From b2392975412e9b069a11843c02b3c0a3e5b6a12f Mon Sep 17 00:00:00 2001
From: Alena Laskavaia <elaskavaia.cdt@gmail.com>
Date: Sat, 20 Mar 2010 14:19:43 +0000
Subject: [PATCH] [306563 ] - fixed false positives

---
 .../org.eclipse.cdt.codan.checkers/plugin.xml |  5 ++-
 .../checkers/StatementHasNoEffectChecker.java | 21 +++++++--
 .../StatementHasNoEffectCheckerTest.java      | 43 +++++++++++++++++--
 3 files changed, 60 insertions(+), 9 deletions(-)

diff --git a/codan/org.eclipse.cdt.codan.checkers/plugin.xml b/codan/org.eclipse.cdt.codan.checkers/plugin.xml
index f2a7a7f1129..e1fb9cd63c0 100644
--- a/codan/org.eclipse.cdt.codan.checkers/plugin.xml
+++ b/codan/org.eclipse.cdt.codan.checkers/plugin.xml
@@ -25,8 +25,9 @@
             category="org.eclipse.cdt.codan.core.categories.ProgrammingProblems"
             defaultSeverity="Warning"
             id="org.eclipse.cdt.codan.internal.checkers.StatementHasNoEffectProblem"
-            name="Statement has no effect">
-      </problem>
+            name="Statement has no effect"
+            messagePattern="Statement has no effect"
+            />
       </checker>
       
       <checker
diff --git a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/StatementHasNoEffectChecker.java b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/StatementHasNoEffectChecker.java
index d380204e1ca..5e929689a2d 100644
--- a/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/StatementHasNoEffectChecker.java
+++ b/codan/org.eclipse.cdt.codan.checkers/src/org/eclipse/cdt/codan/internal/checkers/StatementHasNoEffectChecker.java
@@ -36,10 +36,9 @@ import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPASTBinaryExpression;
  * 
  */
 public class StatementHasNoEffectChecker extends AbstractIndexAstChecker {
-	private static final String ER_ID = "org.eclipse.cdt.codan.internal.checkers.StatementHasNoEffectProblem";
+	private static final String ER_ID = "org.eclipse.cdt.codan.internal.checkers.StatementHasNoEffectProblem"; //$NON-NLS-1$
 
 	public void processAst(IASTTranslationUnit ast) {
-		// traverse the ast using the visitor pattern.
 		ast.accept(new CheckStmpVisitor());
 	}
 
@@ -52,7 +51,7 @@ public class StatementHasNoEffectChecker extends AbstractIndexAstChecker {
 			if (stmt instanceof IASTExpressionStatement) {
 				if (hasNoEffect(((IASTExpressionStatement) stmt)
 						.getExpression())) {
-					reportProblem(ER_ID, stmt, "Statement has no effect");
+					reportProblem(ER_ID, stmt);
 				}
 				return PROCESS_SKIP;
 			}
@@ -70,8 +69,20 @@ public class StatementHasNoEffectChecker extends AbstractIndexAstChecker {
 		private boolean hasNoEffect(IASTExpression e) {
 			if (e instanceof IASTBinaryExpression) {
 				IASTBinaryExpression binExpr = (IASTBinaryExpression) e;
-				if (binExpr.getOperator() == IASTBinaryExpression.op_assign)
+				switch (binExpr.getOperator()) {
+				case IASTBinaryExpression.op_assign:
+				case IASTBinaryExpression.op_binaryAndAssign:
+				case IASTBinaryExpression.op_binaryOrAssign:
+				case IASTBinaryExpression.op_binaryXorAssign:
+				case IASTBinaryExpression.op_divideAssign:
+				case IASTBinaryExpression.op_plusAssign:
+				case IASTBinaryExpression.op_minusAssign:
+				case IASTBinaryExpression.op_multiplyAssign:
+				case IASTBinaryExpression.op_moduloAssign:
+				case IASTBinaryExpression.op_shiftLeftAssign:
+				case IASTBinaryExpression.op_shiftRightAssign:
 					return false;
+				}
 				if (binExpr instanceof CPPASTBinaryExpression) {
 					// unfortunately ICPPASTBinaryExpression does not have
 					// getOverload public method
@@ -97,6 +108,8 @@ public class StatementHasNoEffectChecker extends AbstractIndexAstChecker {
 				case IASTUnaryExpression.op_postFixIncr:
 				case IASTUnaryExpression.op_prefixIncr:
 					return false;
+				case IASTUnaryExpression.op_bracketedPrimary:
+					return hasNoEffect(unaryExpr.getOperand());
 				}
 				return true;
 			}
diff --git a/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/checkers/sample/StatementHasNoEffectCheckerTest.java b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/checkers/sample/StatementHasNoEffectCheckerTest.java
index 93e32702a88..48b87b94157 100644
--- a/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/checkers/sample/StatementHasNoEffectCheckerTest.java
+++ b/codan/org.eclipse.cdt.codan.core.test/src/org/eclipse/cdt/codan/core/checkers/sample/StatementHasNoEffectCheckerTest.java
@@ -25,7 +25,7 @@ public class StatementHasNoEffectCheckerTest extends CheckerTestCase {
 	 }
 	 </code>
 	 */
-	public void test1() {
+	public void testUnaryExpression() {
 		load("test1.c");
 		runOnFile();
 		checkErrorLine(3);
@@ -40,7 +40,7 @@ public class StatementHasNoEffectCheckerTest extends CheckerTestCase {
 	 }
 	 </code>
 	 */
-	public void test2() {
+	public void testBinaryExpression() {
 		load("test2.c");
 		runOnFile();
 		checkErrorLine(4);
@@ -55,9 +55,46 @@ public class StatementHasNoEffectCheckerTest extends CheckerTestCase {
 	 }
 	 </code>
 	 */
-	public void test3() {
+	public void testNormalAssignment() {
 		load("test3.c");
 		runOnFile();
 		checkNoErrors();
 	}
+	/*-
+	 <code file="test4.c">
+	 main() {
+	   int a,b;
+	   
+	   (a=b); // no errors here
+	   a+=b;
+	   a<<=b;
+	   a-=b;
+	   a++;
+	   b--;
+	   --a;
+	   ++b;
+	   a%=2;
+	   a>>=2;
+	 }
+	 </code>
+	 */
+	public void testFalsePositives() {
+		load("test4.c");
+		runOnFile();
+		checkNoErrors();
+	}
+	
+	/*-
+	 <code file="test5.c">
+	 main() {
+	   int a;
+	   a; // error here on line 3
+	 }
+	 </code>
+	 */
+	public void testIdExpression() {
+		load("test5.c");
+		runOnFile();
+		checkErrorLine(3);
+	}
 }