Add pre-PHP 8 and PHP 8.0+ array literal tests for bug-10862

Split tests into four files covering all three PHP version behaviors:
- php74: pre-PHP 8.0, negative keys never affect auto-index
- php80: PHP 8.0+, array literals with negative keys update auto-index
- php82: PHP <= 8.2, imperative assignment does not update for negative keys
- php83: PHP 8.3+, negative keys always update auto-index

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

tests/PHPStan/Analyser/nsrt/bug-10862-php74.php

@@ -0,0 +1,26 @@
+<?php // lint < 8.0
+
+declare(strict_types = 1);
+
+namespace Bug10862Php74;
+
+use function PHPStan\Testing\assertType;
+
+// Pre-PHP 8.0: negative keys never affect auto-index
+
+// Imperative assignment
+function () {
+	$a = [];
+	$a[-4] = 1;
+	$a[] = 2;
+
+	assertType('array{-4: 1, 0: 2}', $a);
+};
+
+// Array literal
+function () {
+	$a = [-4 => 1];
+	$a[] = 2;
+
+	assertType('array{-4: 1, 0: 2}', $a);
+};

tests/PHPStan/Analyser/nsrt/bug-10862-php80.php

@@ -0,0 +1,23 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug10862Php80;
+
+use function PHPStan\Testing\assertType;
+
+// PHP 8.0+: array literal with negative keys updates auto-index
+
+function () {
+	$a = [-4 => 1];
+	$a[] = 2;
+
+	assertType('array{-4: 1, -3: 2}', $a);
+};
+
+function () {
+	$a = [-10 => 'a', -5 => 'b'];
+	$a[] = 'c';
+
+	assertType("array{-10: 'a', -5: 'b', -4: 'c'}", $a);
+};

tests/PHPStan/Analyser/nsrt/bug-10862-php82.php

@@ -6,22 +6,22 @@
 
 use function PHPStan\Testing\assertType;
 
+// PHP <= 8.2: imperative assignment with negative keys does not affect auto-index
+
 function () {
 	$a = [];
 	$a[-4] = 1;
 	$a[] = 2;
 
-	assertType('array{-4: 1, 0: 2}', $a); // PHP <=8.2: next key after -4 is 0
-	assertType('array{-4, 0}', array_keys($a));
+	assertType('array{-4: 1, 0: 2}', $a);
 };
 
 function () {
 	$a = [];
 	$a[-1] = 'x';
 	$a[] = 'y';
 
-	assertType("array{-1: 'x', 0: 'y'}", $a); // PHP <=8.2: next key after -1 is 0
-	assertType('array{-1, 0}', array_keys($a));
+	assertType("array{-1: 'x', 0: 'y'}", $a);
 };
 
 function () {
@@ -30,8 +30,7 @@ function () {
 	$a[-5] = 'b';
 	$a[] = 'c';
 
-	assertType("array{-10: 'a', -5: 'b', 0: 'c'}", $a); // PHP <=8.2: next key is 0
-	assertType('array{-10, -5, 0}', array_keys($a));
+	assertType("array{-10: 'a', -5: 'b', 0: 'c'}", $a);
 };
 
 function () {
@@ -40,6 +39,5 @@ function () {
 	$a[5] = 'b';
 	$a[] = 'c';
 
-	assertType("array{-3: 'a', 5: 'b', 6: 'c'}", $a); // positive key dominates
-	assertType('array{-3, 5, 6}', array_keys($a));
+	assertType("array{-3: 'a', 5: 'b', 6: 'c'}", $a);
 };

tests/PHPStan/Analyser/nsrt/bug-10862-php83.php

@@ -6,22 +6,23 @@
 
 use function PHPStan\Testing\assertType;
 
+// PHP 8.3+: negative keys always affect auto-index (both imperative and literal)
+
+// Imperative assignment
 function () {
 	$a = [];
 	$a[-4] = 1;
 	$a[] = 2;
 
-	assertType('array{-4: 1, -3: 2}', $a); // PHP 8.3+: next key after -4 is -3
-	assertType('array{-4, -3}', array_keys($a));
+	assertType('array{-4: 1, -3: 2}', $a);
 };
 
 function () {
 	$a = [];
 	$a[-1] = 'x';
 	$a[] = 'y';
 
-	assertType("array{-1: 'x', 0: 'y'}", $a); // PHP 8.3+: next key after -1 is 0
-	assertType('array{-1, 0}', array_keys($a));
+	assertType("array{-1: 'x', 0: 'y'}", $a);
 };
 
 function () {
@@ -30,8 +31,7 @@ function () {
 	$a[-5] = 'b';
 	$a[] = 'c';
 
-	assertType("array{-10: 'a', -5: 'b', -4: 'c'}", $a); // PHP 8.3+: next key after max(-10,-5)=-5 is -4
-	assertType('array{-10, -5, -4}', array_keys($a));
+	assertType("array{-10: 'a', -5: 'b', -4: 'c'}", $a);
 };
 
 function () {
@@ -40,6 +40,20 @@ function () {
 	$a[5] = 'b';
 	$a[] = 'c';
 
-	assertType("array{-3: 'a', 5: 'b', 6: 'c'}", $a); // positive key dominates
-	assertType('array{-3, 5, 6}', array_keys($a));
+	assertType("array{-3: 'a', 5: 'b', 6: 'c'}", $a);
+};
+
+// Array literal
+function () {
+	$a = [-4 => 1];
+	$a[] = 2;
+
+	assertType('array{-4: 1, -3: 2}', $a);
+};
+
+function () {
+	$a = [-10 => 'a', -5 => 'b'];
+	$a[] = 'c';
+
+	assertType("array{-10: 'a', -5: 'b', -4: 'c'}", $a);
 };