Suggestion to improve proc type infer, and some complains

[sls1005]

This also failed:
    
    
    on_click (proc(e: auto): (auto | void) = echo e)
    
    
    Run
    
    
    mismatch at position: 1
    required type for fn: proc (e: Event){.closure.}
    but expression 'proc (e: auto): (auto | void) = echo e'
    is of type: proc (e: GenericParam): auto or void
    
    
    Run

While this works:
    
    
    on_click (proc(e: auto): void = echo e)
    
    
    Run

Now I think the compiler has a problem that it cannot recongnize `proc(e: 
auto): auto = echo e` and `proc(e: auto): void = echo e` are the same thing. 
The former is not deduced as the later.