fix broken assertion in type_param

Nested generics (aka method generics) in trait methods don't have an
*additional* Self parameter in their own type parameter list (they have
a Self parameter in the parent generics), so don't try to check we're
correctly adjusting for it.

Fixes #46568.
This commit is contained in:
Ariel Ben-Yehuda 2017-12-13 23:06:54 -06:00
parent e798cb0e52
commit 2679944653
3 changed files with 72 additions and 29 deletions

View File

@ -778,10 +778,20 @@ impl<'a, 'gcx, 'tcx> Generics {
if let Some(idx) = param.idx.checked_sub(self.parent_count() as u32) {
// non-Self type parameters are always offset by exactly
// `self.regions.len()`. In the absence of a Self, this is obvious,
// but even in the absence of a `Self` we just have to "compensate"
// but even in the presence of a `Self` we just have to "compensate"
// for the regions:
//
// For example, for `trait Foo<'a, 'b, T1, T2>`, the
// Without a `Self` (or in a nested generics that doesn't have
// a `Self` in itself, even through it parent does), for example
// for `fn foo<'a, T1, T2>()`, the situation is:
// Substs:
// 0 1 2
// 'a T1 T2
// generics.types:
// 0 1
// T1 T2
//
// And with a `Self`, for example for `trait Foo<'a, 'b, T1, T2>`, the
// situation is:
// Substs:
// 0 1 2 3 4
@ -789,14 +799,20 @@ impl<'a, 'gcx, 'tcx> Generics {
// generics.types:
// 0 1 2
// Self T1 T2
// And it can be seen that to move from a substs offset to a
// generics offset you just have to offset by the number of regions.
//
// And it can be seen that in both cases, to move from a substs
// offset to a generics offset you just have to offset by the
// number of regions.
let type_param_offset = self.regions.len();
let has_self = self.has_self && self.parent.is_none();
let is_separated_self = type_param_offset != 0 && idx == 0 && has_self;
if let Some(idx) = (idx as usize).checked_sub(type_param_offset) {
assert!(!(self.has_self && idx == 0));
assert!(!is_separated_self, "found a Self after type_param_offset");
&self.types[idx]
} else {
assert!(self.has_self && idx == 0);
assert!(is_separated_self, "non-Self param before type_param_offset");
&self.types[0]
}
} else {

View File

@ -33,11 +33,19 @@ struct Foo<T> {
trait X<K>: Sized {
fn foo<'a, L: X<&'a Nested<K>>>();
//~^ ERROR may not live long enough
// check that we give a sane error for `Self`
fn bar<'a, L: X<&'a Nested<Self>>>();
//~^ ERROR may not live long enough
// check that we give a sane error for nested generics
fn baz<'a, L, M: X<&'a Nested<L>>>() {
//~^ ERROR may not live long enough
}
}
trait TraitB {}
struct Nested<K>(K);
impl<K> Nested<K> {
fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {

View File

@ -41,54 +41,73 @@ note: ...so that the reference type `&'a Nested<K>` does not outlive the data it
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0309]: the parameter type `Self` may not live long enough
--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
--> $DIR/lifetime-doesnt-live-long-enough.rs:38:5
|
37 | fn bar<'a, L: X<&'a Nested<Self>>>();
38 | fn bar<'a, L: X<&'a Nested<Self>>>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider adding an explicit lifetime bound `Self: 'a`...
note: ...so that the reference type `&'a Nested<Self>` does not outlive the data it points at
--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
--> $DIR/lifetime-doesnt-live-long-enough.rs:38:5
|
37 | fn bar<'a, L: X<&'a Nested<Self>>>();
38 | fn bar<'a, L: X<&'a Nested<Self>>>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0309]: the parameter type `K` may not live long enough
--> $DIR/lifetime-doesnt-live-long-enough.rs:43:5
error[E0309]: the parameter type `L` may not live long enough
--> $DIR/lifetime-doesnt-live-long-enough.rs:42:5
|
42 | impl<K> Nested<K> {
42 | fn baz<'a, L, M: X<&'a Nested<L>>>() {
| ^ - help: consider adding an explicit lifetime bound `L: 'a`...
| _____|
| |
43 | | //~^ ERROR may not live long enough
44 | | }
| |_____^
|
note: ...so that the reference type `&'a Nested<L>` does not outlive the data it points at
--> $DIR/lifetime-doesnt-live-long-enough.rs:42:5
|
42 | / fn baz<'a, L, M: X<&'a Nested<L>>>() {
43 | | //~^ ERROR may not live long enough
44 | | }
| |_____^
error[E0309]: the parameter type `K` may not live long enough
--> $DIR/lifetime-doesnt-live-long-enough.rs:51:5
|
50 | impl<K> Nested<K> {
| - help: consider adding an explicit lifetime bound `K: 'a`...
43 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
44 | | //~^ ERROR may not live long enough
45 | | }
51 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
52 | | //~^ ERROR may not live long enough
53 | | }
| |_____^
|
note: ...so that the reference type `&'a Nested<K>` does not outlive the data it points at
--> $DIR/lifetime-doesnt-live-long-enough.rs:43:5
--> $DIR/lifetime-doesnt-live-long-enough.rs:51:5
|
43 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
44 | | //~^ ERROR may not live long enough
45 | | }
51 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
52 | | //~^ ERROR may not live long enough
53 | | }
| |_____^
error[E0309]: the parameter type `M` may not live long enough
--> $DIR/lifetime-doesnt-live-long-enough.rs:46:5
--> $DIR/lifetime-doesnt-live-long-enough.rs:54:5
|
46 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
54 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
| ^ -- help: consider adding an explicit lifetime bound `M: 'a`...
| _____|
| |
47 | | //~^ ERROR may not live long enough
48 | | }
55 | | //~^ ERROR may not live long enough
56 | | }
| |_____^
|
note: ...so that the reference type `&'a Nested<M>` does not outlive the data it points at
--> $DIR/lifetime-doesnt-live-long-enough.rs:46:5
--> $DIR/lifetime-doesnt-live-long-enough.rs:54:5
|
46 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
47 | | //~^ ERROR may not live long enough
48 | | }
54 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
55 | | //~^ ERROR may not live long enough
56 | | }
| |_____^
error: aborting due to 6 previous errors
error: aborting due to 7 previous errors