Merge branch 'PHP-7.3' into PHP-7.4

* PHP-7.3:
  Fix memory leak when yielding from non-iterable

Author: nikic

Zend/tests/generators/yield_from_non_iterable.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Yield from non-iterable
+--FILE--
+<?php
+
+function gen() {
+    yield from new stdClass;
+}
+
+try {
+    gen()->current();
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+Can use "yield from" only with arrays and Traversables

Zend/zend_vm_def.h

@@ -7906,6 +7906,7 @@ ZEND_VM_HANDLER(166, ZEND_YIELD_FROM, CONST|TMP|VAR|CV, ANY)
 		}
 	} else {
 		zend_throw_error(NULL, "Can use \"yield from\" only with arrays and Traversables");
+		FREE_OP1();
 		UNDEF_RESULT();
 		HANDLE_EXCEPTION();
 	}

Zend/zend_vm_execute.h

@@ -4483,6 +4483,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_YIELD_FROM_SPEC_CONST_HANDLER(
 		}
 	} else {
 		zend_throw_error(NULL, "Can use \"yield from\" only with arrays and Traversables");
+
 		UNDEF_RESULT();
 		HANDLE_EXCEPTION();
 	}
@@ -18539,6 +18540,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_YIELD_FROM_SPEC_TMP_HANDLER(ZE
 		}
 	} else {
 		zend_throw_error(NULL, "Can use \"yield from\" only with arrays and Traversables");
+		zval_ptr_dtor_nogc(free_op1);
 		UNDEF_RESULT();
 		HANDLE_EXCEPTION();
 	}
@@ -21954,6 +21956,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_YIELD_FROM_SPEC_VAR_HANDLER(ZE
 		}
 	} else {
 		zend_throw_error(NULL, "Can use \"yield from\" only with arrays and Traversables");
+		zval_ptr_dtor_nogc(free_op1);
 		UNDEF_RESULT();
 		HANDLE_EXCEPTION();
 	}
@@ -38123,6 +38126,7 @@ static ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_YIELD_FROM_SPEC_CV_HANDLER(ZEN
 		}
 	} else {
 		zend_throw_error(NULL, "Can use \"yield from\" only with arrays and Traversables");
+
 		UNDEF_RESULT();
 		HANDLE_EXCEPTION();
 	}