fix(compiler): preserve dynamic arithmetic result types

phpunit/code/dynamic-arithmetic-result.php

@@ -0,0 +1,13 @@
+<?php
+function dynamicResult(array $values, int $divisor): array
+{
+    return [$values['x'] / $divisor];
+}
+function nativeIntResult(int $left, int $right): int
+{
+    return $left / $right;
+}
+function nativeFloatResult(float $left, float $right): float
+{
+    return $left / $right;
+}

phpunit/src/DynamicArithmeticResultTest.php

@@ -0,0 +1,31 @@
+<?php
+
+use TypePhp\CompilerTest;
+
+final class DynamicArithmeticResultTest extends \BaseTest
+{
+    public function testDynamicResultRemainsBoxedAndNativeArithmeticStaysNative(): void
+    {
+        global $translator;
+
+        $compiler = CompilerTest::create(TYPEPHP_ROOT_PATH);
+        $translator = $compiler;
+        $source = TYPEPHP_ROOT_PATH . '/phpunit/code/dynamic-arithmetic-result.php';
+        $compiler->addFiles([$source]);
+        $compiler->prepareFile($source);
+        $code = file_get_contents($compiler->convertFile($source));
+        self::assertIsString($code);
+        $dynamic = substr($code, strpos($code, 'php_dynamicresult('));
+        $dynamic = substr($dynamic, 0, strpos($dynamic, "\n}") + 3);
+        self::assertDoesNotMatchRegularExpression('/php::toInt\([^;]*divisor/s', $dynamic);
+        self::assertMatchesRegularExpression('/php::Int php_nativeintresult\(php::Int left, php::Int right\)/', $code);
+        self::assertMatchesRegularExpression('/php::Float php_nativefloatresult\(php::Float left, php::Float right\)/', $code);
+        foreach (['php_nativeintresult(', 'php_nativefloatresult('] as $name) {
+            $body = substr($code, strpos($code, $name));
+            $body = substr($body, 0, strpos($body, "\n}") + 3);
+            self::assertStringContainsString('((left) / (right))', $body);
+            self::assertStringNotContainsString('php::Var', $body);
+        }
+        self::assertMatchesRegularExpression('/php::Var (tmp_var_\d+);.*?\1 = \(+tmp_var_\d+\) \/ \(divisor\)/s', $dynamic);
+    }
+}

src/CompilerBase.php

@@ -3458,6 +3458,13 @@ protected function detectTypeOfExpr($expr): string
                     }
                     return Type::BIGINT;
                 }
+                // A dynamic operand keeps the runtime result type. Inferring
+                // Int from the other operand would truncate floating results
+                // when ordered evaluation materializes this expression.
+                if ($leftType === Type::VAR || $leftType === Type::REF
+                    || $rightType === Type::VAR || $rightType === Type::REF) {
+                    return Type::VAR;
+                }
                 if ($leftType === Type::FLOAT || $rightType === Type::FLOAT) {
                     return Type::FLOAT;
                 }

tests/compiler/dynamic_arithmetic_result.phpt

@@ -0,0 +1,139 @@
+--TEST--
+Dynamic arithmetic values keep PHP numeric semantics in nested array returns
+--FILE--
+<?php
+function dynamic_arithmetic(array $values, int $n): array
+{
+    return [
+        'forward' => [
+            'add' => $values['float'] + $n,
+            'subtract' => $values['float'] - $n,
+            'multiply' => $values['float'] * $n,
+            'divide' => $values['float'] / $n,
+            'integer_divide' => $values['integer'] / $n,
+        ],
+        'reverse' => [
+            'add' => $n + $values['float'],
+            'subtract' => $n - $values['float'],
+            'multiply' => $n * $values['float'],
+            'divide' => $n / $values['float'],
+        ],
+    ];
+}
+
+function dynamic_return(mixed $value, int $n): mixed
+{
+    return $value / $n;
+}
+
+function dynamic_nested(array $values, int $n): mixed
+{
+    return ($values['float'] + $n) * $n;
+}
+
+function dynamic_kinds(mixed $value, int $n, float $fraction): array
+{
+    return [$value / $n, $value + $fraction, $fraction - $value,
+        $value ** $n, $value % $n, $value << $n, $value >> $n,
+        $value & $n, $value | $n, $value ^ $n];
+}
+
+function divisor(): int
+{
+    return 2;
+}
+
+function dynamic_reference_arithmetic(): array
+{
+    $values = [5.5];
+    foreach ($values as &$value) {
+        return [
+            'forward' => [$value / divisor(), $value + divisor(), $value - divisor(), $value * divisor()],
+            'reverse' => [divisor() / $value, divisor() + $value, divisor() - $value, divisor() * $value],
+        ];
+    }
+}
+
+function main()
+{
+    var_dump(dynamic_arithmetic(['float' => 5.5, 'integer' => 5], 2));
+    var_dump(dynamic_return(5.5, 2), dynamic_nested(['float' => 5.5], 2));
+    var_dump(dynamic_kinds(4, 2, 0.5));
+    var_dump(dynamic_reference_arithmetic());
+}
+?>
+--EXPECT--
+array(2) {
+  ["forward"]=>
+  array(5) {
+    ["add"]=>
+    float(7.5)
+    ["subtract"]=>
+    float(3.5)
+    ["multiply"]=>
+    float(11)
+    ["divide"]=>
+    float(2.75)
+    ["integer_divide"]=>
+    float(2.5)
+  }
+  ["reverse"]=>
+  array(4) {
+    ["add"]=>
+    float(7.5)
+    ["subtract"]=>
+    float(-3.5)
+    ["multiply"]=>
+    float(11)
+    ["divide"]=>
+    float(0.36363636363636365)
+  }
+}
+float(2.75)
+float(15)
+array(10) {
+  [0]=>
+  int(2)
+  [1]=>
+  float(4.5)
+  [2]=>
+  float(-3.5)
+  [3]=>
+  int(16)
+  [4]=>
+  int(0)
+  [5]=>
+  int(16)
+  [6]=>
+  int(1)
+  [7]=>
+  int(0)
+  [8]=>
+  int(6)
+  [9]=>
+  int(6)
+}
+array(2) {
+  ["forward"]=>
+  array(4) {
+    [0]=>
+    float(2.75)
+    [1]=>
+    float(7.5)
+    [2]=>
+    float(3.5)
+    [3]=>
+    float(11)
+  }
+  ["reverse"]=>
+  array(4) {
+    [0]=>
+    float(0.36363636363636365)
+    [1]=>
+    float(7.5)
+    [2]=>
+    float(-3.5)
+    [3]=>
+    float(11)
+  }
+}