Bug 159968

Summary: [JSC] Unary + changes evaluation order
Product: WebKit Reporter: Yusuke Suzuki <ysuzuki>
Component: JavaScriptCoreAssignee: Yusuke Suzuki <ysuzuki>
Status: NEW ---    
Severity: Normal    
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

Description Yusuke Suzuki 2016-07-20 04:06:58 PDT
Currently, we just strip the unary + in makeXXXNode. But unary + can change the evaluation order since it performs ToNumber.

Modified tests derived from the Rick Waldron's one. 

            let capture = [];
            let leftValue = { valueOf() { capture.push("leftValue"); return 3; }};
            let rightValue = { valueOf() { capture.push("rightValue"); return 2; }};

            (capture.push("left"), leftValue) ${token} +(capture.push("right"), rightValue);
            //                                         ^
            //                                 Changes the order

            // Expected per operator evaluation order: "left", "right", "rightValue", "leftValue"
            shouldBe(capture[0], "left");
            shouldBe(capture[1], "right");
            shouldBe(capture[2], "rightValue");
            shouldBe(capture[3], "leftValue");