Type Inference issue in spring-boot project

Author: snjeza

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/BoundSet.java

@@ -722,6 +722,7 @@ protected TypeBinding getP(int i) {
 		if (InferenceContext18.DEBUG) {
 			if (!capturesToRemove.isEmpty()) {
 				for (ParameterizedTypeBinding toRemove : capturesToRemove) {
+					if (this.captures.get(toRemove) != null)
 					System.out.println("Removing capture bound " + //$NON-NLS-1$
 							String.valueOf(toRemove.shortReadableName()) +
 							"=capture("+String.valueOf(this.captures.get(toRemove).shortReadableName())+")"); //$NON-NLS-1$ //$NON-NLS-2$

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.java

@@ -462,7 +462,7 @@ public BoundSet inferInvocationType(TypeBinding expectedType, InvocationSite inv
 							return null;
 				// * reduce and incorporate
 					if (!this.currentBounds.reduceOneConstraint(this, constraint))
-						return null;
+						continue;
 				}
 				for (ConstraintFormula constraint : bottomSet) {
 					// https://bugs.openjdk.org/browse/JDK-8052325

org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/GenericsRegressionTest_1_8.java

@@ -2024,28 +2024,17 @@ public void testBug427479b() {
 			"	}\n" +
 			"}\n"
 		},
-		"----------\n" +
-		"1. ERROR in Bug419048.java (at line 9)\n" +
-		"	roster\n" +
-		"                    .stream()\n" +
-		"                    .collect(\n" +
-		"                        Collectors.toMap(\n" +
-		"                            p -> p.getLast(),\n" +
-		"                            p -> p.getLast()\n" +
-		"                        ));\n" +
-		"	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n" +
-		"Type mismatch: cannot convert from Map<Object,Object> to Map<String,Object>\n" +
-		"----------\n" +
-		"2. ERROR in Bug419048.java (at line 13)\n" +
-		"	p -> p.getLast(),\n" +
-		"	       ^^^^^^^\n" +
-		"The method getLast() is undefined for the type Object\n" +
-		"----------\n" +
-		"3. ERROR in Bug419048.java (at line 14)\n" +
-		"	p -> p.getLast()\n" +
-		"	       ^^^^^^^\n" +
-		"The method getLast() is undefined for the type Object\n" +
-		"----------\n");
+		"----------\n"
+		+ "1. ERROR in Bug419048.java (at line 13)\n"
+		+ "	p -> p.getLast(),\n"
+		+ "	       ^^^^^^^\n"
+		+ "The method getLast() is undefined for the type Object\n"
+		+ "----------\n"
+		+ "2. ERROR in Bug419048.java (at line 14)\n"
+		+ "	p -> p.getLast()\n"
+		+ "	       ^^^^^^^\n"
+		+ "The method getLast() is undefined for the type Object\n"
+		+ "----------\n");
 }
 public void testBug427626() {
 	runNegativeTest(
@@ -10964,4 +10953,56 @@ <X, Y extends One<X>> void foo2(Y y1) {
 			"The method bar(One<Inner<?>>) in the type Bug is not applicable for the arguments (One<Inner<X>>)\n" +
 			"----------\n");
 	}
+	public void testSpringBoot() {
+		if (this.complianceLevel < ClassFileConstants.JDK9) {
+			return;
+		}
+		runConformTest(
+			new String[] {
+				"Pairs.java",
+				"""
+				import java.util.Map;
+				import java.util.function.Function;
+
+				public class Pairs<T> {
+
+					public <V> void addMapEntries(Function<T, Map<String, V>> extractor) {
+						add(extractor.andThen(Map::entrySet), Map.Entry::getKey, Map.Entry::getValue);
+					}
+
+					public <E> void add(Function<T, Iterable<E>> elementsExtractor, PairExtractor<E> pairExtractor) {
+						add(elementsExtractor, pairExtractor::getName, pairExtractor::getValue);
+					}
+
+					public <E, V> void add(Function<T, Iterable<E>> elementsExtractor, Function<E, String> nameExtractor,
+							Function<E, V> valueExtractor) {
+					}
+
+					interface PairExtractor<E> {
+						<N> N getName(E element);
+						<V> V getValue(E element);
+						static <T> PairExtractor<T> of(Function<T, ?> nameExtractor, Function<T, ?> valueExtractor) {
+							return new PairExtractor<>() {
+
+								@Override
+								@SuppressWarnings("unchecked")
+								public <N> N getName(T instance) {
+									return (N) nameExtractor.apply(instance);
+								}
+
+								@Override
+								@SuppressWarnings("unchecked")
+								public <V> V getValue(T instance) {
+									return (V) valueExtractor.apply(instance);
+								}
+
+							};
+						}
+					}
+
+				}
+				"""
+		});
+	}
+
 }

org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullTypeAnnotationTest.java

@@ -7175,12 +7175,17 @@ public void test443467() throws Exception {
 			"}\n" +
 			"}\n",
 		},
-		"----------\n" +
-		"1. ERROR in BuildIdeMain.java (at line 9)\n" +
-		"	filter2.map(p -> new SimpleEntry<>(updateToFile.get(p), p->ideFiles.get(p)));\n" +
-		"	                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n" +
-		"Cannot infer type arguments for SimpleEntry<>\n" +
-		"----------\n",
+		"----------\n"
+		+ "1. ERROR in BuildIdeMain.java (at line 9)\n"
+		+ "	filter2.map(p -> new SimpleEntry<>(updateToFile.get(p), p->ideFiles.get(p)));\n"
+		+ "	                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n"
+		+ "The constructor AbstractMap.SimpleEntry<Path,Object>(Path, (<no type> p) -> {}) is undefined\n"
+		+ "----------\n"
+		+ "2. ERROR in BuildIdeMain.java (at line 9)\n"
+		+ "	filter2.map(p -> new SimpleEntry<>(updateToFile.get(p), p->ideFiles.get(p)));\n"
+		+ "	                                                        ^^^^^^^^^^^^^^^^^^\n"
+		+ "The target type of this expression must be a functional interface\n"
+		+ "----------\n",
 		this.LIBS,
 		true/*flush*/);
 }