From 22104911d44bd618de09fadc1d39eee3066f89eb Mon Sep 17 00:00:00 2001
From: Matthew Brennan Jones <matthew.brennan.jones@gmail.com>
Date: Fri, 23 May 2014 20:37:48 -0700
Subject: [PATCH] Added basic checker for duplicate attributes.

---
 README.md                      |   1 +
 analysis/duplicate_attribute.d | 127 +++++++++++++++++++++++++++++++++
 analysis/run.d                 |   5 +-
 3 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 analysis/duplicate_attribute.d

diff --git a/README.md b/README.md
index 5e2028e..c8f4828 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,7 @@ given source files.
 * 'if' statements where the 'else' block is the same as the 'if' block.
 * Unused variables.
 * Unused parameters (check is skipped if function is marked "override")
+* Duplicate attributes
 
 #### Wishlish
 * Assigning to foreach variables that are not "ref".
diff --git a/analysis/duplicate_attribute.d b/analysis/duplicate_attribute.d
new file mode 100644
index 0000000..c2e7870
--- /dev/null
+++ b/analysis/duplicate_attribute.d
@@ -0,0 +1,127 @@
+// Copyright (c) 2014, Matthew Brennan Jones <matthew.brennan.jones@gmail.com>
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+module analysis.duplicate_attribute;
+
+import std.stdio;
+import std.string;
+import std.d.ast;
+import std.d.lexer;
+import analysis.base;
+import analysis.helpers;
+
+// FIXME: Make it work with @safe, @trusted, @system
+// FIXME: Make it work with pure, nothrow
+
+/**
+ * Checks for duplicate attributes such as @property
+ */
+class DuplicateAttributeCheck : BaseAnalyzer
+{
+	alias visit = BaseAnalyzer.visit;
+
+	this(string fileName)
+	{
+		super(fileName);
+	}
+
+	override void visit(const Declaration node)
+	{
+		checkAttributes(node);
+		node.accept(this);
+	}
+
+	void checkAttributes(const Declaration node)
+	{
+		bool hasProperty = false;
+
+		// Check the attributes
+		foreach (attribute; node.attributes)
+		{
+			// Just skip if missing child nodes
+			if (!attribute
+				|| !attribute.storageClass
+				|| !attribute.storageClass.atAttribute
+				|| attribute.storageClass.atAttribute.identifier is Token.init)
+				continue;
+
+			// Is a property
+			auto iden = attribute.storageClass.atAttribute.identifier;
+			checkProperty(iden, hasProperty);
+		}
+
+		// Just return if missing function nodes
+		if (!node.functionDeclaration
+			|| !node.functionDeclaration.memberFunctionAttributes)
+			return;
+
+		// Check the functions
+		foreach (memberFunctionAttribute; node.functionDeclaration.memberFunctionAttributes)
+		{
+			// Just skip if missing child nodes
+			if (!memberFunctionAttribute
+				|| !memberFunctionAttribute.atAttribute
+				|| memberFunctionAttribute.atAttribute.identifier is Token.init)
+				continue;
+
+			// Is a property
+			auto iden = memberFunctionAttribute.atAttribute.identifier;
+			checkProperty(iden, hasProperty);
+		}
+	}
+
+	void checkProperty(const Token iden, ref bool hasProperty)
+	{
+		// Just return if not a property
+		if (!isProperty(iden))
+			return;
+
+		// Already has a property
+		if (hasProperty)
+		{
+			string message = "The attribute '%s' is duplicated.".format(iden.text);
+			addErrorMessage(iden.line, iden.column, message);
+		}
+
+		// Mark it as a property
+		hasProperty = true;
+	}
+}
+
+bool isProperty(const Token token) pure
+{
+	return token.type == tok!"identifier" && token.text == "property";
+}
+
+unittest
+{
+	assertAnalyzerWarnings(q{
+		class CAllocator
+		{
+			@property bool xxx() // ok
+			{
+				return false;
+			}
+
+			@property @property bool aaa() // [warn]: The attribute 'property' is duplicated.
+			{
+				return false;
+			}
+
+			bool bbb() @property @property // [warn]: The attribute 'property' is duplicated.
+			{
+				return false;
+			}
+
+			@property bool ccc() @property // [warn]: The attribute 'property' is duplicated.
+			{
+				return false;
+			}
+		}
+	}c, analysis.run.AnalyzerCheck.duplicate_attribute);
+
+	stderr.writeln("Unittest for DuplicateAttributeCheck passed.");
+}
+
diff --git a/analysis/run.d b/analysis/run.d
index 8737cbc..88b1e55 100644
--- a/analysis/run.d
+++ b/analysis/run.d
@@ -22,6 +22,7 @@ import analysis.range;
 import analysis.ifelsesame;
 import analysis.constructors;
 import analysis.unused;
+import analysis.duplicate_attribute;
 
 enum AnalyzerCheck : int
 {
@@ -36,7 +37,8 @@ enum AnalyzerCheck : int
 	if_else_same_check = 0x100,
 	constructor_check = 0x200,
 	unused_variable_check = 0x400,
-	all = 0x7FF
+	duplicate_attribute = 0x800,
+	all = 0xFFF
 }
 
 void messageFunction(string fileName, size_t line, size_t column, string message,
@@ -104,6 +106,7 @@ string[] analyze(string fileName, ubyte[] code, AnalyzerCheck analyzers, bool st
 	if (analyzers & AnalyzerCheck.if_else_same_check) checks ~= new IfElseSameCheck(fileName);
 	if (analyzers & AnalyzerCheck.constructor_check) checks ~= new ConstructorCheck(fileName);
 	if (analyzers & AnalyzerCheck.unused_variable_check) checks ~= new UnusedVariableCheck(fileName);
+	if (analyzers & AnalyzerCheck.duplicate_attribute) checks ~= new DuplicateAttributeCheck(fileName);
 
 	foreach (check; checks)
 	{