rust/src/test/ui/impl-trait/infinite-impl-trait-issue-38064.rs
Matthew Jasper 65c1f54a06 Forbid impl Trait from referring to unnamable recursive types
There is no type T, such that `T = [T; 2]`, we should not allow this
to be circumvented by impl Trait.
2019-01-03 22:15:02 +00:00

26 lines
553 B
Rust

// Test that attempts to construct infinite types via impl trait fail
// in a graceful way.
//
// Regression test for #38064.
trait Quux {}
fn foo() -> impl Quux { //~ opaque type expands to a recursive type
struct Foo<T>(T);
impl<T> Quux for Foo<T> {}
Foo(bar())
}
fn bar() -> impl Quux { //~ opaque type expands to a recursive type
struct Bar<T>(T);
impl<T> Quux for Bar<T> {}
Bar(foo())
}
// effectively:
// struct Foo(Bar);
// struct Bar(Foo);
// should produce an error about infinite size
fn main() { foo(); }