trigger indentation in multi-line let expression (close #24)

Author: itchyny

indent/haskell.vim

@@ -2,7 +2,7 @@
 " Filename: indent/haskell.vim
 " Author: itchyny
 " License: MIT License
-" Last Change: 2023/11/06 08:17:59.
+" Last Change: 2023/11/07 19:40:39.
 " =============================================================================
 
 if exists('b:did_indent')
@@ -12,7 +12,7 @@ endif
 let b:did_indent = 1
 
 setlocal indentexpr=GetHaskellIndent()
-setlocal indentkeys=!^F,o,O,=wher,=deri,0=in,0=class,0=instance,0=data,0=type,0=else,0<bar>,0},0],0(,0),0#,0,0==
+setlocal indentkeys=!^F,o,O,=wher,=deri,==,0=in,0=class,0=instance,0=data,0=type,0=else,0<bar>,0},0],0(,0),0#,0,0==
 
 let s:save_cpo = &cpo
 set cpo&vim

test/do/where_do.in.hs

@@ -1,3 +1,3 @@
 z = x
-  where f x = do
+where f x = do
 print "hello"

test/function/function_eq_first.in.hs

@@ -1,5 +1,5 @@
 f :: Int -> Int
 f 0
-  = 1
+= 1
 f x
-  = x
+= x

test/function/where_function_eq_first.in.hs

@@ -2,6 +2,6 @@ g = f
 where
 f :: Int -> Int
 f 0
-  = 1
+= 1
 f x
-  = x
+= x

test/let/let.in.hs

@@ -1,3 +1,3 @@
 f = let x = 0
-    y = 1
+y = 1
 in (x, y)

test/let/let_in_let_in.in.hs

@@ -1,5 +1,5 @@
 f = let x = 0
-    y = 1
+y = 1
 in let z = 2
-    u = 3
+u = 3
 in (x, y, z, u)

test/parenthesis/closed_binding.in.hs

@@ -1,5 +1,5 @@
 f x y z
-  = [ x,
+= [ x,
 y,
 z ]
 g x = x