static compiler fails with bug massage for method call in loop increment

This code

@CompileStatic
class X {
    static void bar(){
        for (int i=0;i<1000000; i+=foo()){}
    }
    static foo(){1}
}

may not make so much sense, but should at least not fail during compilation with a GroovyBugError. The message complains about the method call in the i+=foo() part