Fix NAN inferences

Author: VincentLanglet

src/Type/ConstantTypeHelper.php

@@ -16,7 +16,6 @@
 use function is_bool;
 use function is_float;
 use function is_int;
-use function is_nan;
 use function is_object;
 use function is_string;
 
@@ -34,9 +33,6 @@ public static function getTypeFromValue($value): Type
 		if (is_int($value)) {
 			return new ConstantIntegerType($value);
 		} elseif (is_float($value)) {
-			if (is_nan($value)) {
-				return new MixedType();
-			}
 			return new ConstantFloatType($value);
 		} elseif (is_bool($value)) {
 			return new ConstantBooleanType($value);

tests/PHPStan/Analyser/nsrt/bug-13097.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Bug13097;
+
+use function PHPStan\Testing\assertType;
+
+$f = -1 * INF;
+assertType('-INF', $f);
+
+$f = 0 * INF;
+assertType('NAN', $f);
+
+$f = 1 * INF;
+assertType('INF', $f);