9 files changed, 25 insertions, 3 deletions
diff --git a/compiler/main/Finder.hs b/compiler/main/Finder.hs
index 2bfea5d37a..9568ac154c 100644
--- a/compiler/main/Finder.hs
+++ b/compiler/main/Finder.hs
@@ -667,14 +667,18 @@ cantFindErr cannot_find _ dflags mod_name find_result
         <+> quotes (ppr pkgid)
         --FIXME: we don't really want to show the unit id here we should
         -- show the source package id or installed package id if it's ambiguous
-        <> dot $$ cabal_pkg_hidden_hint pkgid
-    cabal_pkg_hidden_hint pkgid
+        <> dot $$ pkg_hidden_hint pkgid
+    pkg_hidden_hint pkgid
      | gopt Opt_BuildingCabalPackage dflags
         = let pkg = expectJust "pkg_hidden" (lookupPackage dflags pkgid)
            in text "Perhaps you need to add" <+>
               quotes (ppr (packageName pkg)) <+>
               text "to the build-depends in your .cabal file."
-     | otherwise = Outputable.empty
+     | otherwise
+         = let pkg = expectJust "pkg_hidden" (lookupPackage dflags pkgid)
+           in text "You can run" <+>
+              quotes (text ":set -package " <> ppr (packageName pkg)) <+>
+              text "to expose it."
 
     mod_hidden pkg =
         text "it is a hidden module in the package" <+> quotes (ppr pkg)
diff --git a/testsuite/tests/ghci/should_fail/T15055.script b/testsuite/tests/ghci/should_fail/T15055.script
new file mode 100644
index 0000000000..800944a5c0
--- /dev/null
+++ b/testsuite/tests/ghci/should_fail/T15055.script
@@ -0,0 +1 @@
+import GHC
diff --git a/testsuite/tests/ghci/should_fail/T15055.stderr b/testsuite/tests/ghci/should_fail/T15055.stderr
new file mode 100644
index 0000000000..dcc297c59a
--- /dev/null
+++ b/testsuite/tests/ghci/should_fail/T15055.stderr
@@ -0,0 +1,5 @@
+
+<no location info>:
+    Could not find module ‘GHC’
+    It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
diff --git a/testsuite/tests/ghci/should_fail/all.T b/testsuite/tests/ghci/should_fail/all.T
index 285137387d..d62c3baa6a 100644
--- a/testsuite/tests/ghci/should_fail/all.T
+++ b/testsuite/tests/ghci/should_fail/all.T
@@ -1,3 +1,4 @@
 test('T10549', [], ghci_script, ['T10549.script'])
 test('T10549a', [], ghci_script, ['T10549a.script'])
 test('T14608', [], ghci_script, ['T14608.script'])
+test('T15055', [], ghci_script, ['T15055.script'])
diff --git a/testsuite/tests/package/package01e.stderr b/testsuite/tests/package/package01e.stderr
index 7dd9f699d9..a755991432 100644
--- a/testsuite/tests/package/package01e.stderr
+++ b/testsuite/tests/package/package01e.stderr
@@ -2,9 +2,11 @@
 package01e.hs:2:1: error:
     Could not find module ‘Data.Map’
     It is a member of the hidden package ‘containers-0.5.11.0’.
+    You can run ‘:set -package containers’ to expose it.
     Use -v to see a list of the files searched for.
 
 package01e.hs:3:1: error:
     Could not find module ‘Data.IntMap’
     It is a member of the hidden package ‘containers-0.5.11.0’.
+    You can run ‘:set -package containers’ to expose it.
     Use -v to see a list of the files searched for.
diff --git a/testsuite/tests/package/package06e.stderr b/testsuite/tests/package/package06e.stderr
index c634d2d46c..59aeb37682 100644
--- a/testsuite/tests/package/package06e.stderr
+++ b/testsuite/tests/package/package06e.stderr
@@ -2,9 +2,11 @@
 package06e.hs:2:1: error:
     Could not find module ‘HsTypes’
     It is a member of the hidden package ‘ghc-8.1’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
 
 package06e.hs:3:1: error:
     Could not find module ‘UniqFM’
     It is a member of the hidden package ‘ghc-8.1’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
diff --git a/testsuite/tests/package/package07e.stderr b/testsuite/tests/package/package07e.stderr
index 9ca835f7ac..d167508659 100644
--- a/testsuite/tests/package/package07e.stderr
+++ b/testsuite/tests/package/package07e.stderr
@@ -7,14 +7,17 @@ package07e.hs:2:1: error:
 package07e.hs:3:1: error:
     Could not find module ‘HsTypes’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
 
 package07e.hs:4:1: error:
     Could not find module ‘HsUtils’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
 
 package07e.hs:5:1: error:
     Could not find module ‘UniqFM’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
diff --git a/testsuite/tests/package/package08e.stderr b/testsuite/tests/package/package08e.stderr
index 5992a4ca49..922c643c89 100644
--- a/testsuite/tests/package/package08e.stderr
+++ b/testsuite/tests/package/package08e.stderr
@@ -7,14 +7,17 @@ package08e.hs:2:1: error:
 package08e.hs:3:1: error:
     Could not find module ‘HsTypes’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
 
 package08e.hs:4:1: error:
     Could not find module ‘HsUtils’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
 
 package08e.hs:5:1: error:
     Could not find module ‘UniqFM’
     It is a member of the hidden package ‘ghc-8.5’.
+    You can run ‘:set -package ghc’ to expose it.
     Use -v to see a list of the files searched for.
diff --git a/testsuite/tests/plugins/T11244.stderr b/testsuite/tests/plugins/T11244.stderr
index 30c8c5b127..472ef4497b 100644
--- a/testsuite/tests/plugins/T11244.stderr
+++ b/testsuite/tests/plugins/T11244.stderr
@@ -1,3 +1,4 @@
 <command line>: Could not find module ‘RuleDefiningPlugin’
 It is a member of the hidden package ‘rule-defining-plugin-0.1’.
+You can run ‘:set -package rule-defining-plugin’ to expose it.
 Use -v to see a list of the files searched for.