// Issue 27282: Example 2: This sidesteps the AST checks disallowing // mutable borrows in match guards by hiding the mutable borrow in a // guard behind a move (of the mutably borrowed match input) within a // closure. // // This example is not rejected by AST borrowck (and then reliably // reaches the panic code when executed, despite the compiler warning // about that match arm being unreachable. #![feature(if_let_guard)] fn main() { let b = &mut true; match b { //~^ ERROR use of moved value: `b` [E0382] &mut false => {}, _ if { (|| { let bar = b; *bar = false; })(); false } => { }, &mut true => { println!("You might think we should get here"); }, _ => panic!("surely we could never get here, since rustc warns it is unreachable."), } let b = &mut true; match b { //~^ ERROR use of moved value: `b` [E0382] &mut false => {} _ if let Some(()) = { (|| { let bar = b; *bar = false; })(); None } => {} &mut true => {} _ => {} } }