Bug 548589 - [1.8][inference] Cannot infer type argument(s) for <R>

map(Function<? super T,? extends R>)

Change-Id: I4f583c8491f730858fcaa94d16494b78aa5cbb92

3 files changed, 36 insertions, 1 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 d2fd242153..1abf4f930e 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
@@ -9926,4 +9926,33 @@ public void testBug508834_comment0() {
 				"}\n"
 			});
 	}
+	public void testBug548589() {
+		runConformTest(
+			new String[] {
+				"InferenceCheck.java",
+				"import java.util.*;\n" + 
+				"import java.util.function.*;\n" + 
+				"\n" + 
+				"public class InferenceCheck {\n" + 
+				"\n" + 
+				"    public interface P<T> {\n" + 
+				"\n" + 
+				"        public boolean apply(T value);        \n" + 
+				"    }\n" + 
+				"\n" + 
+				"    public static <T> P<T> compilation_failed(P<T> predicate) {\n" + 
+				"        List<P<T>> list = Collections.emptyList();\n" + 
+				"        list.stream().map(InferenceCheck::compilation_failed);\n" + 
+				"        return null;\n" + 
+				"    }    \n" + 
+				"\n" + 
+				"    public static <T> P<T> compilation_ok(P<T> predicate) {\n" + 
+				"        List<P<T>> list = Collections.emptyList();\n" + 
+				"        Function<P<T>, P<T>> f = InferenceCheck::compilation_ok;\n" + 
+				"        list.stream().map(f);\n" + 
+				"        return null;\n" + 
+				"    }    \n" + 
+				"}\n"
+			});
+	}
 }
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ConstraintExpressionFormula.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ConstraintExpressionFormula.java
index c47c7249d8..ccf6562ba2 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ConstraintExpressionFormula.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/lookup/ConstraintExpressionFormula.java
@@ -318,6 +318,8 @@ class ConstraintExpressionFormula extends ConstraintFormula {
 				InferenceContext18 innerContext = null;
 				try {
 					innerContext = reference.getInferenceContext((ParameterizedMethodBinding) compileTimeDecl);
+					if (innerContext != null)
+						innerContext.pushBoundsTo(inferenceContext);
 					int innerInferenceKind = determineInferenceKind(compileTimeDecl, argumentTypes, innerContext);
 					inferInvocationApplicability(inferenceContext, original, argumentTypes, original.isConstructor()/*mimic a diamond?*/, innerInferenceKind);
 					if (!inferenceContext.computeB3(reference, r, original))
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 613512c4f1..ae20f29820 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
@@ -488,7 +488,11 @@ public class InferenceContext18 {
 	// ---  not per JLS: emulate how javac passes type bounds from inner to outer: ---
 	/** Not per JLS: push current bounds to outer inference if outer is ready for it. */
 	private void pushBoundsToOuter() {
-		InferenceContext18 outer = this.outerContext;
+		pushBoundsTo(this.outerContext);
+	}
+
+	/** Not per JLS: invent more bubbling up of inner bounds. */
+	public void pushBoundsTo(InferenceContext18 outer) {
 		if (outer != null && outer.stepCompleted >= APPLICABILITY_INFERRED) {
 			boolean deferred = outer.currentInvocation instanceof Invocation; // need to wait till after overload resolution?
 			BoundSet toPush = deferred ? this.currentBounds.copy() : this.currentBounds;