draft

Author: mateoxh

indent/haskell.vim

@@ -76,6 +76,12 @@ function! GetHaskellIndent() abort
   endif
 
   " =
+  if line =~# '\v\='
+    if getline(v:lnum - 1) =~# '\v^\s*-\>'
+      return indent(v:lnum - 1) - &shiftwidth
+    endif
+  endif
+
   if line =~# '\v^\s*\='
     return s:indent_eq()
   endif
@@ -106,6 +112,11 @@ function! GetHaskellIndent() abort
 
   let line = getline(v:lnum - 1)
 
+  " ::
+  if line =~# '::\s*$'
+    return indent(v:lnum - 1) + &shiftwidth
+  endif
+
   " #if, #else, #endif, #include
   if nonblankline =~# '^\s*#'
     return 0

test/typesig/typesig.in.hs

@@ -0,0 +1,4 @@
+foo ::
+Int
+-> Int
+foo = bar

test/typesig/typesig.out.hs

@@ -0,0 +1,4 @@
+foo ::
+  Int
+  -> Int
+foo = bar