Bug 426652 - [1.8][inference] inference loops infinitely on

unconstrained inference variable

3 files changed, 32 insertions, 4 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/GenericsRegressionTest_1_8.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/GenericsRegressionTest_1_8.java
index a67a2fb134..c78a09c6e3 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/GenericsRegressionTest_1_8.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/GenericsRegressionTest_1_8.java
@@ -19,7 +19,7 @@ import junit.framework.Test;
 public class GenericsRegressionTest_1_8 extends AbstractRegressionTest {
 
 static {
-//	TESTS_NAMES = new String[] { "testBug424415c" };
+//	TESTS_NAMES = new String[] { "testBug426540" };
 //	TESTS_NUMBERS = new int[] { 40, 41, 43, 45, 63, 64 };
 //	TESTS_RANGE = new int[] { 11, -1 };
 }
@@ -1317,4 +1317,27 @@ public void testBug426048() {
 		"Syntax error on token \"(\", , expected\n" + 
 		"----------\n");
 }
+public void _testBug426540() {
+	runConformTest(
+		new String[] {
+			"X.java",
+			"import java.util.stream.Stream;\n" + 
+			"import java.util.Collections;\n" + 
+			"import static java.util.stream.Collectors.collectingAndThen;\n" + 
+			"import static java.util.stream.Collectors.toList;\n" + 
+			"public class X {\n" + 
+			"	Object o = ((Stream<Integer>) null).collect(collectingAndThen(toList(), Collections::unmodifiableList));\n" + 
+			"}\n"
+		});
+}
+public void testBug426652() {
+	runConformTest(
+		new String[] {
+			"X.java",
+			"import static java.util.stream.Collectors.toList;\n" + 
+			"public class X {\n" + 
+			"	Object o = toList();\n" + 
+			"}\n"
+		});
+}
 }
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/CaptureBinding18.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/CaptureBinding18.java
index 076c774ce5..0861bf8cab 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/CaptureBinding18.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/CaptureBinding18.java
@@ -65,6 +65,10 @@ public class CaptureBinding18 extends CaptureBinding {
 		return true;
 	}
 
+	public void initializeBounds(Scope scope, ParameterizedTypeBinding capturedParameterizedType) {
+		// nothing to initialize here (and cannot use super methods which requires wildcard to be set).
+	}
+
 	public TypeBinding clone(TypeBinding enclosingType) {
 		return new CaptureBinding18(this.sourceType, this.sourceName, this.originalName, this.captureID, this.environment);
 	}
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.java
index 16731ca4a8..60d07807a7 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.java
@@ -478,7 +478,8 @@ public class InferenceContext18 {
 		boolean haveProperTargetType = targetType != null && targetType.isProperType(true);
 		if (haveProperTargetType) {
 			MethodBinding original = method.originalMethod;
-			BoundSet result = (BoundSet) this.solutionsPerTargetType.get(targetType);
+			Solution solution = (Solution) this.solutionsPerTargetType.get(targetType);
+			BoundSet result = solution != null ? solution.bounds : null;
 			if (result == null) {
 				// start over from a previous candidate but discard its type variable instantiations
 				// TODO: should we retain any instantiations of type variables not owned by the method? 
@@ -667,8 +668,8 @@ public class InferenceContext18 {
 									tmpBoundSet.addBound(new TypeBound(variable, runtimeException, ReductionResult.SAME));
 								} else {
 									// try upper bounds:
+									TypeBinding glb = this.object;
 									if (upperBounds != Binding.NO_TYPES) {
-										TypeBinding glb;
 										if (upperBounds.length == 1) {
 											glb = upperBounds[0];
 										} else {
@@ -680,8 +681,8 @@ public class InferenceContext18 {
 											else
 												glb = new IntersectionCastTypeBinding(glbs, this.environment);
 										}
-										tmpBoundSet.addBound(new TypeBound(variable, glb, ReductionResult.SAME));
 									}
+									tmpBoundSet.addBound(new TypeBound(variable, glb, ReductionResult.SAME));
 								}
 							}
 						}