Fix divergence detection for bare match arms

Fixes #11814 and #11837.

Author: flodiebold

crates/hir_ty/src/infer/expr.rs

@@ -45,10 +45,6 @@ use super::{
 impl<'a> InferenceContext<'a> {
  pub(crate) fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
  let ty = self.infer_expr_inner(tgt_expr, expected);
- if self.resolve_ty_shallow(&ty).is_never() {
- // Any expression that produces a value of type `!` must have diverged
- self.diverges = Diverges::Always;
- }
  if let Some(expected_ty) = expected.only_has_type(&mut self.table) {
  let could_unify = self.unify(&ty, &expected_ty);
  if !could_unify {
@@ -800,6 +796,10 @@ impl<'a> InferenceContext<'a> {
  // use a new type variable if we got unknown here
  let ty = self.insert_type_vars_shallow(ty);
  self.write_expr_ty(tgt_expr, ty.clone());
+ if self.resolve_ty_shallow(&ty).is_never() {
+ // Any expression that produces a value of type `!` must have diverged
+ self.diverges = Diverges::Always;
+ }
  ty
  }
 

crates/hir_ty/src/tests/never_type.rs

@@ -1,6 +1,6 @@
 use expect_test::expect;
 
-use super::{check_infer_with_mismatches, check_types};
+use super::{check_infer_with_mismatches, check_no_mismatches, check_types};
 
 #[test]
 fn infer_never1() {
@@ -441,3 +441,45 @@ fn let_else_must_diverge() {
  "#]],
  );
 }
+
+#[test]
+fn issue_11837() {
+ check_no_mismatches(
+ r#"
+//- minicore: result
+enum MyErr {
+ Err1,
+ Err2,
+}
+
+fn example_ng() {
+ let value: Result<i32, MyErr> = Ok(3);
+
+ loop {
+ let ret = match value {
+ Ok(value) => value,
+ Err(ref err) => {
+ match err {
+ MyErr::Err1 => break,
+ MyErr::Err2 => continue,
+ };
+ }
+ };
+ }
+}
+"#,
+ );
+}
+
+#[test]
+fn issue_11814() {
+ check_no_mismatches(
+ r#"
+fn example() -> bool {
+ match 1 {
+ _ => return true,
+ };
+}
+"#,
+ );
+}