Go’s use of semicolons is one area of confusion for newcomers to the language. It certainly was for me. But it’s more intuitive than it seems.

Here’s the formal explanation:

Semicolons

The formal syntax uses semicolons ";" as terminators in a number of productions. Go programs may omit most of these semicolons using the following two rules:

1. When the input is broken into tokens, a semicolon is automatically inserted into the token stream immediately after a line’s final token if that token is

   • an identifier
   • an integer, floating-point, imaginary, rune, or string literal
   • one of the keywords break, continue, fallthrough, or return
   • one of the operators and punctuation ++, --, ), ], or }

2. To allow complex statements to occupy a single line, a semicolon may be omitted before a closing ")" or "}".

To reflect idiomatic use, code examples in this document elide semicolons using these rules.

What this means in practice is that Go “officially” uses semicolons, a lot like C/C++, kind of “all over the place.”

This is valid Go, which looks a lot like C:

package main;

import "fmt";

func main() {
	var x = 1;
	if (x > 0) {
		fmt.Println(x);
	};
};

But since the Go tokenization process adds most semicolons for you, based on the rules described, we can simplify this code when writing it, to be a bit less tedious:

package main

import "fmt"

func main() {
	var x = 1
	if x > 0 {
		fmt.Println(x)
	}
}

(This example also removes the unnecessary parentheses around the conditional expression, which we’ll get to later.)

So how do you know when it’s safe to remove a semicolon?

Well, you can memorize the rules above. But in practice, you can mostly just always omit them. As a general rule, the only times you need to explicitly type semicolons is when you want to put multiple statements on a single line. In other words, when you prefer a semicolon over a line break.

By convention, this is done in (small) number of cases, such as separating the if statement optional “simple statement” from the expression block:

if x := 1
x > y {
	return x
}

is more commonly expressed with a semicolon as:

if x := 1; x > y {
	return x
}

Quotes from The Go Programming Language Specification, Version of June 29, 2022