[cfe-dev] [clangd] Invalid AST in header when cpp file uses /TP

[Hamza Sood via cfe-dev]

I’m fact, it looks like CL aliases are entirely mishandled in the transfer from source file to header.

“/W3” internally maps to “-Wall”, but transferring that compilation command doesn’t map it back to “/W3”. In CL mode “-Wall” really means “-Weverything”, so the header is likely to display hundreds of unintended warnings.