llvm-project

72c29fa9 - [C++20] [Modules] [Driver] Emit unused argument warning if we use '-fmodule-output' with non-module input

[C++20] [Modules] [Driver] Emit unused argument warning if we use '-fmodule-output' with non-module input We required the file name of an 'importable module unit' should end with .cppm (or .ccm, .cxxm, .c++m). But the driver can accept '-fmodule-output' for files with normal suffixes (e.g., .cpp). This is somewhat inconsistency. In this patch, we only claim the option `-fmodule-output` is used if the type of the input file is modules related. Then now the compiler will emit 'unused argument' warnings if the input file is not modules related.