fix: replace duplicate typeof(long) with typeof(ushort) in BaseSerializer.GetSize(T)

[Evangelink]

Summary

The GetSize<T>() switch expression in BaseSerializer had a duplicate typeof(long) arm that was unreachable dead code. The second arm should be typeof(ushort) to properly cover all the numeric types used in the IPC serializers.

Before:

private static int GetSize<T>() => typeof(T) switch
{
    Type type when type == typeof(int) => sizeof(int),
    Type type when type == typeof(long) => sizeof(long),
    Type type when type == typeof(short) => sizeof(short),
    Type type when type == typeof(bool) => sizeof(bool),
    Type type when type == typeof(byte) => sizeof(byte),
    Type type when type == typeof(long) => sizeof(long),  // ← duplicate, unreachable
    _ => 0,
};

After:

private static int GetSize<T>() => typeof(T) switch
{
    Type type when type == typeof(int) => sizeof(int),
    Type type when type == typeof(long) => sizeof(long),
    Type type when type == typeof(short) => sizeof(short),
    Type type when type == typeof(ushort) => sizeof(ushort),
    Type type when type == typeof(bool) => sizeof(bool),
    Type type when type == typeof(byte) => sizeof(byte),
    _ => 0,
};

No behavioral change — WriteSize<ushort> is not currently called, so this fix adds completeness while removing dead code.

Generated by Adhoc QA · sonnet46 3.2M · ◷

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[Copilot]

Pull request overview

This PR fixes a dead switch arm in BaseSerializer.GetSize<T>() by replacing the duplicate typeof(long) case with typeof(ushort), aligning size calculation coverage with the serializer’s ushort read/write helpers.

Changes:

• Adds ushort size handling in GetSize<T>().
• Removes the unreachable duplicate long switch arm.

Show a summary per file

File	Description
src/Platform/Microsoft.Testing.Platform/IPC/Serializers/BaseSerializer.cs	Updates primitive size mapping used by IPC serialization helpers.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0

[Youssef1313]

Shouldn't this throw unreachable?

[Evangelink]

Good catch — fixed in 6e4ca9b. Replaced _ => 0, with _ => throw ApplicationStateGuard.Unreachable(), to make the invariant explicit (GetSize<T> is private and only called by WriteSize<T> with a known closed set of primitive types).