1 files changed, 31 insertions, 8 deletions

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index fe9139b609..af2d2e95cb 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -4903,8 +4903,9 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast) /* {{{ */
 			zend_error_noreturn(E_COMPILE_ERROR, "Redefinition of parameter $%s",
 				ZSTR_VAL(name));
 		} else if (zend_string_equals_literal(name, "this")) {
-			if (op_array->scope && (op_array->fn_flags & ZEND_ACC_STATIC) == 0) {
-				zend_error_noreturn(E_COMPILE_ERROR, "Cannot re-assign $this");
+			if ((op_array->scope || (op_array->fn_flags & ZEND_ACC_CLOSURE))
+					&& (op_array->fn_flags & ZEND_ACC_STATIC) == 0) {
+				zend_error_noreturn(E_COMPILE_ERROR, "Cannot use $this as parameter");
 			}
 			op_array->this_var = var_node.u.op.var;
 		}
@@ -7313,7 +7314,7 @@ zend_bool zend_is_allowed_in_const_expr(zend_ast_kind kind) /* {{{ */
 		|| kind == ZEND_AST_CONDITIONAL || kind == ZEND_AST_DIM
 		|| kind == ZEND_AST_ARRAY || kind == ZEND_AST_ARRAY_ELEM
 		|| kind == ZEND_AST_CONST || kind == ZEND_AST_CLASS_CONST
-		|| kind == ZEND_AST_MAGIC_CONST;
+		|| kind == ZEND_AST_MAGIC_CONST || kind == ZEND_AST_COALESCE;
 }
 /* }}} */
 
@@ -7447,14 +7448,16 @@ void zend_const_expr_to_zval(zval *result, zend_ast *ast) /* {{{ */
 	zend_compile_const_expr(&ast);
 	if (ast->kind == ZEND_AST_ZVAL) {
 		ZVAL_COPY_VALUE(result, zend_ast_get_zval(ast));
-
-		/* Kill this branch of the original AST, as it was already destroyed.
-		 * It would be nice to find a better solution to this problem in the
-		 * future. */
-		orig_ast->kind = 0;
 	} else {
 		ZVAL_NEW_AST(result, zend_ast_copy(ast));
+		/* destroy the ast here, it might have been replaced */
+		zend_ast_destroy(ast);
 	}
+
+	/* Kill this branch of the original AST, as it was already destroyed.
+	 * It would be nice to find a better solution to this problem in the
+	 * future. */
+	orig_ast->kind = 0;
 }
 /* }}} */
 
@@ -7865,6 +7868,26 @@ void zend_eval_const_expr(zend_ast **ast_ptr) /* {{{ */
 				return;
 			}
 			break;
+		case ZEND_AST_COALESCE:
+			zend_eval_const_expr(&ast->child[0]);
+
+			if (ast->child[0]->kind != ZEND_AST_ZVAL) {
+				/* ensure everything was compile-time evaluated at least once */
+				zend_eval_const_expr(&ast->child[1]);
+				return;
+			}
+
+			if (Z_TYPE_P(zend_ast_get_zval(ast->child[0])) == IS_NULL) {
+				zend_eval_const_expr(&ast->child[1]);
+				*ast_ptr = ast->child[1];
+				ast->child[1] = NULL;
+				zend_ast_destroy(ast);
+			} else {
+				*ast_ptr = ast->child[0];
+				ast->child[0] = NULL;
+				zend_ast_destroy(ast);
+			}
+			return;
 		case ZEND_AST_CONDITIONAL:
 		{
 			zend_ast **child, *child_ast;