Make keyword emulation check case-insensitive

Author: nikic

lib/PhpParser/Lexer/TokenEmulator/KeywordEmulator.php

@@ -9,7 +9,7 @@ abstract function getKeywordToken(): int;
 
     public function isEmulationNeeded(string $code): bool
     {
-        return strpos($code, $this->getKeywordString()) !== false;
+        return strpos(strtolower($code), $this->getKeywordString()) !== false;
     }
 
     public function emulate(string $code, array $tokens): array

test/PhpParser/Lexer/EmulativeTest.php

@@ -24,6 +24,17 @@ public function testReplaceKeywords($keyword, $expectedToken) {
         $this->assertSame(0, $lexer->getNextToken());
     }
 
+    /**
+     * @dataProvider provideTestReplaceKeywords
+     */
+    public function testReplaceKeywordsUppercase($keyword, $expectedToken) {
+        $lexer = $this->getLexer();
+        $lexer->startLexing('<?php ' . strtoupper($keyword));
+
+        $this->assertSame($expectedToken, $lexer->getNextToken());
+        $this->assertSame(0, $lexer->getNextToken());
+    }
+
     /**
      * @dataProvider provideTestReplaceKeywords
      */
@@ -318,8 +329,11 @@ public function provideTestTargetVersion() {
         return [
             ['8.0', 'match', [[Tokens::T_MATCH, 'match']]],
             ['7.4', 'match', [[Tokens::T_STRING, 'match']]],
+            // Keywords are not case-sensitive.
             ['7.4', 'fn', [[Tokens::T_FN, 'fn']]],
+            ['7.4', 'FN', [[Tokens::T_FN, 'FN']]],
             ['7.3', 'fn', [[Tokens::T_STRING, 'fn']]],
+            ['7.3', 'FN', [[Tokens::T_STRING, 'FN']]],
             // Tested here to skip testLeaveStuffAloneInStrings.
             ['8.0', '"$foo?->bar"', [
                 [ord('"'), '"'],