Support constructor Haddocks in more places

This adds support for adding Haddocks on individual non-record fields
of regular (and GADT) constructors. The following now parses just fine
with `-haddock` enabled:

data Foo
  = Baz             -- ^ doc on the `Baz` constructor
      Int           -- ^ doc on the `Int` field of `Baz`
      String        -- ^ doc on the `String` field of `Baz`

  | Int             -- ^ doc on the `Int` field of the `:*` constructor
      :*            -- ^ doc on the `:*` constructor
    String          -- ^ doc on the `String` field of the `:*`
constructor

  | Boa             -- ^ doc on the `Boa` record constructor
      { y :: () }

The change is backwards compatible: if there is only one doc and it
occurs
on the last field, it is lifted to apply to the whole constructor (as
before).

Reviewers: bgamari, alanz

Subscribers: rwbarton, thomie, mpickering, carter

Differential Revision: https://phabricator.haskell.org/D4292

11 files changed, 110 insertions, 0 deletions

diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/all.T b/testsuite/tests/haddock/should_compile_flag_haddock/all.T
index 7db4379b16..90d4a55c3f 100644
--- a/testsuite/tests/haddock/should_compile_flag_haddock/all.T
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/all.T
@@ -39,6 +39,9 @@ test('haddockA029', normal, compile, ['-haddock -ddump-parsed'])
 test('haddockA030', normal, compile, ['-haddock -ddump-parsed'])
 test('haddockA031', normal, compile, ['-haddock -ddump-parsed -XExistentialQuantification'])
 test('haddockA032', normal, compile, ['-haddock -ddump-parsed'])
+test('haddockA035', normal, compile, ['-haddock -ddump-parsed'])
+test('haddockA036', normal, compile, ['-haddock -ddump-parsed'])
+test('haddockA037', normal, compile, ['-haddock -ddump-parsed'])
 
 # The tests below this line are not duplicated in
 # should_compile_noflag_haddock.
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.hs b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.hs
new file mode 100644
index 0000000000..25ed2acb83
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE GADTs #-}
+
+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'
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr
new file mode 100644
index 0000000000..d0e5bbc57d
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA035.stderr
@@ -0,0 +1,9 @@
+
+==================== Parser ====================
+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'
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.hs b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.hs
new file mode 100644
index 0000000000..02dd1f9022
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.hs
@@ -0,0 +1,19 @@
+module ConstructorFields where
+
+data Foo
+  = Bar Int String  -- ^ doc on `Bar` constructor
+
+  | Baz             -- ^ doc on the `Baz` constructor
+      Int           -- ^ doc on the `Int` field of `Baz`
+      String        -- ^ doc on the `String` field of `Baz`
+
+  | Int :+ String   -- ^ doc on the `:+` constructor
+
+  | Int             -- ^ doc on the `Int` field of the `:*` constructor
+      :*            -- ^ doc on the `:*` constructor
+    String          -- ^ doc on the `String` field of the `:*` constructor
+
+  | Boo { x :: () } -- ^ doc on the `Boo` record constructor
+
+  | Boa             -- ^ doc on the `Boa` record constructor
+      { y :: () }
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr
new file mode 100644
index 0000000000..0d884ab0e3
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA036.stderr
@@ -0,0 +1,12 @@
+
+==================== 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 :: ()}
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.hs b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.hs
new file mode 100644
index 0000000000..4571e09583
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.hs
@@ -0,0 +1,10 @@
+module UnamedConstructorFields where
+
+data A = A
+data B = B
+data C = C
+
+-- Haddock on 'A' prevents the haddock on 'C' from being applied to 'MkFoo'
+data Foo = MkFoo A -- ^ 'A' has a comment
+                 B -- This doesn't
+                 C -- ^ 'C' has a comment
diff --git a/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr
new file mode 100644
index 0000000000..8e90efa691
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_flag_haddock/haddockA037.stderr
@@ -0,0 +1,7 @@
+
+==================== Parser ====================
+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
diff --git a/testsuite/tests/haddock/should_compile_noflag_haddock/all.T b/testsuite/tests/haddock/should_compile_noflag_haddock/all.T
index c0d62aed43..edb2bd0e05 100644
--- a/testsuite/tests/haddock/should_compile_noflag_haddock/all.T
+++ b/testsuite/tests/haddock/should_compile_noflag_haddock/all.T
@@ -39,6 +39,9 @@ test('haddockC029', normal, compile, [''])
 test('haddockC030', normal, compile, [''])
 test('haddockC031', normal, compile, ['-XExistentialQuantification'])
 test('haddockC032', normal, compile, [''])
+test('haddockC035', normal, compile, [''])
+test('haddockC036', normal, compile, [''])
+test('haddockC037', normal, compile, [''])
 
 # The tests below this line are not duplicated in
 # should_compile_flag_haddock.
diff --git a/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC035.hs b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC035.hs
new file mode 100644
index 0000000000..25ed2acb83
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC035.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE GADTs #-}
+
+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'
diff --git a/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC036.hs b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC036.hs
new file mode 100644
index 0000000000..02dd1f9022
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC036.hs
@@ -0,0 +1,19 @@
+module ConstructorFields where
+
+data Foo
+  = Bar Int String  -- ^ doc on `Bar` constructor
+
+  | Baz             -- ^ doc on the `Baz` constructor
+      Int           -- ^ doc on the `Int` field of `Baz`
+      String        -- ^ doc on the `String` field of `Baz`
+
+  | Int :+ String   -- ^ doc on the `:+` constructor
+
+  | Int             -- ^ doc on the `Int` field of the `:*` constructor
+      :*            -- ^ doc on the `:*` constructor
+    String          -- ^ doc on the `String` field of the `:*` constructor
+
+  | Boo { x :: () } -- ^ doc on the `Boo` record constructor
+
+  | Boa             -- ^ doc on the `Boa` record constructor
+      { y :: () }
diff --git a/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC037.hs b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC037.hs
new file mode 100644
index 0000000000..4571e09583
--- /dev/null
+++ b/testsuite/tests/haddock/should_compile_noflag_haddock/haddockC037.hs
@@ -0,0 +1,10 @@
+module UnamedConstructorFields where
+
+data A = A
+data B = B
+data C = C
+
+-- Haddock on 'A' prevents the haddock on 'C' from being applied to 'MkFoo'
+data Foo = MkFoo A -- ^ 'A' has a comment
+                 B -- This doesn't
+                 C -- ^ 'C' has a comment