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fix: use `ExprIsRead::Yes` for rhs of ordinary assignments
the rhs of an ordinary assignment `x = *never_ptr` was inferred with
`ExprIsRead::No`, which prevented `NeverToAny` coercion for place
expressions of type `!`. this caused false type mismatches and missing
divergence detection. the destructuring assignment path and let binding
path both correctly use `ExprIsRead::Yes` for the rhs value, since the
value is always consumed (read). this makes the ordinary assignment path
consistent with both.
| -rw-r--r-- | crates/hir-ty/src/infer/expr.rs | 2 | ||||
| -rw-r--r-- | crates/hir-ty/src/tests/never_type.rs | 16 |
2 files changed, 17 insertions, 1 deletions
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs index 9f2d9d25b9..16e7d51e87 100644 --- a/crates/hir-ty/src/infer/expr.rs +++ b/crates/hir-ty/src/infer/expr.rs @@ -751,7 +751,7 @@ impl<'db> InferenceContext<'_, 'db> { if let Some(lhs_ty) = lhs_ty { self.write_pat_ty(target, lhs_ty); - self.infer_expr_coerce(value, &Expectation::has_type(lhs_ty), ExprIsRead::No); + self.infer_expr_coerce(value, &Expectation::has_type(lhs_ty), ExprIsRead::Yes); } else { let rhs_ty = self.infer_expr(value, &Expectation::none(), ExprIsRead::Yes); let resolver_guard = diff --git a/crates/hir-ty/src/tests/never_type.rs b/crates/hir-ty/src/tests/never_type.rs index a89d97984d..e4e7b4cc38 100644 --- a/crates/hir-ty/src/tests/never_type.rs +++ b/crates/hir-ty/src/tests/never_type.rs @@ -787,6 +787,22 @@ fn coerce_ref_mut_binding() -> ! { } #[test] +fn assign_never_place_no_mismatch() { + check_no_mismatches( + r#" +//- minicore: sized +fn foo() { + unsafe { + let p: *mut ! = 0 as _; + let mut x: () = (); + x = *p; + } +} +"#, + ); +} + +#[test] fn never_place_isnt_diverging() { check_infer_with_mismatches( r#" |