The sign problem caused by the C bit field

[anyktx]

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Issues and Steps to Reproduce

I used Visual Studio 2017 to code and compile, and some of the properties went wrong when I set the Style property of YGNode and got the layout results.

When I looked at the definitions of YGStylet and YGLayout, I found that some of the properties were bitfields used. In this case, having this property causes a sign problem. For example, the value of flexDirection is [0,3], when the value is 2 or 3, the bit field that USES two bits will take the previous bit as the symbol, resulting in a negative value. Without experimenting with other compilers, there may not be such a problem, but in Visual Studio such a problem does exist. The properties found to have this problem exist in almost all the properties that use bit fields.

Link to Code

https://github.com/facebook/yoga/blob/master/tests/YGFlexDirectionTest.cpp
This test won't work well in Visual Studio，

[zcbenz]

I can also reproduce this problem, in my case Yoga crashed directly because of wrong flexDirection value.

[Adlai-Holler]

This is blocking my build when I try to import YGNode.h into a C++ context – the compiler errors with "Implicit truncation to bitfield will change value from 4 to -4." I tried changing the enum definition to be unsigned instead of int but that no workm.