CallableTypeNode - support $this in return type

Author: ondrejmirtes

Diff for: src/Parser/TypeParser.php

@@ -526,7 +526,8 @@ private function parseCallableReturnType(TokenIterator $tokens): Ast\Type\TypeNo
 		} elseif ($tokens->tryConsumeTokenType(Lexer::TOKEN_OPEN_PARENTHESES)) {
 			$type = $this->parse($tokens);
 			$tokens->consumeTokenType(Lexer::TOKEN_CLOSE_PARENTHESES);
-
+		} elseif ($tokens->tryConsumeTokenType(Lexer::TOKEN_THIS_VARIABLE)) {
+			$type = new Ast\Type\ThisTypeNode();
 		} else {
 			$type = new Ast\Type\IdentifierTypeNode($tokens->currentTokenValue());
 			$tokens->consumeTokenType(Lexer::TOKEN_IDENTIFIER);

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

@@ -1957,6 +1957,14 @@ public function provideParseData(): array
 					)
 				),
 			],
+			[
+				'callable(): $this',
+				new CallableTypeNode(new IdentifierTypeNode('callable'), [], new ThisTypeNode()),
+			],
+			[
+				'callable(): $this[]',
+				new CallableTypeNode(new IdentifierTypeNode('callable'), [], new ArrayTypeNode(new ThisTypeNode())),
+			],
 		];
 	}