Bug 576152 - Compilation error: "The target type of this expression mustI20210924-0200I20210923-1800

be a functional interface"

Reduced fix for bug 573933 only to case where targetType is instanceof
ParameterizedTypeBinding. The new test case from bug 576152 covers the
case where it can be ArrayBinding.

Change-Id: Iabb6d224b24890f8f9745a1055ad5393d5536f1c
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.core/+/185699
Tested-by: JDT Bot <jdt-bot@eclipse.org>
Reviewed-by: Jay Arthanareeswaran <jarthana@in.ibm.com>
Reviewed-by: Andrey Loskutov <loskutov@gmx.de>

2 files changed, 38 insertions, 1 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/LambdaExpressionsTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/LambdaExpressionsTest.java
index 190d7f27a0..bffc9f25c3 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/LambdaExpressionsTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/LambdaExpressionsTest.java
@@ -7276,6 +7276,42 @@ public void testBug562324b() {
 		},
 		"it runs");
 }
+public void testBug576152() {
+	runConformTest(
+			new String[] {
+					"Example.java",
+					"\n"
+					+ "import java.util.function.Supplier;\n"
+					+ "\n"
+					+ "public class Example {\n"
+					+ "    Example() {\n"
+					+ "        inspect(this::singleMethod);\n"
+					+ "        inspect(this::overloadedMethod);\n"
+					+ "    }\n"
+					+ "    void inspect(Inspector... inspectors) { }\n"
+					+ "    void singleMethod(byte[] input, int offset, int len) { }\n"
+					+ "    void overloadedMethod() { }\n"
+					+ "    void overloadedMethod(byte[] input, int offset, int len) { }\n"
+					+ "\n"
+					+ "    public static void main(String[] args) {\n"
+					+ "    	String s1 = hoge1(String::new);\n"
+					+ "    	String s2 = hoge2(String::new);	// Error. See the attached file.\n"
+					+ "    }\n"
+					+ "    static <T> T hoge1(Supplier<T> sup) {\n"
+					+ "    	return null;\n"
+					+ "    }\n"
+					+ "    static <T> T hoge2(Supplier<T>... sup) {\n"
+					+ "    	return null;\n"
+					+ "    }\n"
+					+ "}\n"
+					+ "\n"
+					+ "@FunctionalInterface\n"
+					+ "interface Inspector {\n"
+					+ "    void update(byte[] input, int offset, int len);\n"
+					+ "}"
+			}
+			);
+}
 public static Class testClass() {
 	return LambdaExpressionsTest.class;
 }
diff --git a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReferenceExpression.java b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReferenceExpression.java
index c33488f435..1dee15bbd9 100644
--- a/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReferenceExpression.java
+++ b/org.eclipse.jdt.core/compiler/org/eclipse/jdt/internal/compiler/ast/ReferenceExpression.java
@@ -1258,7 +1258,8 @@ public class ReferenceExpression extends FunctionalExpression implements IPolyEx
 		} else if (copy.resolvedType != null && copy.resolvedType.isValidBinding() && copy.binding != null && copy.binding.isValidBinding()) {
 			return true;
 		} else {
-			return !isPertinentToApplicability(targetType, null); // not mentioned in JLS (see prior art in LE.internalIsCompatibleWith()
+			boolean notPertinentToApplicability = targetType instanceof ParameterizedTypeBinding && !isPertinentToApplicability(targetType, null); // not mentioned in JLS (see prior art in LE.internalIsCompatibleWith()
+			return notPertinentToApplicability;
 		}
 	}