dscanner.analysis.logic_precedence source code

1 //          Copyright Brian Schott (Hackerpilot) 2014.
2 // Distributed under the Boost Software License, Version 1.0.
3 //    (See accompanying file LICENSE_1_0.txt or copy at
4 //          http://www.boost.org/LICENSE_1_0.txt)
5 
6 module dscanner.analysis.logic_precedence;
7 
8 import std.stdio;
9 import dparse.ast;
10 import dparse.lexer;
11 import dscanner.analysis.base;
12 import dscanner.analysis.helpers;
13 import dsymbol.scope_;
14 
15 /**
16  * Checks for code with confusing && and || operator precedence
17  * ---
18  * if (a && b || c) // bad
19  * if (a && (b || c)) // good
20  * ---
21  */
22 class LogicPrecedenceCheck : BaseAnalyzer
23 {
24 	alias visit = BaseAnalyzer.visit;
25 
26 	enum string KEY = "dscanner.confusing.logical_precedence";
27 
28 	this(string fileName, const(Scope)* sc, bool skipTests = false)
29 	{
30 		super(fileName, sc, skipTests);
31 	}
32 
33 	override void visit(const OrOrExpression orOr)
34 	{
35 		if (orOr.left is null || orOr.right is null)
36 			return;
37 		const AndAndExpression left = cast(AndAndExpression) orOr.left;
38 		const AndAndExpression right = cast(AndAndExpression) orOr.right;
39 		if (left is null && right is null)
40 			return;
41 		if ((left !is null && left.right is null) && (right !is null && right.right is null))
42 			return;
43 		addErrorMessage(orOr.line, orOr.column, KEY,
44 				"Use parenthesis to clarify this expression.");
45 		orOr.accept(this);
46 	}
47 }
48 
49 unittest
50 {
51 	import dscanner.analysis.config : StaticAnalysisConfig, Check, disabledConfig;
52 
53 	StaticAnalysisConfig sac = disabledConfig();
54 	sac.logical_precedence_check = Check.enabled;
55 	assertAnalyzerWarnings(q{
56 		void testFish()
57 		{
58 			if (a && b || c) {} // [warn]: Use parenthesis to clarify this expression.
59 			if ((a && b) || c) {} // Good
60 			if (b || c && d) {} // [warn]: Use parenthesis to clarify this expression.
61 			if (b || (c && d)) {} // Good
62 		}
63 	}c, sac);
64 	stderr.writeln("Unittest for LogicPrecedenceCheck passed.");
65 }