1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
package rule
import (
"fmt"
"go/ast"
"github.com/mgechev/revive/lint"
)
// UnusedReceiverRule lints unused params in functions.
type UnusedReceiverRule struct{}
// Apply applies the rule to given file.
func (*UnusedReceiverRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
var failures []lint.Failure
onFailure := func(failure lint.Failure) {
failures = append(failures, failure)
}
w := lintUnusedReceiverRule{onFailure: onFailure}
ast.Walk(w, file.AST)
return failures
}
// Name returns the rule name.
func (*UnusedReceiverRule) Name() string {
return "unused-receiver"
}
type lintUnusedReceiverRule struct {
onFailure func(lint.Failure)
}
func (w lintUnusedReceiverRule) Visit(node ast.Node) ast.Visitor {
switch n := node.(type) {
case *ast.FuncDecl:
if n.Recv == nil {
return nil // skip this func decl, not a method
}
rec := n.Recv.List[0] // safe to access only the first (unique) element of the list
if len(rec.Names) < 1 {
return nil // the receiver is anonymous: func (aType) Foo(...) ...
}
recID := rec.Names[0]
if recID.Name == "_" {
return nil // the receiver is already named _
}
// inspect the func body looking for references to the receiver id
fselect := func(n ast.Node) bool {
ident, isAnID := n.(*ast.Ident)
return isAnID && ident.Obj == recID.Obj
}
refs2recID := pick(n.Body, fselect, nil)
if len(refs2recID) > 0 {
return nil // the receiver is referenced in the func body
}
w.onFailure(lint.Failure{
Confidence: 1,
Node: recID,
Category: "bad practice",
Failure: fmt.Sprintf("method receiver '%s' is not referenced in method's body, consider removing or renaming it as _", recID.Name),
})
return nil // full method body already inspected
}
return w
}
|
