compiler: report error when trait object type param reference self

Fixes #139082.

Bug: #139082
Signed-off-by: xtex <[email protected]>

Author: xtexx

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_compatibility.rs

@@ -352,6 +352,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     b.projection_term = replace_dummy_self_with_error(tcx, b.projection_term, guar);
                 }
 
+                if let Some(term_ty) = &b.term.as_type() {
+                    let references_self = term_ty.walk().any(|arg| arg == dummy_self.into());
+                    if references_self {
+                        let guar = tcx.dcx().span_delayed_bug(
+                            span,
+                            "trait object projection bounds reference `Self`",
+                        );
+                        b.term = replace_dummy_self_with_error(tcx, b.term, guar);
+                    }
+                }
+
                 ty::ExistentialPredicate::Projection(ty::ExistentialProjection::erase_self_ty(
                     tcx, b,
                 ))