[Analyzer]: Extend string IndexOf => Contains analyzers to Span IndexOf/IndexOfAny/IndexOfAnyExcept

[MihaZupan]

We have an existing analyzer/fixer CA2249 that flags patterns like string.IndexOf('a') >= 0 and suggests replacing the call with string.Contains('a').

We should consider expanding that to also flag patterns like

• span.IndexOf('a') >= 0 => span.Contains('a')
• span.IndexOfAny('a', 'b') >= 0 => span.ContainsAny('a', 'b')
• span.IndexOfAnyExcept('a', 'b') >= 0 => span.ContainsAnyExcept('a', 'b')

and their inverse variants

• span.IndexOf('a') < 0 => !span.Contains('a')
• span.IndexOfAny('a', 'b') < 0 => !span.ContainsAny('a', 'b')
• span.IndexOfAnyExcept('a', 'b') < 0 => !span.ContainsAnyExcept('a', 'b')

Unlike with strings, these shouldn't run into issues w.r.t. culture.

Suggested category: usage / performance Suggested severity: suggestion

[ghost]

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Issue Details

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We have an existing analyzer/fixer [CA2249](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2249) that flags patterns like `string.IndexOf('a') >= 0` and suggests replacing the call with `string.Contains('a')`. We should consider expanding that to also flag patterns like - `span.IndexOf('a') >= 0` => `span.Contains('a')` - `span.IndexOfAny('a', 'b') >= 0` => `span.ContainsAny('a', 'b')` - `span.IndexOfAnyExcept('a', 'b') >= 0` => `span.ContainsAnyExcept('a', 'b')` Unlike with strings, these shouldn't run into issues w.r.t. culture. Suggested category: usage / performance Suggested severity: suggestion

Author:	MihaZupan
Assignees:	-
Labels:	`area-System.Memory`, `code-analyzer`, `code-fixer`
Milestone:	-