bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/infer/expr.rs')
-rw-r--r--crates/hir-ty/src/infer/expr.rs45
1 files changed, 34 insertions, 11 deletions
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs
index 023e19d25e..8895dc095f 100644
--- a/crates/hir-ty/src/infer/expr.rs
+++ b/crates/hir-ty/src/infer/expr.rs
@@ -84,6 +84,30 @@ impl<'a> InferenceContext<'a> {
}
}
+ pub(super) fn infer_expr_coerce_never(&mut self, expr: ExprId, expected: &Expectation) -> Ty {
+ let ty = self.infer_expr_inner(expr, expected);
+ // While we don't allow *arbitrary* coercions here, we *do* allow
+ // coercions from ! to `expected`.
+ if ty.is_never() {
+ if let Some(adjustments) = self.result.expr_adjustments.get(&expr) {
+ return if let [Adjustment { kind: Adjust::NeverToAny, target }] = &**adjustments {
+ target.clone()
+ } else {
+ self.err_ty()
+ };
+ }
+
+ let adj_ty = self.table.new_type_var();
+ self.write_expr_adj(
+ expr,
+ vec![Adjustment { kind: Adjust::NeverToAny, target: adj_ty.clone() }],
+ );
+ adj_ty
+ } else {
+ ty
+ }
+ }
+
fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
self.db.unwind_if_cancelled();
@@ -91,7 +115,7 @@ impl<'a> InferenceContext<'a> {
Expr::Missing => self.err_ty(),
&Expr::If { condition, then_branch, else_branch } => {
let expected = &expected.adjust_for_branches(&mut self.table);
- self.infer_expr(
+ self.infer_expr_coerce_never(
condition,
&Expectation::HasType(self.result.standard_types.bool_.clone()),
);
@@ -415,7 +439,7 @@ impl<'a> InferenceContext<'a> {
for arm in arms.iter() {
if let Some(guard_expr) = arm.guard {
self.diverges = Diverges::Maybe;
- self.infer_expr(
+ self.infer_expr_coerce_never(
guard_expr,
&Expectation::HasType(self.result.standard_types.bool_.clone()),
);
@@ -1146,7 +1170,6 @@ impl<'a> InferenceContext<'a> {
let coerce_ty = expected.coercion_target_type(&mut self.table);
let old_resolver =
mem::replace(&mut self.resolver, resolver_for_expr(self.db.upcast(), self.owner, expr));
-
let (break_ty, ty) =
self.with_breakable_ctx(BreakableKind::Block, Some(coerce_ty.clone()), label, |this| {
for stmt in statements {
@@ -1188,14 +1211,14 @@ impl<'a> InferenceContext<'a> {
}
}
&Statement::Expr { expr, has_semi } => {
- this.infer_expr(
- expr,
- &if has_semi {
- Expectation::none()
- } else {
- Expectation::HasType(this.result.standard_types.unit.clone())
- },
- );
+ if has_semi {
+ this.infer_expr(expr, &Expectation::none());
+ } else {
+ this.infer_expr_coerce(
+ expr,
+ &Expectation::HasType(this.result.standard_types.unit.clone()),
+ );
+ }
}
}
}