better perf by avoiding redundant casts

[SimonCropp]

No description provided.

[Copilot]

Pull request overview

This PR performs small, targeted micro-optimizations across SqlClient hot paths by replacing repeated is checks + explicit casts with C# pattern matching (is T t) to avoid redundant casts/unboxing and simplify code.

Changes:

• Replace if (x is T) { (T)x ... } patterns with if (x is T t) { t ... } in multiple locations.
• Simplify a couple of ConvertTo(...) TypeConverter implementations by combining type checks and casts.
• Minor readability cleanup in exception handling and bulk-copy XML handling.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsParser.cs	Uses pattern-matching locals to avoid repeated casts/unboxing while writing/serializing values (RPC params, bulk copy, and serialization paths).
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlUtil.cs	Simplifies SqlException detection/cast when building error arrays.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlParameter.cs	TypeConverter ConvertTo now pattern-matches SqlParameter once before calling instance descriptor conversion.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlConnectionStringBuilder.cs	TypeConverter ConvertTo now pattern-matches SqlConnectionStringBuilder before instance descriptor conversion.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlCommand.cs	Avoids duplicate cast by binding SqlString via pattern matching in ANSI size computation logic.
src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlBulkCopy.cs	Avoids duplicate cast when converting XmlReader to XmlDataFeed for XML/JSON bulk copy values.

[paulmedynski]

Looks great!

[paulmedynski]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[codecov]

Codecov Report

❌ Patch coverage is 29.41176% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.12%. Comparing base (569ada7) to head (9d7e7d7).
⚠️ Report is 74 commits behind head on main.

Files with missing lines	Patch %	Lines
...qlClient/src/Microsoft/Data/SqlClient/TdsParser.cs	0.00%	10 Missing ⚠️
...lient/src/Microsoft/Data/SqlClient/SqlParameter.cs	50.00%	2 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (569ada7) and HEAD (9d7e7d7). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (569ada7)	HEAD (9d7e7d7)
CI-SqlClient	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4018      +/-   ##
==========================================
- Coverage   72.36%   66.12%   -6.25%     
==========================================
  Files         287      271      -16     
  Lines       43149    65716   +22567     
==========================================
+ Hits        31223    43452   +12229     
- Misses      11926    22264   +10338     

Flag	Coverage Δ
CI-SqlClient	?
PR-SqlClient-Project	66.12% <29.41%> (?)

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