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: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: bgamari, simonpj, austin

Reviewed By: bgamari

Subscribers: duog, rwbarton, thomie

GHC Trac Issues: #14075

Differential Revision: https://phabricator.haskell.org/D3815

9 files changed, 34 insertions, 0 deletions

diff --git a/testsuite/tests/driver/T14075/F.hs b/testsuite/tests/driver/T14075/F.hs
new file mode 100644
index 0000000000..3e32036eb4
--- /dev/null
+++ b/testsuite/tests/driver/T14075/F.hs
@@ -0,0 +1 @@
+module F () where
diff --git a/testsuite/tests/driver/T14075/F.hs-boot b/testsuite/tests/driver/T14075/F.hs-boot
new file mode 100644
index 0000000000..41008d554f
--- /dev/null
+++ b/testsuite/tests/driver/T14075/F.hs-boot
@@ -0,0 +1,6 @@
+module F where
+
+import O (O)
+
+newtype F = F ()
+instance O F where
diff --git a/testsuite/tests/driver/T14075/Makefile b/testsuite/tests/driver/T14075/Makefile
new file mode 100644
index 0000000000..505274a181
--- /dev/null
+++ b/testsuite/tests/driver/T14075/Makefile
@@ -0,0 +1,6 @@
+TOP=../../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
+T14075:
+	! '$(TEST_HC)' $(TEST_HC_OPTS) -j2 F O V
diff --git a/testsuite/tests/driver/T14075/O.hs b/testsuite/tests/driver/T14075/O.hs
new file mode 100644
index 0000000000..2cbb8bb0ef
--- /dev/null
+++ b/testsuite/tests/driver/T14075/O.hs
@@ -0,0 +1,3 @@
+module O (O) where
+
+class O a where
diff --git a/testsuite/tests/driver/T14075/T14075.stderr b/testsuite/tests/driver/T14075/T14075.stderr
new file mode 100644
index 0000000000..0493a96f12
--- /dev/null
+++ b/testsuite/tests/driver/T14075/T14075.stderr
@@ -0,0 +1,7 @@
+
+F.hs:1:1: error:
+    instance O.O F.F -- Defined at F.hs-boot:6:10
+      is defined in the hs-boot file, but not in the module itself
+
+F.hs-boot:5:1: error:
+    ‘F.F’ is exported by the hs-boot file, but not exported by the module
diff --git a/testsuite/tests/driver/T14075/T14075.stdout b/testsuite/tests/driver/T14075/T14075.stdout
new file mode 100644
index 0000000000..18f17be1ee
--- /dev/null
+++ b/testsuite/tests/driver/T14075/T14075.stdout
@@ -0,0 +1,3 @@
+[1 of 4] Compiling O                ( O.hs, O.o )
+[2 of 4] Compiling F[boot]          ( F.hs-boot, F.o-boot )
+[3 of 4] Compiling F                ( F.hs, F.o )
diff --git a/testsuite/tests/driver/T14075/V.hs b/testsuite/tests/driver/T14075/V.hs
new file mode 100644
index 0000000000..cf06b93dcc
--- /dev/null
+++ b/testsuite/tests/driver/T14075/V.hs
@@ -0,0 +1,3 @@
+module V () where
+
+import {-# SOURCE #-} F ()
diff --git a/testsuite/tests/driver/T14075/V.hs-boot b/testsuite/tests/driver/T14075/V.hs-boot
new file mode 100644
index 0000000000..ec64e228fc
--- /dev/null
+++ b/testsuite/tests/driver/T14075/V.hs-boot
@@ -0,0 +1 @@
+module V where
diff --git a/testsuite/tests/driver/T14075/all.T b/testsuite/tests/driver/T14075/all.T
new file mode 100644
index 0000000000..646976a5b2
--- /dev/null
+++ b/testsuite/tests/driver/T14075/all.T
@@ -0,0 +1,4 @@
+test('T14075',
+     [extra_files(['F.hs', 'F.hs-boot', 'O.hs', 'V.hs', 'V.hs-boot'])],
+     run_command,
+     ['$MAKE -s --no-print-directory T14075'])