when there are 3 or more return statements in the loop

emit the first 3 errors and duplicated diagnostic information
using take of iterator for the first third return
	modified:   compiler/rustc_typeck/src/check/coercion.rs
	new file:   src/test/ui/typeck/issue-100285.rs
	new file:   src/test/ui/typeck/issue-100285.stderr
This commit is contained in:
Yiming Lei 2022-08-09 11:27:04 -07:00
parent 6d3f1beae1
commit 0471e2780f
3 changed files with 65 additions and 1 deletions

View file

@ -0,0 +1,22 @@
fn foo(n: i32) -> i32 {
for i in 0..0 {
//~^ ERROR: mismatched types [E0308]
if n < 0 {
return i;
} else if n < 10 {
return 1;
} else if n < 20 {
return 2;
} else if n < 30 {
return 3;
} else if n < 40 {
return 4;
} else {
return 5;
}
}
//~| help: return a value for the case when the loop has zero elements to iterate on, or consider changing the return type to account for that possibility
}
fn main() {}

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@ -0,0 +1,34 @@
error[E0308]: mismatched types
--> $DIR/issue-100285.rs:2:5
|
LL | fn foo(n: i32) -> i32 {
| --- expected `i32` because of return type
LL | / for i in 0..0 {
LL | |
LL | | if n < 0 {
LL | | return i;
... |
LL | |
LL | | }
| |_____^ expected `i32`, found `()`
|
note: the function expects a value to always be returned, but loops might run zero times
--> $DIR/issue-100285.rs:2:5
|
LL | for i in 0..0 {
| ^^^^^^^^^^^^^ this might have zero elements to iterate on
...
LL | return i;
| -------- if the loop doesn't execute, this value would never get returned
LL | } else if n < 10 {
LL | return 1;
| -------- if the loop doesn't execute, this value would never get returned
LL | } else if n < 20 {
LL | return 2;
| -------- if the loop doesn't execute, this value would never get returned
= note: if the loop doesn't execute, 3 other values would never get returned
= help: return a value for the case when the loop has zero elements to iterate on, or consider changing the return type to account for that possibility
error: aborting due to previous error
For more information about this error, try `rustc --explain E0308`.