Fix recompilation avoidance bug for implementor of hsig.

Authored by ezyang on Mar 26 2017, 12:50 AM.

Description

Fix recompilation avoidance bug for implementor of hsig.

Summary:
I observed a bug where if I modified the module which implemented
an hsig in another package, GHC would not recompile the signature
in this situation.

The root cause was that we were conflating modules from user
imports, and "system" module dependencies (from signature
merging and instantiation.) So this patch handles them separately.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: simonpj, bgamari, austin

Subscribers: rwbarton, thomie, snowleopard

Differential Revision: https://phabricator.haskell.org/D3381

(cherry picked from commit 5fb485a3e1e83a1f5c6acf989be292940229e1a4)

Details

Committed
bgamariApr 2 2017, 8:19 PM
Pushed
bgamariApr 10 2017, 6:53 PM
Differential Revision
D3381: Fix recompilation avoidance bug for implementor of hsig.
Parents
rGHCDIFF55e1053ef693: Correctly handle wired in unit IDs in -instantiated-with
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