cmake_minimum_required(VERSION 3.12)

project(Foo)

set(FAKE_LIB "${CMAKE_BINARY_DIR}/libfoo.a")
file(WRITE "${FAKE_LIB}")

file(WRITE foo.cpp "int main() {}")

add_library(bar INTERFACE)
target_link_libraries(bar INTERFACE ${FAKE_LIB})

add_library(baz INTERFACE)
target_link_libraries(baz INTERFACE ${FAKE_LIB})

add_executable(foo foo.cpp)

target_link_libraries(foo PRIVATE bar)
target_link_libraries(foo PRIVATE baz)