Use the same technique for finding list assignments as phpcs might

See squizlabs/PHP_CodeSniffer#3632

Author: sirbrillig

VariableAnalysis/Lib/Helpers.php

@@ -654,7 +654,70 @@ public static function getArrowFunctionOpenClose(File $phpcsFile, $stackPtr)
 	}
 
 	/**
-	 * Return a list of indices for variables assigned within a list assignment
+	 * Determine if a token is a list opener for list assignment/destructuring.
+	 *
+	 * The index provided can be either the opening square brace of a short list
+	 * assignment like the first character of `[$a] = $b;` or the `list` token of
+	 * an expression like `list($a) = $b;` or the opening parenthesis of that
+	 * expression.
+	 *
+	 * @param File $phpcsFile
+	 * @param int  $listOpenerIndex
+	 *
+	 * @return bool
+	 */
+	private static function isListAssignment(File $phpcsFile, $listOpenerIndex)
+	{
+		$tokens = $phpcsFile->getTokens();
+		// Match `[$a] = $b;` except for when the previous token is a parenthesis.
+		if ($tokens[$listOpenerIndex]['code'] === T_OPEN_SHORT_ARRAY) {
+			return true;
+		}
+		// Match `list($a) = $b;`
+		if ($tokens[$listOpenerIndex]['code'] === T_LIST) {
+			return true;
+		}
+
+		// If $listOpenerIndex is the open parenthesis of `list($a) = $b;`, then
+		// match that too.
+		if ($tokens[$listOpenerIndex]['code'] === T_OPEN_PARENTHESIS) {
+			$previousTokenPtr = $phpcsFile->findPrevious(Tokens::$emptyTokens, $listOpenerIndex - 1, null, true);
+			if (
+				isset($tokens[$previousTokenPtr])
+				&& $tokens[$previousTokenPtr]['code'] === T_LIST
+			) {
+				return true;
+			}
+			return true;
+		}
+
+		// If the list opener token is a square bracket that is preceeded by a
+		// close parenthesis that has an owner which is a scope opener, then this
+		// is a list assignment and not an array access.
+		//
+		// Match `if (true) [$a] = $b;`
+		if ($tokens[$listOpenerIndex]['code'] === T_OPEN_SQUARE_BRACKET) {
+			$previousTokenPtr = $phpcsFile->findPrevious(Tokens::$emptyTokens, $listOpenerIndex - 1, null, true);
+			if (
+				isset($tokens[$previousTokenPtr])
+				&& $tokens[$previousTokenPtr]['code'] === T_CLOSE_PARENTHESIS
+				&& isset($tokens[$previousTokenPtr]['parenthesis_owner'])
+				&& isset(Tokens::$scopeOpeners[$tokens[$tokens[$previousTokenPtr]['parenthesis_owner']]['code']])
+			) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * Return a list of indices for variables assigned within a list assignment.
+	 *
+	 * The index provided can be either the opening square brace of a short list
+	 * assignment like the first character of `[$a] = $b;` or the `list` token of
+	 * an expression like `list($a) = $b;` or the opening parenthesis of that
+	 * expression.
 	 *
 	 * @param File $phpcsFile
 	 * @param int  $listOpenerIndex
@@ -666,22 +729,6 @@ public static function getListAssignments(File $phpcsFile, $listOpenerIndex)
 		$tokens = $phpcsFile->getTokens();
 		self::debug('getListAssignments', $listOpenerIndex, $tokens[$listOpenerIndex]);
 
-		// If the list opener token is preceeded by a variable or a bracket (a
-		// multidimensional array), this is an array access and not a list
-		// assignment.
-		$previousStatementPtr = self::getPreviousStatementPtr($phpcsFile, $listOpenerIndex);
-		$previousTokenPtr = $phpcsFile->findPrevious(Tokens::$emptyTokens, $listOpenerIndex - 1, $previousStatementPtr, true);
-		$arrayAccessEvidence = [
-			T_VARIABLE,
-			T_CLOSE_SQUARE_BRACKET,
-		];
-		if (
-			isset($tokens[$previousTokenPtr])
-			&& in_array($tokens[$previousTokenPtr]['code'], $arrayAccessEvidence, true)
-		) {
-			return null;
-		}
-
 		// First find the end of the list
 		$closePtr = null;
 		if (isset($tokens[$listOpenerIndex]['parenthesis_closer'])) {
@@ -735,6 +782,10 @@ public static function getListAssignments(File $phpcsFile, $listOpenerIndex)
 			++$currentPtr;
 		}
 
+		if (! self::isListAssignment($phpcsFile, $listOpenerIndex)) {
+			return null;
+		}
+
 		return $variablePtrs;
 	}