Commit 4717ce86 authored by Edward Z. Yang's avatar Edward Z. Yang Committed by Ben Gamari
Browse files

Fix incorrect retypecheck loop in -j (#14075)

The parallel codepath was incorrectly retypechecking the
hs-boot ModIface prior to typechecking the hs file,
which was inconsistent with the non-parallel case.  The
non-parallel case gets it right: you don't want to retypecheck
the hs-boot file itself (forwarding its declarations to hs)
because you need it to be consistently knot-tied with itself
when you compare the interfaces.
Signed-off-by: default avatarEdward Z. Yang <>

Test Plan: validate

Reviewers: bgamari, simonpj, austin

Reviewed By: bgamari

Subscribers: duog, rwbarton, thomie

GHC Trac Issues: #14075

Differential Revision:
parent afc2f798
......@@ -1172,7 +1172,13 @@ parUpsweep_one mod home_mod_map comp_graph_loops lcl_dflags mHscMessage cleanup
Just (ms_mod lcl_mod, type_env_var) }
lcl_hsc_env'' <- case finish_loop of
Nothing -> return lcl_hsc_env'
-- In the non-parallel case, the retypecheck prior to
-- typechecking the loop closer includes all modules
-- EXCEPT the loop closer. However, our precomputed
-- SCCs include the loop closer, so we have to filter
-- it out.
Just loop -> typecheckLoop lcl_dflags lcl_hsc_env' $
filter (/= moduleName (fst this_build_mod)) $
map (moduleName . fst) loop
-- Compile the module.
......@@ -1195,8 +1201,10 @@ parUpsweep_one mod home_mod_map comp_graph_loops lcl_dflags mHscMessage cleanup
let hsc_env' = hsc_env
{ hsc_HPT = addToHpt (hsc_HPT hsc_env)
this_mod mod_info }
-- If this module is a loop finisher, now is the time to
-- re-typecheck the loop.
-- We've finished typechecking the module, now we must
-- retypecheck the loop AGAIN to ensure unfoldings are
-- updated. This time, however, we include the loop
-- closer!
hsc_env'' <- case finish_loop of
Nothing -> return hsc_env'
Just loop -> typecheckLoop lcl_dflags hsc_env' $
......@@ -1672,6 +1680,42 @@ reTypecheckLoop hsc_env ms graph
mss = mgModSummaries graph
appearsAsBoot = (`elemModuleSet` mgBootModules graph)
-- | Given a non-boot ModSummary @ms@ of a module, for which there exists a
-- corresponding boot file in @graph@, return the set of modules which
-- transitively depend on this boot file. This function is slightly misnamed,
-- but its name "getModLoop" alludes to the fact that, when getModLoop is called
-- with a graph that does not contain @ms@ (non-parallel case) or is an
-- SCC with hs-boot nodes dropped (parallel-case), the modules which
-- depend on the hs-boot file are typically (but not always) the
-- modules participating in the recursive module loop. The returned
-- list includes the hs-boot file.
-- Example:
-- let g represent the module graph:
-- C.hs
-- A.hs-boot imports C.hs
-- B.hs imports A.hs-boot
-- A.hs imports B.hs
-- genModLoop A.hs g == Just [A.hs-boot, B.hs, A.hs]
-- It would also be permissible to omit A.hs from the graph,
-- in which case the result is [A.hs-boot, B.hs]
-- Example:
-- A counter-example to the claim that modules returned
-- by this function participate in the loop occurs here:
-- let g represent the module graph:
-- C.hs
-- A.hs-boot imports C.hs
-- B.hs imports A.hs-boot
-- A.hs imports B.hs
-- D.hs imports A.hs-boot
-- genModLoop A.hs g == Just [A.hs-boot, B.hs, A.hs, D.hs]
-- Arguably, D.hs should import A.hs, not A.hs-boot, but
-- a dependency on the boot file is not illegal.
:: ModSummary
-> [ModSummary]
......@@ -1687,6 +1731,8 @@ getModLoop ms graph appearsAsBoot
this_mod = ms_mod ms
-- NB: sometimes mods has duplicates; this is harmless because
-- any duplicates get clobbered in addListToHpt and never get forced.
typecheckLoop :: DynFlags -> HscEnv -> [ModuleName] -> IO HscEnv
typecheckLoop dflags hsc_env mods = do
debugTraceMsg dflags 2 $
module F where
import O (O)
newtype F = F ()
instance O F where
include $(TOP)/mk/
include $(TOP)/mk/
! '$(TEST_HC)' $(TEST_HC_OPTS) -j2 F O V
module O (O) where
class O a where
F.hs:1:1: error:
instance O.O F.F -- Defined at F.hs-boot:6:10
is defined in the hs-boot file, but not in the module itself
F.hs-boot:5:1: error:
‘F.F’ is exported by the hs-boot file, but not exported by the module
[1 of 4] Compiling O ( O.hs, O.o )
[2 of 4] Compiling F[boot] ( F.hs-boot, F.o-boot )
[3 of 4] Compiling F ( F.hs, F.o )
module V () where
import {-# SOURCE #-} F ()
[extra_files(['F.hs', 'F.hs-boot', 'O.hs', 'V.hs', 'V.hs-boot'])],
['$MAKE -s --no-print-directory T14075'])
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