groovy switch: nasty bug

I found nasty error in Groovy compiler. Consider the following code:

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byte b = 1 switch(b) { case 0..9: println 'it is between 0 and 9' break default: println 'it is something else' }

It executes 'default' part, not the part with 0..9, which is not what a programmer would typically expect.
The reason behind it should be related to type conversion between "byte" and "int" types. With the following workaround:

1	swtch((int)b)

the program executes "proper" case.