rust-clippy/tests/ui/drop_bounds.stderr

error: Bounds of the form `T: Drop` are useless. Use `std::mem::needs_drop` to detect if a type has drop glue.
  --> $DIR/drop_bounds.rs:2:11
   |
LL | fn foo<T: Drop>() {}
   |           ^^^^
   |
   = note: #[deny(clippy::drop_bounds)] on by default

error: Bounds of the form `T: Drop` are useless. Use `std::mem::needs_drop` to detect if a type has drop glue.
  --> $DIR/drop_bounds.rs:5:8
   |
LL |     T: Drop,
   |        ^^^^

error: aborting due to 2 previous errors
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			error: Bounds of the form `T: Drop` are useless. Use `std::mem::needs_drop` to detect if a type has drop glue.
			`--> $DIR/drop_bounds.rs:2:11`
			`\|`
			`LL \| fn foo<T: Drop>() {}`
			`\| ^^^^`
			`\|`
			`= note: #[deny(clippy::drop_bounds)] on by default`

			error: Bounds of the form `T: Drop` are useless. Use `std::mem::needs_drop` to detect if a type has drop glue.
Fix formatting 2019-02-19 02:36:58 +00:00			`--> $DIR/drop_bounds.rs:5:8`
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			`\|`
Fix formatting 2019-02-19 02:36:58 +00:00			`LL \| 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
			`error: aborting due to 2 previous errors`