Make ExpressionParser::parseNameToStringMapping non-static.

src/ExpressionParser.php

@@ -433,11 +433,14 @@ public function parseMappingExpression()
     }
 
     /*
-     * This method is static to make it testable.
-     * Calling `$this->parser->getStream()` as done in `parseMappingExpression()` only works if
-     * `parser->parse()` has been called, but that won't ever call this method.
+     * Unlike its sibling methods above, method requires a TokenStream parameter.
+     * 
+     * The reason is that calling `$this->parser->getStream()` (as in `parseMappingExpression()`)
+     * only works _while_ `parser->parse()` is running, because that method sets and unsets the $stream property.
+     * 
+     * The upside is that this method is fully pure, since it doesn't depend on the state of $this.
      */
-    public static function parseNameToStringMapping(TokenStream $stream, bool $allowOptionalKeys): ArrayExpression
+    public function parseNameToStringMapping(TokenStream $stream, bool $allowOptionalKeys): ArrayExpression
     {
         $stream->expect(Token::PUNCTUATION_TYPE, '{', 'A mapping element was expected');
 

src/TokenParser/TypesTokenParser.php

@@ -44,7 +44,7 @@ public function parse(Token $token): Node
     {
         $stream = $this->parser->getStream();
 
-        $expression = ExpressionParser::parseNameToStringMapping($stream, true);
+        $expression = $this->parser->getExpressionParser()->parseNameToStringMapping($stream, true);
 
         $stream->expect(Token::BLOCK_END_TYPE);
 

tests/ExpressionParserTest.php

@@ -213,10 +213,13 @@ public function getTestsForSequence()
     public function testNameToStringMapping(string $template, ArrayExpression $expected, bool $allowOptionalKeys): void
     {
         $env = new Environment(new ArrayLoader(), ['cache' => false, 'autoescape' => false]);
+        $parser = new Parser($env);
         $stream = $env->tokenize(new Source($template, ''));
         $stream->next();
-
-        $this->assertEquals($expected, ExpressionParser::parseNameToStringMapping($stream, $allowOptionalKeys));
+
+        $expressionParser = new ExpressionParser($parser, $env);
+
+        $this->assertEquals($expected, $expressionParser->parseNameToStringMapping($stream, $allowOptionalKeys));
     }
 
     public function getTestsForNameToStringMapping(): array
@@ -274,11 +277,15 @@ public function getTestsForNameToStringMapping(): array
     public function testNameToStringMappingSyntaxError(string $template, bool $allowOptionalKeys): void
     {
         $this->expectException(SyntaxError::class);
-        
+
         $env = new Environment(new ArrayLoader(), ['cache' => false, 'autoescape' => false]);
+        $parser = new Parser($env);
         $stream = $env->tokenize(new Source($template, ''));
-
-        ExpressionParser::parseNameToStringMapping($stream, $allowOptionalKeys);
+        $stream->next();
+
+        $expressionParser = new ExpressionParser($parser, $env);
+
+        $expressionParser->parseNameToStringMapping($stream, $allowOptionalKeys);
     }
 
     public function getFailingTestsForNameToStringMapping(): array