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
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
//
// RedundantComparisonWithNullIssue.cs
//
// Author:
// Ji Kun <jikun.nus@gmail.com>
//
// Copyright (c) 2013 Ji Kun
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.using System;
using System.Collections.Generic;
using ICSharpCode.NRefactory.PatternMatching;
using System.Linq;
using ICSharpCode.NRefactory.Refactoring;
namespace ICSharpCode.NRefactory.CSharp.Refactoring
{
[IssueDescription("Redundant comparison with 'null'",
Description = "When 'is' keyword is used, which implicitly check null.",
Category = IssueCategories.Redundancies,
Severity = Severity.Warning,
ResharperDisableKeyword = "RedundantComparisonWithNull",
IssueMarker = IssueMarker.GrayOut)]
public class RedundantComparisonWithNullIssue : ICodeIssueProvider
{
private static readonly Pattern pattern1
= new Choice {
// a is Record && a != null
new BinaryOperatorExpression(
PatternHelper.OptionalParentheses(
new IsExpression {
Expression = new AnyNode("a"),
Type = new AnyNode("t")
}),
BinaryOperatorType.ConditionalAnd,
PatternHelper.OptionalParentheses(
PatternHelper.CommutativeOperator(new Backreference("a"),
BinaryOperatorType.InEquality,
new NullReferenceExpression())
)
),
// a != null && a is Record
new BinaryOperatorExpression (
PatternHelper.OptionalParentheses(
PatternHelper.CommutativeOperator(new AnyNode("a"),
BinaryOperatorType.InEquality,
new NullReferenceExpression())
),
BinaryOperatorType.ConditionalAnd,
PatternHelper.OptionalParentheses(
new IsExpression {
Expression = new Backreference("a"),
Type = new AnyNode("t")
})
)
};
public IEnumerable<CodeIssue> GetIssues(BaseRefactoringContext context)
{
return new GatherVisitor(context).GetIssues();
}
class GatherVisitor : GatherVisitorBase<RedundantComparisonWithNullIssue>
{
public GatherVisitor(BaseRefactoringContext ctx)
: base(ctx)
{
}
public override void VisitBinaryOperatorExpression(BinaryOperatorExpression binaryOperatorExpression)
{
base.VisitBinaryOperatorExpression(binaryOperatorExpression);
Match m1 = pattern1.Match(binaryOperatorExpression);
if (m1.Success) {
AddIssue(binaryOperatorExpression, ctx.TranslateString("Remove expression"), script => {
var isExpr = m1.Get<AstType>("t").Single().Parent;
script.Replace(binaryOperatorExpression, isExpr);
});
return;
}
}
}
}
}
|
