Metadata: 'non-stable parameter names' flag for callables

^KT-34602

libraries/kotlinx-metadata/jvm/test/kotlinx/metadata/test/MetadataSmokeTest.kt

@@ -9,7 +9,7 @@ import kotlinx.metadata.*
 import kotlinx.metadata.jvm.*
 import org.jetbrains.org.objectweb.asm.ClassWriter
 import org.jetbrains.org.objectweb.asm.Opcodes
-import org.junit.Assert.assertEquals
+import org.junit.Assert.*
 import org.junit.Test
 import java.net.URLClassLoader
 import kotlin.coroutines.CoroutineContext
@@ -169,4 +169,38 @@ class MetadataSmokeTest {
         ) as KotlinClassMetadata.SyntheticClass
         metadata.accept(KmLambda())
     }
+
+    @Test
+    fun unstableParameterNames() {
+        @Suppress("unused")
+        class Test(a: String, b: Int, c: Boolean) {
+            fun foo(a: String, b: Int, c: Boolean) = Unit
+        }
+
+        val classWithStableParameterNames =
+            (KotlinClassMetadata.read(Test::class.java.readMetadata()) as KotlinClassMetadata.Class).toKmClass()
+
+        classWithStableParameterNames.constructors.forEach { assertFalse(Flag.Constructor.HAS_NON_STABLE_PARAMETER_NAMES(it.flags)) }
+        classWithStableParameterNames.functions.forEach { assertFalse(Flag.Function.HAS_NON_STABLE_PARAMETER_NAMES(it.flags)) }
+
+        val newMetadata = KotlinClassMetadata.Class.Writer().let { writer ->
+            KmClass().apply {
+                classWithStableParameterNames.accept(
+                    object : KmClassVisitor(this) {
+                        override fun visitConstructor(flags: Flags) =
+                            super.visitConstructor(flags + flagsOf(Flag.Constructor.HAS_NON_STABLE_PARAMETER_NAMES))
+
+                        override fun visitFunction(flags: Flags, name: String) =
+                            super.visitFunction(flags + flagsOf(Flag.Function.HAS_NON_STABLE_PARAMETER_NAMES), name)
+                    }
+                )
+            }.accept(writer)
+            writer.write()
+        }
+
+        val classWithUnstableParameterNames = newMetadata.toKmClass()
+
+        classWithUnstableParameterNames.constructors.forEach { assertTrue(Flag.Constructor.HAS_NON_STABLE_PARAMETER_NAMES(it.flags)) }
+        classWithUnstableParameterNames.functions.forEach { assertTrue(Flag.Function.HAS_NON_STABLE_PARAMETER_NAMES(it.flags)) }
+    }
 }

libraries/kotlinx-metadata/src/kotlinx/metadata/Flag.kt

@@ -224,6 +224,12 @@ class Flag(private val offset: Int, private val bitWidth: Int, private val value
          */
         @JvmField
         val IS_PRIMARY = Flag(F.IS_SECONDARY, 0)
+
+        /**
+         * Signifies that the corresponding constructor has non-stable parameter names, i.e. cannot be called with named arguments.
+         */
+        @JvmField
+        val HAS_NON_STABLE_PARAMETER_NAMES = Flag(F.IS_CONSTRUCTOR_WITH_NON_STABLE_PARAMETER_NAMES)
     }
 
     /**
@@ -302,6 +308,12 @@ class Flag(private val offset: Int, private val bitWidth: Int, private val value
          */
         @JvmField
         val IS_EXPECT = Flag(F.IS_EXPECT_FUNCTION)
+
+        /**
+         * Signifies that the corresponding function has non-stable parameter names, i.e. cannot be called with named arguments.
+         */
+        @JvmField
+        val HAS_NON_STABLE_PARAMETER_NAMES = Flag(F.IS_FUNCTION_WITH_NON_STABLE_PARAMETER_NAMES)
     }
 
     /**

libraries/tools/kotlinp/src/org/jetbrains/kotlin/kotlinp/printers.kt

@@ -958,7 +958,8 @@ private val CLASS_FLAGS_MAP = COMMON_FLAGS_MAP + mapOf(
 )
 
 private val CONSTRUCTOR_FLAGS_MAP = VISIBILITY_FLAGS_MAP + mapOf(
-    Flag.Constructor.IS_PRIMARY to "/* primary */"
+    Flag.Constructor.IS_PRIMARY to "/* primary */",
+    Flag.Constructor.HAS_NON_STABLE_PARAMETER_NAMES to "/* non-stable parameter names */"
 )
 
 private val FUNCTION_FLAGS_MAP = COMMON_FLAGS_MAP + mapOf(
@@ -973,7 +974,9 @@ private val FUNCTION_FLAGS_MAP = COMMON_FLAGS_MAP + mapOf(
     Flag.Function.IS_TAILREC to "tailrec",
     Flag.Function.IS_EXTERNAL to "external",
     Flag.Function.IS_SUSPEND to "suspend",
-    Flag.Function.IS_EXPECT to "expect"
+    Flag.Function.IS_EXPECT to "expect",
+
+    Flag.Function.HAS_NON_STABLE_PARAMETER_NAMES to "/* non-stable parameter names */"
 )
 
 private val PROPERTY_FLAGS_MAP = COMMON_FLAGS_MAP + mapOf(