rust/tests/ui/drop_bounds.rs

#![allow(unused)]
fn foo<T: Drop>() {}
fn bar<T>()
where
    T: Drop,
{
}
fn main() {}
Add a lint to warn on `T: Drop` bounds What it does: Checks for generics with `std::ops::Drop` as bounds. Why is this bad? `Drop` bounds do not really accomplish anything. A type may have compiler-generated drop glue without implementing the `Drop` trait itself. The `Drop` trait also only has one method, `Drop::drop`, and that function is by fiat not callable in user code. So there is really no use case for using `Drop` in trait bounds. Known problems: None. Example: ```rust fn foo<T: Drop>() {} ``` 2019-02-17 04:28:16 +00:00			`#![allow(unused)]`
			`fn foo<T: Drop>() {}`
Fix formatting 2019-02-19 02:36:58 +00:00			`fn bar<T>()`
			`where`
			`T: Drop,`
			`{`
			`}`
Add a lint to warn on `T: Drop` bounds What it does: Checks for generics with `std::ops::Drop` as bounds. Why is this bad? `Drop` bounds do not really accomplish anything. A type may have compiler-generated drop glue without implementing the `Drop` trait itself. The `Drop` trait also only has one method, `Drop::drop`, and that function is by fiat not callable in user code. So there is really no use case for using `Drop` in trait bounds. Known problems: None. Example: ```rust fn foo<T: Drop>() {} ``` 2019-02-17 04:28:16 +00:00			`fn main() {}`