Auto merge of #141731 - compiler-errors:tweak-fast-path-trait, r=lcnr

Tweak fast path trait handling

(1.) Make it more sound by considering polarity (lol)

(2.) Make it more general, by considering higher-ranked size/copy/clone

(2.) Make it less observable, by only doing copy/clone fast path if there are no regions involved

r? lcnr

1 files changed, 2 insertions, 4 deletions

diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index 77b9becba57..404674c359e 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1882,10 +1882,8 @@ impl<'tcx> Ty<'tcx> {
             // Needs normalization or revealing to determine, so no is the safe answer.
             ty::Alias(..) => false,
 
-            ty::Param(..) | ty::Placeholder(..) | ty::Infer(..) | ty::Error(..) => false,
-
-            ty::Bound(..) => {
-                bug!("`is_trivially_pure_clone_copy` applied to unexpected type: {:?}", self);
+            ty::Param(..) | ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(..) => {
+                false
             }
         }
     }