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Resolve match arm ty when arms diverge

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This commit is contained in:
Esteban Küber 2019-05-01 14:57:24 -07:00
parent a55c2eb325
commit 24fddb15e8
3 changed files with 43 additions and 18 deletions
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2
src/librustc/infer/error_reporting/mod.rs
View file

@ -644,7 +644,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
for sp in prior_arms {
err.span_label(*sp, format!(
"this is found to be of type `{}`",
last_ty,
self.resolve_type_vars_if_possible(&last_ty),
));
}
} else if let Some(sp) = prior_arms.last() {

24
src/test/ui/match/match-type-err-first-arm.rs
View file

@ -3,8 +3,7 @@ fn main() {
let _ = test_func2(1);
}
fn test_func1(n: i32) -> i32 {
//~^ NOTE expected `i32` because of return type
fn test_func1(n: i32) -> i32 { //~ NOTE expected `i32` because of return type
match n {
12 => 'b',
//~^ ERROR mismatched types
@ -14,10 +13,8 @@ fn test_func1(n: i32) -> i32 {
}
fn test_func2(n: i32) -> i32 {
let x = match n {
//~^ NOTE `match` arms have incompatible types
12 => 'b',
//~^ NOTE this is found to be of type `char`
let x = match n { //~ NOTE `match` arms have incompatible types
12 => 'b', //~ NOTE this is found to be of type `char`
_ => 42,
//~^ ERROR match arms have incompatible types
//~| NOTE expected char, found integer
@ -27,8 +24,7 @@ fn test_func2(n: i32) -> i32 {
}
fn test_func3(n: i32) -> i32 {
let x = match n {
//~^ NOTE `match` arms have incompatible types
let x = match n { //~ NOTE `match` arms have incompatible types
1 => 'b',
2 => 'b',
3 => 'b',
@ -43,3 +39,15 @@ fn test_func3(n: i32) -> i32 {
};
x
}
fn test_func4() {
match Some(0u32) { //~ NOTE `match` arms have incompatible types
Some(x) => {
x //~ NOTE this is found to be of type `u32`
},
None => {}
//~^ ERROR match arms have incompatible types
//~| NOTE expected u32, found ()
//~| NOTE expected type `u32`
};
}

35
src/test/ui/match/match-type-err-first-arm.stderr
View file

@ -1,24 +1,23 @@
error[E0308]: mismatched types
--> $DIR/match-type-err-first-arm.rs:9:15
--> $DIR/match-type-err-first-arm.rs:8:15
|
LL | fn test_func1(n: i32) -> i32 {
| --- expected `i32` because of return type
...
LL | match n {
LL | 12 => 'b',
| ^^^ expected i32, found char
error[E0308]: match arms have incompatible types
--> $DIR/match-type-err-first-arm.rs:21:14
--> $DIR/match-type-err-first-arm.rs:18:14
|
LL | let x = match n {
| _____________-
LL | |
LL | | 12 => 'b',
| | --- this is found to be of type `char`
LL | |
LL | | _ => 42,
| | ^^ expected char, found integer
... |
LL | |
LL | |
LL | |
LL | | };
| |_____- `match` arms have incompatible types
@ -27,13 +26,13 @@ LL | | };
found type `{integer}`
error[E0308]: match arms have incompatible types
--> $DIR/match-type-err-first-arm.rs:39:14
--> $DIR/match-type-err-first-arm.rs:35:14
|
LL | let x = match n {
| _____________-
LL | |
LL | | 1 => 'b',
LL | | 2 => 'b',
LL | | 3 => 'b',
... |
LL | | 6 => 'b',
| | --- this and all prior arms are found to be of type `char`
@ -48,6 +47,24 @@ LL | | };
= note: expected type `char`
found type `{integer}`
error: aborting due to 3 previous errors
error[E0308]: match arms have incompatible types
--> $DIR/match-type-err-first-arm.rs:48:17
|
LL | / match Some(0u32) {
LL | | Some(x) => {
LL | | x
| | - this is found to be of type `u32`
LL | | },
LL | | None => {}
| | ^^ expected u32, found ()
... |
LL | |
LL | | };
| |_____- `match` arms have incompatible types
|
= note: expected type `u32`
found type `()`
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0308`.