Repro:
1. Open and run the project notice the MissingMethodException after play.

2.Notice that the snippet below (from Test.cs) is compiled fine, and the error is thrown only after playing:

public CanvasGroup canvasGroup;
void Start ()
{
this.canvasGroup.alpha = 0.5f;
}

same with 'this.Canvas' and probably other types as long as the variable of the same name is defined e.g 'public Canvas canvas;', if it's 'Canvas canvas123' it sill compiles fine as long as 'this.canvas123' is used.