Merge #8133

8133: Ignore type bindings in generic_predicates_for_param (fix panic on ena and crates depending on it) r=flodiebold a=flodiebold

This allows us to handle more cases without a query cycle, which includes certain cases that rustc accepted. That in turn means we avoid triggering salsa-rs/salsa#257 on valid code (it will still happen if the user writes an actual cycle).

We actually accept more definitions than rustc now; that's because rustc only ignores bindings when looking up super traits, whereas we now also ignore them when looking for predicates to disambiguate associated type shorthand. We could introduce a separate query for super traits if necessary, but for now I think this should be fine.

Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 44eaeffb9..e3ac37e4c 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -2068,7 +2068,10 @@ impl Type {
                 match pred {
                     WhereClause::Implemented(trait_ref) => {
                         cb(type_.clone());
-                        walk_substs(db, type_, &trait_ref.substitution, cb);
+                        // skip the self type. it's likely the type we just got the bounds from
+                        for ty in trait_ref.substitution.iter().skip(1) {
+                            walk_type(db, &type_.derived(ty.clone()), cb);
+                        }
                     }
                     _ => (),
                 }