[Everyday C#] Fundamentals: Equality comparisons#54849
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Add fundamentals concept article on object equality for classes, structs, records, and tuples. Covers value equality vs. reference equality, Equals/==/ReferenceEquals semantics, IEquatable<T> implementation pattern, and record compiler-generated equality. Backed by a net10.0 snippet project (0 warnings, 0 errors). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 5dca83ef-a274-4737-96d5-a311bfe58550
Relocate the Equality fundamentals article and snippets from Type system to the new Expressions folder, and update the TOC and relative links for the new location. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bc6b7895-3b18-45ff-99de-540618819cb3
Clarify default equality behavior, operator terminology, and manual value equality guidance. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bc6b7895-3b18-45ff-99de-540618819cb3
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bc6b7895-3b18-45ff-99de-540618819cb3
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bc6b7895-3b18-45ff-99de-540618819cb3
Deemphasize the value of IEquatable<T> throughout the article.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: bc6b7895-3b18-45ff-99de-540618819cb3
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Pull request overview
Adds a new Everyday C# Fundamentals article that explains equality comparisons across common C# type categories, backed by a buildable snippet project, and wires the article into the C# TOC.
Changes:
- Adds a new article:
fundamentals/expressions/equality.md. - Adds a buildable snippet project under
fundamentals/expressions/snippets/equality/used by the article. - Updates the C# TOC to link the new article under Expressions and statements.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| docs/csharp/toc.yml | Adds a TOC entry for the new equality article. |
| docs/csharp/fundamentals/expressions/equality.md | Introduces the new equality comparisons article and references snippets. |
| docs/csharp/fundamentals/expressions/snippets/equality/Program.cs | Adds runnable examples demonstrating default equality behavior and IEquatable<T>. |
| docs/csharp/fundamentals/expressions/snippets/equality/equality.csproj | Adds a minimal project file to build and run the snippet code. |
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Run another edit pass on this PR.
This organization of the material works much better.
BillWagner
marked this pull request as ready for review
July 22, 2026 18:29
wadepickett
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@BillWagner: Approved, great work! See my few very minor suggestions inline that you could take or leave.
Co-authored-by: Wade Pickett <wpickett@microsoft.com>
BillWagner
enabled auto-merge (squash)
July 23, 2026 16:00
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@BillWagner , re-approved.
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Closes #54112
Phase E / PR 14b of the Everyday C# Fundamentals restructuring.
Summary:
docs/csharp/fundamentals/expressions/equality.mdin the newfundamentals/expressions/folder, added to the TOC under "Expressions and statements".==,!=,Equals,GetHashCode,ReferenceEquals), and how to add value equality by hand (with a record-first IMPORTANT callout).snippets/equality/), verifieddotnet build0 warnings/0 errors on net10.0 withdotnet runoutput matching the article.operators.mdis intentionally deferred to PR 16 and is not included here.Internal previews