diff options
Diffstat (limited to 'tests/ui/nll/match-guards-always-borrow.rs')
-rw-r--r-- | tests/ui/nll/match-guards-always-borrow.rs | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/tests/ui/nll/match-guards-always-borrow.rs b/tests/ui/nll/match-guards-always-borrow.rs new file mode 100644 index 000000000..ff63cc092 --- /dev/null +++ b/tests/ui/nll/match-guards-always-borrow.rs @@ -0,0 +1,64 @@ +#![feature(if_let_guard)] + +// Here is arielb1's basic example from rust-lang/rust#27282 +// that AST borrowck is flummoxed by: + +fn should_reject_destructive_mutate_in_guard() { + match Some(&4) { + None => {}, + ref mut foo if { + (|| { let bar = foo; bar.take() })(); + //~^ ERROR cannot move out of `foo` in pattern guard [E0507] + false } => { }, + Some(s) => std::process::exit(*s), + } + + match Some(&4) { + None => {}, + ref mut foo if let Some(()) = { + (|| { let bar = foo; bar.take() })(); + //~^ ERROR cannot move out of `foo` in pattern guard [E0507] + None } => { }, + Some(s) => std::process::exit(*s), + } +} + +// Here below is a case that needs to keep working: we only use the +// binding via immutable-borrow in the guard, and we mutate in the arm +// body. +fn allow_mutate_in_arm_body() { + match Some(&4) { + None => {}, + ref mut foo if foo.is_some() => { foo.take(); () } + Some(s) => std::process::exit(*s), + } + + match Some(&4) { + None => {}, + ref mut foo if let Some(_) = foo => { foo.take(); () } + Some(s) => std::process::exit(*s), + } +} + +// Here below is a case that needs to keep working: we only use the +// binding via immutable-borrow in the guard, and we move into the arm +// body. +fn allow_move_into_arm_body() { + match Some(&4) { + None => {}, + mut foo if foo.is_some() => { foo.unwrap(); () } + Some(s) => std::process::exit(*s), + } + + match Some(&4) { + None => {}, + mut foo if let Some(_) = foo => { foo.unwrap(); () } + Some(s) => std::process::exit(*s), + } +} + +fn main() { + should_reject_destructive_mutate_in_guard(); + allow_mutate_in_arm_body(); + allow_move_into_arm_body(); +} |