bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/infer/mutability.rs')
-rw-r--r--crates/hir-ty/src/infer/mutability.rs33
1 files changed, 29 insertions, 4 deletions
diff --git a/crates/hir-ty/src/infer/mutability.rs b/crates/hir-ty/src/infer/mutability.rs
index abb702d150..66267e08db 100644
--- a/crates/hir-ty/src/infer/mutability.rs
+++ b/crates/hir-ty/src/infer/mutability.rs
@@ -1,7 +1,7 @@
//! Finds if an expression is an immutable context or a mutable context, which is used in selecting
//! between `Deref` and `DerefMut` or `Index` and `IndexMut` or similar.
-use chalk_ir::Mutability;
+use chalk_ir::{cast::Cast, Mutability};
use hir_def::{
hir::{Array, BinaryOp, BindingAnnotation, Expr, ExprId, PatId, Statement, UnaryOp},
lang_item::LangItem,
@@ -9,7 +9,10 @@ use hir_def::{
use hir_expand::name::Name;
use intern::sym;
-use crate::{lower::lower_to_chalk_mutability, Adjust, Adjustment, AutoBorrow, OverloadedDeref};
+use crate::{
+ infer::Expectation, lower::lower_to_chalk_mutability, Adjust, Adjustment, AutoBorrow, Interner,
+ OverloadedDeref, TyBuilder, TyKind,
+};
use super::InferenceContext;
@@ -101,7 +104,7 @@ impl InferenceContext<'_> {
Expr::RecordLit { path: _, fields, spread, ellipsis: _, is_assignee_expr: _ } => {
self.infer_mut_not_expr_iter(fields.iter().map(|it| it.expr).chain(*spread))
}
- &Expr::Index { base, index, is_assignee_expr: _ } => {
+ &Expr::Index { base, index, is_assignee_expr } => {
if mutability == Mutability::Mut {
if let Some((f, _)) = self.result.method_resolutions.get_mut(&tgt_expr) {
if let Some(index_trait) = self
@@ -115,6 +118,7 @@ impl InferenceContext<'_> {
.method_by_name(&Name::new_symbol_root(sym::index_mut.clone()))
{
*f = index_fn;
+ let mut base_ty = None;
let base_adjustments = self
.result
.expr_adjustments
@@ -122,11 +126,32 @@ impl InferenceContext<'_> {
.and_then(|it| it.last_mut());
if let Some(Adjustment {
kind: Adjust::Borrow(AutoBorrow::Ref(mutability)),
- ..
+ target,
}) = base_adjustments
{
+ // For assignee exprs `IndexMut` obiligations are already applied
+ if !is_assignee_expr {
+ if let TyKind::Ref(_, _, ty) = target.kind(Interner) {
+ base_ty = Some(ty.clone());
+ }
+ }
*mutability = Mutability::Mut;
}
+
+ // Apply `IndexMut` obligation for non-assignee expr
+ if let Some(base_ty) = base_ty {
+ let index_ty =
+ if let Some(ty) = self.result.type_of_expr.get(index) {
+ ty.clone()
+ } else {
+ self.infer_expr(index, &Expectation::none())
+ };
+ let trait_ref = TyBuilder::trait_ref(self.db, index_trait)
+ .push(base_ty)
+ .fill(|_| index_ty.clone().cast(Interner))
+ .build();
+ self.push_obligation(trait_ref.cast(Interner));
+ }
}
}
}