diff options
Diffstat (limited to 'compiler/rustc_error_codes/src')
| -rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0311.md | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0311.md b/compiler/rustc_error_codes/src/error_codes/E0311.md index a9d44dcdcee..9521adc2522 100644 --- a/compiler/rustc_error_codes/src/error_codes/E0311.md +++ b/compiler/rustc_error_codes/src/error_codes/E0311.md @@ -29,22 +29,21 @@ Rust book) to the `nested_borrow_mut` and `borrow_mut` functions. In both cases the input is a reference to `self`, so the compiler attempts to assign the the same lifetime to the input and output. -Looking specifically at `nested_borrow_mut`, -we see that there are three object references to keep track of, -along with their associated lifetimes: +Looking specifically at `nested_borrow_mut`, we see that there are three object +references to keep track of, along with their associated lifetimes: - `self` (which is a `&mut T`) - `u_ref` (which is a `&mut U`) - `v_ref` (which is a `&mut V`) The `borrow_mut()` method implicitly requires that that the input and output -have the same lifetime bounds. Thus: +have the same lifetime bounds. Thus the lines: ```rust let u_ref = self.borrow_mut(); let v_ref = u_ref.borrow_mut(); ``` -Imply that `u_ref` and `self` must share a lifetime bound, and also that +imply that `u_ref` and `self` must share a lifetime bound, and also that `v_ref` and `u_ref` share a lifetime bound. The problem is that the function signature for `nested_borrow_mut` only gives the compiler information about the lifetimes of `self` and `v_ref` -- nothing about `u_ref`. |