In the master branch !5478 (closed) fixed #19460 (closed). As #19460 (closed) has highest priority and didn't get fixed in the ghc-9.2 branch, backport MR !5478 (closed) to GHC 9.2. Add test T19460.
MR !5478 (closed): Always generate ModDetails from ModIface
This vastly reduces memory usage when compiling with --make mode, from
about 900M when compiling Cabal to about 300M.
As a matter of uniformity, it also ensures that reading from an interface performs the same as using the in-memory cache. We can also delete all the horrible knot-tying in updateIdInfos.
Goes some way to fixing #13586 (closed)
Accept new output of tests fixing some bugs along the way