// run-pass #![allow(non_upper_case_globals)] // Issue 23611: this test is ensuring that, for an instance `X` of the // enum `E`, if you swap in a different variant during the execution // of the `<E as Drop>::drop`, then the appropriate substructure will // be torn down after the `<E as Drop>::drop` method returns. use std::cell::RefCell; use std::mem; use self::d::D; pub fn main() { let log = RefCell::new(vec![]); d::println("created empty log"); test(&log); // println!("log: {:?}", &log.borrow()[..]); assert_eq!( &log.borrow()[..], [ // created empty log // +-- Make D(test_1, 10000000) // | +-- Make D(g_b_5, 50000001) // | | in g_B(b2b0) from E::drop, b=b4b0 // | +-- Drop D(g_b_5, 50000001) 50000001, // | // | +-- Make D(drop_6, 60000002) // | | +-- Make D(g_b_5, 50000003) // | | | in g_B(b2b0) from E::drop, b=b4b1 // | | +-- Drop D(g_b_5, 50000003) 50000003, // | | // | | +-- Make D(GaspB::drop_3, 30000004) // | | | +-- Make D(g_b_5, 50000005) // | | | | in g_B(b4b2) from GaspB::drop // | | | +-- Drop D(g_b_5, 50000005) 50000005, // | | | // | | +-- Drop D(GaspB::drop_3, 30000004) 30000004, // | | // +-- Drop D(test_1, 10000000) 10000000, // | // +-- Make D(GaspA::drop_2, 20000006) // | | +-- Make D(f_a_4, 40000007) // | | | in f_A(a3a0) from GaspA::drop // | | +-- Drop D(f_a_4, 40000007) 40000007, // | | // +-- Drop D(GaspA::drop_2, 20000006) 20000006, // | // +-- Drop D(drop_6, 60000002) 60000002 // ]); // For reference purposes, the old (incorrect) behavior would produce the following // output, which you can compare to the above: // // created empty log // +-- Make D(test_1, 10000000) // | +-- Make D(g_b_5, 50000001) // | | in g_B(b2b0) from E::drop, b=b4b0 // | +-- Drop D(g_b_5, 50000001) // | // | +-- Make D(drop_6, 60000002) // | | +-- Make D(g_b_5, 50000003) // | | | in g_B(b2b0) from E::drop, b=b4b1 // | | +-- Drop D(g_b_5, 50000003) // | | // | | +-- Make D(GaspB::drop_3, 30000004) // | | | +-- Make D(g_b_5, 50000005) // | | | | in g_B(b4b2) from GaspB::drop // | | | +-- Drop D(g_b_5, 50000005) // | | | // | | +-- Drop D(GaspB::drop_3, 30000004) // | | // +-- Drop D(test_1, 10000000) // | // +-- Make D(GaspB::drop_3, 30000006) // | | +-- Make D(f_a_4, 40000007) // | | | in f_A(a3a0) from GaspB::drop // | | +-- Drop D(f_a_4, 40000007) // | | // +-- Drop D(GaspB::drop_3, 30000006) // | // +-- Drop D(drop_6, 60000002) // Note that this calls f_A from GaspB::drop (and thus creates a D // with a uid incorporating the origin of GaspB's drop that // surrounds the f_A invocation), but the code as written only // ever hands f_A off to instances of GaspA, and thus one should // be able to prove the invariant that f_A is *only* invoked from // from an instance of GaspA (either via the GaspA drop // implementation or the E drop implementation). Yet the old (bad) // behavior allowed a call to f_A to leak in while we are tearing // down a value of type GaspB. } fn test<'a>(log: d::Log<'a>) { let _e = E::B(GaspB(g_b, 0xB4B0, log, D::new("test", 1, log)), true); } struct GaspA<'a>(for <'b> fn(u32, &'b str, d::Log<'a>), u32, d::Log<'a>, d::D<'a>); struct GaspB<'a>(for <'b> fn(u32, &'b str, d::Log<'a>), u32, d::Log<'a>, d::D<'a>); impl<'a> Drop for GaspA<'a> { fn drop(&mut self) { let _d = d::D::new("GaspA::drop", 2, self.2); (self.0)(self.1, "GaspA::drop", self.2); } } impl<'a> Drop for GaspB<'a> { fn drop(&mut self) { let _d = d::D::new("GaspB::drop", 3, self.2); (self.0)(self.1, "GaspB::drop", self.2); } } enum E<'a> { A(GaspA<'a>, bool), B(GaspB<'a>, bool), } fn f_a(x: u32, ctxt: &str, log: d::Log) { let _d = d::D::new("f_a", 4, log); d::println(&format!("in f_A({:x}) from {}", x, ctxt)); } fn g_b(y: u32, ctxt: &str, log: d::Log) { let _d = d::D::new("g_b", 5, log); d::println(&format!("in g_B({:x}) from {}", y, ctxt)); } impl<'a> Drop for E<'a> { fn drop(&mut self) { let (do_drop, log) = match *self { E::A(GaspA(ref f, ref mut val_a, log, ref _d_a), ref mut do_drop) => { f(0xA1A0, &format!("E::drop, a={:x}", val_a), log); *val_a += 1; // swap in do_drop := false to avoid infinite dtor regress (mem::replace(do_drop, false), log) } E::B(GaspB(ref g, ref mut val_b, log, ref _d_b), ref mut do_drop) => { g(0xB2B0, &format!("E::drop, b={:x}", val_b), log); *val_b += 1; // swap in do_drop := false to avoid infinite dtor regress (mem::replace(do_drop, false), log) } }; #[allow(unused_must_use)] if do_drop { mem::replace(self, E::A(GaspA(f_a, 0xA3A0, log, D::new("drop", 6, log)), true)); } } } // This module provides simultaneous printouts of the dynamic extents // of all of the D values, in addition to logging the order that each // is dropped. // // This code is similar to a support code module embedded within // test/run-pass/issue-123338-ensure-param-drop-order.rs; however, // that (slightly simpler) code only identifies objects in the log via // (creation) time-stamps; this incorporates both timestamping and the // point of origin within the source code into the unique ID (uid). const PREF_INDENT: u32 = 20; pub mod d { #![allow(unused_parens)] use std::fmt; use std::mem; use std::cell::RefCell; static mut counter: u16 = 0; static mut trails: u64 = 0; pub type Log<'a> = &'a RefCell<Vec<u32>>; pub fn current_width() -> u32 { unsafe { max_width() - trails.leading_zeros() } } pub fn max_width() -> u32 { unsafe { (mem::size_of_val(&trails)*8) as u32 } } pub fn indent_println(my_trails: u32, s: &str) { let mut indent: String = String::new(); for i in 0..my_trails { unsafe { if trails & (1 << i) != 0 { indent = indent + "| "; } else { indent = indent + " "; } } } println!("{}{}", indent, s); } pub fn println(s: &str) { indent_println(super::PREF_INDENT, s); } fn first_avail() -> u32 { unsafe { for i in 0..64 { if trails & (1 << i) == 0 { return i; } } } panic!("exhausted trails"); } pub struct D<'a> { name: &'static str, i: u8, uid: u32, trail: u32, log: Log<'a> } impl<'a> fmt::Display for D<'a> { fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result { write!(w, "D({}_{}, {})", self.name, self.i, self.uid) } } impl<'a> D<'a> { pub fn new(name: &'static str, i: u8, log: Log<'a>) -> D<'a> { unsafe { let trail = first_avail(); let ctr = ((i as u32) * 10_000_000) + (counter as u32); counter += 1; trails |= (1 << trail); let ret = D { name: name, i: i, log: log, uid: ctr, trail: trail }; indent_println(trail, &format!("+-- Make {}", ret)); ret } } } impl<'a> Drop for D<'a> { fn drop(&mut self) { unsafe { trails &= !(1 << self.trail); }; self.log.borrow_mut().push(self.uid); indent_println(self.trail, &format!("+-- Drop {}", self)); indent_println(::PREF_INDENT, ""); } } }