| // Test a `exists<'a> { forall<'b> { 'a = 'b } }` pattern -- which should not compile! |
| // |
| // In particular, we test this pattern in trait solving, where it is not connected |
| // to any part of the source code. |
| |
| fn foo<'a>() -> fn(&'a u32) { |
| panic!() |
| } |
| |
| fn main() { |
| // Here, proving that `fn(&'a u32) <: for<'b> fn(&'b u32)`: |
| // |
| // - instantiates `'b` with a placeholder `!b`, |
| // - requires that `&!b u32 <: &'a u32` and hence that `!b: 'a`, |
| // - but we can never know this. |
| |
| let _: for<'b> fn(&'b u32) = foo(); //~ ERROR mismatched types |
| } |
