Bug 134252

Summary:	check-webkit-style should warn about signed values in bit fields
Product:	WebKit	Reporter:	Brent Fulgham <bfulgham>
Component:	Tools / Tests	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	ap, joepeck
Priority:	P2
Version:	528+ (Nightly build)
Hardware:	Unspecified
OS:	Unspecified

Description Brent Fulgham 2014-06-24 09:36:06 PDT

MSVC backs its enumerated types as signed values. This causes problems when enums are used as elements in a bit field, because MSVC wants to include a sign bit in the encoding. This means we loose one bit of resolution, often causing incorrect behavior. See Bug 134237 for some details on this problem.

Because of this, 'check-webkit-style' should warn when a developer attempts to insert an enum or other potentially signed value in a bit field.

Should be rejected:
    SendCallbackPolicy sendLoadCallbacks : 1;
    ContentSniffingPolicy sniffContent : 1;
    DataBufferingPolicy dataBufferingPolicy : 1;

Should be allowed:
    unsigned sendLoadCallbacks : 1;
    bool sniffContent : 1;
    unsigned dataBufferingPolicy : 1;