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Add some comments related to place op typeck

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This commit is contained in:
Gary Guo 2020-06-16 22:48:35 +01:00
parent 5cedf5dfba
commit 2b7d858866
2 changed files with 7 additions and 6 deletions
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7
src/librustc_typeck/check/mod.rs
View file

@ -3219,10 +3219,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
// When there is an auto mutable borrow, it is equivalent to `&mut expr`,
// thus `expr` is ought to be typechecked with needs = [`Needs::MutPlace`].
// However in many cases it might not be checked this way originally, e.g.
// the receiver of a method call. We need to fix them up.
// If there is an mutable auto-borrow, it is equivalent to `&mut <expr>`.
// In this case implicit use of `Deref` and `Index` within `<expr>` should
// instead be `DerefMut` and `IndexMut`, so fix those up.
if autoborrow_mut {
self.convert_place_derefs_to_mutable(expr);
}

6
src/librustc_typeck/check/place_op.rs
View file

@ -11,10 +11,11 @@ use rustc_span::symbol::{sym, Ident};
use rustc_span::Span;
impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
/// Type-check `*oprnd_expr` with `oprnd_expr` type-checked already.
pub(super) fn lookup_derefing(
&self,
expr: &hir::Expr<'_>,
oprnd: &'tcx hir::Expr<'tcx>,
oprnd_expr: &'tcx hir::Expr<'tcx>,
oprnd_ty: Ty<'tcx>,
) -> Option<Ty<'tcx>> {
if let Some(mt) = oprnd_ty.builtin_deref(true) {
@ -25,7 +26,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let method = self.register_infer_ok_obligations(ok);
if let ty::Ref(region, _, hir::Mutability::Not) = method.sig.inputs()[0].kind {
self.apply_adjustments(
oprnd,
oprnd_expr,
vec![Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(region, AutoBorrowMutability::Not)),
target: method.sig.inputs()[0],
@ -39,6 +40,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Some(ty)
}
/// Type-check `*base_expr[index_expr]` with `base_expr` and `index_expr` type-checked already.
pub(super) fn lookup_indexing(
&self,
expr: &hir::Expr<'_>,