I've run into the same issue as described in oapi-codegen/oapi-codegen#1344 with in: query parameters annotated with x-go-type-skip-optional-pointer extension.

I was a bit surprised at the beginning because codegen generates the code with plain struct field (i.e. skips pointer) as expected in the query string params struct but fails with panic during runtime. Turns out it wasn't that hard to fix and it seems am useful addition for users that desire zero values for optional parameters instead of pointers with nil value to communicate lack of parameter.