[Analyzer] Use IndexOfAnyValues instead of inlined or cached array

[stephentoub]

#68328 is adding a new caching mechanism for IndexOfAny, such that instead of:

private static readonly char[] s_values = new[] { ... }
...
int index = span.IndexOfAny(s_values);

you can write:

private static readonly IndexOfAnyValues<char> s_values = IndexOfAnyValues.Create(new[] { ... }); 
...
int index = span.IndexOfAny(s_values);

We should consider an info-level performance analyzer that will flag cases like that above or where IndexOfAny is being called with an inline array (e.g. IndexOfAny(new[] { ... })) (or with a string constant containing the characters), and recommend switching to use IndexOfAnyValues, ideally with a fixer to automatically make the change.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[stephentoub]

cc: @MihaZupan, @marklio

[ghost]

Tagging subscribers to this area: @dotnet/area-system-memory
See info in area-owners.md if you want to be subscribed.

Issue Details

---

#68328 is adding a new caching mechanism for IndexOfAny, such that instead of:

private static readonly char[] s_values = new[] { ... }
...
int index = span.IndexOfAny(s_values);

you can write:

private static readonly IndexOfAnyValues<char> s_values = IndexOfAnyValues.Create(new[] { ... }); 
...
int index = span.IndexOfAny(s_values);

We should consider an info-level performance analyzer that will flag cases like that above or where IndexOfAny is being called with an inline array (e.g. IndexOfAny(new[] { ... })) (or with a string constant containing the characters), and recommend switching to use IndexOfAnyValues, ideally with a fixer to automatically make the change.

Author:	stephentoub
Assignees:	-
Labels:	area-System.Memory, tenet-performance, code-analyzer, code-fixer
Milestone:	8.0.0

[bartonjs]

Video

The analyzer looks good as proposed.

Category: Performance
Severity: Info (which may get lowered based on the amount of noise in testing/development)

[MihaZupan]

Marking as 8.0 given we're backporting it in dotnet/roslyn-analyzers#6924