Use span-based string.Concat

[terrajobst]

The rule should flag instances of a pattern like str1 + str2.Substring(...) + str3 or string.Concat(str1, str2.Substring(...), str3) and instead switch to using the span-based string.Concat(str1, str2.AsSpan(...), str3).

Category: Performance
Suggested severity: Info

[jeffhandley]

Estimates:

• Analyzer: Medium
• Fixer: Medium

[Mrnikbobjeff]

The invocation of concat with substring can be caught by the string.Substring(x) analyzer which is already proposed

[buyaa-n]

Should this analyzer flag a case without Substring() and suggest Concat? like str1 + str2 + str3 => string.Concat(str1, str2, str3)