diff --git a/tests/compiler/basic/pow-int-overflow-native-type.phpt b/tests/compiler/basic/pow-int-overflow-native-type.phpt
index 45b7083d..bccfa002 100644
--- a/tests/compiler/basic/pow-int-overflow-native-type.phpt
+++ b/tests/compiler/basic/pow-int-overflow-native-type.phpt
@@ -5,9 +5,13 @@ pow int overflow
 use native_types;
 function main()
 {
+    // PHP 8.5 warns when the overflowing float is narrowed to a native int.
+    // This test covers the resulting value; a version-specific companion test
+    // covers the warning so this expectation remains stable on PHP 8.4/8.5.
+    error_reporting(E_ERROR);
     $a = 2 ** 80;
     echo $a, PHP_EOL;
 }
 ?>
 --EXPECT--
-0
\ No newline at end of file
+0
diff --git a/tests/compiler/basic/pow-int-overflow-warning-php85.phpt b/tests/compiler/basic/pow-int-overflow-warning-php85.phpt
new file mode 100644
index 00000000..46bb8262
--- /dev/null
+++ b/tests/compiler/basic/pow-int-overflow-warning-php85.phpt
@@ -0,0 +1,20 @@
+--TEST--
+PHP 8.5 warns when pow overflow is narrowed to a native int
+--SKIPIF--
+<?php
+if (PHP_VERSION_ID < 80500) {
+    die('skip requires PHP 8.5 or newer');
+}
+?>
+--FILE--
+<?php
+use native_types;
+function main(): void
+{
+    $value = 2 ** 80;
+    echo $value, PHP_EOL;
+}
+?>
+--EXPECTF--
+Warning: The float %s is not representable as an int, cast occurred in %s on line %d
+0
diff --git a/tests/compiler/float_edge/edge-cases.phpt b/tests/compiler/float_edge/edge-cases.phpt
index e14b1c1e..40905e38 100644
--- a/tests/compiler/float_edge/edge-cases.phpt
+++ b/tests/compiler/float_edge/edge-cases.phpt
@@ -3,6 +3,7 @@ Float edge cases: NAN, INF, -INF
 --FILE--
 <?php
 function main(): void {
+    error_reporting(E_ERROR);
     var_dump(NAN);
     var_dump(INF);
     var_dump(-INF);
@@ -13,7 +14,10 @@ function main(): void {
     var_dump(is_infinite(1.5));
     var_dump(is_finite(INF));
     var_dump(is_finite(1.5));
-    echo NAN . "\n";
+    // Keep the NAN-to-string conversion at runtime so error_reporting() can
+    // suppress PHP 8.5's new warning in this cross-version value test.
+    $nan = NAN;
+    echo $nan . "\n";
     echo INF . "\n";
     echo -INF . "\n";
     var_dump(INF + INF);
diff --git a/tests/compiler/float_edge/nan-string-warning-php85.phpt b/tests/compiler/float_edge/nan-string-warning-php85.phpt
new file mode 100644
index 00000000..c3afe8ce
--- /dev/null
+++ b/tests/compiler/float_edge/nan-string-warning-php85.phpt
@@ -0,0 +1,18 @@
+--TEST--
+PHP 8.5 warns when NAN is coerced to string
+--SKIPIF--
+<?php
+if (PHP_VERSION_ID < 80500) {
+    die('skip requires PHP 8.5 or newer');
+}
+?>
+--FILE--
+<?php
+function main(): void
+{
+    echo NAN . "\n";
+}
+?>
+--EXPECTF--
+Warning: unexpected NAN value was coerced to string in %s on line %d
+NAN