diff options
Diffstat (limited to 'compiler/rustc_mir_build/src')
| -rw-r--r-- | compiler/rustc_mir_build/src/build/expr/as_place.rs | 32 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/cx/expr.rs | 8 |
2 files changed, 33 insertions, 7 deletions
diff --git a/compiler/rustc_mir_build/src/build/expr/as_place.rs b/compiler/rustc_mir_build/src/build/expr/as_place.rs index 70a74910a68..89a1f06d3d1 100644 --- a/compiler/rustc_mir_build/src/build/expr/as_place.rs +++ b/compiler/rustc_mir_build/src/build/expr/as_place.rs @@ -647,13 +647,31 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { match place_ty.kind() { ty::Array(_elem_ty, len_const) => { - // We know how long an array is, so just use that as a constant - // directly -- no locals needed. We do need one statement so - // that borrow- and initialization-checking consider it used, - // though. FIXME: Do we really *need* to count this as a use? - // Could partial array tracking work off something else instead? - self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place); - let const_ = Const::from_ty_const(*len_const, usize_ty, self.tcx); + let ty_const = if let Some((_, len_ty)) = len_const.try_to_valtree() + && len_ty != self.tcx.types.usize + { + // Bad const generics can give us a constant from the type that's + // not actually a `usize`, so in that case give an error instead. + // FIXME: It'd be nice if the type checker made sure this wasn't + // possible, instead. + let err = self.tcx.dcx().span_delayed_bug( + span, + format!( + "Array length should have already been a type error, as it's {len_ty:?}" + ), + ); + ty::Const::new_error(self.tcx, err) + } else { + // We know how long an array is, so just use that as a constant + // directly -- no locals needed. We do need one statement so + // that borrow- and initialization-checking consider it used, + // though. FIXME: Do we really *need* to count this as a use? + // Could partial array tracking work off something else instead? + self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place); + *len_const + }; + + let const_ = Const::from_ty_const(ty_const, usize_ty, self.tcx); Operand::Constant(Box::new(ConstOperand { span, user_ty: None, const_ })) } ty::Slice(_elem_ty) => { diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs index 6770e562d50..65a91d003af 100644 --- a/compiler/rustc_mir_build/src/thir/cx/expr.rs +++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs @@ -25,6 +25,14 @@ use crate::thir::cx::Cx; use crate::thir::util::UserAnnotatedTyHelpers; impl<'tcx> Cx<'tcx> { + /// Create a THIR expression for the given HIR expression. This expands all + /// adjustments and directly adds the type information from the + /// `typeck_results`. See the [dev-guide] for more details. + /// + /// (The term "mirror" in this case does not refer to "flipped" or + /// "reversed".) + /// + /// [dev-guide]: https://rustc-dev-guide.rust-lang.org/thir.html pub(crate) fn mirror_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) -> ExprId { // `mirror_expr` is recursing very deep. Make sure the stack doesn't overflow. ensure_sufficient_stack(|| self.mirror_expr_inner(expr)) |