Go gotcha: Why can't I multiply a time.Duration with an integer?

Package: time

Why doesn’t this compile?

n := 100
time.Sleep(n * time.Millisecond)
invalid operation: n * time.Millisecond (mismatched types int and time.Duration)
Answer

There is no mixing of numeric types in Go. You can only multiply a time.Duration with

  • another time.Duration, or
  • an untyped integer constant.

Here are three correct examples:

var n time.Duration = 100
time.Sleep(n * time.Millisecond)
const n = 100
time.Sleep(n * time.Millisecond)
time.Sleep(100 * time.Millisecond)

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