Closed
Description
What it does
Similar to extra_unused_lifetimes, checks for unused type parameters on functions and warns that this is likely unintended, suggesting that they be removed. (Note: should this only apply to functions, or are there other places it could be run?)
Lint Name
extra_unused_type_parameters
Category
complexity
Advantage
- Calling functions with unused type parameters requires adding a turbofish, since inferring them is impossible. The turbofish itself is useless other than to satisfy the compiler.
- If refactoring a function with a long signature and removing the use of generics, it's easy to miss removing the corresponding type parameter, especially if the function is
puband isn't used elsewhere. This accidentally exposes downstream users to the author's mistake, which is bad news.
Drawbacks
I can't think of any besides maybe the lint name, which might need some bikeshedding. Also, maybe a extra_unused_generics lint could be introduced that implies both extra_unused_lifetimes and extra_unused_type_params?
Example
pub fn foo<T>(x: u8) {
// T unused in function body as well
// ..
}Could be written as:
pub fn foo(x: u8) {
// ..
}