63911: Compare opcodes of the op_array to determine different functions

NEWS

@@ -16,6 +16,8 @@ PHP                                                                        NEWS
     files). (petk)
   . Fixed bug #74922 (Composed class has fatal error with duplicate, equal const
     properties). (pmmaga)
+  . Fixed bug #63911 (identical trait methods raise errors during composition). 
+    (pmmaga)
 
 - BCMath:
   . Fixed bug #66364 (BCMath bcmul ignores scale parameter). (cmb)

Zend/tests/traits/bug63911.phpt

@@ -0,0 +1,26 @@
+--TEST--
+Bug #63911 (Ignore conflicting trait methods originationg from identical sub traits)
+--FILE--
+<?php
+trait A
+{
+    public function a(){
+        echo 'Done';
+    }
+}
+trait B
+{
+    use A;
+}
+trait C
+{
+    use A;
+}
+class D
+{
+    use B, C;
+}
+
+(new D)->a();
+--EXPECT--
+Done

Zend/zend_inheritance.c

@@ -1165,6 +1165,11 @@ static void zend_add_trait_method(zend_class_entry *ce, const char *name, zend_s
 	zend_function *new_fn;
 
 	if ((existing_fn = zend_hash_find_ptr(&ce->function_table, key)) != NULL) {
+		/* if it is the same function regardless of where it is coming from, there is no conflict and we do not need to add it again */
+		if (existing_fn->op_array.opcodes == fn->op_array.opcodes) {
+			return;
+		}
+
 		if (existing_fn->common.scope == ce) {
 			/* members from the current class override trait methods */
 			/* use temporary *overriden HashTable to detect hidden conflict */