Fix @var tag with $this

Author: ondrejmirtes

Diff for: src/Parser/PhpDocParser.php

@@ -358,6 +358,9 @@ private function parseOptionalVariableName(TokenIterator $tokens): string
 		if ($tokens->isCurrentTokenType(Lexer::TOKEN_VARIABLE)) {
 			$parameterName = $tokens->currentTokenValue();
 			$tokens->next();
+		} elseif ($tokens->isCurrentTokenType(Lexer::TOKEN_THIS_VARIABLE)) {
+			$parameterName = '$this';
+			$tokens->next();
 
 		} else {
 			$parameterName = '';

Diff for: tests/PHPStan/Parser/PhpDocParserTest.php

@@ -417,6 +417,66 @@ public function provideVarTagsData(): \Iterator
 			]),
 		];
 
+		yield [
+			'OK without description with variable $this',
+			'/** @var Foo $this */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@var',
+					new VarTagValueNode(
+						new IdentifierTypeNode('Foo'),
+						'$this',
+						''
+					)
+				),
+			]),
+		];
+
+		yield [
+			'OK without description and with no space between type and variable name with variable $this',
+			'/** @var Foo$this */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@var',
+					new VarTagValueNode(
+						new IdentifierTypeNode('Foo'),
+						'$this',
+						''
+					)
+				),
+			]),
+		];
+
+		yield [
+			'OK with description with variable $this',
+			'/** @var Foo $this Testing */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@var',
+					new VarTagValueNode(
+						new IdentifierTypeNode('Foo'),
+						'$this',
+						'Testing'
+					)
+				),
+			]),
+		];
+
+		yield [
+			'OK with description and with no space between type and variable name with variable $this',
+			'/** @var Foo$this Testing */',
+			new PhpDocNode([
+				new PhpDocTagNode(
+					'@var',
+					new VarTagValueNode(
+						new IdentifierTypeNode('Foo'),
+						'$this',
+						'Testing'
+					)
+				),
+			]),
+		];
+
 		yield [
 			'OK with variable name and description and without all optional spaces',
 			'/** @var(Foo)$foo#desc*/',