[C# 13]: New Feature - Overload Resolution Priority

[BillWagner]

Visual Studio release

Other (please put exact version in description textbox)

Link to speclet

• Speclet

Link to Pull request

• PR

New behavior

Merged in 17.12p1

This PR specifies an attribute that can raise or lower the relative likelihood that an overload is chosen as "better" than another overload.

It is used later in the overload resolution as an "escape hatch" or "tie breaker" to pick a preferred overload, typically for performance reasons.

Areas affected

• Add to What's new in C# 13: Add links to updated docs in the What's new in C# 13 article.
• Update language reference: Detail the areas in the language reference that will be updated for this feature.
• Update compiler messages: Add new (or updated) pages for new compiler messages. Include related message.
• Include in Everyday C# section*: Is this new feature included in Everyday C#?
• Tutorials: Are new tutorials required for this feature? If so, detail below

Language reference tasks

We don't expect a lot of developers will directly use this feature. The runtime team is leveraging it to make Span based overloads preferred over allocating overloads.

• Add the attribute to the code generation page on attributes.
• Update the text on overload resolution to mention this feature.
• Linke from What's new
• Update errrors and warnings
• Publish speclet.

Tutorial tasks

None.

Everyday C# tasks

None.

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Associated WorkItem - 310943