Add debug strings to frontend scopes-related structures

Such as:
- PackageFragmentProviders, and, in particular,
CompositePackageFragmentProviders
- JavaPackageFragments
- Scopes produced by those providers

The rationale is that a lot of frontend-facing bugs (like red code) are
easily recognizeable in resolution. But at that point you just see a
bunch of scopes, without meaningful toStrings, you don't know who has
produced them, and what's exactly wrong.

With this commit it should make debugging slightly easier: now at least
you'll be able to see that "this scope is a scope of package fragment
for foo.bar of module baz" and decide whether the declaration should or
should not have been resolved from such scope.

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/DeserializedPackageFragmentImpl.kt

@@ -49,12 +49,13 @@ abstract class DeserializedPackageFragmentImpl(
         _proto = null
         _memberScope = DeserializedPackageMemberScope(
             this, proto.`package`, nameResolver, metadataVersion, containerSource, components,
-            classNames = {
-                classDataFinder.allClassIds.filter { classId ->
-                    !classId.isNestedClass && classId !in ClassDeserializer.BLACK_LIST
-                }.map { it.shortClassName }
-            }
-        )
+            "scope of $this"
+        ) {
+            classDataFinder.allClassIds.filter { classId ->
+                !classId.isNestedClass && classId !in ClassDeserializer.BLACK_LIST
+            }.map { it.shortClassName }
+        }
+
     }
 
     override fun getMemberScope(): MemberScope = _memberScope

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/MetadataPackageFragmentProvider.kt

@@ -110,10 +110,18 @@ class MetadataPackageFragment(
             val stream = finder.findMetadata(ClassId(fqName, Name.identifier(partName))) ?: continue
             val (proto, nameResolver, version) = readProto(stream)
 
-            scopes.add(DeserializedPackageMemberScope(
-                this, proto.`package`, nameResolver, version, containerSource = null, components = components,
-                classNames = { emptyList() }
-            ))
+            scopes.add(
+                DeserializedPackageMemberScope(
+                    this,
+                    proto.`package`,
+                    nameResolver,
+                    version,
+                    containerSource = null,
+                    components = components,
+                    debugName = "scope with top-level callables and type aliases (no classes) for package part $partName of $this",
+                    classNames = { emptyList() },
+                )
+            )
         }
 
         // Also add the deserialized scope that can load all classes from this package
@@ -121,7 +129,9 @@ class MetadataPackageFragment(
             this, ProtoBuf.Package.getDefaultInstance(),
             NameResolverImpl(ProtoBuf.StringTable.getDefaultInstance(), ProtoBuf.QualifiedNameTable.getDefaultInstance()),
             BuiltInsBinaryVersion.INSTANCE, // Exact version does not matter here
-            containerSource = null, components = components, classNames = { emptyList() }
+            containerSource = null, components = components,
+            debugName = "scope for all classes of $this",
+            classNames = { emptyList() },
         ) {
             override fun hasClass(name: Name): Boolean = hasTopLevelClass(name)
             override fun definitelyDoesNotContainName(name: Name) = false
@@ -129,7 +139,7 @@ class MetadataPackageFragment(
             override fun getNonDeclaredClassifierNames(): Set<Name>? = null
         })
 
-        return ChainedMemberScope.create("Metadata scope", scopes)
+        return ChainedMemberScope.create(".kotlin_metadata parts scope of $this", scopes)
     }
 
     override fun getMemberScope() = memberScope()

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/builtins/BuiltInsPackageFragmentImpl.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.builtins.BuiltInsBinaryVersion
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.serialization.deserialization.DeserializedPackageFragmentImpl
 import org.jetbrains.kotlin.storage.StorageManager
 import java.io.InputStream
@@ -52,4 +53,6 @@ class BuiltInsPackageFragmentImpl private constructor(
             return BuiltInsPackageFragmentImpl(fqName, storageManager, module, proto, version, isFallback)
         }
     }
+
+    override fun toString(): String = "builtins package fragment for $fqName from $module"
 }

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/descriptors/DeserializedPackageMemberScope.kt

@@ -39,7 +39,8 @@ open class DeserializedPackageMemberScope(
     metadataVersion: BinaryVersion,
     containerSource: DeserializedContainerSource?,
     components: DeserializationComponents,
-    classNames: () -> Collection<Name>
+    private val debugName: String,
+    classNames: () -> Collection<Name>,
 ) : DeserializedMemberScope(
     components.createContext(
         packageDescriptor, nameResolver, TypeTable(proto.typeTable),
@@ -74,4 +75,6 @@ open class DeserializedPackageMemberScope(
     override fun addEnumEntryDescriptors(result: MutableCollection<DeclarationDescriptor>, nameFilter: (Name) -> Boolean) {
         // Do nothing
     }
+
+    override fun toString(): String = debugName
 }