People are adding compile time asserts to check whether strings are the expected length. In GCC and Clang strlen("foo") is expanded at compile time so this works, but in Sparse it triggers a "bad constant expression" warning. Implement expand_strlen() to handle string literals. Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Link: https://lore.kernel.org/all/CANiDSCsBAq3Yx4ybarUb_1NkQ-bvfXvWqb-DfqXatkiYJFZWiQ@mail.gmail.com/ Signed-off-by: Chris Li <sparse@chrisli.org>