This is exemplified by ide-backend tests "GHC API expects 'main' to be present in 'Main' (#170)" and "buildExe doesn't expect 'Main.main' to be present nor to be in IO (#170)". This is a minor discrepancy between GHC API and buildExe, because it does not manifested if each "Main.main" exists and has an explicit type signature.
This is exemplified by ide-backend tests "GHC API expects 'main' to be present in 'Main' (#170)" and "buildExe doesn't expect 'Main.main' to be present nor to be in IO (#170)". This is a minor discrepancy between GHC API and buildExe, because it does not manifested if each "Main.main" exists and has an explicit type signature.