Bug 434602 - Possible error with inferred null annotations leading to

contradictory null annotations
- incl. fix of TVB.declaringElement if cloned during initialization

5 files changed, 110 insertions, 4 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullTypeAnnotationTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullTypeAnnotationTest.java
index 840a577fb4..7c31a77079 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullTypeAnnotationTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullTypeAnnotationTest.java
@@ -5667,6 +5667,91 @@ public void testTypeVariable15a() {
 		"Illegal redefinition of parameter arg, inherited method from ITest declares this parameter as \'List<T>\' (mismatching null constraints)\n" + 
 		"----------\n");
 }
+// https://bugs.eclipse.org/bugs/show_bug.cgi?id=434602
+// Possible error with inferred null annotations leading to contradictory null annotations
+public void testTypeVariable16() {
+	runNegativeTestWithLibs(
+			new String[] {
+				"X.java",
+				"import org.eclipse.jdt.annotation.NonNullByDefault;\n" +
+				"import org.eclipse.jdt.annotation.Nullable;\n" +
+				"\n" +
+				"class Y { void doit() {} }\n" +
+				"@NonNullByDefault\n" +
+				"class X {\n" +
+				"	void foo() {\n" +
+				"		X x = new X();\n" +
+				"		Y y = x.bar(); // Error: Contradictory null annotations before the fix\n" +
+				"		y.doit(); // check that @Nullable from bar's declaration has effect on 'y'\n" +
+				"	}\n" +
+				"\n" +
+				"	public <T extends Y> @Nullable T bar() {\n" +
+				"		return null;\n" +
+				"	}\n" +
+				"}\n"
+			},
+			getCompilerOptions(),
+			"----------\n" + 
+			"1. ERROR in X.java (at line 10)\n" + 
+			"	y.doit(); // check that @Nullable from bar's declaration has effect on 'y'\n" + 
+			"	^\n" + 
+			"Potential null pointer access: The variable y may be null at this location\n" + 
+			"----------\n");
+}
+// https://bugs.eclipse.org/bugs/show_bug.cgi?id=434602
+// Possible error with inferred null annotations leading to contradictory null annotations
+// Method part of parameterized class.
+public void testTypeVariable16a() {
+	runConformTestWithLibs(
+			new String[] {
+				"X.java",
+				"import org.eclipse.jdt.annotation.NonNullByDefault;\n" +
+				"import org.eclipse.jdt.annotation.Nullable;\n" +
+				"\n" +
+				"class Y {}\n" +
+				"@NonNullByDefault\n" +
+				"public class X <T> {\n" +
+				"	void foo() {\n" +
+				"		X<Y> x = new X<Y>();\n" +
+				"		x.bar(); // Error: Contradictory null annotations before the fix\n" +
+				"	}\n" +
+				"\n" +
+				"	public @Nullable T bar() {\n" +
+				"		return null;\n" +
+				"	}\n" +
+				"}\n"
+			},
+			getCompilerOptions(),
+			"");
+}
+public void testTypeVariable16b() {
+	runNegativeTestWithLibs(
+			new String[] {
+				"X.java",
+				"import org.eclipse.jdt.annotation.Nullable;\n" +
+				"import org.eclipse.jdt.annotation.NonNull;\n" +
+				"\n" +
+				"class Y {}\n" +
+				"class Y2 extends Y {}\n" +
+				"\n" +
+				"class X {\n" +
+				"	void foo() {\n" +
+				"		X x = new X();\n" +
+				"		x.bar(null); // null arg is illegal\n" +
+				"	}\n" +
+				"	public <T extends @NonNull Y> @Nullable T bar(T t) {\n" +
+				"		return null; // OK\n" +
+				"	}\n" +
+				"}\n"
+			},
+			getCompilerOptions(),
+			"----------\n" + 
+			"1. ERROR in X.java (at line 10)\n" + 
+			"	x.bar(null); // null arg is illegal\n" + 
+			"	      ^^^^\n" + 
+			"Null type mismatch: required \'@NonNull Y\' but the provided value is null\n" + 
+			"----------\n");
+}
 public void testBug434600() {
 	runConformTestWithLibs(
 		new String[] {
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java
index b6ed2c8c94..baf0271e07 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/BinaryTypeBinding.java
@@ -28,6 +28,7 @@
  *								Bug 390889 - [1.8][compiler] Evaluate options to support 1.7- projects against 1.8 JRE.
  *								Bug 438458 - [1.8][null] clean up handling of null type annotations wrt type variables
  *								Bug 439516 - [1.8][null] NonNullByDefault wrongly applied to implicit type bound of binary type
+ *								Bug 434602 - Possible error with inferred null annotations leading to contradictory null annotations
  *    Jesper Steen Moller - Contributions for
  *								Bug 412150 [1.8] [compiler] Enable reflected parameter names during annotation processing
  *								Bug 412153 - [1.8][compiler] Check validity of annotations which may be repeatable
@@ -767,9 +768,9 @@ private MethodBinding createMethod(IBinaryMethod method, long sourceLevel, char[
 	if (use15specifics)
 		result.tagBits |= method.getTagBits();
 	result.typeVariables = typeVars;
-	// fixup the declaring element of the type variable
+	// fixup the declaring element of all type variables
 	for (int i = 0, length = typeVars.length; i < length; i++)
-		typeVars[i].declaringElement = result;
+		this.environment.typeSystem.fixTypeVariableDeclaringElement(typeVars[i], result);
 
 	return result;
 }
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java
index 5fe450c9c5..8144e21b9f 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/LookupEnvironment.java
@@ -26,6 +26,7 @@
  *								Bug 424624 - [1.8][null] if a static-object with annotation @NonNull is used, a warning is shown
  *								Bug 438458 - [1.8][null] clean up handling of null type annotations wrt type variables
  *								Bug 439516 - [1.8][null] NonNullByDefault wrongly applied to implicit type bound of binary type
+ *								Bug 434602 - Possible error with inferred null annotations leading to contradictory null annotations
  *******************************************************************************/
 package org.eclipse.jdt.internal.compiler.lookup;
 
@@ -62,7 +63,7 @@ public class LookupEnvironment implements ProblemReasons, TypeConstants {
 	private int lastCompletedUnitIndex = -1;
 	private int lastUnitIndex = -1;
 
-	private TypeSystem typeSystem;
+	TypeSystem typeSystem;
 	
 	public INameEnvironment nameEnvironment;
 	public CompilerOptions globalOptions;
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.java
index fb5cbb3259..26019083de 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.java
@@ -19,6 +19,7 @@
  *								Bug 418743 - [1.8][null] contradictory annotations on invocation of generic method not reported
  *								Bug 416182 - [1.8][compiler][null] Contradictory null annotations not rejected
  *								Bug 429958 - [1.8][null] evaluate new DefaultLocation attribute of @NonNullByDefault
+ *								Bug 434602 - Possible error with inferred null annotations leading to contradictory null annotations
  *******************************************************************************/
 package org.eclipse.jdt.internal.compiler.lookup;
 
@@ -739,7 +740,7 @@ public class ParameterizedGenericMethodBinding extends ParameterizedMethodBindin
         // check this variable can be substituted given parameterized type
         if (originalVariable.rank < length && TypeBinding.equalsEquals(variables[originalVariable.rank], originalVariable)) {
         	TypeBinding substitute = this.typeArguments[originalVariable.rank];
-        	return originalVariable.hasTypeAnnotations() ? this.environment.createAnnotatedType(substitute, originalVariable.getTypeAnnotations()) : substitute;
+        	return originalVariable.combineTypeAnnotations(substitute);
         }
 	    return originalVariable;
 	}
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeSystem.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeSystem.java
index f2316883a1..de1b4c20ad 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeSystem.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/TypeSystem.java
@@ -7,6 +7,8 @@
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
+ *     Stephan Herrmann - Contribution for
+ *								Bug 434602 - Possible error with inferred null annotations leading to contradictory null annotations
  *******************************************************************************/
 package org.eclipse.jdt.internal.compiler.lookup;
 
@@ -376,4 +378,20 @@ public class TypeSystem {
 		}
 		return cacheDerivedType(keyType, new IntersectionCastTypeBinding(intersectingTypes, this.environment));
 	}
+	
+	/**
+	 * If a TVB was created with a dummy declaring element and needs to be fixed now,
+	 * make sure that this update affects all early clones, too.
+	 */
+	public void fixTypeVariableDeclaringElement(TypeVariableBinding var, Binding declaringElement) {
+		int id = var.id;
+		if (id < this.typeid && this.types[id] != null) {
+			for (TypeBinding t : this.types[id]) {
+				if (t instanceof TypeVariableBinding)
+					((TypeVariableBinding)t).declaringElement = declaringElement;
+			}
+		} else {
+			var.declaringElement = declaringElement;
+		}
+	}
 }
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