diff --git a/src/lint/linter/ArcanistXHPASTLinter.php b/src/lint/linter/ArcanistXHPASTLinter.php
--- a/src/lint/linter/ArcanistXHPASTLinter.php
+++ b/src/lint/linter/ArcanistXHPASTLinter.php
@@ -61,8 +61,10 @@
   const LINT_INNER_FUNCTION             = 59;
   const LINT_DEFAULT_PARAMETERS         = 60;
   const LINT_LOWERCASE_FUNCTIONS        = 61;
+  const LINT_INDENTATION                = 62;
 
   private $blacklistedFunctions = array();
+  private $indentation = 2;
   private $naminghook;
   private $printfFunctions = array();
   private $switchhook;
@@ -191,6 +193,8 @@
         => pht('Default Parameters'),
       self::LINT_LOWERCASE_FUNCTIONS
         => pht('Lowercase Functions'),
+      self::LINT_INDENTATION
+        => pht('Indentation'),
     );
   }
 
@@ -240,6 +244,7 @@
       self::LINT_INNER_FUNCTION             => $warning,
       self::LINT_DEFAULT_PARAMETERS         => $warning,
       self::LINT_LOWERCASE_FUNCTIONS        => $advice,
+      self::LINT_INDENTATION                => $advice,
     );
   }
 
@@ -249,6 +254,11 @@
         'type' => 'optional map<string, string>',
         'help' => pht('Blacklisted functions which should not be used.'),
       ),
+      'xhpast.indentation' => array(
+        'type' => 'optional int',
+        'help' => pht(
+          'Number of whitespace characters to be used for indentation.'),
+      ),
       'xhpast.naminghook' => array(
         'type' => 'optional string',
         'help' => pht(
@@ -285,6 +295,9 @@
       case 'xhpast.blacklisted.function':
         $this->blacklistedFunctions = $value;
         return;
+      case 'xhpast.indentation':
+        $this->indentation = $value;
+        return;
       case 'xhpast.naminghook':
         $this->naminghook = $value;
         return;
@@ -307,7 +320,7 @@
 
   public function getVersion() {
     // The version number should be incremented whenever a new rule is added.
-    return '24';
+    return '25';
   }
 
   protected function resolveFuture($path, Future $future) {
@@ -395,6 +408,7 @@
       'lintInnerFunctions' => self::LINT_INNER_FUNCTION,
       'lintDefaultParameters' => self::LINT_DEFAULT_PARAMETERS,
       'lintLowercaseFunctions' => self::LINT_LOWERCASE_FUNCTIONS,
+      'lintIndentation' => self::LINT_INDENTATION,
     );
 
     foreach ($method_codes as $method => $codes) {
@@ -3727,6 +3741,42 @@
     }
   }
 
+  private function lintIndentation(XHPASTNode $root) {
+    $nodes = $root->selectDescendantsOfType('n_STATEMENT');
+
+    foreach ($nodes as $node) {
+      $indent = $node->getIndentation();
+      $expected = $this->getExpectedIndentation($node);
+
+      if ($indent != $expected) {
+        $this->raiseLintAtNode(
+          $node,
+          self::LINT_INDENTATION,
+          pht('Incorrect indentation, expected "%s"', $expected));
+      }
+    }
+  }
+
+  private function getExpectedIndentation(XHPASTNode $node) {
+    $level = 0;
+
+    for (; $node !== null; $node = $node->getParentNode()) {
+      switch ($node->getTypeName()) {
+        case 'n_STATEMENT_LIST':
+          $level++;
+          break;
+
+        default:
+          break;
+      }
+    }
+
+    if ($level <= 0) {
+      return '';
+    }
+    return str_repeat(' ', $this->indentation * ($level - 1));
+  }
+
   /**
    * Retrieve all calls to some specified function(s).
    *
diff --git a/src/lint/linter/__tests__/xhpast/call-time-pass-by-reference.lint-test b/src/lint/linter/__tests__/xhpast/call-time-pass-by-reference.lint-test
--- a/src/lint/linter/__tests__/xhpast/call-time-pass-by-reference.lint-test
+++ b/src/lint/linter/__tests__/xhpast/call-time-pass-by-reference.lint-test
@@ -1,8 +1,8 @@
 <?php
 class MyClass {
-    public function myfunc($var) {
-        echo $var;
-    }
+  public function myfunc($var) {
+    echo $var;
+  }
 }
 
 $myvar = true;
diff --git a/src/lint/linter/__tests__/xhpast/duplicate-switch-case.lint-test b/src/lint/linter/__tests__/xhpast/duplicate-switch-case.lint-test
--- a/src/lint/linter/__tests__/xhpast/duplicate-switch-case.lint-test
+++ b/src/lint/linter/__tests__/xhpast/duplicate-switch-case.lint-test
@@ -3,26 +3,38 @@
 $y = null;
 switch ($x) {}
 switch ($x) {
-  case 1:     break;
-  case '1':   break;
-  case true:  break;
-  case null:  break;
-  default:    break;
+  case 1:
+    break;
+  case '1':
+    break;
+  case true:
+    break;
+  case null:
+    break;
+  default:
+    break;
 }
 switch ($x) {
-  case 'foo': break;
-  case 'bar': break;
-  case 'foo': break;
+  case 'foo':
+    break;
+  case 'bar':
+    break;
+  case 'foo':
+    break;
 
   default:
     switch ($y) {
-      case 'foo': break;
-      case 'bar': break;
-      case 'baz': break;
-      case 'baz': break;
+      case 'foo':
+        break;
+      case 'bar':
+        break;
+      case 'baz':
+        break;
+      case 'baz':
+        break;
     }
     break;
 }
 ~~~~~~~~~~
-error:15:3
-error:22:7
+error:22:3
+error:33:7
diff --git a/src/lint/linter/__tests__/xhpast/indentation.lint-test b/src/lint/linter/__tests__/xhpast/indentation.lint-test
new file mode 100644
--- /dev/null
+++ b/src/lint/linter/__tests__/xhpast/indentation.lint-test
@@ -0,0 +1,50 @@
+<?php
+
+function foo() {
+    return;
+}
+
+switch ($x) {
+  case 'x':
+    break;
+
+  case 'y':
+  break;
+
+  default: break;
+}
+
+foo(); bar();
+
+if ($x) { // comment
+echo 'x';
+}
+~~~~~~~~~~
+advice:3:17
+advice:11:12
+advice:14:11
+advice:17:7
+advice:19:11
+~~~~~~~~~~
+<?php
+
+function foo() {
+  return;
+}
+
+switch ($x) {
+  case 'x':
+    break;
+
+  case 'y':
+    break;
+
+  default:
+    break;
+}
+
+foo(); bar();
+
+if ($x) { // comment
+  echo 'x';
+}
diff --git a/src/lint/linter/__tests__/xhpast/php54-features.lint-test b/src/lint/linter/__tests__/xhpast/php54-features.lint-test
--- a/src/lint/linter/__tests__/xhpast/php54-features.lint-test
+++ b/src/lint/linter/__tests__/xhpast/php54-features.lint-test
@@ -1,14 +1,12 @@
 <?php
 
 f()[0];
-    m()[0];
 
 // The check above should be this, see T4334.
 // $o->m()[0];
 
 ~~~~~~~~~~
 error:3:5
-error:4:9
 ~~~~~~~~~~
 ~~~~~~~~~~
 {"config": {"xhpast.php-version": "5.3.0"}}
diff --git a/src/lint/linter/__tests__/xhpast/switches.lint-test b/src/lint/linter/__tests__/xhpast/switches.lint-test
--- a/src/lint/linter/__tests__/xhpast/switches.lint-test
+++ b/src/lint/linter/__tests__/xhpast/switches.lint-test
@@ -64,9 +64,17 @@
       return;
     }
   case 4:
-    function f() { throw new Exception(); }
-    g(function() { return; });
-    final class C { public function m() { return; } }
+    function f() {
+      throw new Exception();
+    }
+    g(function() {
+      return;
+    });
+    final class C {
+      public function m() {
+        return;
+      }
+    }
     interface I {}
   case 5:
     do {
@@ -89,8 +97,8 @@
 warning:53:3
 warning:57:3
 warning:66:3
-warning:71:3
-warning:75:3
+warning:79:3
+warning:83:3
 ~~~~~~~~~~
 ~~~~~~~~~~
 {"config":{"xhpast.switchhook":"ArcanistTestXHPASTLintSwitchHook"}}
diff --git a/src/lint/linter/__tests__/xhpast/undeclared-variables.lint-test b/src/lint/linter/__tests__/xhpast/undeclared-variables.lint-test
--- a/src/lint/linter/__tests__/xhpast/undeclared-variables.lint-test
+++ b/src/lint/linter/__tests__/xhpast/undeclared-variables.lint-test
@@ -184,6 +184,22 @@
 error:51:10 worst ever
 warning:61:3
 error:87:3 This stuff is basically testing the lexer/parser for function decls.
+advice:90:29
+advice:90:35
+advice:91:30
+advice:91:36
+advice:92:36
+advice:92:42
+advice:93:37
+advice:93:43
+advice:94:27
+advice:94:33
+advice:95:28
+advice:95:34
+advice:96:34
+advice:96:40
+advice:97:35
+advice:97:41
 error:104:15 Variables in instance derefs should be checked, static should not.
 error:118:3 isset() and empty() should not trigger errors.
 error:122:3 Should only warn once in this function.