QGraphicalEffects not compatible with OpenGL 3.2+ on macOS

If QtGraphicalEffects are used in QML with an OpenGL context higher than 3.1 artifacts appear or elements are missing. The QtCreator debug console shows a list of shader compilation errors.

Steps to reproduce: Create Qt Quick Application Project. Import and use any QtGraphicalEffects Item in main.qml
In main.cpp set QSurfaceFormat::defaultFormat() to a CoreProfile with version 3.2 or greater before main.qml file is loaded.

Cause: macOS's graphics driver does not support OpenGL compatibility profiles. This leads to syntax errors in GLSL shader code because for example "varying" is no longer a valid keyword in OpenGL 3.2 GLSL 1.5.
This is not an issue with a specific OS X version or GPU vendor. It is an issue of shader code that is not version aware. The underlying cause is Apple's decision to not support any OpenGL compatibility profiles.

This issue was first reported here https://bugreports.qt.io/browse/QTBUG-42107

Possible Solution: Detect OpenGL core profile and version number in qt-fixes/qtdeclarative/src/quick/items/qquickopenglshadereffect.cpp and modify shader code to comply with GLSL 150 core before it is compiled on macOS.
This solution would fix ALL QtGraphicalEffects and also any custom ShaderEffects which are written as inline QML strings.
The existing +glslcore folder mechanism could also be used to provide compatible shader code, if a ShaderEffect is used with urls instead of inline shader strings.
This is hover not a solution for all graphical effects because some are build from multiple strings and variables.