1 warning: captured variable cannot escape `FnMut` closure body
2 --> $DIR/issue-40510-3.rs:11:9
5 | - inferred to be a `FnMut` closure
9 | |_________^ returns a closure that contains a reference to a captured variable, which then escapes the closure body
11 = note: `FnMut` closures only have access to their captured variables while they are executing...
12 = note: ...therefore, they cannot allow references to captured variables to escape
13 = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
14 = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
16 error: compilation successful
17 --> $DIR/issue-40510-3.rs:22:1
22 error: aborting due to previous error