8277864: Compilation error thrown while doing a boxing conversion on selector expression

Reviewed-by: jlaskey, vromero

Author: lahodaj

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TransPatterns.java

@@ -347,8 +347,9 @@ private void handleSwitch(JCTree tree,
                 }
             }
             selector = translate(selector);
-            statements.append(make.at(tree.pos).VarDef(temp, !hasNullCase ? attr.makeNullCheck(selector)
-                                                                          : selector));
+            boolean needsNullCheck = !hasNullCase && !seltype.isPrimitive();
+            statements.append(make.at(tree.pos).VarDef(temp, needsNullCheck ? attr.makeNullCheck(selector)
+                                                                            : selector));
             VarSymbol index = new VarSymbol(Flags.SYNTHETIC,
                     names.fromString(tree.pos + target.syntheticNameChar() + "index"),
                     syms.intType,

test/langtools/tools/javac/patterns/Switches.java

@@ -28,7 +28,7 @@
 
 /*
  * @test
- * @bug 8262891 8268333 8268896 8269802 8269808 8270151 8269113
+ * @bug 8262891 8268333 8268896 8269802 8269808 8270151 8269113 8277864
  * @summary Check behavior of pattern switches.
  * @compile --enable-preview -source ${jdk.version} Switches.java
  * @run main/othervm --enable-preview Switches
@@ -85,6 +85,9 @@ void run() {
         assertEquals(2, switchOverNull1());
         assertEquals(2, switchOverNull2());
         assertEquals(2, switchOverNull3());
+        assertEquals(5, switchOverPrimitiveInt(0));
+        assertEquals(7, switchOverPrimitiveInt(1));
+        assertEquals(9, switchOverPrimitiveInt(2));
     }
 
     void run(Function<Object, Integer> mapper) {
@@ -591,6 +594,14 @@ private int  switchOverNull3() {
         };
     }
 
+    private int switchOverPrimitiveInt(Integer i) {
+        return switch (i) {
+            case 0 -> 5 + 0;
+            case Integer j && j == 1 -> 6 + j;
+            case Integer j -> 7 + j;
+        };
+    }
+
     //verify that for cases like:
     //case ConstantClassClash ->
     //ConstantClassClash is interpreted as a field, not as a class