Diagnostic / Code Fixer idea

[TonyValenti]

I've noticed that in performance sensitive situations, dictionaries are often refactored into static switch statements.

It would be nice if there was a diagnostic/code fixer that could detect dictionaries that are never mutated and extract them out into a static switch-expression-based method.

[huoyaoyuan]

I've noticed that in performance sensitive situations, dictionaries are often refactored into static switch statements.

It heavily depends on what the key/data type is. In fact for larger types, switch statements should be refactored in to dictionary.

Additionally, neither switch statement nor dictionary are performant enough for critical scenarios. A smallint->bool match may be manually optimized into a shift on magic constant.