test more cases

Author: staabm

src/Analyser/TypeSpecifier.php

@@ -352,9 +352,9 @@ public function specifyTypesInCondition(
 			}
 
 			// infer $list[$index] after $index < count($list) - N
+			// infer $list[$index] after $index <= count($list) - N
 			if (
 				$context->true()
-				&& !$orEqual
 				&& $expr->right instanceof Expr\BinaryOp\Minus
 				&& $expr->right->left instanceof FuncCall
 				&& $expr->right->left->name instanceof Name
@@ -369,7 +369,7 @@ public function specifyTypesInCondition(
 				$subtractedType = $scope->getType($expr->right->right);
 				if (
 					$countArgType->isList()->yes()
-					&& IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($subtractedType)->yes()
+					&& IntegerRangeType::fromInterval(1, null)->isSuperTypeOf($subtractedType)->yes()
 				) {
 					$arrayArg = $expr->right->left->getArgs()[0]->value;
 					$dimFetch = new ArrayDimFetch($arrayArg, $expr->left);

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -1186,6 +1186,10 @@ public function testBug13770(): void
 				'Offset -1|3|6|10 might not exist on list<int>.',
 				126,
 			],
+			[
+				'Offset int<0, max> might not exist on list<int>.',
+				139,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Arrays/data/bug-13770.php

@@ -128,4 +128,30 @@ public function constantMaybeNegativeIntLessThanCount(array $array, int $index):
 
 		return 0;
 	}
+
+	/**
+	 * @param list<int> $array
+	 * @param 0|positive-int $index
+	 */
+	public function ZeroOrMoreIntLessThanOrEqualCount(array $array, int $index): int
+	{
+		if ($index <= count($array)) {
+			return $array[$index]; // SHOULD still report - off by one
+		}
+
+		return 0;
+	}
+
+	/**
+	 * @param list<int> $array
+	 * @param 0|positive-int $index
+	 */
+	public function ZeroOrMoreMinusOneIntLessThanOrEqualCount(array $array, int $index): int
+	{
+		if ($index <= count($array) - 1) {
+			return $array[$index];
+		}
+
+		return 0;
+	}
 }