Operator ^ lifts the declaration of a variable to the enclosing scope when used in if and for statements:

if ^f, err := os.Open("foo.bar"); err != nil {
	return fmt.Errorf("error opening file: %w", err)
}
f.Read() 	// ok: f is in scope now

Using ^f, the declaration of f escapes the if statement while keeping err local to the if statement.

The expression ^f, err := works just like f, err := except that if f is declared, it is declared in the enclosing block.

Other notes:

1. ^ can only be used with if and for; anywhere else it is illegal

   To be more exact:
   - in the ShortVarDecl of the SimpleStatement of the IfStmt
   - in the InitStmt of the ForClause of the ForStmt
   - in the RangeClause of the ForStmt

2. Single lifts are allowed only; ^^f is illegal, etc.

3. I know that ^ is used as bitwise XOR operator; this should be no problem as for example * is also used for both derefencing and multiplication operator

4. I chose ^ because it is a visual cue for the effect of the operation.