diff --git a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassHeader.kt b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassHeader.kt
index baa88fddb99..a14db2afebf 100644
--- a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassHeader.kt
+++ b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassHeader.kt
@@ -3,6 +3,8 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
+@file:Suppress("MemberVisibilityCanBePrivate")
+
 package kotlinx.metadata.jvm
 
 import org.jetbrains.kotlin.metadata.jvm.deserialization.JvmBytecodeBinaryVersion
diff --git a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassMetadata.kt b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassMetadata.kt
index 2dfa35983d3..881dfed1632 100644
--- a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassMetadata.kt
+++ b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/KotlinClassMetadata.kt
@@ -29,7 +29,7 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
     class Class internal constructor(header: KotlinClassHeader) : KotlinClassMetadata(header) {
         private val classData by lazy(PUBLICATION) {
             val data1 = (header.data1.takeIf(Array<*>::isNotEmpty)
-                    ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
+                ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
             JvmProtoBufUtil.readClassDataFrom(data1, header.data2)
         }
 
@@ -68,12 +68,12 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
                 metadataVersion: IntArray = KotlinClassHeader.COMPATIBLE_METADATA_VERSION,
                 bytecodeVersion: IntArray = KotlinClassHeader.COMPATIBLE_BYTECODE_VERSION,
                 extraInt: Int = 0
-            ): KotlinClassMetadata.Class {
+            ): Class {
                 val (d1, d2) = writeProtoBufData(t.build(), c)
                 val metadata = KotlinClassHeader(
                     KotlinClassHeader.CLASS_KIND, metadataVersion, bytecodeVersion, d1, d2, null, null, extraInt
                 )
-                return KotlinClassMetadata.Class(metadata)
+                return Class(metadata)
             }
         }
     }
@@ -84,7 +84,7 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
     class FileFacade internal constructor(header: KotlinClassHeader) : KotlinClassMetadata(header) {
         private val packageData by lazy(PUBLICATION) {
             val data1 = (header.data1.takeIf(Array<*>::isNotEmpty)
-                    ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
+                ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
             JvmProtoBufUtil.readPackageDataFrom(data1, header.data2)
         }
 
@@ -123,12 +123,12 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
                 metadataVersion: IntArray = KotlinClassHeader.COMPATIBLE_METADATA_VERSION,
                 bytecodeVersion: IntArray = KotlinClassHeader.COMPATIBLE_BYTECODE_VERSION,
                 extraInt: Int = 0
-            ): KotlinClassMetadata.FileFacade {
+            ): FileFacade {
                 val (d1, d2) = writeProtoBufData(t.build(), c)
                 val metadata = KotlinClassHeader(
                     KotlinClassHeader.FILE_FACADE_KIND, metadataVersion, bytecodeVersion, d1, d2, null, null, extraInt
                 )
-                return KotlinClassMetadata.FileFacade(metadata)
+                return FileFacade(metadata)
             }
         }
     }
@@ -196,15 +196,15 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
                 metadataVersion: IntArray = KotlinClassHeader.COMPATIBLE_METADATA_VERSION,
                 bytecodeVersion: IntArray = KotlinClassHeader.COMPATIBLE_BYTECODE_VERSION,
                 extraInt: Int = 0
-            ): KotlinClassMetadata.SyntheticClass {
+            ): SyntheticClass {
                 val proto = t?.build()
                 val (d1, d2) =
-                        if (proto != null) writeProtoBufData(proto, c)
-                        else Pair(emptyArray(), emptyArray())
+                    if (proto != null) writeProtoBufData(proto, c)
+                    else Pair(emptyArray(), emptyArray())
                 val metadata = KotlinClassHeader(
                     KotlinClassHeader.SYNTHETIC_CLASS_KIND, metadataVersion, bytecodeVersion, d1, d2, null, null, extraInt
                 )
-                return KotlinClassMetadata.SyntheticClass(metadata)
+                return SyntheticClass(metadata)
             }
         }
     }
@@ -241,12 +241,12 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
                 metadataVersion: IntArray = KotlinClassHeader.COMPATIBLE_METADATA_VERSION,
                 bytecodeVersion: IntArray = KotlinClassHeader.COMPATIBLE_BYTECODE_VERSION,
                 extraInt: Int = 0
-            ): KotlinClassMetadata.MultiFileClassFacade {
+            ): MultiFileClassFacade {
                 val metadata = KotlinClassHeader(
                     KotlinClassHeader.MULTI_FILE_CLASS_FACADE_KIND, metadataVersion, bytecodeVersion, partClassNames.toTypedArray(),
                     null, null, null, extraInt
                 )
-                return KotlinClassMetadata.MultiFileClassFacade(metadata)
+                return MultiFileClassFacade(metadata)
             }
         }
     }
@@ -260,7 +260,7 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
     class MultiFileClassPart internal constructor(header: KotlinClassHeader) : KotlinClassMetadata(header) {
         private val packageData by lazy(PUBLICATION) {
             val data1 = (header.data1.takeIf(Array<*>::isNotEmpty)
-                    ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
+                ?: throw InconsistentKotlinMetadataException("data1 must not be empty"))
             JvmProtoBufUtil.readPackageDataFrom(data1, header.data2)
         }
 
@@ -307,12 +307,12 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
                 metadataVersion: IntArray = KotlinClassHeader.COMPATIBLE_METADATA_VERSION,
                 bytecodeVersion: IntArray = KotlinClassHeader.COMPATIBLE_BYTECODE_VERSION,
                 extraInt: Int = 0
-            ): KotlinClassMetadata.MultiFileClassPart {
+            ): MultiFileClassPart {
                 val (d1, d2) = writeProtoBufData(t.build(), c)
                 val metadata = KotlinClassHeader(
                     KotlinClassHeader.MULTI_FILE_CLASS_PART_KIND, metadataVersion, bytecodeVersion, d1, d2, facadeClassName, null, extraInt
                 )
-                return KotlinClassMetadata.MultiFileClassPart(metadata)
+                return MultiFileClassPart(metadata)
             }
         }
     }
@@ -344,12 +344,12 @@ sealed class KotlinClassMetadata(val header: KotlinClassHeader) {
 
             return try {
                 when (header.kind) {
-                    KotlinClassHeader.CLASS_KIND -> KotlinClassMetadata.Class(header)
-                    KotlinClassHeader.FILE_FACADE_KIND -> KotlinClassMetadata.FileFacade(header)
-                    KotlinClassHeader.SYNTHETIC_CLASS_KIND -> KotlinClassMetadata.SyntheticClass(header)
-                    KotlinClassHeader.MULTI_FILE_CLASS_FACADE_KIND -> KotlinClassMetadata.MultiFileClassFacade(header)
-                    KotlinClassHeader.MULTI_FILE_CLASS_PART_KIND -> KotlinClassMetadata.MultiFileClassPart(header)
-                    else -> KotlinClassMetadata.Unknown(header)
+                    KotlinClassHeader.CLASS_KIND -> Class(header)
+                    KotlinClassHeader.FILE_FACADE_KIND -> FileFacade(header)
+                    KotlinClassHeader.SYNTHETIC_CLASS_KIND -> SyntheticClass(header)
+                    KotlinClassHeader.MULTI_FILE_CLASS_FACADE_KIND -> MultiFileClassFacade(header)
+                    KotlinClassHeader.MULTI_FILE_CLASS_PART_KIND -> MultiFileClassPart(header)
+                    else -> Unknown(header)
                 }
             } catch (e: InconsistentKotlinMetadataException) {
                 throw e
diff --git a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensions.kt b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensions.kt
index fc5bafd904d..c86a8900b16 100644
--- a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensions.kt
+++ b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmExtensions.kt
@@ -3,6 +3,8 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
+@file:Suppress("unused")
+
 package kotlinx.metadata.jvm
 
 import kotlinx.metadata.*
diff --git a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmMetadataUtil.kt b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmMetadataUtil.kt
index f6b88eb9a09..4a70f123154 100644
--- a/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmMetadataUtil.kt
+++ b/libraries/kotlinx-metadata/jvm/src/kotlinx/metadata/jvm/jvmMetadataUtil.kt
@@ -4,6 +4,7 @@
  */
 
 @file:JvmName("JvmMetadataUtil")
+
 package kotlinx.metadata.jvm
 
 import kotlinx.metadata.ClassName
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/ClassName.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/ClassName.kt
index 5d814579d07..51cadd79426 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/ClassName.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/ClassName.kt
@@ -4,6 +4,7 @@
  */
 
 @file:JvmName("ClassNameKt")
+
 package kotlinx.metadata
 
 /**
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/Flags.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/Flags.kt
index a7d0e6dbbfb..72bc003539a 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/Flags.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/Flags.kt
@@ -4,6 +4,7 @@
  */
 
 @file:JvmName("FlagsKt")
+
 package kotlinx.metadata
 
 /**
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/MetadataExtensions.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/MetadataExtensions.kt
index 92f48349a7b..291e556b7dc 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/MetadataExtensions.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/extensions/MetadataExtensions.kt
@@ -56,7 +56,9 @@ interface MetadataExtensions {
 
     fun writeTypeAliasExtensions(type: KmExtensionType, proto: ProtoBuf.TypeAlias.Builder, c: WriteContext): KmTypeAliasExtensionVisitor?
 
-    fun writeValueParameterExtensions(type: KmExtensionType, proto: ProtoBuf.ValueParameter.Builder, c: WriteContext): KmValueParameterExtensionVisitor?
+    fun writeValueParameterExtensions(
+        type: KmExtensionType, proto: ProtoBuf.ValueParameter.Builder, c: WriteContext
+    ): KmValueParameterExtensionVisitor?
 
     fun createClassExtension(): KmClassExtension
 
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/readers.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/readers.kt
index a9f443cdeff..4639ffdbbaf 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/readers.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/readers.kt
@@ -12,7 +12,7 @@ import org.jetbrains.kotlin.metadata.deserialization.*
 import org.jetbrains.kotlin.metadata.deserialization.Flags as F
 
 /**
- * Allows to populate [BasicReadContext] with additional data
+ * Allows to populate [ReadContext] with additional data
  * that can be used when reading metadata in [MetadataExtensions].
  */
 interface ReadContextExtension
@@ -337,7 +337,7 @@ private fun ProtoBuf.Type.accept(v: KmTypeVisitor, c: ReadContext) {
         hasTypeParameter() -> v.visitTypeParameter(typeParameter)
         hasTypeParameterName() -> {
             val id = c.getTypeParameterId(typeParameterName)
-                    ?: throw InconsistentKotlinMetadataException("No type parameter id for ${c[typeParameterName]}")
+                ?: throw InconsistentKotlinMetadataException("No type parameter id for ${c[typeParameterName]}")
             v.visitTypeParameter(id)
         }
         else -> {
@@ -355,7 +355,7 @@ private fun ProtoBuf.Type.accept(v: KmTypeVisitor, c: ReadContext) {
 
         if (variance != null) {
             val argumentType = argument.type(c.types)
-                    ?: throw InconsistentKotlinMetadataException("No type argument for non-STAR projection in Type")
+                ?: throw InconsistentKotlinMetadataException("No type argument for non-STAR projection in Type")
             v.visitArgument(argumentType.typeFlags, variance)?.let { argumentType.accept(it, c) }
         } else {
             v.visitStarProjection()
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writeUtils.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writeUtils.kt
index 780a886c75a..b76c0453c44 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writeUtils.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writeUtils.kt
@@ -76,7 +76,7 @@ fun KmAnnotationArgument<*>.writeAnnotationArgument(strings: StringTable): Proto
             }
             is KmAnnotationArgument.ULongValue -> {
                 this.type = ProtoBuf.Annotation.Argument.Value.Type.LONG
-                this.intValue = value.toLong()
+                this.intValue = value
                 this.flags = Flags.IS_UNSIGNED.toFlags(true)
             }
             is KmAnnotationArgument.StringValue -> {
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writers.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writers.kt
index 52b1d7c549b..bddb1c83ed1 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writers.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/impl/writers.kt
@@ -499,7 +499,7 @@ open class PackageWriter(stringTable: StringTable, contextExtensions: List<Write
 
 open class ModuleFragmentWriter(stringTable: StringTable, contextExtensions: List<WriteContextExtension> = emptyList()) :
     KmModuleFragmentVisitor() {
-    protected val t = ProtoBuf.PackageFragment.newBuilder()
+    protected val t = ProtoBuf.PackageFragment.newBuilder()!!
     protected val c: WriteContext = WriteContext(stringTable, contextExtensions)
 
     override fun visitPackage(): KmPackageVisitor? = object : PackageWriter(c.strings, c.contextExtensions) {
diff --git a/libraries/kotlinx-metadata/src/kotlinx/metadata/util.kt b/libraries/kotlinx-metadata/src/kotlinx/metadata/util.kt
index e7d81770386..8433f5ab5f0 100644
--- a/libraries/kotlinx-metadata/src/kotlinx/metadata/util.kt
+++ b/libraries/kotlinx-metadata/src/kotlinx/metadata/util.kt
@@ -3,6 +3,8 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
+@file:Suppress("unused")
+
 package kotlinx.metadata
 
 /**