diff --git a/phpunit/code/bigfloat-unsupported-mod.php b/phpunit/code/bigfloat-unsupported-mod.php
new file mode 100644
index 00000000..fac352a5
--- /dev/null
+++ b/phpunit/code/bigfloat-unsupported-mod.php
@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+use native_types;
+function main()
+{
+    $a = std::bigFloat("3.14");
+    $b = std::bigFloat("2.71");
+    $c = $a % $b;
+}
diff --git a/phpunit/code/bigfloat-unsupported-shift.php b/phpunit/code/bigfloat-unsupported-shift.php
new file mode 100644
index 00000000..44f353f0
--- /dev/null
+++ b/phpunit/code/bigfloat-unsupported-shift.php
@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+use native_types;
+function main()
+{
+    $a = std::bigFloat("10.0");
+    $b = 2;
+    $c = $a << $b;
+}
diff --git a/phpunit/code/decimal-unsupported-bitand.php b/phpunit/code/decimal-unsupported-bitand.php
new file mode 100644
index 00000000..83484bb5
--- /dev/null
+++ b/phpunit/code/decimal-unsupported-bitand.php
@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+use native_types;
+function main()
+{
+    $a = std::decimal("3.14");
+    $b = std::decimal("2.71");
+    $c = $a & $b;
+}
diff --git a/phpunit/code/decimal-unsupported-bitor.php b/phpunit/code/decimal-unsupported-bitor.php
new file mode 100644
index 00000000..91178992
--- /dev/null
+++ b/phpunit/code/decimal-unsupported-bitor.php
@@ -0,0 +1,9 @@
+<?php
+declare(strict_types=1);
+use native_types;
+function main()
+{
+    $a = std::decimal("100");
+    $b = std::decimal("200");
+    $c = $a | $b;
+}
diff --git a/phpunit/src/BigNumberUnsupportedOpTest.php b/phpunit/src/BigNumberUnsupportedOpTest.php
new file mode 100644
index 00000000..8ec34035
--- /dev/null
+++ b/phpunit/src/BigNumberUnsupportedOpTest.php
@@ -0,0 +1,24 @@
+<?php
+
+class BigNumberUnsupportedOpTest extends \BaseTest
+{
+    public function testBigFloatMod()
+    {
+        $this->exec("Operator '%' is not supported for Big* numeric types", 'bigfloat-unsupported-mod.php');
+    }
+
+    public function testDecimalBitAnd()
+    {
+        $this->exec("Operator '&' is not supported for Big* numeric types", 'decimal-unsupported-bitand.php');
+    }
+
+    public function testBigFloatShiftLeft()
+    {
+        $this->exec("Operator '<<' is not supported for Big* numeric types", 'bigfloat-unsupported-shift.php');
+    }
+
+    public function testDecimalBitOr()
+    {
+        $this->exec("Operator '|' is not supported for Big* numeric types", 'decimal-unsupported-bitor.php');
+    }
+}
diff --git a/src/Php/Parser/BinaryOpTrait.php b/src/Php/Parser/BinaryOpTrait.php
index 0ff4147c..759051d9 100644
--- a/src/Php/Parser/BinaryOpTrait.php
+++ b/src/Php/Parser/BinaryOpTrait.php
@@ -106,6 +106,12 @@ trait BinaryOpTrait
             }
         }
 
+        // Any Big*-typed operand reaching here means no Big* block handled the operator
+        $bigTypes = [self::TYPE_BIGFLOAT, self::TYPE_DECIMAL, self::TYPE_BIGINT];
+        if (in_array($leftType, $bigTypes, true) || in_array($rightType, $bigTypes, true)) {
+            $this->fatalError($left, "Operator '{$op}' is not supported for Big* numeric types");
+        }
+
         // Only promote between native types (Int ↔ Float).  When one side is
         // php::Var, let the Variant operator handle type coercion so that
         // run-time PHP type-juggling rules are followed correctly.