Fix for issue eclipse-jdt#3535 on unboxing and widening primitive conversion with (eclipse-jdt#3744)

exact conversion check - case UNBOXING_AND_WIDENING_PRIMITIVE_CONVERSION

Author: mpalat

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/IGenerateTypeCheck.java

@@ -14,6 +14,7 @@
 package org.eclipse.jdt.internal.compiler.ast;
 
 import org.eclipse.jdt.internal.compiler.ast.Pattern.PrimitiveConversionRoute;
+import org.eclipse.jdt.internal.compiler.codegen.BranchLabel;
 import org.eclipse.jdt.internal.compiler.codegen.CodeStream;
 import org.eclipse.jdt.internal.compiler.lookup.BaseTypeBinding;
 import org.eclipse.jdt.internal.compiler.lookup.BlockScope;
@@ -52,11 +53,38 @@ default void generateTypeCheck(TypeBinding providedType, TypeReference expectedT
 				TypeBinding boxType = scope.environment().computeBoxingType(expectedTypeRef.resolvedType);
 				codeStream.instance_of(expectedTypeRef, boxType);
 			}
-			case UNBOXING_CONVERSION,
-			UNBOXING_AND_WIDENING_PRIMITIVE_CONVERSION -> {
+			case UNBOXING_CONVERSION -> {
 				codeStream.instance_of(scope.getJavaLangObject());
 				setPatternIsTotalType();
 			}
+			case UNBOXING_AND_WIDENING_PRIMITIVE_CONVERSION -> {
+				codeStream.dup();
+				codeStream.instance_of(providedType);
+				BranchLabel iLabel = new BranchLabel(codeStream);
+				BranchLabel postCheck = new BranchLabel(codeStream);
+
+				codeStream.ifne(iLabel);
+				codeStream.pop();
+				codeStream.iconst_0();
+				codeStream.goto_(postCheck);
+
+				iLabel.place();
+				codeStream.checkcast(providedType);
+				TypeBinding unboxedType = scope.environment().computeBoxingType(providedType);
+				codeStream.generateUnboxingConversion(unboxedType.id);
+				int expectedTypeId = expectedTypeRef.resolvedType.id;
+				int unboxedProvidedTypeId = unboxedType.id;
+				if (BaseTypeBinding.isExactWidening(expectedTypeId, unboxedProvidedTypeId)) {
+					codeStream.pop();
+					codeStream.iconst_1();
+				} else {
+					codeStream.invokeExactConversionsSupport(BaseTypeBinding.getRightToLeft(expectedTypeId, unboxedProvidedTypeId));
+				}
+
+				codeStream.goto_(postCheck);
+				postCheck.place();
+				setPatternIsTotalType();
+			}
 			case NO_CONVERSION_ROUTE -> {
 				codeStream.instance_of(expectedTypeRef, expectedTypeRef.resolvedType);
 				break;

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

@@ -7416,7 +7416,7 @@ public T get() {
 			"1");
 	}
 
-	public void testIssue3535() {
+	public void testIssue3535_001() {
 		runConformTest(new String[] {
 			"X.java",
 			"""
@@ -7449,6 +7449,39 @@ void put( T t) {
 			},
 			"3");
 	}
+	public void testIssue3535_002() {
+		runConformTest(new String[] {
+			"X.java",
+			"""
+				public class X {
+
+					static Integer getInteger() {
+						return Integer.MAX_VALUE;
+					}
+					public int foo() {
+						Integer i = 10;
+						Y<Integer> f = new Y<>();
+						f.put(X.getInteger()); // This makes all the difference
+						return f.get() instanceof float ? 3 : 2;
+					}
+					public static void main(String[] args) {
+						System.out.println(new X().foo());
+					}
+
+				}
+				class Y <T> {
+				    T t;
+				    T get() {
+				        return t;
+				    }
+				    void put( T t) {
+				    	this.t = t;
+				    }
+				}
+				"""
+			},
+			"2");
+	}
 	public void testIssue3536() {
 		runConformTest(new String[] {
 			"X.java",