[Enhanced Switch] Bug 575652 - [17][codegen][switch pattern] Unnecessary

casts in switch * Fixes eclipse-jdt#3465
srikanth-sankaran · Dec 18, 2024 · 427208c · 427208c
1 parent 9d3138b
commit 427208c
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diff --git a/...clipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/TypePattern.java b/...clipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/TypePattern.java
@@ -90,8 +90,8 @@ public void generateCode(BlockScope currentScope, CodeStream codeStream, BranchL
 		} else {
 
 			if (!this.isTotalTypeNode) {
-				boolean checkCast = JavaFeature.PRIMITIVES_IN_PATTERNS.isSupported(currentScope.compilerOptions()) ?
-								!this.local.binding.type.isBaseType() : true;
+				boolean checkCast = TypeBinding.notEquals(this.outerExpressionType, this.local.binding.type) &&
+											(JavaFeature.PRIMITIVES_IN_PATTERNS.isSupported(currentScope.compilerOptions()) ? !this.local.binding.type.isBaseType() : true);
 				if (checkCast)
 					codeStream.checkcast(this.local.binding.type);
 			}

diff --git a/....tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java b/....tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java
@@ -9670,4 +9670,135 @@ public static void main(String[] args) {
 		String unexpectedOutput = "static synthetic int[] $SWITCH_TABLE$E();\n";
 		SwitchPatternTest.verifyClassFile(expectedOutput, unexpectedOutput, "X.class", ClassFileBytesDisassembler.SYSTEM);
 	}
+
+	// https://github.com/eclipse-jdt/eclipse.jdt.core/issues/3465
+	// [Enhanced Switch] Bug 575652 - [17][codegen][switch pattern] Unnecessary casts in switch
+	public void testIssue3465() throws Exception {
+		runConformTest(
+			new String[] {
+				"X.java",
+				"""
+				import static java.util.stream.IntStream.rangeClosed;
+
+				public interface X {
+				  static String fizzbuzz(int i) {
+				    return switch((Integer) i) {
+				      case Integer v when v % 15 == 0 -> "FizzBuzz";
+				      case Integer v when v % 5 == 0 -> "Buzz";
+				      case Integer v when v % 3 == 0 -> "Fizz";
+				      case Integer v -> "" + v;
+				    };
+				  }
+
+				  static void main(String[] args) {
+				    rangeClosed(1, 100).mapToObj(i -> fizzbuzz(i)).forEach(System.out::println);
+				  }
+				}
+				"""
+			},
+			"""
+			1
+			2
+			Fizz
+			4
+			Buzz
+			Fizz
+			7
+			8
+			Fizz
+			Buzz
+			11
+			Fizz
+			13
+			14
+			FizzBuzz
+			16
+			17
+			Fizz
+			19
+			Buzz
+			Fizz
+			22
+			23
+			Fizz
+			Buzz
+			26
+			Fizz
+			28
+			29
+			FizzBuzz
+			31
+			32
+			Fizz
+			34
+			Buzz
+			Fizz
+			37
+			38
+			Fizz
+			Buzz
+			41
+			Fizz
+			43
+			44
+			FizzBuzz
+			46
+			47
+			Fizz
+			49
+			Buzz
+			Fizz
+			52
+			53
+			Fizz
+			Buzz
+			56
+			Fizz
+			58
+			59
+			FizzBuzz
+			61
+			62
+			Fizz
+			64
+			Buzz
+			Fizz
+			67
+			68
+			Fizz
+			Buzz
+			71
+			Fizz
+			73
+			74
+			FizzBuzz
+			76
+			77
+			Fizz
+			79
+			Buzz
+			Fizz
+			82
+			83
+			Fizz
+			Buzz
+			86
+			Fizz
+			88
+			89
+			FizzBuzz
+			91
+			92
+			Fizz
+			94
+			Buzz
+			Fizz
+			97
+			98
+			Fizz
+			Buzz""");
+		String expectedOutput = "typeSwitch";
+		String unexpectedOutput = "checkcast";
+		SwitchPatternTest.verifyClassFile(expectedOutput, unexpectedOutput, "X.class", ClassFileBytesDisassembler.SYSTEM);
+	}
 }