Use IntegerRangeType in modulo-operator

Author: staabm

src/Analyser/MutatingScope.php

@@ -1111,6 +1111,48 @@ private function resolveType(Expr $node): Type
 }
 
 if ($node instanceof Node\Expr\BinaryOp\Mod || $node instanceof Expr\AssignOp\Mod) {
+if ($node instanceof Node\Expr\AssignOp) {
+$left = $node->var;
+$right = $node->expr;
+} else {
+$left = $node->left;
+$right = $node->right;
+}
+
+$leftType = $this->getType($left);
+$rightType = $this->getType($right);
+
+$integer = new IntegerType();
+$positiveInt = IntegerRangeType::fromInterval(0, null);
+if ($integer->isSuperTypeOf($rightType)->yes()) {
+$rangeMin = null;
+$rangeMax = null;
+
+if ($rightType instanceof IntegerRangeType) {
+$rangeMax = $rightType->getMax() !== null ? $rightType->getMax() - 1 : null;
+} elseif ($rightType instanceof ConstantIntegerType) {
+$rangeMax = $rightType->getValue() - 1;
+} elseif ($rightType instanceof UnionType) {
+foreach ($rightType->getTypes() as $type) {
+if ($type instanceof IntegerRangeType) {
+$rangeMax = max($rangeMax, $type->getMax() !== null ? $type->getMax() - 1 : null);
+} elseif ($type instanceof ConstantIntegerType) {
+$rangeMax = max($rangeMax, $type->getValue() - 1);
+}
+}
+}
+
+if ($positiveInt->isSuperTypeOf($leftType)->yes()) {
+$rangeMin = 0;
+} elseif ($rangeMax !== null) {
+$rangeMin = $rangeMax * -1;
+}
+
+return IntegerRangeType::fromInterval($rangeMin, $rangeMax);
+} elseif ($positiveInt->isSuperTypeOf($leftType)->yes()) {
+return IntegerRangeType::fromInterval(0, null);
+}
+
 return new IntegerType();
 }
 

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -463,6 +463,7 @@ public function dataFileAsserts(): iterable
 }
 
 yield from $this->gatherAssertTypes(__DIR__ . '/data/class-constant-types.php');
+yield from $this->gatherAssertTypes(__DIR__ . '/data/modulo-operator.php');
 }
 
 /**

tests/PHPStan/Analyser/data/modulo-operator.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace ModuloOperator;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+/**
+ * @param positive-int $p
+ * @param int<5, 10> $range
+ * @param int<0, max> $zeroOrMore
+ * @param 1|2|3 $intConst
+ * @param int<min, 3>|int<4, max> $unionRange
+ * @param int<min, 3>|7 $hybridUnionRange
+ */
+function doBar(int $i, $p, $range, $zeroOrMore, $intConst, $unionRange, $hybridUnionRange, $mixed)
+{
+assertType('int<-1, 1>', $i % 2);
+assertType('int<0, 1>', $p % 2);
+
+assertType('int<-2, 2>', $i % 3);
+assertType('int<0, 2>', $p % 3);
+
+assertType('0|1|2', $intConst % 3);
+assertType('int<-2, 2>', $i % $intConst);
+assertType('int<0, 2>', $p % $intConst);
+
+assertType('int<0, 2>', $range % 3);
+
+assertType('int<-9, 9>', $i % $range);
+assertType('int<0, 9>', $p % $range);
+
+assertType('int', $i % $unionRange);
+assertType('int<0, max>', $p % $unionRange);
+
+assertType('int<-6, 6>', $i % $hybridUnionRange);
+assertType('int<0, 6>', $p % $hybridUnionRange);
+
+assertType('int<0, max>', $zeroOrMore % $mixed);
+}
+}