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Diffstat (limited to 'crates/hir-ty/src/infer/expr.rs')
| -rw-r--r-- | crates/hir-ty/src/infer/expr.rs | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs index fef02e63b7..2bb384ba22 100644 --- a/crates/hir-ty/src/infer/expr.rs +++ b/crates/hir-ty/src/infer/expr.rs @@ -558,7 +558,7 @@ impl<'a> InferenceContext<'a> { } .intern(Interner) } - &Expr::Box { expr } => self.infer_expr_box(expr), + &Expr::Box { expr } => self.infer_expr_box(expr, expected), Expr::UnaryOp { expr, op } => { let inner_ty = self.infer_expr_inner(*expr, &Expectation::none()); let inner_ty = self.resolve_ty_shallow(&inner_ty); @@ -786,10 +786,23 @@ impl<'a> InferenceContext<'a> { ty } - fn infer_expr_box(&mut self, inner_expr: ExprId) -> chalk_ir::Ty<Interner> { - let inner_ty = self.infer_expr_inner(inner_expr, &Expectation::none()); - if let Some(box_) = self.resolve_boxed_box() { - TyBuilder::adt(self.db, box_) + fn infer_expr_box(&mut self, inner_expr: ExprId, expected: &Expectation) -> Ty { + if let Some(box_id) = self.resolve_boxed_box() { + let table = &mut self.table; + let inner_exp = expected + .to_option(table) + .as_ref() + .map(|e| e.as_adt()) + .flatten() + .filter(|(e_adt, _)| e_adt == &box_id) + .map(|(_, subts)| { + let g = subts.at(Interner, 0); + Expectation::rvalue_hint(table, Ty::clone(g.assert_ty_ref(Interner))) + }) + .unwrap_or_else(Expectation::none); + + let inner_ty = self.infer_expr_inner(inner_expr, &inner_exp); + TyBuilder::adt(self.db, box_id) .push(inner_ty) .fill_with_defaults(self.db, || self.table.new_type_var()) .build() |