Timeline for Why does C# type pattern matching use a different variable scoping behavior than traditional switch blocks?

7 events

when toggle format	what		by	license	comment
May 16, 2019 at 15:55	vote	accept	rory.ap
May 16, 2019 at 7:08	history	edited	David Arno	CC BY-SA 4.0	added 1276 characters in body
May 15, 2019 at 18:41	comment	added	David Arno		@RobertHarvey, Absolutely. In fact the OP's examples would read better if they'd used `case Cat cat` and `case Dog dog` . The re-use of variable names comes into its own though with when guards. `case Cat cat1 when cat1.Claws == Claws.Retractable:...` and `case Cat cat2 ...` would be ugly. Being able to use `cat` in both cases improves readability in my view.
May 15, 2019 at 15:34	comment	added	Robert Harvey		Fair enough, though it now occurs to me that the OP's example would have worked just as well if C# still insisted on different variables for each `case`, as Microsoft's code samples demonstrate.
May 15, 2019 at 15:21	comment	added	David Arno		@RobertHarvey, No. They did it that way, despite it being very controversial at the time, because it works well in most scenarios. I argued at the time that the benefits that those inconsistent rules brought did not outweigh sullying the language with those inconsistencies. I lost the argument. Given that most developers seem happy with the language designers’ decision, it was good that I lost.
May 15, 2019 at 15:16	comment	added	Robert Harvey		In other words, "They did it this way because they did it this way?"
May 15, 2019 at 14:54	history	answered	David Arno	CC BY-SA 4.0