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
parent
e798cb0e52
commit
2679944653
@ -778,10 +778,20 @@ pub fn type_param(&'tcx self,
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if let Some(idx) = param.idx.checked_sub(self.parent_count() as u32) {
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// non-Self type parameters are always offset by exactly
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// `self.regions.len()`. In the absence of a Self, this is obvious,
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// but even in the absence of a `Self` we just have to "compensate"
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// but even in the presence of a `Self` we just have to "compensate"
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// for the regions:
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//
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// For example, for `trait Foo<'a, 'b, T1, T2>`, the
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// Without a `Self` (or in a nested generics that doesn't have
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// a `Self` in itself, even through it parent does), for example
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// for `fn foo<'a, T1, T2>()`, the situation is:
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// Substs:
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// 0 1 2
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// 'a T1 T2
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// generics.types:
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// 0 1
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// T1 T2
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//
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// And with a `Self`, for example for `trait Foo<'a, 'b, T1, T2>`, the
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// situation is:
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// Substs:
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// 0 1 2 3 4
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@ -789,14 +799,20 @@ pub fn type_param(&'tcx self,
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// generics.types:
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// 0 1 2
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// Self T1 T2
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// And it can be seen that to move from a substs offset to a
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// generics offset you just have to offset by the number of regions.
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//
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// And it can be seen that in both cases, to move from a substs
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// offset to a generics offset you just have to offset by the
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// number of regions.
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let type_param_offset = self.regions.len();
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let has_self = self.has_self && self.parent.is_none();
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let is_separated_self = type_param_offset != 0 && idx == 0 && has_self;
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if let Some(idx) = (idx as usize).checked_sub(type_param_offset) {
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assert!(!(self.has_self && idx == 0));
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assert!(!is_separated_self, "found a Self after type_param_offset");
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&self.types[idx]
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} else {
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assert!(self.has_self && idx == 0);
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assert!(is_separated_self, "non-Self param before type_param_offset");
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&self.types[0]
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}
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} else {
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@ -33,11 +33,19 @@ struct Foo<T> {
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trait X<K>: Sized {
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fn foo<'a, L: X<&'a Nested<K>>>();
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//~^ ERROR may not live long enough
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// check that we give a sane error for `Self`
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fn bar<'a, L: X<&'a Nested<Self>>>();
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//~^ ERROR may not live long enough
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// check that we give a sane error for nested generics
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fn baz<'a, L, M: X<&'a Nested<L>>>() {
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//~^ ERROR may not live long enough
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}
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}
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trait TraitB {}
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struct Nested<K>(K);
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impl<K> Nested<K> {
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fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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@ -41,54 +41,73 @@ note: ...so that the reference type `&'a Nested<K>` does not outlive the data it
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error[E0309]: the parameter type `Self` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:38:5
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37 | fn bar<'a, L: X<&'a Nested<Self>>>();
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38 | fn bar<'a, L: X<&'a Nested<Self>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: consider adding an explicit lifetime bound `Self: 'a`...
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note: ...so that the reference type `&'a Nested<Self>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:38:5
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37 | fn bar<'a, L: X<&'a Nested<Self>>>();
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38 | fn bar<'a, L: X<&'a Nested<Self>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error[E0309]: the parameter type `K` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:43:5
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error[E0309]: the parameter type `L` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:42:5
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42 | impl<K> Nested<K> {
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42 | fn baz<'a, L, M: X<&'a Nested<L>>>() {
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| ^ - help: consider adding an explicit lifetime bound `L: 'a`...
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| _____|
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| |
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43 | | //~^ ERROR may not live long enough
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44 | | }
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| |_____^
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note: ...so that the reference type `&'a Nested<L>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:42:5
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42 | / fn baz<'a, L, M: X<&'a Nested<L>>>() {
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43 | | //~^ ERROR may not live long enough
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44 | | }
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| |_____^
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error[E0309]: the parameter type `K` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:51:5
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50 | impl<K> Nested<K> {
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| - help: consider adding an explicit lifetime bound `K: 'a`...
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43 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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44 | | //~^ ERROR may not live long enough
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45 | | }
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51 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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52 | | //~^ ERROR may not live long enough
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53 | | }
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| |_____^
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note: ...so that the reference type `&'a Nested<K>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:43:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:51:5
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43 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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44 | | //~^ ERROR may not live long enough
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45 | | }
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51 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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52 | | //~^ ERROR may not live long enough
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53 | | }
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| |_____^
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error[E0309]: the parameter type `M` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:46:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:54:5
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46 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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54 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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| ^ -- help: consider adding an explicit lifetime bound `M: 'a`...
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| _____|
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| |
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47 | | //~^ ERROR may not live long enough
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48 | | }
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55 | | //~^ ERROR may not live long enough
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56 | | }
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| |_____^
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note: ...so that the reference type `&'a Nested<M>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:46:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:54:5
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46 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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47 | | //~^ ERROR may not live long enough
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48 | | }
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54 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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55 | | //~^ ERROR may not live long enough
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56 | | }
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| |_____^
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error: aborting due to 6 previous errors
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error: aborting due to 7 previous errors
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