diff --git a/src/test/ui/impl-trait/nested-rpit-hrtb.rs b/src/test/ui/impl-trait/nested-rpit-hrtb.rs new file mode 100644 index 00000000000..abf6a7e956c --- /dev/null +++ b/src/test/ui/impl-trait/nested-rpit-hrtb.rs @@ -0,0 +1,64 @@ +// Test the interaction between rested RPIT and HRTB. + +trait Foo<'a> { + type Assoc; +} + +impl Foo<'_> for () { + type Assoc = (); +} + +// Alternative version of `Foo` whose impl uses `'a`. +trait Bar<'a> { + type Assoc; +} + +impl<'a> Bar<'a> for () { + type Assoc = &'a (); +} + +trait Qux<'a> {} + +impl Qux<'_> for () {} + +// This is not supported. +fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {} +//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet + +// This is not supported. +fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {} +//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet + +fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {} +//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet + +fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {} +//~^ ERROR higher kinded lifetime bounds on nested opaque types are not supported yet + +// This should pass. +fn one_hrtb_mention_fn_trait_param<'b>() -> impl for<'a> Foo<'a, Assoc = impl Qux<'b>> {} + +// This should pass. +fn one_hrtb_mention_fn_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'b> {} + +// This should pass. +fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {} + +// This should pass. +fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {} + +// This should pass. +fn two_htrb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Qux<'b>> {} + +// `'b` is not in scope for the outlives bound. +fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {} +//~^ ERROR use of undeclared lifetime name `'b` [E0261] + +// This should pass. +fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Qux<'b>> {} + +// `'b` is not in scope for the outlives bound. +fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {} +//~^ ERROR use of undeclared lifetime name `'b` [E0261] + +fn main() {} diff --git a/src/test/ui/impl-trait/nested-rpit-hrtb.stderr b/src/test/ui/impl-trait/nested-rpit-hrtb.stderr new file mode 100644 index 00000000000..3dbe6ebadfb --- /dev/null +++ b/src/test/ui/impl-trait/nested-rpit-hrtb.stderr @@ -0,0 +1,82 @@ +error[E0261]: use of undeclared lifetime name `'b` + --> $DIR/nested-rpit-hrtb.rs:54:77 + | +LL | fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {} + | ^^ undeclared lifetime + | + = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html +help: consider making the bound lifetime-generic with a new `'b` lifetime + | +LL | fn two_htrb_outlives() -> impl for<'b, 'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {} + | +++ +help: consider introducing lifetime `'b` here + | +LL | fn two_htrb_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {} + | ++++ + +error[E0261]: use of undeclared lifetime name `'b` + --> $DIR/nested-rpit-hrtb.rs:61:82 + | +LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {} + | ^^ undeclared lifetime + | +help: consider making the bound lifetime-generic with a new `'b` lifetime + | +LL | fn two_htrb_outlives_uses() -> impl for<'b, 'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {} + | +++ +help: consider introducing lifetime `'b` here + | +LL | fn two_htrb_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {} + | ++++ + +error: higher kinded lifetime bounds on nested opaque types are not supported yet + --> $DIR/nested-rpit-hrtb.rs:25:69 + | +LL | fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {} + | ^^ + | +note: lifetime declared here + --> $DIR/nested-rpit-hrtb.rs:25:36 + | +LL | fn one_hrtb_outlives() -> impl for<'a> Foo<'a, Assoc = impl Sized + 'a> {} + | ^^ + +error: higher kinded lifetime bounds on nested opaque types are not supported yet + --> $DIR/nested-rpit-hrtb.rs:29:68 + | +LL | fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {} + | ^^ + | +note: lifetime declared here + --> $DIR/nested-rpit-hrtb.rs:29:39 + | +LL | fn one_hrtb_trait_param() -> impl for<'a> Foo<'a, Assoc = impl Qux<'a>> {} + | ^^ + +error: higher kinded lifetime bounds on nested opaque types are not supported yet + --> $DIR/nested-rpit-hrtb.rs:32:74 + | +LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {} + | ^^ + | +note: lifetime declared here + --> $DIR/nested-rpit-hrtb.rs:32:41 + | +LL | fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {} + | ^^ + +error: higher kinded lifetime bounds on nested opaque types are not supported yet + --> $DIR/nested-rpit-hrtb.rs:35:73 + | +LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {} + | ^^ + | +note: lifetime declared here + --> $DIR/nested-rpit-hrtb.rs:35:44 + | +LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {} + | ^^ + +error: aborting due to 6 previous errors + +For more information about this error, try `rustc --explain E0261`.