func CheckNilFuncComparison()

in gotypes/nilfunc/main.go [56:92]

31 lines of code
9 McCabe index (conditional complexity)


func CheckNilFuncComparison(info *types.Info, n ast.Node) {
	e, ok := n.(*ast.BinaryExpr)
	if !ok {
		return // not a binary operation
	}
	if e.Op != token.EQL && e.Op != token.NEQ {
		return // not a comparison
	}

	// If this is a comparison against nil, find the other operand.
	var other ast.Expr
	if info.Types[e.X].IsNil() {
		other = e.Y
	} else if info.Types[e.Y].IsNil() {
		other = e.X
	} else {
		return // not a comparison against nil
	}

	// Find the object.
	var obj types.Object
	switch v := other.(type) {
	case *ast.Ident:
		obj = info.Uses[v]
	case *ast.SelectorExpr:
		obj = info.Uses[v.Sel]
	default:
		return // not an identifier or selection
	}

	if _, ok := obj.(*types.Func); !ok {
		return // not a function or method
	}

	fmt.Printf("%s: comparison of function %v %v nil is always %v\n",
		fset.Position(e.Pos()), obj.Name(), e.Op, e.Op == token.NEQ)
}