From 218caa410aa38c29984be31a5229b9fa717560ee Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:19:13 +0200 Subject: Merging upstream version 1.68.2+dfsg1. Signed-off-by: Daniel Baumann --- tests/ui/traits/wf-object/no-duplicates.rs | 33 ++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 tests/ui/traits/wf-object/no-duplicates.rs (limited to 'tests/ui/traits/wf-object/no-duplicates.rs') diff --git a/tests/ui/traits/wf-object/no-duplicates.rs b/tests/ui/traits/wf-object/no-duplicates.rs new file mode 100644 index 000000000..678ede582 --- /dev/null +++ b/tests/ui/traits/wf-object/no-duplicates.rs @@ -0,0 +1,33 @@ +// The purpose of this test is to demonstrate that duplicating object safe traits +// that are not auto-traits is rejected even though one could reasonably accept this. + +// Some arbitrary object-safe trait: +trait Obj {} + +// Demonstrate that recursive expansion of trait aliases doesn't affect stable behavior: +type _0 = dyn Obj + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Some variations: + +type _1 = dyn Send + Obj + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _2 = dyn Obj + Send + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _3 = dyn Obj + Send + Send; // But it is OK to duplicate auto traits. + +// Take higher ranked types into account. + +// Note that `'a` and `'b` are intentionally different to make sure we consider +// them semantically the same. +trait ObjL<'l> {} +type _4 = dyn for<'a> ObjL<'a> + for<'b> ObjL<'b>; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +trait ObjT {} +type _5 = dyn ObjT fn(&'a u8)> + ObjT fn(&'b u8)>; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +fn main() {} -- cgit v1.2.3