Fixed bug #79790

I haven't tracked down in detail where the interaction with
increment_function comes from, but the root problem here is failure
to handle the illegal offset type exception.

Author: nikic

NEWS

@@ -2,6 +2,9 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.0.0alpha3
 
+- Core:
+  . Fixed bug #79790 ("Illegal offset type" exception during AST evaluation
+    not handled properly). (Nikita)
 
 09 Jul 2020, PHP 8.0.0alpha2
 

Zend/tests/bug79790.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Bug #79790: "Illegal offset type" exception during AST evaluation not handled properly
+--FILE--
+<?php
+b();
+function b($a = array()[array ()]) {
+    ++$c[function () {}];
+}
+?>
+--EXPECTF--
+Fatal error: Uncaught TypeError: Illegal offset type in %s:%d
+Stack trace:
+#0 %s(%d): b()
+#1 {main}
+  thrown in %s on line %d

Zend/zend_ast.c

@@ -750,6 +750,9 @@ ZEND_API int ZEND_FASTCALL zend_ast_evaluate(zval *result, zend_ast *ast, zend_c
 
 				zval_ptr_dtor_nogc(&op1);
 				zval_ptr_dtor_nogc(&op2);
+				if (UNEXPECTED(EG(exception))) {
+					return FAILURE;
+				}
 			}
 			break;
 		default: