#4900: DEPENDS pragma -------------------------------------+------------------------------------ Reporter: cdsmith | Owner: parcs Type: feature request | Status: patch Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: TH_Depends | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by parcs): I hit a couple of obstacles regarding the implementation: 1. There is no way to distinguish between usage files added via TH and other usage files (e.g. #included files). This is necessary to avoid re- summarization when only the former kind of usage file has changed. 2. The usage files of a boot module get lost after compiling the corresponding source module. This means that modifying a usage file included by a boot module will not trigger recompilation in GHCi. The first obstacle could be solved by adding a new field to the `UsageFile` constructor containing the kind of usage file (LINE pragma, #include, TH, etc..) and checking only the relevant kinds of usage files during re-summarisation. I don't know what could be done about 2nd obstacle, though. It looks like we can't depend on reading the HPT during the downsweep since the the boot interface gets overwritten by the source interface after the source module gets compiled. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4900#comment:67 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler