allowComparingOnlyComparableTypes: add support for BcMath\Number

README.md

@@ -56,8 +56,8 @@ Few rules are enabled, but do nothing unless configured, those are marked with `
 ## Rules:
 
 ### allowComparingOnlyComparableTypes
-- Denies using comparison operators `>,<,<=,>=,<=>` over anything other than `int|string|float|DateTimeInterface` or same size tuples containing comparable types. Null is not allowed.
-- Mixing different types in those operators is also forbidden, only exception is comparing floats with integers
+- Denies using comparison operators `>,<,<=,>=,<=>` over anything other than `int|string|float|DateTimeInterface|BcMath\Number` or same size tuples containing comparable types. Null is not allowed.
+- Mixing different types in those operators is also forbidden, only exception is comparing floats with integers and integers with `BcMath\Number`
 - Mainly targets to accidental comparisons of objects, enums or arrays which is valid in PHP, but very tricky
 
 ```php

src/Rule/AllowComparingOnlyComparableTypesRule.php

@@ -22,6 +22,7 @@
 use PHPStan\Type\TypeCombinator;
 use PHPStan\Type\VerbosityLevel;
 use function count;
+use const PHP_VERSION_ID;
 
 /**
  * @implements Rule<BinaryOp>
@@ -60,9 +61,12 @@ public function processNode(
         $rightTypeDescribed = $rightType->describe($rightType->isArray()->no() ? VerbosityLevel::typeOnly() : VerbosityLevel::value());
 
         if (!$this->isComparable($leftType) || !$this->isComparable($rightType)) {
-            $error = RuleErrorBuilder::message("Comparison {$leftTypeDescribed} {$node->getOperatorSigil()} {$rightTypeDescribed} contains non-comparable type, only int|float|string|DateTimeInterface or comparable tuple is allowed.")
-                ->identifier('shipmonk.comparingNonComparableTypes')
-                ->build();
+            $builder = RuleErrorBuilder::message("Comparison {$leftTypeDescribed} {$node->getOperatorSigil()} {$rightTypeDescribed} contains non-comparable type, only int|float|string|DateTimeInterface or comparable tuple is allowed.")
+                ->identifier('shipmonk.comparingNonComparableTypes');
+            if (PHP_VERSION_ID >= 80_400) {
+                $builder->addTip('Also BcMath\Number is allowed.');
+            }
+            $error = $builder->build();
             return [$error];
         }
 
@@ -82,8 +86,9 @@ private function isComparable(Type $type): bool
         $floatType = new FloatType();
         $stringType = new StringType();
         $dateTimeType = new ObjectType(DateTimeInterface::class);
+        $bcMathNumberType = new ObjectType('BcMath\Number');
 
-        if ($this->containsOnlyTypes($type, [$intType, $floatType, $stringType, $dateTimeType])) {
+        if ($this->containsOnlyTypes($type, [$intType, $floatType, $stringType, $dateTimeType, $bcMathNumberType])) {
             return true;
         }
 
@@ -111,6 +116,15 @@ private function isComparableTogether(
         $floatType = new FloatType();
         $stringType = new StringType();
         $dateTimeType = new ObjectType(DateTimeInterface::class);
+        $bcMathNumberType = new ObjectType('BcMath\Number');
+
+        if ($this->containsOnlyTypes($leftType, [$bcMathNumberType])) {
+            return $this->containsOnlyTypes($rightType, [$bcMathNumberType, $intType]);
+        }
+
+        if ($this->containsOnlyTypes($rightType, [$bcMathNumberType])) {
+            return $this->containsOnlyTypes($leftType, [$bcMathNumberType, $intType]);
+        }
 
         if ($this->containsOnlyTypes($leftType, [$intType, $floatType])) {
             return $this->containsOnlyTypes($rightType, [$intType, $floatType]);

tests/Rule/data/AllowComparingOnlyComparableTypesRule/code.php

@@ -2,6 +2,7 @@
 
 namespace AllowComparingOnlyComparableTypesRule;
 
+use BcMath\Number;
 use DateTime;
 use DateTimeImmutable;
 
@@ -19,6 +20,7 @@ interface Bar {}
     Foo&Bar $fooAndBar,
     DateTime $dateTime,
     DateTimeImmutable $dateTimeImmutable,
+    Number $number,
     string $string,
     int $int,
     ?int $nullableInt,
@@ -45,10 +47,21 @@ interface Bar {}
     $string > $int; // error: Cannot compare different types in string > int.
     $float > $int;
     $dateTime > $string; // error: Cannot compare different types in DateTime > string.
+    $int > $number;
+    $number > $int;
+    $number > $float; // error: Cannot compare different types in BcMath\Number > float.
+    $number > $string; // error: Cannot compare different types in BcMath\Number > string.
+    $number > $intOrFloat; // error: Cannot compare different types in BcMath\Number > float|int.
+    $number > $foo; // error: Comparison BcMath\Number > AllowComparingOnlyComparableTypesRule\Foo contains non-comparable type, only int|float|string|DateTimeInterface or comparable tuple is allowed.
+    $number > $nullableInt; // error: Comparison BcMath\Number > int|null contains non-comparable type, only int|float|string|DateTimeInterface or comparable tuple is allowed.
 
     [$int, $string] > [$int, $string];
     [[$int]] > [[$int]];
     [$int, $float, $intOrFloat, $intOrFloat] > [$int, $int, $int, $float];
+    [$number] > [$number];
+    [$number] > [$int];
+    [$number, $int] > [$int, $number];
+    [$number] > [$string]; // error: Cannot compare different types in array{BcMath\Number} > array{string}.
     [$int, $string] > $foos; // error: Comparison array{int, string} > array contains non-comparable type, only int|float|string|DateTimeInterface or comparable tuple is allowed.
     [$int] > [$int, $int]; // error: Cannot compare different types in array{int} > array{int, int}.
     [$int, $string] > [$int]; // error: Cannot compare different types in array{int, string} > array{int}.