Improve declaration formatting linter rule for anonymous functions

Summary: Ref T8742. Anonymous functions should have a space after the `function` keyword. Additionally, ensure that there is a space before and after the `use` token.

Test Plan: Modified existing test cases.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Maniphest Tasks: T8742

Differential Revision: https://secure.phabricator.com/D13804

src/lint/linter/__tests__/xhpast/decl-parens-hug-closing.lint-test

@@ -23,6 +23,7 @@ final class X {
 f(function ($x) {});
 f(function ($x ) {});
 f(function ($x ) use ($z) {});
+f(function ($x)use($z) {});
 ~~~~~~~~~~
 warning:4:14
 warning:5:11
@@ -31,8 +32,10 @@ error:10:13
 warning:13:23
 warning:16:31
 warning:19:33
-warning:24:14
-warning:25:14
+warning:24:15
+warning:25:15
+warning:26:16
+warning:26:19
 ~~~~~~~~~~
 <?php
 
@@ -59,3 +62,4 @@ final class X {
 f(function ($x) {});
 f(function ($x) {});
 f(function ($x) use ($z) {});
+f(function ($x) use ($z) {});

src/lint/linter/__tests__/xhpast/php53-features.lint-test

@@ -4,7 +4,6 @@ namespace a;
 use b, c;
 f(function () {});
 g(function () use ($c) {});
-h(function /* ! */ () use ($c) {});
 static::m();
 1 ? 1 : 2;
 1 ?: 2;
@@ -16,10 +15,9 @@ error:3:1
 error:4:5
 error:5:3
 error:6:3
-error:7:3
-error:8:1
-error:10:1
-error:13:6
+error:7:1
+error:9:1
+error:12:6
 ~~~~~~~~~~
 ~~~~~~~~~~
 {

src/lint/linter/xhpast/rules/ArcanistDeclarationParenthesesXHPASTLinterRule.php

@@ -32,6 +32,18 @@ final class ArcanistDeclarationParenthesesXHPASTLinterRule
       $trailing = $last->getNonsemanticTokensBefore();
       $trailing_text = implode('', mpull($trailing, 'getValue'));
 
+      if ($dec->getChildByIndex(2)->getTypeName() == 'n_EMPTY') {
+        // Anonymous functions.
+        if ($leading_text != ' ') {
+          $this->raiseLintAtOffset(
+            $first->getOffset() - strlen($leading_text),
+            pht(
+              'Convention: space before opening parenthesis in '.
+              'anonymous function declarations.'),
+            $leading_text,
+            ' ');
+        }
+      } else {
         if (preg_match('/^\s+$/', $leading_text)) {
           $this->raiseLintAtOffset(
             $first->getOffset() - strlen($leading_text),
@@ -41,6 +53,7 @@ final class ArcanistDeclarationParenthesesXHPASTLinterRule
             $leading_text,
             '');
         }
+      }
 
       if (preg_match('/^\s+$/', $trailing_text)) {
         $this->raiseLintAtOffset(
@@ -51,6 +64,33 @@ final class ArcanistDeclarationParenthesesXHPASTLinterRule
           $trailing_text,
           '');
       }
+
+      $use_list = $dec->getChildByIndex(4);
+      if ($use_list->getTypeName() == 'n_EMPTY') {
+        continue;
+      }
+      $use_token = $use_list->selectTokensOfType('T_USE');
+
+      foreach ($use_token as $use) {
+        $before = $use->getNonsemanticTokensBefore();
+        $after  = $use->getNonsemanticTokensAfter();
+
+        if (!$before) {
+          $this->raiseLintAtOffset(
+            $use->getOffset(),
+            pht('Convention: space before `%s` token.', 'use'),
+            '',
+            ' ');
+        }
+
+        if (!$after) {
+          $this->raiseLintAtOffset(
+            $use->getOffset() + strlen($use->getValue()),
+            pht('Convention: space after `%s` token.', 'use'),
+            '',
+            ' ');
+        }
+      }
     }
   }