>(
-        this StringBuilder target,
-        char separator,
-        params T[] values) =>
-        target.AppendJoinCore(separator, values);
-
-    /// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.text.stringbuilder.appendjoin?view=net-11.0#system-text-stringbuilder-appendjoin-1(system-string-system-collections-generic-ienumerable((-0)))
-    public static StringBuilder AppendJoin<T>(
-        this StringBuilder target,
-        string separator,
-        params T[] values) =>
-        target.AppendJoinCore(separator, values);
-
     static StringBuilder AppendJoinCore<T>(
         this StringBuilder target,
         char separator,

src/Split/net461/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net462/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net47/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net471/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net472/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net48/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/net481/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/netstandard2.0/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Split/uap10.0/Polyfill_StringBuilder_AppendJoin.cs

@@ -43,18 +43,6 @@ public static StringBuilder AppendJoin(
 		char separator,
 		params object?[] values) =>
 		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		char separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
-	/// <summary>Concatenates and appends the members of a collection, using the specified char separator between each member.</summary>
-	public static StringBuilder AppendJoin<T>(
-		this StringBuilder target,
-		string separator,
-		params T[] values) =>
-		target.AppendJoinCore(separator, values);
 	static StringBuilder AppendJoinCore<T>(
 		this StringBuilder target,
 		char separator,

src/Tests/PolyfillTests_StringBuilder.cs

@@ -175,14 +175,54 @@ public async Task AppendJoin()
         await AssertAsync();
         builder.AppendJoin(',', new object[] {"value1", "value2"}.Select(_ => _));
         await AssertAsync();
-        // ReSharper disable once RedundantExplicitParamsArrayCreation
         builder.AppendJoin<string>(',', ["value1", "value2"]);
         await AssertAsync();
 
+        // A non-array collection must bind to the IEnumerable<T> overload, not be
+        // captured as a single element of a params array.
+        List<string> list = ["value1", "value2"];
+        builder.AppendJoin(',', list);
+        await AssertAsync();
+        builder.AppendJoin(",", list);
+        await AssertAsync();
+
         async Task AssertAsync()
         {
             await Assert.That(builder.ToString()).IsEqualTo("value1,value2");
             builder.Clear();
         }
     }
+
+    // The BCL has no AppendJoin overload taking a params array of an open generic type.
+    // Adding one makes it beat AppendJoin<T>(separator, IEnumerable<T>) for any non-array
+    // collection: the collection is captured as a single element, so AppendJoin(',', list)
+    // silently appends "System.Collections.Generic.List`1[System.String]" instead of its
+    // contents. It compiles, so only the output reveals it, and only on the frameworks
+    // where the polyfill is active.
+    [Test]
+    public async Task AppendJoinHasNoGenericParamsOverload()
+    {
+        var offenders = typeof(Polyfills.Polyfill)
+            .GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static)
+            .Where(_ => _.Name == "AppendJoin")
+            .Select(_ => _.GetParameters())
+            .Where(_ => _.Length > 0 && IsGenericParamsArray(_[^1]))
+            .ToList();
+
+        await Assert.That(offenders).IsEmpty();
+
+        static bool IsGenericParamsArray(ParameterInfo parameter)
+        {
+            if (parameter.ParameterType.GetElementType() is not {IsGenericParameter: true})
+            {
+                return false;
+            }
+
+            return parameter
+                .GetCustomAttributes(inherit: false)
+                .Any(_ => _.GetType().Name is
+                    nameof(ParamArrayAttribute) or
+                    "ParamCollectionAttribute");
+        }
+    }
 }