Give right hand type higher priority in coercions

gcc/rust/ChangeLog:

	* typecheck/rust-type-util.cc: Use right hand type on error.

Signed-off-by: Pierre-Emmanuel Patry <[email protected]>

Author: P-E-P

gcc/rust/typecheck/rust-type-util.cc

@@ -267,6 +267,12 @@ coercion_site (HirId id, TyTy::TyWithLocation lhs, TyTy::TyWithLocation rhs,
 		      TyTy::TyWithLocation (receiver, rhs.get_locus ()), locus,
 		      true /*emit_error*/, true /*commit*/, true /*infer*/,
 		      true /*cleanup*/);
+  if (coerced->get_kind () == TyTy::TypeKind::ERROR)
+    {
+      delete coerced;
+      coerced = lhs.get_ty ();
+    }
+
   context->insert_autoderef_mappings (id, std::move (result.adjustments));
   return coerced;
 }