Serialize docstrings to ifaces, display them with new GHCi :doc command

If `-haddock` is set, we now extract docstrings from the renamed ast
and serialize them in the .hi-files.

This includes some of the changes from D4749 with the notable
exceptions of the docstring lexing and renaming.

A currently limited and experimental GHCi :doc command can be used
to display docstrings for declarations.

The formatting of pretty-printed docstrings is changed slightly,
causing some changes in testsuite/tests/haddock.

Test Plan: ./validate

Reviewers: alexbiehl, hvr, gershomb, harpocrates, bgamari

Reviewed By: alexbiehl

Subscribers: rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4758

22 files changed, 49 insertions, 38 deletions

diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/T11768.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/T11768.stderr
index 060dd06ad2..997c2ef24c 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/T11768.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/T11768.stderr
@@ -3,10 +3,10 @@
 module T11768 where
 data Foo
   = Foo
-  deriving Eq  Documenting a single type
+  deriving Eq " Documenting a single type"
 data Bar
   = Bar
-  deriving (Eq  Documenting one of multiple types, Ord)
+  deriving (Eq " Documenting one of multiple types", Ord)
 <document comment>
 deriving instance Read Bar
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA014.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA014.stderr
index a70f624278..f55f8afab1 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA014.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA014.stderr
@@ -1,6 +1,6 @@
 
 ==================== Parser ====================
- a header
+" a header"
 module HeaderTest where
 <document comment>
 x = 0
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA015.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA015.stderr
index 3bfc17d811..15adf3e54e 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA015.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA015.stderr
@@ -1,6 +1,6 @@
 
 ==================== Parser ====================
- a header
+" a header"
 module HeaderTest where
 <document comment>
 x = 0
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA016.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA016.stderr
index 48dd0870c9..e9ccec44a0 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA016.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA016.stderr
@@ -1,6 +1,6 @@
 
 ==================== Parser ====================
-Module description
+"Module description"
 module A where
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA018.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA018.stderr
index 2aa5245f50..357f7540e2 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA018.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA018.stderr
@@ -1,6 +1,6 @@
 
 ==================== Parser ====================
- module header bla bla 
+" module header bla bla "
 module A where
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA019.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA019.stderr
index ca316bc8b8..c7a34730d9 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA019.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA019.stderr
@@ -1,7 +1,7 @@
 
 ==================== Parser ====================
 module A (
-         bla bla,  blabla 
+        " bla bla", " blabla "
     ) where
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA020.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA020.stderr
index 2aaa3eba98..660b28036e 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA020.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA020.stderr
@@ -1,7 +1,7 @@
 
 ==================== Parser ====================
 module A (
-         bla bla,  blabla , x, <IEGroup: 2>,  qweljqwelkqjwelqjkq
+        " bla bla", " blabla ", x, <IEGroup: 2>, " qweljqwelkqjwelqjkq"
     ) where
 x = True
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA021.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA021.stderr
index 162c403b84..befbee45f9 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA021.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA021.stderr
@@ -1,8 +1,8 @@
 
 ==================== Parser ====================
 module A (
-         bla bla,  blabla , x, <IEGroup: 2>,  qweljqwelkqjwelqjkq, y,
-         dkashdakj, z, <IEGroup: 1>
+        " bla bla", " blabla ", x, <IEGroup: 2>, " qweljqwelkqjwelqjkq", y,
+        " dkashdakj", z, <IEGroup: 1>
     ) where
 x = True
 y = False
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA023.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA023.stderr
index fcb953a495..d04558c301 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA023.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA023.stderr
@@ -1,7 +1,7 @@
 
 ==================== Parser ====================
 module ShouldCompile where
-test :: (Eq a) => [a]  doc1 -> [a]  doc2 -> [a]  doc3
+test :: (Eq a) => [a] " doc1" -> [a] " doc2 " -> [a] " doc3"
 test xs ys = xs
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA024.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA024.stderr
index 9f57f5df07..c453e071a3 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA024.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA024.stderr
@@ -1,7 +1,7 @@
 
 ==================== Parser ====================
 module ShouldCompile where
-test2 :: a  doc1 -> b  doc2 -> a  doc 3 
+test2 :: a " doc1 " -> b " doc2 " -> a " doc 3 "
 test2 x y = x
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA025.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA025.stderr
index 472ec1a1eb..e0b8a4a7bf 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA025.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA025.stderr
@@ -1,7 +1,7 @@
 
 ==================== Parser ====================
 module ShouldCompile where
-test2 :: a  doc1  -> a
+test2 :: a " doc1 " -> a
 test2 x = x
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA026.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA026.stderr
index 5f7335b6b9..37135099a0 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA026.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA026.stderr
@@ -2,7 +2,7 @@
 ==================== Parser ====================
 module ShouldCompile where
 test ::
-  (Eq a) => [a]  doc1 -> forall b. [b]  doc2 -> [a]  doc3
+  (Eq a) => [a] " doc1" -> forall b. [b] " doc2 " -> [a] " doc3"
 test xs ys = xs
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA027.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA027.stderr
index e7707c5ec0..0bbb612119 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA027.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA027.stderr
@@ -2,9 +2,9 @@
 ==================== Parser ====================
 module ShouldCompile where
 test ::
-  [a]  doc1
+  [a] " doc1"
   -> forall b.
-     (Ord b) => [b]  doc2  -> forall c. (Num c) => [c]  doc3 -> [a]
+     (Ord b) => [b] " doc2 " -> forall c. (Num c) => [c] " doc3" -> [a]
 test xs ys zs = xs
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA028.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA028.stderr
index 47d2468ea5..3c1bbc9565 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA028.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA028.stderr
@@ -2,7 +2,7 @@
 ==================== Parser ====================
 module ShouldCompile where
 data a <--> b = Mk a b
-test :: [a]  doc1  -> a <--> b -> [a]  blabla
+test :: [a] " doc1 " -> a <--> b -> [a] " blabla"
 test xs ys = xs
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA029.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA029.stderr
index 820ffa6708..7271238e3e 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA029.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA029.stderr
@@ -2,6 +2,6 @@
 ==================== Parser ====================
 module ShouldCompile where
 data A
-  =  A comment that documents the first constructor A | B | C | D
+  = " A comment that documents the first constructor" A | B | C | D
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA030.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA030.stderr
index b0ef139199..e09cfa2187 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA030.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA030.stderr
@@ -2,6 +2,9 @@
 ==================== Parser ====================
 module ShouldCompile where
 data A
-  =  comment for A  A |  comment for B  B |  comment for C   C | D
+  = " comment for A " A |
+    " comment for B " B |
+    " comment for C  " C |
+    D
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA031.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA031.stderr
index 1d033cd6d7..eb6fcaef1e 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA031.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA031.stderr
@@ -3,7 +3,7 @@
 module ShouldCompile where
 data A
   = A |
-     comment for B  forall a. B a a |
-     comment for C  forall a. Num a => C a
+    " comment for B " forall a. B a a |
+    " comment for C " forall a. Num a => C a
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA032.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA032.stderr
index 5cf2d9b034..eec30285f5 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA032.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA032.stderr
@@ -3,8 +3,8 @@
 module ShouldCompile where
 data R a
   = R {field1 :: a,
-       field2 :: a  comment for field2,
-       field3 :: a  comment for field3,
-       field4 :: a  comment for field4 }
+       field2 :: a " comment for field2",
+       field3 :: a " comment for field3",
+       field4 :: a " comment for field4 "}
 
 
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA034.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA034.stderr
index f743393349..64478fed12 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA034.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA034.stderr
@@ -2,4 +2,6 @@
 ==================== Parser ====================
 module Hi where
 <document comment>
-data Hi where  This is a GADT constructor. Hi :: () -> Hi
+data Hi where " This is a GADT constructor." Hi :: () -> Hi
+
+
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr
index d0e5bbc57d..3f12a0cffd 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr
@@ -3,7 +3,9 @@
 module Hi where
 data Hi
   where
-      Hi :: ()  This is a comment on the '()' field of 'Hi'
-            -> Int
-               -> String  This is a comment on the 'String' field of 'Hi'
-                  -> Hi  This is a comment on the return type of 'Hi'
+    Hi :: () " This is a comment on the '()' field of 'Hi'"
+          -> Int
+             -> String " This is a comment on the 'String' field of 'Hi'"
+                -> Hi " This is a comment on the return type of 'Hi'"
+
+
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr
index 0d884ab0e3..5cd0a59a05 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr
@@ -2,11 +2,13 @@
 ==================== Parser ====================
 module ConstructorFields where
 data Foo
-  =  doc on `Bar` constructor Bar Int String |
-     doc on the `Baz` constructor
-    Baz Int  doc on the `Int` field of `Baz` String  doc on the `String` field of `Baz` |
-     doc on the `:+` constructor Int :+ String |
-     doc on the `:*` constructor
-    Int  doc on the `Int` field of the `:*` constructor :* String  doc on the `String` field of the `:*` constructor |
-     doc on the `Boo` record constructor Boo {x :: ()} |
-     doc on the `Boa` record constructor Boa {y :: ()}
+  = " doc on `Bar` constructor" Bar Int String |
+    " doc on the `Baz` constructor"
+    Baz Int " doc on the `Int` field of `Baz`" String " doc on the `String` field of `Baz`" |
+    " doc on the `:+` constructor" Int :+ String |
+    " doc on the `:*` constructor"
+    Int " doc on the `Int` field of the `:*` constructor" :* String " doc on the `String` field of the `:*` constructor" |
+    " doc on the `Boo` record constructor" Boo {x :: ()} |
+    " doc on the `Boa` record constructor" Boa {y :: ()}
+
+
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr
index 8e90efa691..b9ecfa6303 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr
@@ -4,4 +4,6 @@ module UnamedConstructorFields where
 data A = A
 data B = B
 data C = C
-data Foo = MkFoo A  'A' has a comment B C  'C' has a comment
+data Foo = MkFoo A " 'A' has a comment" B C " 'C' has a comment"
+
+