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
@@ -2806,6 +2806,29 @@
         }
       }
     }
+
+    $magic_constants = $root->selectTokensOfTypes(array(
+      'T_CLASS_C',
+      'T_METHOD_C',
+      'T_FUNC_C',
+      'T_LINE',
+      'T_FILE',
+      'T_NS_C',
+      'T_DIR',
+      'T_TRAIT_C',
+    ));
+
+    foreach ($magic_constants as $magic_constant) {
+      $value = $magic_constant->getValue();
+
+      if ($value != strtoupper($value)) {
+        $this->raiseLintAtToken(
+          $magic_constant,
+          self::LINT_KEYWORD_CASING,
+          pht('Magic constants should be uppercase.'),
+          strtoupper($value));
+      }
+    }
   }
 
   private function lintStrings(XHPASTNode $root) {
diff --git a/src/lint/linter/__tests__/xhpast/keyword-casing.lint-test b/src/lint/linter/__tests__/xhpast/keyword-casing.lint-test
--- a/src/lint/linter/__tests__/xhpast/keyword-casing.lint-test
+++ b/src/lint/linter/__tests__/xhpast/keyword-casing.lint-test
@@ -14,6 +14,8 @@
 
 new C();
 NeW C();
+
+echo __file__;
 ~~~~~~~~~~
 warning:6:1
 warning:7:1
@@ -22,6 +24,7 @@
 warning:11:1
 warning:13:22
 warning:16:1
+warning:18:6
 ~~~~~~~~~~
 <?php
 
@@ -39,3 +42,5 @@
 
 new C();
 new C();
+
+echo __FILE__;