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Remove MIR borrowck hack for old match scopes

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This commit is contained in:
Matthew Jasper 2019-04-03 19:30:18 +01:00
parent f506aea1fa
commit 0f507246e7
1 changed files with 8 additions and 31 deletions
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39
src/librustc_mir/dataflow/impls/mod.rs
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@ -11,8 +11,7 @@ use super::MoveDataParamEnv;
use crate::util::elaborate_drops::DropFlagState;
use super::move_paths::{HasMoveData, MoveData, MovePathIndex, InitIndex};
use super::move_paths::{LookupResult, InitKind};
use super::move_paths::{HasMoveData, MoveData, MovePathIndex, InitIndex, InitKind};
use super::{BitDenotation, BlockSets, InitialFlow};
use super::drop_flag_effects_for_function_entry;
@ -470,35 +469,13 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for EverInitializedPlaces<'a, 'gcx, 'tc
sets.gen_all(&init_loc_map[location]);
match stmt.kind {
mir::StatementKind::StorageDead(local) |
mir::StatementKind::StorageLive(local) => {
// End inits for StorageDead and StorageLive, so that an immutable
// variable can be reinitialized on the next iteration of the loop.
//
// FIXME(#46525): We *need* to do this for StorageLive as well as
// StorageDead, because lifetimes of match bindings with guards are
// weird - i.e., this code
//
// ```
// fn main() {
// match 0 {
// a | a
// if { println!("a={}", a); false } => {}
// _ => {}
// }
// }
// ```
//
// runs the guard twice, using the same binding for `a`, and only
// storagedeads after everything ends, so if we don't regard the
// storagelive as killing storage, we would have a multiple assignment
// to immutable data error.
if let LookupResult::Exact(mpi) =
rev_lookup.find(&mir::Place::Base(mir::PlaceBase::Local(local))) {
debug!("stmt {:?} at loc {:?} clears the ever initialized status of {:?}",
stmt, location, &init_path_map[mpi]);
sets.kill_all(&init_path_map[mpi]);
}
mir::StatementKind::StorageDead(local) => {
// End inits for StorageDead, so that an immutable variable can
// be reinitialized on the next iteration of the loop.
let move_path_index = rev_lookup.find_local(local);
debug!("stmt {:?} at loc {:?} clears the ever initialized status of {:?}",
stmt, location, &init_path_map[move_path_index]);
sets.kill_all(&init_path_map[move_path_index]);
}
_ => {}
}