diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs index 19b5c8689c840..a3034ad1e6564 100644 --- a/compiler/rustc_borrowck/src/lib.rs +++ b/compiler/rustc_borrowck/src/lib.rs @@ -183,9 +183,6 @@ fn do_mir_borrowck<'tcx>( let location_table = LocationTable::new(body); let move_data = MoveData::gather_moves(body, tcx, |_| true); - let promoted_move_data = promoted - .iter_enumerated() - .map(|(idx, body)| (idx, MoveData::gather_moves(body, tcx, |_| true))); let flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data) .iterate_to_fixpoint(tcx, body, Some("borrowck")) @@ -235,10 +232,14 @@ fn do_mir_borrowck<'tcx>( false }; - for (idx, move_data) in promoted_move_data { + // While promoteds should mostly be correct by construction, we need to check them for + // invalid moves to detect moving out of arrays:`struct S; fn main() { &([S][0]); }`. + for promoted_body in &promoted { use rustc_middle::mir::visit::Visitor; - - let promoted_body = &promoted[idx]; + // This assumes that we won't use some of the fields of the `promoted_mbcx` + // when detecting and reporting move errors. While it would be nice to move + // this check out of `MirBorrowckCtxt`, actually doing so is far from trivial. + let move_data = MoveData::gather_moves(promoted_body, tcx, |_| true); let mut promoted_mbcx = MirBorrowckCtxt { infcx: &infcx, body: promoted_body, @@ -262,9 +263,6 @@ fn do_mir_borrowck<'tcx>( move_errors: Vec::new(), diags, }; - MoveVisitor { ctxt: &mut promoted_mbcx }.visit_body(promoted_body); - promoted_mbcx.report_move_errors(); - struct MoveVisitor<'a, 'b, 'infcx, 'tcx> { ctxt: &'a mut MirBorrowckCtxt<'b, 'infcx, 'tcx>, } @@ -276,6 +274,8 @@ fn do_mir_borrowck<'tcx>( } } } + MoveVisitor { ctxt: &mut promoted_mbcx }.visit_body(promoted_body); + promoted_mbcx.report_move_errors(); } let mut mbcx = MirBorrowckCtxt {