Below is an error message I have seen a number of times after rebasing my git worktree, i.e. this is how to "reproduce": git fetch origin git rebase origin/master git submodule update ./hadrian/build.sh (Obviously some details are elided, and this is not a complete reproduction.) I don't have many copies of the error, but I do remember seeing the complaint about "No generator for .../PmOracle.hs" on other occasions. Any idea what this comes from? -Bryan --- 8< --- Error when running Shake build system: at action, called at src/Rules.hs:71:19 in main:Rules at need, called at src/Rules.hs:93:5 in main:Rules * Depends on: _build/stage0/lib/package.conf.d/ghc-8.9.0.20190929.conf at need, called at src/Rules/Register.hs:113:5 in main:Rules.Register * Depends on: _build/stage0/compiler/build/libHSghc-8.9.0.20190929.a * Depends on: _build/stage0/compiler/build/GHCi.o * Depends on: _build/stage0/compiler/build/GHCi.o _build/stage0/compiler/build/GHCi.hi * Depends on: OracleQ (KeyValues ("_build/stage0/compiler/.dependencies","_build/stage0/compiler/build/GHCi.o")) * Depends on: _build/stage0/compiler/.dependencies * Depends on: _build/stage0/compiler/.dependencies.mk at need, called at src/Rules/Dependencies.hs:26:9 in main:Rules.Dependencies * Depends on: _build/stage0/compiler/build/PmOracle.hs at error, called at src/Rules/Generate.hs:105:34 in main:Rules.Generate * Raised the exception: No generator for _build/stage0/compiler/build/PmOracle.hs.