Attachment #161856 for bug #305590

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/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at

public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
	LocalVariableBinding local = this.expression.localVariableBinding();
	if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {
		flowContext.recordUsingNullReference(currentScope, local,
			this.expression, FlowContext.CAN_ONLY_NULL | FlowContext.IN_INSTANCEOF, flowInfo);
		flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo).
			unconditionalInits();
		FlowInfo initsWhenTrue = flowInfo.copy();
		initsWhenTrue.markAsComparedEqualToNonNull(local);
		flowContext.recordUsingNullReference(currentScope, local,
				this.expression, FlowContext.CAN_ONLY_NULL | FlowContext.IN_INSTANCEOF, flowInfo);
		// no impact upon enclosing try context
		return FlowInfo.conditional(initsWhenTrue, flowInfo.copy());
	}




		"    12  return\n";
	checkDisassembledClassFile(OUTPUT_DIR + File.separator + "X.class", "X", expectedOutput);
}

// https://bugs.eclipse.org/bugs/show_bug.cgi?id=305590
// To verify that a "instanceof always yields false" warning is not elicited in the
// case when the expression has been assigned a non null value in the instanceof check.
public void testBug305590() {
	runNegativeTest(
		new String[] {
			"X.java",
			"public class X {\n" +
			"  public void foo() {\n" +
			"	 Object str = null;\n" +
			"	 if ((str = \"str\") instanceof String) {}\n" + // shouldn't warn
			"	 str = null;\n" +
			"	 if ((str = \"str\") instanceof Number) {}\n" + // shouldn't warn
			"	 str = null;\n" +
			"	 if (str instanceof String) {}\n" + // should warn
			"  }\n" +
			"}"},
		"----------\n" +
		"1. ERROR in X.java (at line 8)\n" + 
		"	if (str instanceof String) {}\n" + 
		"	    ^^^\n" + 
		"instanceof always yields false: The variable str can only be null at this location\n" + 
		"----------\n",
	    JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
}
}

Return to bug 305590

Lines 11636-11639 Link Here

(-)src/org/eclipse/jdt/core/tests/compiler/regression/NullReferenceTest.java (+26 lines)
11636	" 12 return\n";	11636	" 12 return\n";
11637	checkDisassembledClassFile(OUTPUT_DIR + File.separator + "X.class", "X", expectedOutput);	11637	checkDisassembledClassFile(OUTPUT_DIR + File.separator + "X.class", "X", expectedOutput);
11638	}	11638	}
		11639
		11640	// https://bugs.eclipse.org/bugs/show_bug.cgi?id=305590
		11641	// To verify that a "instanceof always yields false" warning is not elicited in the
		11642	// case when the expression has been assigned a non null value in the instanceof check.
		11643	public void testBug305590() {
		11644	runNegativeTest(
		11645	new String[] {
		11646	"X.java",
		11647	"public class X {\n" +
		11648	" public void foo() {\n" +
		11649	" Object str = null;\n" +
		11650	" if ((str = \"str\") instanceof String) {}\n" + // shouldn't warn
		11651	" str = null;\n" +
		11652	" if ((str = \"str\") instanceof Number) {}\n" + // shouldn't warn
		11653	" str = null;\n" +
		11654	" if (str instanceof String) {}\n" + // should warn
		11655	" }\n" +
		11656	"}"},
		11657	"----------\n" +
		11658	"1. ERROR in X.java (at line 8)\n" +
		11659	" if (str instanceof String) {}\n" +
		11660	" ^^^\n" +
		11661	"instanceof always yields false: The variable str can only be null at this location\n" +
		11662	"----------\n",
		11663	JavacTestOptions.Excuse.EclipseWarningConfiguredAsError);
		11664	}
11639	}	11665	}

Lines 1-5 Link Here

(-)compiler/org/eclipse/jdt/internal/compiler/ast/InstanceOfExpression.java (-3 / +3 lines)
1	/*******************************************************************************	1	/*******************************************************************************
2	* Copyright (c) 2000, 2009 IBM Corporation and others.	2	* Copyright (c) 2000, 2010 IBM Corporation and others.
3	* All rights reserved. This program and the accompanying materials	3	* All rights reserved. This program and the accompanying materials
4	* are made available under the terms of the Eclipse Public License v1.0	4	* are made available under the terms of the Eclipse Public License v1.0
5	* which accompanies this distribution, and is available at	5	* which accompanies this distribution, and is available at
Lines 32-43 Link Here
32	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {	32	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
33	LocalVariableBinding local = this.expression.localVariableBinding();	33	LocalVariableBinding local = this.expression.localVariableBinding();
34	if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {	34	if (local != null && (local.type.tagBits & TagBits.IsBaseType) == 0) {
35	flowContext.recordUsingNullReference(currentScope, local,
36	this.expression, FlowContext.CAN_ONLY_NULL \| FlowContext.IN_INSTANCEOF, flowInfo);
37	flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo).	35	flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo).
38	unconditionalInits();	36	unconditionalInits();
39	FlowInfo initsWhenTrue = flowInfo.copy();	37	FlowInfo initsWhenTrue = flowInfo.copy();
40	initsWhenTrue.markAsComparedEqualToNonNull(local);	38	initsWhenTrue.markAsComparedEqualToNonNull(local);
		39	flowContext.recordUsingNullReference(currentScope, local,
		40	this.expression, FlowContext.CAN_ONLY_NULL \| FlowContext.IN_INSTANCEOF, flowInfo);
41	// no impact upon enclosing try context	41	// no impact upon enclosing try context
42	return FlowInfo.conditional(initsWhenTrue, flowInfo.copy());	42	return FlowInfo.conditional(initsWhenTrue, flowInfo.copy());
43	}	43	}