Importing a class with `\Trait\` in the namespace throws `unexpected 'Trait' (T_TRAIT)`

[robin-vendredi]

I stumbled upon an issue while using @prettier/plugin-php and I believe it's a bug coming from the php-parser lib - please let me know if I'm mistaken. Thank you for your work maintaining php-parser.

What I did

Starting from a fresh install of 3.0.3, importing any namespace containing \Trait\ in the path results in a unexpected 'Trait' (T_TRAIT) error.

Code to reproduce:

var parser = require('php-parser');

var eval = parser.parseEval('use App\\Trait\\Foo;');

console.log( 'Eval parse:', eval );

throws

/code/phpparser/node_modules/php-parser/src/parser.js:345
    throw err;
    ^

SyntaxError: Parse Error : syntax error, unexpected 'Trait' (T_TRAIT), expecting ';' on line 1
    at Parser.raiseError (/code/phpparser/node_modules/php-parser/src/parser.js:337:17)
    at Parser.error (/code/phpparser/node_modules/php-parser/src/parser.js:384:15)
    at Parser.expect (/code/phpparser/node_modules/php-parser/src/parser.js:546:10)
    at Parser.read_use_statement (/code/phpparser/node_modules/php-parser/src/parser/namespace.js:127:10)
    at Parser.read_top_statement (/code/phpparser/node_modules/php-parser/src/parser/statement.js:53:21)
    at Parser.read_start (/code/phpparser/node_modules/php-parser/src/parser/main.js:18:19)
    at Parser.parse (/code/phpparser/node_modules/php-parser/src/parser.js:290:22)
    at Engine.parseEval (/code/phpparser/node_modules/php-parser/src/index.js:146:22)
    at Function.Engine.parseEval (/code/phpparser/node_modules/php-parser/src/index.js:134:15)
    at Object.<anonymous> (/code/phpparser/test.js:4:19) {
  lineNumber: 1,
  fileName: 'eval',
  columnNumber: 8
}

Changing the path to use App\\TraitX\\Foo; or anything else in the \Trait\ section of the namespace fixes the error.

What I expected

Being able to have Trait in my namespace without the parser throwing an error.

[ichiriac]

The problem comes from the lexer, it differs from PHP lexer here :
https://github.com/php/php-src/blob/master/Zend/zend_language_scanner.l#L2363

Introduced 2 years ago :
php/php-src@7a3dcc3

This issue may apply on any namespace usage (example a catch with a namespace and a token keyword)

@czosel :

A quick fix could be to introduce the \ here :
https://github.com/glayzzle/php-parser/blob/main/src/lexer/utils.js#L54
=> It may be good, but T_STRING can now have namespaces (so for identifiers like classes or function names you need to return another token in order catch errors)

You could also create this token : T_NAME_QUALIFIED
Implement the parsing branch on the T_STRING :

php-parser/src/lexer/tokens.js

Line 33 in 02410c1

}

=> pseudo algorithm: if next char is \ then consume_LABEL until is not followed by \ and return a T_NAME_QUALIFIED token

The T_NAME_FULLY_QUALIFIED could also be implemented but may be more complex to be done

It could also be handled at the parsing/grammar level but it may introduce more complexity to ignore tokens at the namespace reading level

[czosel]

Fixed in 3.1.0-beta.6 🎉