rust/tests/ui/nll/issue-53040.stderr

error: captured variable cannot escape `FnMut` closure body
  --> $DIR/issue-53040.rs:3:8
   |
LL |     let mut v: Vec<()> = Vec::new();
   |         ----- variable defined here
LL |     || &mut v;
   |      - ^^^^^-
   |      | |    |
   |      | |    variable captured here
   |      | returns a reference to a captured variable which escapes the closure body
   |      inferred to be a `FnMut` closure
   |
   = note: `FnMut` closures only have access to their captured variables while they are executing...
   = note: ...therefore, they cannot allow references to captured variables to escape

error: aborting due to previous error
Improve errors for `FnMut` closures. This commit improves the errors for `FnMut` closures where a reference to a captured variable is escaping. 2018-10-03 23:50:23 +00:00			error: captured variable cannot escape `FnMut` closure body
remove feature(nll) in more cases. 2019-09-06 14:23:00 +00:00			`--> $DIR/issue-53040.rs:3:8`
Improve errors for `FnMut` closures. This commit improves the errors for `FnMut` closures where a reference to a captured variable is escaping. 2018-10-03 23:50:23 +00:00			`\|`
Display information about captured variable in `FnMut` error Fixes #69446 When we encounter a region error involving an `FnMut` closure, we display a specialized error message. However, we currently do not tell the user which upvar was captured. This makes it difficult to determine the cause of the error, especially when the closure is large. This commit records marks constraints involving closure upvars with `ConstraintCategory::ClosureUpvar`. When we decide to 'blame' a `ConstraintCategory::Return`, we additionall store the captured upvar if we found a `ConstraintCategory::ClosureUpvar` in the path. When generating an error message, we point to relevant spans if we have closure upvar information available. We further customize the message if an `async` closure is being returned, to make it clear that the captured variable is being returned indirectly. 2020-05-24 01:40:55 +00:00			`LL \| let mut v: Vec<()> = Vec::new();`
			`\| ----- variable defined here`
Improve errors for `FnMut` closures. This commit improves the errors for `FnMut` closures where a reference to a captured variable is escaping. 2018-10-03 23:50:23 +00:00			`LL \| \|\| &mut v;`
Display information about captured variable in `FnMut` error Fixes #69446 When we encounter a region error involving an `FnMut` closure, we display a specialized error message. However, we currently do not tell the user which upvar was captured. This makes it difficult to determine the cause of the error, especially when the closure is large. This commit records marks constraints involving closure upvars with `ConstraintCategory::ClosureUpvar`. When we decide to 'blame' a `ConstraintCategory::Return`, we additionall store the captured upvar if we found a `ConstraintCategory::ClosureUpvar` in the path. When generating an error message, we point to relevant spans if we have closure upvar information available. We further customize the message if an `async` closure is being returned, to make it clear that the captured variable is being returned indirectly. 2020-05-24 01:40:55 +00:00			`\| - ^^^^^-`
			`\| \| \| \|`
			`\| \| \| variable captured here`
			`\| \| returns a reference to a captured variable which escapes the closure body`
Improve errors for `FnMut` closures. This commit improves the errors for `FnMut` closures where a reference to a captured variable is escaping. 2018-10-03 23:50:23 +00:00			\| inferred to be a `FnMut` closure
			`\|`
			= note: `FnMut` closures only have access to their captured variables while they are executing...
			`= note: ...therefore, they cannot allow references to captured variables to escape`

			`error: aborting due to previous error`