Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Invalid ? suggestion on mismatched Ok(T) #116968

Merged
merged 2 commits into from
Oct 27, 2023
Merged

Invalid ? suggestion on mismatched Ok(T) #116968

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6c97f13
Invalid `?` suggestion on mismatched `Ok(T)`
eopb Oct 20, 2023
24cdb27
let_chainify `suggest_coercing_result_via_try_operator`
eopb Oct 22, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 22 additions & 31 deletions compiler/rustc_hir_typeck/src/demand.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -961,38 +961,29 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
expected: Ty<'tcx>,
found: Ty<'tcx>,
) -> bool {
let ty::Adt(e, args_e) = expected.kind() else {
return false;
};
let ty::Adt(f, args_f) = found.kind() else {
return false;
};
if e.did() != f.did() {
return false;
}
if Some(e.did()) != self.tcx.get_diagnostic_item(sym::Result) {
return false;
}
let map = self.tcx.hir();
if let Some(hir::Node::Expr(expr)) = map.find_parent(expr.hir_id)
&& let hir::ExprKind::Ret(_) = expr.kind
{
// `return foo;`
} else if map.get_return_block(expr.hir_id).is_some() {
// Function's tail expression.
} else {
return false;
}
let e = args_e.type_at(1);
let f = args_f.type_at(1);
if self
.infcx
.type_implements_trait(
self.tcx.get_diagnostic_item(sym::Into).unwrap(),
[f, e],
self.param_env,
)
.must_apply_modulo_regions()
let returned = matches!(
map.find_parent(expr.hir_id),
Some(hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Ret(_), .. }))
) || map.get_return_block(expr.hir_id).is_some();
if returned
&& let ty::Adt(e, args_e) = expected.kind()
&& let ty::Adt(f, args_f) = found.kind()
&& e.did() == f.did()
&& Some(e.did()) == self.tcx.get_diagnostic_item(sym::Result)
&& let e_ok = args_e.type_at(0)
&& let f_ok = args_f.type_at(0)
&& self.infcx.can_eq(self.param_env, f_ok, e_ok)
&& let e_err = args_e.type_at(1)
&& let f_err = args_f.type_at(1)
&& self
.infcx
.type_implements_trait(
self.tcx.get_diagnostic_item(sym::Into).unwrap(),
[f_err, e_err],
self.param_env,
)
.must_apply_modulo_regions()
{
err.multipart_suggestion(
"use `?` to coerce and return an appropriate `Err`, and wrap the resulting value \
Expand Down
6 changes: 6 additions & 0 deletions tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
fn foo() -> Result<String, ()> {
let out: Result<(), ()> = Ok(());
out //~ ERROR mismatched types
}

fn main() {}
15 changes: 15 additions & 0 deletions tests/ui/type/type-check/issue-116967-cannot-coerce-returned-result.stderr
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
error[E0308]: mismatched types
--> $DIR/issue-116967-cannot-coerce-returned-result.rs:3:5
|
LL | fn foo() -> Result<String, ()> {
| ------------------ expected `Result<String, ()>` because of return type
LL | let out: Result<(), ()> = Ok(());
LL | out
| ^^^ expected `Result<String, ()>`, found `Result<(), ()>`
|
= note: expected enum `Result<String, _>`
found enum `Result<(), _>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.
Loading