In CMake for my project I have the following:

if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
    message("Using GCC compiler")
elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
    message("Using Clang compiler")
elseif (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
    message("Using MSVC compiler")
    add_compile_options(
        /MP # MULTIPROCESSOR COMPILE 
        /Oi # ENABLE COMPILER INTRINSICS
        /utf-8
        $<$<CONFIG:DEBUG>:/fsanitize=address /fsanitize=fuzzer> 
    ) 

else ()
    message("Unknown compiler: ${CMAKE_CXX_COMPILER_ID}")
endif ()

It generates fine, but in Visual Studio when I try to compile it gives the error:

Error C1083 Cannot open source file: ‘$<1:/fsanitize=address’: No such
file or directory MyProject F:$<1:fsanitize=address 1

It’s specifically that generator expression line that causes this. Why is this making the compiler look for a source file? Is the MyProject F:$<1:fsanitize=address 1 a clue?