[BUGFIX] Fix undefined local variable in CalcFunction::parse()

This is the 8.x backport of #593.

Fixes #585

Author: oliverklee

CHANGELOG.md

@@ -21,6 +21,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
+- Fix undefined local variable in `CalcFunction::parse()` (#593)
 - Fix PHP notice caused by parsing invalid color values having less than 6 characters (#485)
 - Fix (regression) failure to parse at-rules with strict parsing (#456)
 

config/phpstan-baseline.neon

@@ -10,8 +10,3 @@ parameters:
 			count: 2
 			path: ../src/RuleSet/DeclarationBlock.php
 
-		-
-			message: "#^Variable \\$oVal might not be defined\\.$#"
-			count: 1
-			path: ../src/Value/CalcFunction.php
-

src/Value/CalcFunction.php

@@ -91,7 +91,7 @@ public static function parse(ParserState $oParserState, $bIgnoreCase = false)
                         sprintf(
                             'Next token was expected to be an operand of type %s. Instead "%s" was found.',
                             implode(', ', $aOperators),
-                            $oVal
+                            $oParserState->peek()
                         ),
                         '',
                         'custom',