Ensure suggestion correctness

This commit is contained in:
Esteban Küber 2023-01-08 19:12:15 +00:00
parent fcf0ed9018
commit df81147b51
6 changed files with 130 additions and 1 deletions

View File

@ -713,6 +713,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
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 = substs_e.type_at(1);
let f = substs_f.type_at(1);
if self

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@ -0,0 +1,24 @@
struct A;
struct B;
impl From<A> for B {
fn from(_: A) -> Self { B }
}
fn foo4(x: Result<(), A>) -> Result<(), B> {
match true {
true => x, //~ ERROR mismatched types
false => x,
}
}
fn foo5(x: Result<(), A>) -> Result<(), B> {
match true {
true => return x, //~ ERROR mismatched types
false => return x,
}
}
fn main() {
let _ = foo4(Ok(()));
let _ = foo5(Ok(()));
let _: Result<(), B> = { //~ ERROR mismatched types
Err(A);
};
}

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@ -0,0 +1,47 @@
error[E0308]: mismatched types
--> $DIR/coerce-result-return-value-2.rs:8:17
|
LL | fn foo4(x: Result<(), A>) -> Result<(), B> {
| ------------- expected `Result<(), B>` because of return type
LL | match true {
LL | true => x,
| ^ expected struct `B`, found struct `A`
|
= note: expected enum `Result<_, B>`
found enum `Result<_, A>`
help: you can rely on the implicit conversion that `?` does to transform the error type
|
LL | true => Ok(x?),
| +++ ++
error[E0308]: mismatched types
--> $DIR/coerce-result-return-value-2.rs:14:24
|
LL | fn foo5(x: Result<(), A>) -> Result<(), B> {
| ------------- expected `Result<(), B>` because of return type
LL | match true {
LL | true => return x,
| ^ expected struct `B`, found struct `A`
|
= note: expected enum `Result<_, B>`
found enum `Result<_, A>`
help: you can rely on the implicit conversion that `?` does to transform the error type
|
LL | true => return Ok(x?),
| +++ ++
error[E0308]: mismatched types
--> $DIR/coerce-result-return-value-2.rs:21:28
|
LL | let _: Result<(), B> = {
| ____________________________^
LL | | Err(A);
LL | | };
| |_____^ expected enum `Result`, found `()`
|
= note: expected enum `Result<(), B>`
found unit type `()`
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0308`.

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@ -10,7 +10,15 @@ fn foo1(x: Result<(), A>) -> Result<(), B> {
fn foo2(x: Result<(), A>) -> Result<(), B> {
return Ok(x?); //~ ERROR mismatched types
}
fn foo3(x: Result<(), A>) -> Result<(), B> {
if true {
Ok(x?) //~ ERROR mismatched types
} else {
Ok(x?) //~ ERROR mismatched types
}
}
fn main() {
let _ = foo1(Ok(()));
let _ = foo2(Ok(()));
let _ = foo3(Ok(()));
}

View File

@ -10,7 +10,15 @@ fn foo1(x: Result<(), A>) -> Result<(), B> {
fn foo2(x: Result<(), A>) -> Result<(), B> {
return x; //~ ERROR mismatched types
}
fn foo3(x: Result<(), A>) -> Result<(), B> {
if true {
x //~ ERROR mismatched types
} else {
x //~ ERROR mismatched types
}
}
fn main() {
let _ = foo1(Ok(()));
let _ = foo2(Ok(()));
let _ = foo3(Ok(()));
}

View File

@ -28,6 +28,38 @@ help: you can rely on the implicit conversion that `?` does to transform the err
LL | return Ok(x?);
| +++ ++
error: aborting due to 2 previous errors
error[E0308]: mismatched types
--> $DIR/coerce-result-return-value.rs:15:9
|
LL | fn foo3(x: Result<(), A>) -> Result<(), B> {
| ------------- expected `Result<(), B>` because of return type
LL | if true {
LL | x
| ^ expected struct `B`, found struct `A`
|
= note: expected enum `Result<_, B>`
found enum `Result<_, A>`
help: you can rely on the implicit conversion that `?` does to transform the error type
|
LL | Ok(x?)
| +++ ++
error[E0308]: mismatched types
--> $DIR/coerce-result-return-value.rs:17:9
|
LL | fn foo3(x: Result<(), A>) -> Result<(), B> {
| ------------- expected `Result<(), B>` because of return type
...
LL | x
| ^ expected struct `B`, found struct `A`
|
= note: expected enum `Result<_, B>`
found enum `Result<_, A>`
help: you can rely on the implicit conversion that `?` does to transform the error type
|
LL | Ok(x?)
| +++ ++
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0308`.