Make PropertyMetadataImpl a data class

To allow property delegates to use property metadata as a key in the hash map,
and to improve debugging experience

compiler/testData/builtin-classes.txt

@@ -1076,10 +1076,12 @@ public interface PropertyMetadata {
         public abstract fun <get-name>(): kotlin.String
 }
 
-public final class PropertyMetadataImpl : kotlin.PropertyMetadata {
+kotlin.data() public final class PropertyMetadataImpl : kotlin.PropertyMetadata {
     /*primary*/ public constructor PropertyMetadataImpl(/*0*/ name: kotlin.String)
     public open override /*1*/ val name: kotlin.String
         public open override /*1*/ fun <get-name>(): kotlin.String
+    public final /*synthesized*/ fun component1(): kotlin.String
+    public final /*synthesized*/ fun copy(/*0*/ name: kotlin.String = ...): kotlin.PropertyMetadataImpl
 }
 
 public interface Range</*0*/ T : kotlin.Comparable<T>> {

compiler/testData/codegen/box/delegatedProperty/propertyMetadataEqualsHashCodeToString.kt

@@ -0,0 +1,36 @@
+import java.util.HashSet
+
+class A {
+    val foo: String by O
+    val Int.foo: String by O
+
+    fun foo42() = 42.foo
+}
+
+val foo: String by O
+val Int.foo: String by O
+
+object O {
+    val metadatas = HashSet<PropertyMetadata>()
+
+    fun get(t: Any?, p: PropertyMetadata): String {
+        metadatas.add(p)
+        return ""
+    }
+}
+
+fun box(): String {
+    A().foo
+    A().foo42()
+    foo
+    42.foo
+
+    if (O.metadatas.size() != 1)
+        return "Too many different PropertyMetadata instances: ${O.metadatas}"
+
+    val m = O.metadatas.iterator().next()
+    if (m.toString() != "PropertyMetadata(name=foo)")
+        return "Wrong toString(): $m"
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -2851,6 +2851,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("propertyMetadataEqualsHashCodeToString.kt")
+        public void testPropertyMetadataEqualsHashCodeToString() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/delegatedProperty/propertyMetadataEqualsHashCodeToString.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("propertyMetadataShouldBeCached.kt")
         public void testPropertyMetadataShouldBeCached() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/delegatedProperty/propertyMetadataShouldBeCached.kt");

core/builtins/src/kotlin/PropertyMetadata.kt

@@ -29,4 +29,6 @@ public interface PropertyMetadata {
 /**
  * @suppress
  */
-public class PropertyMetadataImpl(override val name: String): PropertyMetadata
+public data class PropertyMetadataImpl(override val name: String): PropertyMetadata {
+    override fun toString() = "PropertyMetadata(name=$name)"
+}