fix: handle panic for unsupported operations and missing return type

Author: Marsman1996

source/rust_verify/src/rust_to_vir_expr.rs

@@ -3043,8 +3043,9 @@ fn binopkind_to_binaryop_inner<'tcx>(
         BinOpKind::BitAnd => {
             match ((tc.expr_ty_adjusted(lhs)).kind(), (tc.expr_ty_adjusted(rhs)).kind()) {
                 (TyKind::Bool, TyKind::Bool) => {
-                    panic!(
-                        "bitwise AND for bools (i.e., the not-short-circuited version) not supported"
+                    unsupported_err!(
+                        lhs.span,
+                        "bitwise AND for bools (i.e., the not-short-circuited version)"
                     );
                 }
                 (TyKind::Int(_), TyKind::Int(_)) => {
@@ -3059,7 +3060,8 @@ fn binopkind_to_binaryop_inner<'tcx>(
         BinOpKind::BitOr => {
             match ((tc.expr_ty_adjusted(lhs)).kind(), (tc.expr_ty_adjusted(rhs)).kind()) {
                 (TyKind::Bool, TyKind::Bool) => {
-                    panic!(
+                    unsupported_err!(
+                        lhs.span,
                         "bitwise OR for bools (i.e., the not-short-circuited version) not supported"
                     );
                 }

source/vir/src/modes.rs

@@ -2888,7 +2888,7 @@ fn check_expr_handle_mut_arg(
             match (e1, typing.ret_mode) {
                 (None, _) => {}
                 (Some(v), None) if is_unit(&v.typ) => {}
-                (_, None) => panic!("internal error: missing return type"),
+                (_, None) => return Err(error(&expr.span, "missing return type")),
                 (Some(e1), Some(ret_mode)) => {
                     let proph = check_expr_has_mode(
                         ctxt,