[Enhanced Switch][Null] Missing Null pointer access warning with total/unconditional patterns in case labels

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

@@ -373,9 +373,9 @@ protected boolean needToCheckFlowInAbsenceOfDefaultBranch() {
 	public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, FlowInfo flowInfo) {
 		try {
 			flowInfo = this.expression.analyseCode(currentScope, flowContext, flowInfo);
-			if (isNullHostile()) {
+			if (!this.containsNull && this.expression.resolvedType instanceof ReferenceBinding)
 				this.expression.checkNPE(currentScope, flowContext, flowInfo, 1);
-			}
+
 			SwitchFlowContext switchContext =
 				new SwitchFlowContext(flowContext, this, (this.breakLabel = new BranchLabel()), true, true);
 
@@ -461,16 +461,6 @@ else if ((statement.bits & ASTNode.DocumentedFallthrough) == 0) // the case is n
 			if (this.scope != null) this.scope.enclosingCase = null; // no longer inside switch case block
 		}
 	}
-	private boolean isNullHostile() {
-		if (this.containsNull)
-			return false;
-		if ((this.expression.implicitConversion & TypeIds.UNBOXING) != 0)
-			return true;
-		if (this.expression.resolvedType != null && (this.expression.resolvedType.id == T_JavaLangString || this.expression.resolvedType.isEnum()))
-			return true;
-		return this.totalPattern == null;
-	}
-
 	/**
 	 * Switch on String code generation
 	 * This assumes that hashCode() specification for java.lang.String is API

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

@@ -69,18 +69,7 @@ public FlowInfo analyseCode(BlockScope currentScope, FlowContext flowContext, Fl
 			return patternInfo; // exclude anonymous blokes from flow analysis.
 
 		patternInfo.markAsDefinitelyAssigned(this.local.binding);
-		if (!this.isTotalTypeNode) {
-			// non-total type patterns create a nonnull local:
-			patternInfo.markAsDefinitelyNonNull(this.local.binding);
-		} else {
-			// total type patterns inherit the nullness of the value being switched over, unless ...
-			if (flowContext.associatedNode instanceof SwitchStatement swStmt) {
-				int nullStatus = swStmt.containsNull
-						? FlowInfo.NON_NULL // ... null is handled in a separate case
-						: swStmt.expression.nullStatus(patternInfo, flowContext);
-				patternInfo.markNullStatus(this.local.binding, nullStatus);
-			}
-		}
+		patternInfo.markAsDefinitelyNonNull(this.local.binding);
 		return patternInfo;
 	}
 

org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/NullAnnotationTests21.java

@@ -107,29 +107,23 @@ public void test_totalTypePatternDoesNotAdmitNull() {
 				  "				case Number n0 -> consumeNumber(n0);\n" +
 				  "			}\n" +
 				  "		} catch (NullPointerException npe) {\n" +
-				  "			// ignoring the unchecked warning, and expecting the NPE:\n" +
+				  "			// Expecting an NPE because selector is null\n" +
 				  "			System.out.print(npe.getMessage());\n" +
 				  "		}\n" +
 				  "	}\n" +
 				  "	void consumeInt(@NonNull Integer i) {\n" +
 				  "		System.out.print(i);\n" +
 				  "	}\n" +
 				  "	void consumeNumber(@NonNull Number n) {\n" +
+				  "     System.out.println(\"consumeNumber \");\n" +
 				  "		System.out.print(n.toString());\n" +
 				  "	}\n" +
 				  "	public static void main(String... args) {\n" +
 				  "		new X().foo(null);\n" +
 				  "	}\n" +
 				  "}\n"
 			};
-		runner.expectedCompilerLog =
-				"----------\n" +
-				"1. WARNING in X.java (at line 7)\n" +
-				"	case Number n0 -> consumeNumber(n0);\n" +
-				"	                                ^^\n" +
-				"Null type safety (type annotations): The expression of type \'Number\' needs unchecked conversion to conform to \'@NonNull Number\'\n" +
-				"----------\n";
-//		runner.expectedOutputString = "Cannot invoke \"Object.toString()\" because \"n\" is null";
+		runner.expectedCompilerLog = "";
 		runner.expectedOutputString = "null";
 		runner.runConformTest();
 	}
@@ -234,10 +228,10 @@ public void test_totalTypePatternNullableExpression() {
 			};
 		runner.expectedCompilerLog =
 				"----------\n" +
-				"1. ERROR in X.java (at line 6)\n" +
-				"	case Number n0 -> consumeNumber(n0);\n" +
-				"	                                ^^\n" +
-				"Null type mismatch: required \'@NonNull Number\' but the provided value is inferred as @Nullable\n" +
+				"1. ERROR in X.java (at line 4)\n" +
+				"	switch (n) {\n" +
+				"	        ^\n" +
+				"Potential null pointer access: this expression has a '@Nullable' type\n" +
 				"----------\n";
 		runner.runNegativeTest();
 	}
@@ -1244,4 +1238,46 @@ static Stuff match(PatternMatching pm, int v) {
 				""";
 		runner.runNegativeTest();
 	}
+
+	// https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3381
+	// [Enhanced Switch][Null] Missing Null pointer access warning with total/unconditional patterns
+	public void testIssue3381() {
+		Runner runner = getDefaultRunner();
+		runner.testFiles = new String[] {
+			"X.java",
+			"""
+			import org.eclipse.jdt.annotation.Nullable;
+
+			public class X {
+				void foo() {
+					@Nullable Integer i = null;
+					switch (i) {
+						case Integer ii -> System.out.println();
+					}
+				}
+				void goo() {
+					@Nullable Integer i = null;
+					switch (i) {
+						default -> System.out.println();
+					}
+				}
+			}
+			"""
+		};
+		runner.expectedCompilerLog =
+				"""
+				----------
+				1. ERROR in X.java (at line 6)
+					switch (i) {
+					        ^
+				Null pointer access: The variable i can only be null at this location
+				----------
+				2. ERROR in X.java (at line 12)
+					switch (i) {
+					        ^
+				Null pointer access: This expression of type Integer is null but requires auto-unboxing
+				----------
+				""";
+		runner.runNegativeTest();
+	}
 }