Data constructors are sometimes incorrectly exploded

[ag-eitilt]

This is likely rightfully two separate bugs, but they're closely-related enough that a fix to one is likely going to fix the other. First of all, if a data constructor with too long of a definition gets run through the formatter, it gets exploded and the exploded form is parsed as a completely different structure:

 data SomeData =
-    LongConstructor LongTypeName1 LongTypeName2 LongTypeName3 LongTypeName4 LongTypeName5 LongTypeName6 LongTypeName7
+    LongConstructor
+    LongTypeName1
+    LongTypeName2
+    LongTypeName3
+    LongTypeName4
+    LongTypeName5
+    LongTypeName6
+    LongTypeName7
     ShortConstructor

Data constructors this long aren't common and probably aren't great practice to begin with, but everything in this ticket can be replicated with simpler structures as well; I discovered it on private code with a constructor which only takes three parameters, but where each of those parameters has been annotated with a name for easier documentation.

The second, stranger bug is that this seems to be at least partially affected by comments preceding the constructor:

 data SomeData =
     LongConstructor LongTypeName1 LongTypeName2 LongTypeName3 LongTypeName4 LongTypeName5 LongTypeName6
     ShortConstructor

but

 data SomeData =
     # comment
-    LongConstructor LongTypeName1 LongTypeName2 LongTypeName3 LongTypeName4 LongTypeName5 LongTypeName6
+    LongConstructor
+    LongTypeName1
+    LongTypeName2
+    LongTypeName3
+    LongTypeName4
+    LongTypeName5
+    LongTypeName6
     ShortConstructor

It does seem like this is looking at the wrap length -- cutting it down so the line is only 100 characters wide stops all incorrect wrapping, though I've not taken the time to locate the breakpoint for the wrap-even-without-comment length.