Why Can't I Use Short Variable Declarations (`:=`) at the Package Level in Go?

Short Variable Declaration at Package Level

In Go, short variable declaration (using :=) is allowed within functions, but not at the package level. This can be puzzling, as using := outside a function looks like regular declaration without a type.

Reason for the Restriction

According to Ian Lance Taylor, one of Go's creators, the restriction exists solely to simplify parsing. Top-level declarations always start with a keyword, such as var, func, import, etc. This simplifies the syntax and makes parsing more straightforward for the compiler.

Example

Package-level declaration using var is allowed:

Short variable declaration using := is not allowed at package level:

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