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promote-not: add test that distinguishes promotion from outer scope rule

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This commit is contained in:
Ralf Jung 2024-03-11 14:15:46 +01:00
parent 279465b5e8
commit fb802f2e6e
2 changed files with 42 additions and 22 deletions
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12
tests/ui/consts/promote-not.rs
View File

@ -40,7 +40,16 @@ pub const fn promote_union() {
let _val: &'static _ = &(Cell::new(1), 2).1; //~ ERROR temporary value dropped while borrowed let _val: &'static _ = &(Cell::new(1), 2).1; //~ ERROR temporary value dropped while borrowed
}; };
const TEST_DROP: String = String::new(); // This gets accepted by the "outer scope" rule, not promotion.
const TEST_DROP_OUTER_SCOPE: &String = &String::new();
// To demonstrate that, we can rewrite it as follows. If this was promotion it would still work.
const TEST_DROP_NOT_PROMOTE: &String = {
let x = &String::new(); //~ ERROR destructor of `String` cannot be evaluated at compile-time
// The "dropped while borrowed" error seems to be suppressed, but the key point is that this
// fails to compile.
x
};
fn main() { fn main() {
// We must not promote things with interior mutability. Not even if we "project it away". // We must not promote things with interior mutability. Not even if we "project it away".
@ -59,6 +68,7 @@ fn main() {
let _val: &'static _ = &([1,2,3][4]+1); //~ ERROR temporary value dropped while borrowed let _val: &'static _ = &([1,2,3][4]+1); //~ ERROR temporary value dropped while borrowed
// No promotion of temporaries that need to be dropped. // No promotion of temporaries that need to be dropped.
const TEST_DROP: String = String::new();
let _val: &'static _ = &TEST_DROP; let _val: &'static _ = &TEST_DROP;
//~^ ERROR temporary value dropped while borrowed //~^ ERROR temporary value dropped while borrowed
let _val: &'static _ = &&TEST_DROP; let _val: &'static _ = &&TEST_DROP;

52
tests/ui/consts/promote-not.stderr
View File

@ -38,6 +38,15 @@ LL | let _val: &'static _ = &(Cell::new(1), 2).1;
LL | }; LL | };
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0493]: destructor of `String` cannot be evaluated at compile-time
--> $DIR/promote-not.rs:47:14
|
LL | let x = &String::new();
| ^^^^^^^^^^^^^ the destructor for this type cannot be evaluated in constants
...
LL | };
| - value is dropped here
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:21:32 --> $DIR/promote-not.rs:21:32
| |
@ -59,7 +68,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:47:29 --> $DIR/promote-not.rs:56:29
| |
LL | let _val: &'static _ = &(Cell::new(1), 2).0; LL | let _val: &'static _ = &(Cell::new(1), 2).0;
| ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -70,7 +79,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:48:29 --> $DIR/promote-not.rs:57:29
| |
LL | let _val: &'static _ = &(Cell::new(1), 2).1; LL | let _val: &'static _ = &(Cell::new(1), 2).1;
| ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -81,7 +90,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:51:29 --> $DIR/promote-not.rs:60:29
| |
LL | let _val: &'static _ = &(1/0); LL | let _val: &'static _ = &(1/0);
| ---------- ^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^ creates a temporary value which is freed while still in use
@ -92,7 +101,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:52:29 --> $DIR/promote-not.rs:61:29
| |
LL | let _val: &'static _ = &(1/(1-1)); LL | let _val: &'static _ = &(1/(1-1));
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
@ -103,7 +112,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:53:29 --> $DIR/promote-not.rs:62:29
| |
LL | let _val: &'static _ = &((1+1)/(1-1)); LL | let _val: &'static _ = &((1+1)/(1-1));
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -114,7 +123,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:54:29 --> $DIR/promote-not.rs:63:29
| |
LL | let _val: &'static _ = &(i32::MIN/-1); LL | let _val: &'static _ = &(i32::MIN/-1);
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -125,7 +134,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:55:29 --> $DIR/promote-not.rs:64:29
| |
LL | let _val: &'static _ = &(i32::MIN/(0-1)); LL | let _val: &'static _ = &(i32::MIN/(0-1));
| ---------- ^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -136,7 +145,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:56:29 --> $DIR/promote-not.rs:65:29
| |
LL | let _val: &'static _ = &(-128i8/-1); LL | let _val: &'static _ = &(-128i8/-1);
| ---------- ^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -147,7 +156,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:57:29 --> $DIR/promote-not.rs:66:29
| |
LL | let _val: &'static _ = &(1%0); LL | let _val: &'static _ = &(1%0);
| ---------- ^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^ creates a temporary value which is freed while still in use
@ -158,7 +167,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:58:29 --> $DIR/promote-not.rs:67:29
| |
LL | let _val: &'static _ = &(1%(1-1)); LL | let _val: &'static _ = &(1%(1-1));
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
@ -169,7 +178,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:59:29 --> $DIR/promote-not.rs:68:29
| |
LL | let _val: &'static _ = &([1,2,3][4]+1); LL | let _val: &'static _ = &([1,2,3][4]+1);
| ---------- ^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -180,7 +189,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:62:29 --> $DIR/promote-not.rs:72:29
| |
LL | let _val: &'static _ = &TEST_DROP; LL | let _val: &'static _ = &TEST_DROP;
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
@ -191,7 +200,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:64:29 --> $DIR/promote-not.rs:74:29
| |
LL | let _val: &'static _ = &&TEST_DROP; LL | let _val: &'static _ = &&TEST_DROP;
| ---------- ^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -202,7 +211,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:64:30 --> $DIR/promote-not.rs:74:30
| |
LL | let _val: &'static _ = &&TEST_DROP; LL | let _val: &'static _ = &&TEST_DROP;
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
@ -213,7 +222,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:67:29 --> $DIR/promote-not.rs:77:29
| |
LL | let _val: &'static _ = &(&TEST_DROP,); LL | let _val: &'static _ = &(&TEST_DROP,);
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -224,7 +233,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:67:31 --> $DIR/promote-not.rs:77:31
| |
LL | let _val: &'static _ = &(&TEST_DROP,); LL | let _val: &'static _ = &(&TEST_DROP,);
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
@ -235,7 +244,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:70:29 --> $DIR/promote-not.rs:80:29
| |
LL | let _val: &'static _ = &[&TEST_DROP; 1]; LL | let _val: &'static _ = &[&TEST_DROP; 1];
| ---------- ^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -246,7 +255,7 @@ LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:70:31 --> $DIR/promote-not.rs:80:31
| |
LL | let _val: &'static _ = &[&TEST_DROP; 1]; LL | let _val: &'static _ = &[&TEST_DROP; 1];
| ---------- ^^^^^^^^^ - temporary value is freed at the end of this statement | ---------- ^^^^^^^^^ - temporary value is freed at the end of this statement
@ -255,7 +264,7 @@ LL | let _val: &'static _ = &[&TEST_DROP; 1];
| type annotation requires that borrow lasts for `'static` | type annotation requires that borrow lasts for `'static`
error[E0716]: temporary value dropped while borrowed error[E0716]: temporary value dropped while borrowed
--> $DIR/promote-not.rs:79:26 --> $DIR/promote-not.rs:89:26
| |
LL | let x: &'static _ = &UnionWithCell { f1: 0 }; LL | let x: &'static _ = &UnionWithCell { f1: 0 };
| ---------- ^^^^^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use | ---------- ^^^^^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
@ -265,6 +274,7 @@ LL |
LL | } LL | }
| - temporary value is freed at the end of this statement | - temporary value is freed at the end of this statement
error: aborting due to 25 previous errors error: aborting due to 26 previous errors
For more information about this error, try `rustc --explain E0716`. Some errors have detailed explanations: E0493, E0716.
For more information about an error, try `rustc --explain E0493`.