Fix indentation of subforms within letfn

clj/dev-resources/test-special-case-indent.in

@@ -0,0 +1,39 @@
+(let [x (fn [y] 1)]
+  (->> "ola"
+     (x)))
+
+(letfn [(x [y] 1)]
+  (->> "ola"
+     (x)))
+
+(->> "ola"
+   (x))
+
+(defn foo []
+  (letfn [(x [y] 1)]
+    (->> "ola"
+       (x))))
+
+(letfn [(twice [x]
+               (* x 2))
+        (six-times [y]
+(* (twice y) 3))]
+  (println "Twice 15 =" (twice 15))
+  (println "Six times 15 =" (six-times 15)))
+
+(letfn [(twice [x]
+            (* x 2))]
+       (->> "ola"
+                (x)))
+
+(letfn [(foo [x y]
+               (->> x
+                  y
+                      :bar))
+(twice [x]
+            (* x 2))
+        (six-times [y]
+(* (twice y) 3))]
+      (foo #{:foo :bar :biz} :foo))
+
+;; vim:ft=clojure:

clj/dev-resources/test-special-case-indent.out

@@ -0,0 +1,39 @@
+(let [x (fn [y] 1)]
+  (->> "ola"
+       (x)))
+
+(letfn [(x [y] 1)]
+  (->> "ola"
+       (x)))
+
+(->> "ola"
+     (x))
+
+(defn foo []
+  (letfn [(x [y] 1)]
+    (->> "ola"
+         (x))))
+
+(letfn [(twice [x]
+          (* x 2))
+        (six-times [y]
+          (* (twice y) 3))]
+  (println "Twice 15 =" (twice 15))
+  (println "Six times 15 =" (six-times 15)))
+
+(letfn [(twice [x]
+          (* x 2))]
+  (->> "ola"
+       (x)))
+
+(letfn [(foo [x y]
+          (->> x
+               y
+               :bar))
+        (twice [x]
+          (* x 2))
+        (six-times [y]
+          (* (twice y) 3))]
+  (foo #{:foo :bar :biz} :foo))
+
+;; vim:ft=clojure:

clj/test/vim_clojure_static/indent_test.clj

@@ -33,3 +33,8 @@
   (test-indent "dispatch macro indentation is handled correctly"
                :in "test-dispatch-macro-indent.in"
                :out "test-dispatch-macro-indent.out"))
+
+(deftest test-special-case-indent
+  (test-indent "special case indentation is handled correctly"
+               :in "test-special-case-indent.in"
+               :out "test-special-case-indent.out"))

indent/clojure.vim

@@ -169,7 +169,35 @@ if exists("*searchpairpos")
 
 		call search('\S', 'W')
 		let w = s:strip_namespace_and_macro_chars(s:current_word())
+
 		if g:clojure_special_indent_words =~# '\V\<' . w . '\>'
+
+			" `letfn` is a special-special-case.
+			if w ==# 'letfn'
+				" Earlier code left the cursor at:
+				"     (letfn [...] ...)
+				"      ^
+
+				" Search and get coordinates of first `[`
+				"     (letfn [...] ...)
+				"            ^
+				call search('\[', 'W')
+				let pos = getcurpos()
+				let letfn_bracket = [pos[1], pos[2]]
+
+				" Move cursor to start of the form this function was
+				" initially called on.  Grab the coordinates of the
+				" closest outer `[`.
+				call cursor(a:position)
+				let outer_bracket = s:match_pairs('\[', '\]', 0)
+
+				" If the located square brackets are not the same,
+				" don't use special-case formatting.
+				if outer_bracket != letfn_bracket
+					return 0
+				endif
+			endif
+
 			return 1
 		endif