Apply string interpolation optimizations to netstandard2.0 as well

src/Microsoft.VisualStudio.Validation/Assumes.cs

@@ -163,8 +163,6 @@ public static partial class Assumes
         }
     }
 
-#if NET6_0_OR_GREATER
-
     /// <summary>
     /// Throws an public exception if a condition evaluates to true.
     /// </summary>
@@ -178,8 +176,6 @@ public static partial class Assumes
         }
     }
 
-#endif
-
     /// <summary>
     /// Throws an public exception if a condition evaluates to false.
     /// </summary>
@@ -219,8 +215,6 @@ public static partial class Assumes
         }
     }
 
-#if NET6_0_OR_GREATER
-
     /// <summary>
     /// Throws an public exception if a condition evaluates to false.
     /// </summary>
@@ -234,8 +228,6 @@ public static partial class Assumes
         }
     }
 
-#endif
-
     /// <summary>
     /// Unconditionally throws an <see cref="InternalErrorException"/>.
     /// </summary>

src/Microsoft.VisualStudio.Validation/Polyfill.cs

@@ -1,8 +1,9 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-#if !NET5_0_OR_GREATER
+#if !NET6_0_OR_GREATER
 
+#pragma warning disable SA1402 // File may only contain a single type
 #pragma warning disable SA1649 // File name should match first type name
 #pragma warning disable SA1600 // Elements should be documented
 
@@ -15,6 +16,24 @@ namespace System.Runtime.CompilerServices
         {
         }
     }
+
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct, AllowMultiple = false, Inherited = false)]
+    internal sealed class InterpolatedStringHandlerAttribute : Attribute
+    {
+        public InterpolatedStringHandlerAttribute()
+        {
+        }
+    }
+
+    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+    internal sealed class InterpolatedStringHandlerArgumentAttribute : Attribute
+    {
+        public InterpolatedStringHandlerArgumentAttribute(string argument) => this.Arguments = new string[] { argument };
+
+        public InterpolatedStringHandlerArgumentAttribute(params string[] arguments) => this.Arguments = arguments;
+
+        public string[] Arguments { get; }
+    }
 }
 
 #endif

src/Microsoft.VisualStudio.Validation/Report.cs

@@ -91,8 +91,6 @@ public static class Report
         }
     }
 
-#if NET6_0_OR_GREATER
-
     /// <summary>
     /// Reports an error if a condition does not evaluate to true.
     /// </summary>
@@ -105,8 +103,6 @@ public static class Report
         }
     }
 
-#endif
-
     /// <summary>
     /// Reports a certain failure.
     /// </summary>

src/Microsoft.VisualStudio.Validation/Requires.cs

@@ -418,8 +418,6 @@ public static class Requires
         }
     }
 
-#if NET6_0_OR_GREATER
-
     /// <summary>
     /// Throws an <see cref="ArgumentException"/> if a condition does not evaluate to true.
     /// </summary>
@@ -432,8 +430,6 @@ public static class Requires
         }
     }
 
-#endif
-
     /// <summary>
     /// Throws an <see cref="ArgumentException"/> if a condition does not evaluate to true.
     /// </summary>

src/Microsoft.VisualStudio.Validation/ValidationInterpolatedStringHandler.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-#if NET6_0_OR_GREATER
-
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -14,9 +12,12 @@ namespace Microsoft;
 [InterpolatedStringHandler]
 public ref struct ValidationInterpolatedStringHandler
 {
+    private StringBuilder? stringBuilder;
+
+#if NET6_0_OR_GREATER
     /// <summary>The handler we use to perform the formatting.</summary>
     private StringBuilder.AppendInterpolatedStringHandler stringBuilderHandler;
-    private StringBuilder? stringBuilder;
+#endif
 
     /// <summary>Initializes a new instance of the <see cref="ValidationInterpolatedStringHandler"/> struct.</summary>
     /// <param name="literalLength">The number of constant characters outside of interpolation expressions in the interpolated string.</param>
@@ -33,11 +34,17 @@ public ref struct ValidationInterpolatedStringHandler
         else
         {
             // Only used when failing an assert.  Additional allocation here doesn't matter; just create a new StringBuilder.
+#if NET6_0_OR_GREATER
             this.stringBuilderHandler = new StringBuilder.AppendInterpolatedStringHandler(literalLength, formattedCount, this.stringBuilder = new StringBuilder());
+#else
+            this.stringBuilder = new();
+#endif
             shouldAppend = true;
         }
     }
 
+#if NET6_0_OR_GREATER
+
     /// <summary>Writes the specified string to the handler.</summary>
     /// <param name="value">The string to write.</param>
     public void AppendLiteral(string value) => this.stringBuilderHandler.AppendLiteral(value);
@@ -92,15 +99,47 @@ public ref struct ValidationInterpolatedStringHandler
     /// <param name="format">The format string.</param>
     public void AppendFormatted(object? value, int alignment = 0, string? format = null) => this.stringBuilderHandler.AppendFormatted(value, alignment, format);
 
+#else
+
+    /// <summary>Writes the specified string to the handler.</summary>
+    /// <param name="value">The string to write.</param>
+    public void AppendLiteral(string value) => this.stringBuilder!.Append(value);
+
+    /// <summary>Writes the specified value to the handler.</summary>
+    /// <param name="value">The value to write.</param>
+    /// <typeparam name="T">The type of the value to write.</typeparam>
+    public void AppendFormatted<T>(T value) => this.stringBuilder!.Append(value);
+
+    /// <summary>Writes the specified value to the handler.</summary>
+    /// <param name="value">The value to write.</param>
+    /// <param name="alignment">Minimum number of characters that should be written for this value.  If the value is negative, it indicates left-aligned and the required minimum is the absolute value.</param>
+    /// <param name="format">The format string.</param>
+    /// <typeparam name="T">The type of the value to write.</typeparam>
+    public void AppendFormatted<T>(T value, int alignment = 0, string? format = null)
+    {
+        string result = value is IFormattable ? ((IFormattable)value).ToString(format, null) : (value?.ToString() ?? string.Empty);
+        bool left = alignment < 0;
+        alignment = Math.Abs(alignment);
+        if (result.Length < alignment)
+        {
+            string padding = new string(' ', alignment - result.Length);
+            result = left ? result + padding : padding + result;
+        }
+
+        this.stringBuilder!.Append(result);
+    }
+
+#endif
+
     /// <summary>Extracts the built string from the handler.</summary>
     /// <returns>The formatted string.</returns>
     internal string ToStringAndClear()
     {
         string s = this.stringBuilder?.ToString() ?? string.Empty;
         this.stringBuilder = null;
+#if NET6_0_OR_GREATER
         this.stringBuilderHandler = default;
+#endif
         return s;
     }
 }
-
-#endif

src/Microsoft.VisualStudio.Validation/ValidationInterpolatedStringHandlerInvertedCondition.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-#if NET6_0_OR_GREATER
-
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -14,9 +12,12 @@ namespace Microsoft;
 [InterpolatedStringHandler]
 public ref struct ValidationInterpolatedStringHandlerInvertedCondition
 {
+    private StringBuilder? stringBuilder;
+
+#if NET6_0_OR_GREATER
     /// <summary>The handler we use to perform the formatting.</summary>
     private StringBuilder.AppendInterpolatedStringHandler stringBuilderHandler;
-    private StringBuilder? stringBuilder;
+#endif
 
     /// <summary>Initializes a new instance of the <see cref="ValidationInterpolatedStringHandlerInvertedCondition"/> struct.</summary>
     /// <param name="literalLength">The number of constant characters outside of interpolation expressions in the interpolated string.</param>
@@ -33,11 +34,17 @@ public ref struct ValidationInterpolatedStringHandlerInvertedCondition
         else
         {
             // Only used when failing an assert.  Additional allocation here doesn't matter; just create a new StringBuilder.
+#if NET6_0_OR_GREATER
             this.stringBuilderHandler = new StringBuilder.AppendInterpolatedStringHandler(literalLength, formattedCount, this.stringBuilder = new StringBuilder());
+#else
+            this.stringBuilder = new();
+#endif
             shouldAppend = true;
         }
     }
 
+#if NET6_0_OR_GREATER
+
     /// <summary>Writes the specified string to the handler.</summary>
     /// <param name="value">The string to write.</param>
     public void AppendLiteral(string value) => this.stringBuilderHandler.AppendLiteral(value);
@@ -92,15 +99,47 @@ public ref struct ValidationInterpolatedStringHandlerInvertedCondition
     /// <param name="format">The format string.</param>
     public void AppendFormatted(object? value, int alignment = 0, string? format = null) => this.stringBuilderHandler.AppendFormatted(value, alignment, format);
 
+#else
+
+    /// <summary>Writes the specified string to the handler.</summary>
+    /// <param name="value">The string to write.</param>
+    public void AppendLiteral(string value) => this.stringBuilder!.Append(value);
+
+    /// <summary>Writes the specified value to the handler.</summary>
+    /// <param name="value">The value to write.</param>
+    /// <typeparam name="T">The type of the value to write.</typeparam>
+    public void AppendFormatted<T>(T value) => this.stringBuilder!.Append(value);
+
+    /// <summary>Writes the specified value to the handler.</summary>
+    /// <param name="value">The value to write.</param>
+    /// <param name="alignment">Minimum number of characters that should be written for this value.  If the value is negative, it indicates left-aligned and the required minimum is the absolute value.</param>
+    /// <param name="format">The format string.</param>
+    /// <typeparam name="T">The type of the value to write.</typeparam>
+    public void AppendFormatted<T>(T value, int alignment = 0, string? format = null)
+    {
+        string result = value is IFormattable ? ((IFormattable)value).ToString(format, null) : (value?.ToString() ?? string.Empty);
+        bool left = alignment < 0;
+        alignment = Math.Abs(alignment);
+        if (result.Length < alignment)
+        {
+            string padding = new string(' ', alignment - result.Length);
+            result = left ? result + padding : padding + result;
+        }
+
+        this.stringBuilder!.Append(result);
+    }
+
+#endif
+
     /// <summary>Extracts the built string from the handler.</summary>
     /// <returns>The formatted string.</returns>
     internal string ToStringAndClear()
     {
         string s = this.stringBuilder?.ToString() ?? string.Empty;
         this.stringBuilder = null;
+#if NET6_0_OR_GREATER
         this.stringBuilderHandler = default;
+#endif
         return s;
     }
 }
-
-#endif

src/Microsoft.VisualStudio.Validation/Verify.cs

@@ -61,8 +61,6 @@ public static partial class Verify
         }
     }
 
-#if NET6_0_OR_GREATER
-
     /// <summary>
     /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
     /// </summary>
@@ -75,8 +73,6 @@ public static partial class Verify
         }
     }
 
-#endif
-
     /// <summary>
     /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
     /// </summary>

test/Microsoft.VisualStudio.Validation.Tests/AssumesTests.cs

@@ -34,8 +34,6 @@ public partial class AssumesTests : IDisposable
         Assert.ThrowsAny<Exception>(() => Assumes.False(true, TestMessage, "arg1", "arg2"));
     }
 
-#if NET6_0_OR_GREATER
-
     [Fact]
     public void True_InterpolatedString()
     {
@@ -72,8 +70,6 @@ public partial class AssumesTests : IDisposable
         Assert.StartsWith("Some generated string method.", ex.Message);
     }
 
-#endif
-
     [Fact]
     public void Fail()
     {

test/Microsoft.VisualStudio.Validation.Tests/ReportTests.Debug.cs

@@ -107,8 +107,6 @@ public class ReportDebugTests : IDisposable
         }
     }
 
-#if NET6_0_OR_GREATER
-
     [Fact]
     public void IfNot_InterpolatedString()
     {
@@ -124,14 +122,16 @@ public class ReportDebugTests : IDisposable
             Report.IfNot(true, $"a{FormattingMethod()}c");
             Assert.Equal(0, formatCount);
             listener.Value.Setup(l => l.WriteLine("abc")).Verifiable();
+#if NETCOREAPP
             listener.Value.Setup(l => l.Fail("abc", string.Empty)).Verifiable();
+#else
+            listener.Value.Setup(l => l.Fail("abc")).Verifiable();
+#endif
             Report.IfNot(false, $"a{FormattingMethod()}c");
             Assert.Equal(1, formatCount);
         }
     }
 
-#endif
-
     [Fact]
     public void IfNotPresent()
     {

test/Microsoft.VisualStudio.Validation.Tests/ReportTests.Release.cs

@@ -76,8 +76,6 @@ public class ReportReleaseTests : IDisposable
         }
     }
 
-#if NET6_0_OR_GREATER
-
     [Fact]
     public void IfNot_InterpolatedString()
     {
@@ -97,8 +95,6 @@ public class ReportReleaseTests : IDisposable
         }
     }
 
-#endif
-
     [Fact]
     public void IfNotPresent()
     {

test/Microsoft.VisualStudio.Validation.Tests/RequiresTests.cs

@@ -150,8 +150,6 @@ public class RequiresTests
         Assert.StartsWith(TestStrings.FormatSomeError3Args("arg1", "arg2", "arg3"), ex.Message);
     }
 
-#if NET6_0_OR_GREATER
-
     [Fact]
     public void Argument_InterpolatedString()
     {
@@ -170,8 +168,6 @@ public class RequiresTests
         Assert.StartsWith("Some generated string method.", ex.Message);
     }
 
-#endif
-
     [Fact]
     public void Fail()
     {

test/Microsoft.VisualStudio.Validation.Tests/VerifyTests.cs

@@ -21,8 +21,6 @@ public class VerifyTests
         Assert.Throws<InvalidOperationException>(() => Verify.Operation(false, "throw", "arg1", "arg2", "arg3"));
     }
 
-#if NET6_0_OR_GREATER
-
     [Fact]
     public void Operation_InterpolatedString()
     {
@@ -41,8 +39,6 @@ public class VerifyTests
         Assert.StartsWith("Some generated string method.", ex.Message);
     }
 
-#endif
-
     [Fact]
     public void OperationWithHelp()
     {