[fixcode] Accept the warning fixit for single argument function types requiring parentheses.

Author: akyrtzi

lib/FrontendTool/FrontendTool.cpp

@@ -568,6 +568,7 @@ class JSONFixitWriter : public DiagnosticConsumer {
     if (Info.ID == diag::forced_downcast_coercion.ID ||
         Info.ID == diag::forced_downcast_noop.ID ||
         Info.ID == diag::variable_never_mutated.ID ||
+        Info.ID == diag::function_type_no_parens.ID ||
         Info.ID == diag::parameter_extraneous_double_up.ID)
       return true;
     return false;

test/FixCode/fixits-apply.swift

@@ -63,4 +63,4 @@ func ftest1() {
   let myvar = 0
 }
 
-func ftest2(x x: Int) {}
+func ftest2(x x: Int -> Int) {}

test/FixCode/fixits-apply.swift.result

@@ -66,4 +66,4 @@ func ftest1() {
   let myvar = 0
 }
 
-func ftest2(x: Int) {}
+func ftest2(x: (Int) -> Int) {}