Fix indentation after async protocol method

Author: taku0

swift-mode-lexer.el

@@ -642,6 +642,13 @@ return non-nil."
                                       (swift-mode:forward-token-simple)))
              "let"))
 
+     ;; After async
+     ;;
+     ;; Suppresses implicit semicolon if before let.
+     ((and (equal (swift-mode:token:text previous-token) "async")
+           (equal (swift-mode:token:text next-token) "let"))
+      nil)
+
      ;; Suppress implicit semicolon around else
      ((or
        (equal (swift-mode:token:text previous-token) "else")
@@ -721,7 +728,7 @@ return non-nil."
      ;; Suppress implicit semicolon after keywords that cannot end statements.
      ((member (swift-mode:token:text previous-token)
               '("while" "for" "switch" "case" "default" "catch" "if" "guard"
-                "let" "var" "throw" "import" "async"))
+                "let" "var" "throw" "import"))
       nil)
 
      ;; Inserts implicit semicolon before keywords that starts a new

test/swift-files/indent/declarations.swift

@@ -698,6 +698,7 @@ protocol Foo {
     func foo(x: Int, y: Int) throws -> (A, B)
     func bar(x: Int) throws
     func baz(x: () throws -> Int) rethrows
+    func aaa() async
     init<A, B>(x: Int) throws
       where
         A: C