propagate user-ascribes types down onto resulting bindings
But only in very simple cases.
This commit is contained in:
Niko Matsakis
parent
a8710539cb
commit
e87bf30f5f
14 changed files with 171 additions and 35 deletions
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@ -3,10 +3,41 @@
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#![feature(nll)]
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fn variable_no_initializer() {
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// FIXME: It is unclear to me whether this should be an error or not.
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let x = 22;
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let y: &'static u32;
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y = &x; //~ ERROR
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}
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fn tuple_no_initializer() {
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// FIXME(#47187): We are not propagating ascribed type through tuples.
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let x = 22;
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let (y, z): (&'static u32, &'static u32);
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y = &x;
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}
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fn ref_with_ascribed_static_type() -> u32 {
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// Check the behavior in some wacky cases.
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let x = 22;
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let y = &x; //~ ERROR
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let ref z: &'static u32 = y; //~ ERROR
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**z
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}
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fn ref_with_ascribed_any_type() -> u32 {
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let x = 22;
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let y = &x;
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let ref z: &u32 = y;
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**z
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}
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struct Single<T> { value: T }
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fn struct_no_initializer() {
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// FIXME(#47187): We are not propagating ascribed type through patterns.
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let x = 22;
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let Single { value: y }: Single<&'static u32>;
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y = &x;
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}
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@ -39,8 +70,6 @@ fn pair_variable_with_initializer() {
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let (y, _): (&'static u32, u32) = (&x, 44); //~ ERROR
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}
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struct Single<T> { value: T }
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fn struct_single_field_variable_with_initializer() {
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let x = 22;
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let Single { value: y }: Single<&'static u32> = Single { value: &x }; //~ ERROR
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@ -73,7 +102,7 @@ fn static_to_a_to_static_through_variable<'a>(x: &'a u32) -> &'static u32 {
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}
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fn static_to_a_to_static_through_tuple<'a>(x: &'a u32) -> &'static u32 {
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// FIXME: The fact that this type-checks is perhaps surprising.
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// FIXME(#47187): The fact that this type-checks is perhaps surprising.
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// What happens is that the right-hand side is constrained to have
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// type `&'a u32`, which is possible, because it has type
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// `&'static u32`. The variable `y` is then forced to have type
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@ -1,5 +1,37 @@
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:15:27
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--> $DIR/patterns.rs:8:9
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LL | y = &x; //~ ERROR
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| ^^ borrowed value does not live long enough
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LL | }
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| - `x` dropped here while still borrowed
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:22:13
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LL | let y = &x; //~ ERROR
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| ^^ borrowed value does not live long enough
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...
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LL | }
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| - `x` dropped here while still borrowed
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `y` does not live long enough
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--> $DIR/patterns.rs:23:9
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LL | let ref z: &'static u32 = y; //~ ERROR
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| ^^^^^ borrowed value does not live long enough
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LL | **z
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LL | }
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| - `y` dropped here while still borrowed
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:46:27
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LL | let y: &'static u32 = &x; //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -9,7 +41,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:20:27
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--> $DIR/patterns.rs:51:27
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LL | let _: &'static u32 = &x; //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -20,7 +52,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: borrowed value does not live long enough
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--> $DIR/patterns.rs:22:41
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--> $DIR/patterns.rs:53:41
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LL | let _: Vec<&'static String> = vec![&String::new()];
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| ^^^^^^^^^^^^^ - temporary value only lives until here
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@ -30,7 +62,7 @@ LL | let _: Vec<&'static String> = vec![&String::new()];
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: borrowed value does not live long enough
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--> $DIR/patterns.rs:25:52
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--> $DIR/patterns.rs:56:52
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LL | let (_, a): (Vec<&'static String>, _) = (vec![&String::new()], 44);
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| ^^^^^^^^^^^^^ - temporary value only lives until here
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@ -40,7 +72,7 @@ LL | let (_, a): (Vec<&'static String>, _) = (vec![&String::new()], 44);
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: borrowed value does not live long enough
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--> $DIR/patterns.rs:28:53
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--> $DIR/patterns.rs:59:53
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LL | let (_a, b): (Vec<&'static String>, _) = (vec![&String::new()], 44);
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| ^^^^^^^^^^^^^ - temporary value only lives until here
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@ -50,7 +82,7 @@ LL | let (_a, b): (Vec<&'static String>, _) = (vec![&String::new()], 44);
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:34:40
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--> $DIR/patterns.rs:65:40
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LL | let (_, _): (&'static u32, u32) = (&x, 44); //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -60,7 +92,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:39:40
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--> $DIR/patterns.rs:70:40
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LL | let (y, _): (&'static u32, u32) = (&x, 44); //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -70,7 +102,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:46:69
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--> $DIR/patterns.rs:75:69
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LL | let Single { value: y }: Single<&'static u32> = Single { value: &x }; //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -80,7 +112,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:51:69
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--> $DIR/patterns.rs:80:69
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LL | let Single { value: _ }: Single<&'static u32> = Single { value: &x }; //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -90,7 +122,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error[E0597]: `x` does not live long enough
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--> $DIR/patterns.rs:59:17
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--> $DIR/patterns.rs:88:17
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LL | value1: &x, //~ ERROR
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| ^^ borrowed value does not live long enough
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@ -101,7 +133,7 @@ LL | }
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= note: borrowed value must be valid for the static lifetime...
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error: unsatisfied lifetime constraints
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--> $DIR/patterns.rs:72:5
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--> $DIR/patterns.rs:101:5
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LL | fn static_to_a_to_static_through_variable<'a>(x: &'a u32) -> &'static u32 {
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| -- lifetime `'a` defined here
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@ -110,13 +142,13 @@ LL | y //~ ERROR
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| ^ returning this value requires that `'a` must outlive `'static`
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error: unsatisfied lifetime constraints
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--> $DIR/patterns.rs:88:40
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--> $DIR/patterns.rs:117:40
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LL | fn a_to_static_then_static<'a>(x: &'a u32) -> &'static u32 {
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| -- lifetime `'a` defined here
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LL | let (y, _z): (&'static u32, u32) = (x, 44); //~ ERROR
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| ^^^^^^^ requires that `'a` must outlive `'static`
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error: aborting due to 12 previous errors
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error: aborting due to 15 previous errors
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For more information about this error, try `rustc --explain E0597`.
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