Improve error message

Author: nikic

Zend/tests/constants/final_constants/final_const11.phpt

@@ -19,4 +19,4 @@ class C2 extends C implements I
 
 ?>
 --EXPECTF--
-Fatal error: Cannot inherit previously-inherited or override constant C2::C from interface I in %s on line %d
+Fatal error: Class C2 inherits both C::C and I::C, which is ambiguous in %s on line %d

Zend/tests/constants/final_constants/final_const12.phpt

@@ -19,4 +19,4 @@ interface I3 extends I1, I2
 
 ?>
 --EXPECTF--
-Fatal error: Cannot inherit previously-inherited or override constant I3::C from interface I2 in %s on line %d
+Fatal error: Class I3 inherits both I1::C and I2::C, which is ambiguous in %s on line %d

Zend/tests/constants/final_constants/final_const8.phpt

@@ -19,4 +19,4 @@ class C implements I1, I2
 
 ?>
 --EXPECTF--
-Fatal error: Cannot inherit previously-inherited or override constant C::C from interface I2 in %s on line %d
+Fatal error: Class C inherits both I1::C and I2::C, which is ambiguous in %s on line %d

Zend/tests/errmsg_025.phpt

@@ -17,4 +17,4 @@ class test implements test1, test2 {
 echo "Done\n";
 ?>
 --EXPECTF--
-Fatal error: Cannot inherit previously-inherited or override constant test::FOO from interface test2 in %s on line %d
+Fatal error: Class test inherits both test1::FOO and test2::FOO, which is ambiguous in %s on line %d

Zend/zend_inheritance.c

@@ -1630,8 +1630,7 @@ ZEND_API void zend_do_inheritance_ex(zend_class_entry *ce, zend_class_entry *par
 /* }}} */
 
 static bool do_inherit_constant_check(
-	zend_class_entry *ce, zend_class_constant *parent_constant,
-	zend_string *name, const zend_class_entry *iface
+	zend_class_entry *ce, zend_class_constant *parent_constant, zend_string *name
 ) {
 	zval *zv = zend_hash_find_ex(&ce->constants_table, name, 1);
 	if (zv == NULL) {
@@ -1641,12 +1640,17 @@ static bool do_inherit_constant_check(
 	zend_class_constant *old_constant = Z_PTR_P(zv);
 	if ((ZEND_CLASS_CONST_FLAGS(parent_constant) & ZEND_ACC_FINAL)) {
 		zend_error_noreturn(E_COMPILE_ERROR, "%s::%s cannot override final constant %s::%s",
-			ZSTR_VAL(old_constant->ce->name), ZSTR_VAL(name), ZSTR_VAL(iface->name), ZSTR_VAL(name)
+			ZSTR_VAL(old_constant->ce->name), ZSTR_VAL(name),
+			ZSTR_VAL(parent_constant->ce->name), ZSTR_VAL(name)
 		);
 	}
 
 	if (old_constant->ce != parent_constant->ce && old_constant->ce != ce) {
-		zend_error_noreturn(E_COMPILE_ERROR, "Cannot inherit previously-inherited or override constant %s::%s from interface %s", ZSTR_VAL(ce->name), ZSTR_VAL(name), ZSTR_VAL(iface->name));
+		zend_error_noreturn(E_COMPILE_ERROR,
+			"Class %s inherits both %s::%s and %s::%s, which is ambiguous",
+			ZSTR_VAL(ce->name),
+			ZSTR_VAL(old_constant->ce->name), ZSTR_VAL(name),
+			ZSTR_VAL(parent_constant->ce->name), ZSTR_VAL(name));
 	}
 
 	return false;
@@ -1655,7 +1659,7 @@ static bool do_inherit_constant_check(
 
 static void do_inherit_iface_constant(zend_string *name, zend_class_constant *c, zend_class_entry *ce, zend_class_entry *iface) /* {{{ */
 {
-	if (do_inherit_constant_check(ce, c, name, iface)) {
+	if (do_inherit_constant_check(ce, c, name)) {
 		zend_class_constant *ct;
 		if (Z_TYPE(c->value) == IS_CONSTANT_AST) {
 			ce->ce_flags &= ~ZEND_ACC_CONSTANTS_UPDATED;
@@ -1722,7 +1726,7 @@ ZEND_API void zend_do_implement_interface(zend_class_entry *ce, zend_class_entry
 	if (ignore) {
 		/* Check for attempt to redeclare interface constants */
 		ZEND_HASH_FOREACH_STR_KEY_PTR(&iface->constants_table, key, c) {
-			do_inherit_constant_check(ce, c, key, iface);
+			do_inherit_constant_check(ce, c, key);
 		} ZEND_HASH_FOREACH_END();
 	} else {
 		if (ce->num_interfaces >= current_iface_num) {
@@ -1767,7 +1771,7 @@ static void zend_do_implement_interfaces(zend_class_entry *ce, zend_class_entry
 				}
 				/* skip duplications */
 				ZEND_HASH_FOREACH_STR_KEY_PTR(&iface->constants_table, key, c) {
-					do_inherit_constant_check(ce, c, key, iface);
+					do_inherit_constant_check(ce, c, key);
 				} ZEND_HASH_FOREACH_END();
 
 				iface = NULL;