Q: Difference between "variable declaration" and "short variable declaration" at local scope in Go According to this question how-to-define-a-single-byte-variable-in-go-lang
At a local scope:
var c byte = 'A' 

and
c := byte('A')

My questions are: 


*

*Do they have the same mechanism?

*Which one is more easy to understand by a go compiler?


A: They are the same type (byte is an alias for uint8) and value. For example,
package main

import "fmt"

func main() {
    var c byte = 'A'
    d := byte('A')
    fmt.Printf("c: %[1]T %[1]v d: %[2]T %[2]v c==d: %v", c, d, c == d)
}

Output:
c: uint8 65 d: uint8 65 c==d: true

They are equally efficient; the runtime code is the same. They are both easy to understand by Go compilers.

The Go Programming Language Specification.
A short variable declaration uses the syntax:
ShortVarDecl = IdentifierList ":=" ExpressionList .

It is shorthand for a regular variable declaration with initializer
  expressions but no types: 
"var" IdentifierList = ExpressionList .


The "best" is a matter of style. Which reads better in a given context?

The Go Programming Language
Alan A. A. Donovan · Brian W.Kernighan
Because of their brevity and flexibility, short variable
  declarations are used to declare and initialize the majority of local
  variables. A var declaration tends to be reserved for local variables
  that need an explicit type that differs from that of the initializer
  expression, or for when the variable will be assigned a value later
  and its initial value is unimportant.

