makeSubBlock

    fn makeSubBlock(gz: *GenZir, scope: *Scope) GenZir {
        return .{
            .is_comptime = gz.is_comptime,
            .is_typeof = gz.is_typeof,
            .decl_node_index = gz.decl_node_index,
            .decl_line = gz.decl_line,
            .parent = scope,
            .astgen = gz.astgen,
            .suspend_node = gz.suspend_node,
            .nosuspend_node = gz.nosuspend_node,
            .any_defer_node = gz.any_defer_node,
            .instructions = gz.instructions,
            .instructions_top = gz.instructions.items.len,
        };
    }